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Plornson, Pavard F.; And OthersControl of Domestic Pats S Mice, TrainingGuide-- Fodent Control Series.Public Health Service (DHFY) , Pockville, Md.Consumer Protection and Environmental Health Service.PHS-Pub-56369u8p.Public Health Service (DHEW), Constaer Protectionand Environmental Health Service, Pureau ofCommunity Environmental Manaaement, E800 FishersLane, Rockville, Md. 20Pc2 (Free)

FDFS Price ME-$0. HC Not Available from ERRS.*Animal Science, Pioloay, Environmental Influences,Instructional Materials, *Fats, *Resource Materials,Podenticides, *Teaching GuidesPublic Health Service, U.S. Department of Health,Education, and Welfare

As one booklet in a series on rodent control, thistraining guide has been developed to assist administrators,rodent-control operators, and others responsible for rodent-controloperations in the training of employees in this field. Topics coveredinclude rodents and human welfare, description and habits of domesticrats and mice, rodent-borne diseases, control of rodent populations,sanitation control, rodent killing, ratproofing, and organization ofcommunity rat-control programs. Throughout, the theme is emphasizedthat controlling rat populations, not individual rats, is the key toa successful rodent-control program in a community. Control measuresmust become a way of life in the community if rat populations are tobe keot low or eliminated. Selected references and audio-visual aidsare listed. (Pt)

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U $ DEPARTMENT OF HEALTH EDUCATIONWELFARE

OFFICE OF EDUCATIONTHIS DOCUMENT HAS SEEN REPRODUCEDEXACTLY AS RECEIVED FROM THE PERSON ORCRGANIZATION ORIGINATING IT POINTS OFVIEW OR OPINIONS STATED DO NOT NECESSARILY REPRESENT OFFICIAL OFFICE OF EDUCATION POSITION OR POLICY

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Control of Domestic Rats & Mice

TRAINING GUIDE RODENT CONTROL SERIES

Bayard F. Bjornson, Harry D. Pratt, and Kent S. Littig

Prepared and printed 1956Revised In 1960 and leaved as PHS Publication 563

Revised In 1968 and Peeved In 1969 as P115 Publication 563

U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFAREPublic Health Service

Consumer Protection and Environmental Health ServiceEnvironmental Control Administration

Rodville, Maryland 20852

Controlling rat populations, not individualrats, is the key to a successful rodent-controlprogram in a community.

Note: The use of trade names and the names of supply ormanufacturing firms is for identification purposesonly and does not constitute endorsement by thePublic Health Service.

ii

FOREWORD

This training guide has been developed to assist administra-tors, rodent-control operators, and others responsible for rodent-control operations in the training of employees in this field.

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CONTENTS

PageRODENTS AND HUMAN WELFARE 1

Economic Importance 1

Rat Bites 1

. Rodent-Borne Diseases 2Rat-Bite Fever 2Leptospirosis 2Salmonellosis 2Trichinosis 2Murine Typhus Fever 2Plague 2Rickettsialpox 3Other Diseases 3

DESCRIPTION AND HABITS OF DOMESTICRATS AND MICE 4

Biological Factors 4Norway Rat 4Roof Rat SHouse Mouse s

Senses, Agility, and Reactions 5

RECOGNIZING RAT AND MOUSE SIGNS 7

Droppings 7

Runways 7

Rubmarks 8

Burrows 8

Gnawings 8

Tracks 8

CONTROL OF RODENT POPULATIONS 9Basic Principles 9

Population Forces 9Population Changes 9

Limiting Factors 9

SANITATION FOR RAT AND MOUSE CONTROL .... 11

Storage of Refuse 11

Storage of Usable Materials 13

Collection of Refuse 14

Disposal of Refuse isRefuse and Sewer Rats 16

V

PageRODENT KILLING 17

Relation to Other Control Procedures 17Poisons and Baits 17

Poisons and Their Mode of Action 17Suggested Bait Formulas 21

Anticoagulants 21Single-Dose Poisons 22Paraffin Formulations 23

Preparation of Baits 24Bait Placement 24

Anticoagulant Baits 24Poisoned Water 25Single-Dose Poisons 25Pre-baiting 26Poisoning at Dumps 26Poisoning in Sewers 27

Trapping 28Gassing 30Other Killing Methods 30Related Problems 31

Ectoparasite Control 31Dead-Rodent Odors 32Carcass Disposal 32

RATPROOFING 33Devices 33Materials 33

Other Considerations 33New Construction 34

ORGANIZATION OF COMMUNITYRAT-CONTROL PROGRAMS 35

Organizational Structure 35Information and Education Program 36

SUMMARY 37

SELECTED REFERENCES 38

SUGGESTED AUDIOVISUAL AIDS 41

Motion Pictures 41Filmstrips 41

TABLES

THE CHEMICAL CONTROL OF RODENTS itSOME CHARACTERISTICS OF COMMON

RODENTICIDES 18

vi

Control of Domestic Rats & Mice

kODENTS AND HUMAN WELFARERats and mice have accompanied man to most

of the areas of the world he has settled. His-torically they have been responsible for morehuman illness and deaths than any other groupof mammals. They are universally feared anddespised, yet man's indifference and careless-ness in handling food and refuse have fosteredpopulations of them in such close proximityto his home and work that they are commonlyreferred to as "domestic" rodents.

ECONOMIC IMPORTANCE

Rats in the human environment cause enor-mous economic losses. They consume or con-taminate vast quantities of food and feed, andthey destroy other property, as when theycause fires by gnawing the insulation from elec-tric wires. Many fires of unknown origin mustbe attributed to rats.

No reliable estimate of the rat population ofthe United States is available as a basis forcalculating these losses, although the figure ofone rat for every person has frequently beenquoted in the literature. If, in consideration ofrecent improvements in environmental sanita-tion and rodent control, this rough estimate usedin the past is reduced by one-half, that is, to anestimated one rat for each two people, then theUnited States has some 100,000,000 rats. Eachrat damages between $1 and $10 worth of foodand other materials per year by gnawing andfeeding, and contaminates S to 10 times more

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Thus, rats may cost the United States between$500,000,000 and $1,000,000,000 annually in termsof direct economic losses.

RAT BITES

In addition to the annual dollar losses due torats, there is also the intangible cost of rat-associated injury and illness. Rat bites create aserious health problem and are far more commonthan mast people realize. In some of the largercities, hundreds of rat bites are reported eachyear, and certainly there are many cases thatare never reported.

Based upon available records, large metropol-itan areas of the United States experience ratbite at the rate of approximately 10 per 100,000persons per year. This amounts to three to fourthousand cases annually just in the large citiesalone, and the cases unreported from them andfrom the smaller cities and towns undoubtedlytotal several thousand more.

Helpless infants and defenseless adults (in-valids and unconscious persons) are particularlysubject to attack by rats, and occasionally arat-bite wound causes death. The victim of anattack is usually terrified by the experience,and the mental and emotional scars that remainare oftc:i deeper than the physical scars. Rat-bite wounds should be promptly and carefullydisinfected to prevent secondary infection, andwhere necessary the victim should then bereferred to a doctor.

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.1 P

RODENT-BORNE DISEASES

Rats and mice are responsible for spread of anumber of diseases, either directly, as by con-tamination of human food with their urine orfeces, or indirectly, by way of rodent fleas andmites. Following are brief descriptions of themore common of these diseases.

RAT-BITE FEVER

Causative agent, Streptobacillus moniliformisThe bacteria that cause rat-bite fevers are

found on the teeth and gums of many rats and aretransferred from rat to man by the bite of therat. The most frequently occurring rat-bite feverin the United States is called Haverhill fever.It is similar to rat-bite fever of the Orient calledscdoku (caused by Spiri JILIN rvinus).

1EPTOSPIROSIS

(Weil's Disease)Causative agent, Lepto-spira spp., primarily L, icterohemorrhagiae

Leptospirosis is a mild to severe infection thatis seldom fatal. Hum. -1 cases of the disease re-sult from direct or indirect contact with infectedurine of rodents and of c,rtain other animals.The spirochetes, which are found in water or onfood, may enter through raucous membranes orminute cuts or abrasions of the skin. Thus,Weil's disease is often found in sailors, miners,sewer workers, fish or poultry dealers, andabbatoir workers. In a recent study in Hawaii,Norway rats, roof rats, and house mice werefound to have high L. icterohemorrhaghecarrier rates.

SALMONEILOSIS

Causative agent, Salmonella spp.Salmonellosis, which is generally classed as

food poisoning, is a common disease of world-wide distribution. It is an acute gastroenteritisproduced by members of the Salmonella groupof bacteria pathogenic to man and other animals.They are spread in various ways, one beingthrough food contaminated with rat or mousefeces containing Salmonella organisms.

2

TRICHINOSIS

Causative agent, Trichinella spiralisTrichinosis results from an infection of the

intestines and muscles by larvae and cysts ofTrichinella spiralis. Man, hogs, and rodents maydevelop the disease from eating infected porkthat is raw or insufficiently cooked. In addition,research has shown that hogs experimentallyfed trichina-infected feces of rats and micereadily become infected. This indicates thatrodents may play an important role in spreadingtrichinosis to hogs fed on garbage containinginfected rat feces. Such interchange of organ-isms may significantly help to maintain therodent-swine-man cycle of this disease.

MURINE TYPHUS FEVER

Causative agent, Rickettsia typhiMurine typhus fever is distributed through-

out the Southeastern and Gulf Coast States andsouthern California. Rats are the reservoir ani-mals from which the disease reaches man by wayof rat fleas. The oriental rat Ilea, Xenopsyllacheopis, is considered the most mportant vectorof the disease. The causative organism entersthe bloodstream whe- feces of infected fleas arescratched or rubbed into a flea-bite wound orother break in the skin. Murine typhus is similarto epidemic or louse-borne typhus, but illness ismuch milder and the fatality rate in untreatedcases is much lower.

PLAGUE

Causative agent, Pasteurella pestIsPlague Is the ''Black Death" that once killed

millions of people in Europe, Asia, and Africa.No serious outbreaks of plague have occurredin the United States since 1924. However, a res-ervoir of the disease exists in wild rodents ofthe western states, where the bacteria are trans-mitted from one rodent to another and sometimesto man by the bite of rodent fleas. There is al-ways the danger that domestic rodents willbecome infected, and that they, in turn, willcarry the infection to Luntan population centers.The disease is generally fatal to the rat and theRea, and the death rate in untreated human casesis extremely high.

RICKETTStALPDX Boston, Mass., West Hartford, Conn., New York,N.Y., Cleveland, Ohio. and Philadelphia, Pa.

Causative agent, Rickettsia akar!Rickettsialpox is a mild nonfatal disease re

sembling chickenpox. It is transmitted from thehouse mouse to man by the bite of the huuse-mouse mite, Liponyssoides sanguineus. In thiscountry rickettsialpox has been reported from

OTHER DISEASES

A number of other diseases of less frequentoccurrence are associated with domestic rodents.Among them are tonoplasmosis, listeriosis, andlymphocytic choriomeningitis.

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RATASSOCIATED SALMONELLOSIS CYCLE

3

DESCRIPTION AND HABITS OF DOMESTIC RATS AND MICE

The term "domestic rodents" includes Norwayrats, roof rats, and house micemembers of theorder Rodentia, family Muridae. These rodentsare best characterized by having a single pairof incisor teeth on each jaw and by the absenceof canine teeth.

BIOLOGICAL FACTORS

NORWAY RAT

The Norway rat (Rattus norvegicus), pre-dominantly a burrowing rodent, is the mostcommon and the largest of the domestic rats.It is distributed generally throughout the tem-perate regions of the world, including theUnited States. Common names for the species

are the brown rat, the house rat, the barn rat,the sewer rat and the wharf rat.Adult weight: 16 or more ounces; adults average

about a pound.Fur: Coarse, generally reddish brown to gray-

ish brown, with riany variations,Body: Heavy-set, and with muzzle blunt,Tail: Bicolored, shorter than body and head

combined.Ears: Small, close-set,Droppings: Large (4- to 34-inch long), capsule-

shaped (see figure, page 7).Sexual maturity: Attained in 2 to 3 months.Gestation period: Averages 22 days.Young: Average 8 to 12 per litter.Number of litters: Averages 4 to 7 per year.Number weaned: Averages about 20 young per

year per female.

FIELD IDENTIFICATION OF DOMESTIC RODENTS

ROOF RAT Ratio raffia

LONGER THANHEAD + 1300Y

TAIL

SHORTER THANHEAD + BODY

LIGHTSLENDER

(1/

BODY

HEAVYTHICK

LARGE

EAR

SMALL

POINTED

LARGE

EYE NOSE

SMALL /BLUNT

NORWAY RAT Rattus norvegicusSCALE IN INCHES

N VO 1

YOUNG RAT

HOUSE MOUSEMus musculus

PREPARED BY R I BROWNU.S. Novammenl ml

WEALTH, EDUCATION, AND !SWAMPAN Suomi

Communicable Dime CentelCamt3,3

4

Length of life: Averages about 1 year.Harborage: Outdoorsin burrows in the ground

and under foundations of buildings, and inrubbish dumps; indoorsbetween floors andwalls, in enclosed spaces of cabinets, shelving,and appliances, in piles of rubbish, and in anyother space concealed from view.

Range: Frequently 100-150 feet.Food and water: Omnivorous; garbage, meat,

fish and cereal baits are well accepted; dailyrequirement is 3A to 1 ounce of dry food, %to 1 ounce of water.

ROOF RAT

The roof rat (Rattus rattus) is somewhatsmaller than the Norway rat and is a more agileclimber. In the United States its range is con-fined largely to the South and to the Pacificcoast and Hawaii. Worldwide, it is found mostabundantly in the tropical or temperate regionsbut is rare or absent in the colder portions ofthe world.Adult weight: 8 to 12 ounces.Fur: Three color phases in the United States:

the black rat (Rattus rattus rattus), black toslate-gray colored; the Alexandrine rat (Rat-tus rattus alexandrinus), tawny above andgrayish-white below; the fruit rat (Rattusrattus frugivorus), also tawny above, withwhite to lemon colored belly. All three sub-species have long prominent guard hairs, andthey interbreed,

Body: Slender, muzzle pointed.Tail: Single color, longer than body and head

combined.Ears: Large, prominent.Droppings: Medium-sized (1/2- to u-inch long),

spindle-shaped (see figure, page 7).Sexual maturity: Attained in 2 to 3 months.Gestation period: Averages 22 days.Young: Average 6 to 8 per litter.Number of litters: Averages 4 to 6 per year.Number weaned: Averages about 20 young per

female.Length of life: Averages about 1 year.Harborage: Above ground level; indoorsin

attics, between walls, and in enclosed spacesof cabinets and shelving; outdoorsin treesand dense vine growth, and in some Californiacities, in sewers.

Range: Frequently 100.150 feet.Food and water: Omnivorous; vegetables, fruits

and cereal grains preferred; daily require-ment is to I ounce of dry food and up to1 ounce of water.

HOUSE MOUSE

The house mouse (Mus musculus), the small-est of the domestic rodents, is widespread andabundant throughout the United States. It isfound throughout the world from the tropicsto the Arctic regions.Adult weight: 1/2 to 3/4 ounce.Fur: Dusky-gray.Body; Small, slender.Tall: Semi-naked, about as long as body and

head combined.Ears: Moderately large, prominent.Droppings: Small (:)in- to Vt-inch long), rod-

shaped (see figure, page 7).Sexual maturity: Attained in PA months.Gestation period: Averages 19 days.Young: Average 5 to 6 per litter.Number of litters: As many as 8 per year.Number weaned: Averages 30-35 young per year

per female.Length of life: About 1 year.Harborage: Nest in any convenient space in

walls, cabinets, furniture or stored goods.Range: Frequently 10 to 30 feet.Food and water: Omnivorous; cereal grains pre-

ferred; the mouse is a nibbler; daily require-ment is IA -ounce of dry food, requires littlewater (1), 1,(, of an ounce per day), often ob-tained in the foods it eats.

SENSES, AGILITY, AND REACTIONS OFRODENTS

TouchWell developed in highly sensitive whisk-ers or vibrissae, and certain guard (tactile) hairs.Rats and mice prefer to run along walls Al be-tween things where they can keep their whiskersin contact with side surfaces.VisionNot too well developed. Apparently theyare color blind, so any distinctive coloring ofpoison baits does not reduce their acceptance torats.SmellKeen. Rodents apparently like the odorsof most foods eaten by man. They are accus-tomed to the smell of man, so his odor on baitsar I traps does not repel them.

TasteNot as sensitive as in man. Rats associatesickness caused by poison bait with the bait andnot the poison. They prefer fresh food to de-cayed food.HearingA keen sense of hearing. They can lo-cate the source of a noise within 6 aches. Un-usual noises lause rodents to attempt escape.BalanceExcellent. A falling rodent always landson its feet. The roof rat even maintains itsbalance well while walking on suspended wires.Reaction to Strange ObjectsRats may avoid a newsound or a strange object in their environmentfor three or more days, particularly if theirassociates are alarmed by it. Other objects arereadily accepted by them (examples: food, gar-bage). As rodent population pressures build, the

NORWAY AND ROOF RATS

rats frequently exhibit "chain-fright reaction"to disturbances. Mice are more likely to explorenew objects, and to be caught in newly settraps.ClimbingRoof rats and house mice are goodclimbers, and the Norway rat can climb quitewell when necessary (see under Ratproofing,page 33).lumping and ReachingRats can jump nearly 2 feetvertically, 3 feet with a running start; they canjump 4 feet horizontally, and 8 feet from anelevation that i> IS feet above the finish point.Rats can reach upward about 18 inches.SwimmingRodents are good swimmers. They areable to swim up through floor drains and toilet-bowl traps.

HOME RANGE OF

6

RECOGNIZING RAT AND MOUSE SIGNS

Rats and mice are habittally nocturnal andsecretive and are rarely seen during the dayexcept when infestations are heavy. Therefore,it is necessary to interpret signs of their ac-tivities properly in order to plan control work.These signs are found in secluded places, suchas along walls, ander piles of rubbish, and be-hind or under boxes, boards, and thick vegeta-tion. From the rodent signs, one can tell thespecies present, and whether a rodent infesta-tion is current or old, heavy or light.

DROPPINGS

Fresh droppings of feces are usually moist,soft, sliny, and dark, but in a few days they

NORWAY RATAbout 1/2 to 3/4 inch long,

and 1/4 inch thick

ROOF RATAbout 1/3 to 1/2 inch long,3/16 inch or less thick

7

become dry and hard. Old droppings are dulland grayish and crumble when pressed with astick.

RUNV4AYS

Rats habitually use the same runways betweenfood, water, and harborage. Because of thekeenly developed sense of touch in their vibris-sae (whiskers) and in specialized hairs alongthe body, rats prefer continual body contactwith at least one vertical surface, such as a fenceor wall. Rats also follow "odor trails." Outdoors,their runways are narrow pathways of beatenearth swept clear of debris. Indoors, greasy run-ways are found along walls, steps, and rafters.Undisturbed cobwebs and dust in a runway in-dicate that it is not in use.

HOUSE MOUSE3/16 to 1/2 inch long andwithout ridges

POINTED

ENLARGED

AMERICANCOCKROACH A out 1/8 inch long,

with ridges

RUBMARKS

Along regularly traveled runways, a dark,greasy mark forms from contact by the rodent'sbody. Fresh marks are soft and will smear ifrubbed. As the grease ages, it dries and gathersdust and will flake off when scratched with afingernail. The rubmarks of the Norway rat aremost commonly found along runways nearground or floor level, while those made by theroof rat are most commonly seen overhead asswing marks beneath beams or rafters at thepoint where they connect to the walls. Mice donot leave detectable rubmarks except when theinfestation is heavy.

BURROWS

The Norway rat prefers burrows for nestingand harborage; the roof rat burrows only oc-casionally. Burrows are found in earth banks,along walls, under rubbish or concrete slabs, andin similar places. If a burrow is in use, its en-trance will be free of cobwebs and dust. Freshrubmarks on hardpacked soil at the openingindicate a well established and presently usedburrow. The presence of fresh fragments offood or freshly dug earth at the burrow en-trances also indicates current use by rats.

GNAWINGS

The incisor teeth of rats grow 4 to 5 inches ayear, so these rodents must do some gnawingeach day in order to keep their teeth shortenough to use. Rats also gnaw to gain entranceand to obtain food. When gnawings in wood arefresh, they are light colored and show distinctteeth marks. Small chips of wood or other ma-terials indicate recent gnawing. With age, woodgnawings become dark and smooth fromweathering and from frequent contact with therodent's body.

TRACKS

Fresh tracks are sharp and distinct, whereasold tracks are covered with dust and are there-fore less distinct. The tracks of the 5-toed rearpaws are more commonly observed than arethose of the 4-toed front paws, but both may bepresent. Smooth tracking patches of any dustmaterial, such as flour or talc, placed along run-ways are of value in checking for rodent activ-ity. To see tracks in the dust, the inspectorshould hold a flashlight at an angle that causesthe tracks to cast distinct shadows. Tail marks,too, are often visible in dust or tracking patches.

8

CONTROL OF RODENT POPULATIONS

BASIC PRINCIPLES

Controlling rat populations, not individualrats, is the key to a successful rodent-controlprogram in a community. Examples of popula-tions are the rats within a city block, those ina sewer, the rats infesting a farm, or thoseliving in or around a feed mill. At any giventime, each city block has a certain capacity tosupport rats. This capacit" is related to theavailability of food, harborage, living space andother vital rodent requirements. The rat popula-tion in a block cannot long be greater than thiscapacity. Permanent reduction of one or morevital factors in the block, particularly food, willresult in a permanent reduction in the rodentpopulation.

POPULATION FORCES

Forces that determine the size of a rodentpopulation at a given time are : reproduction,mortality, and movements info or out of an area.Reproduction tends to increase a population,mortality to decrease it, and movements canwork either way. Rats breed during the entireyear, with peaks in spring and fall. Winter isthe 1,.f.st time to conduct a poisoning campaignon a rat population, since breeding is then at aminimum. The next best times are summer, thenfall. In field tests, populations poisoned in thewinter took 12 months to return to normal; thosepoisoned in summer, only 6 months.

POPULATION CHANGES

As rat and mouse populations increase in size,the mortality rate also increases until a state ofequilibrium is reached. Increased competitiondue to population pressure increases the mor-tality and movements of rodents. Movementsinto or out of an area are less important indetermining the size of rat populations thaneither reproduction or mortality. Roderrs oftenmigrate much greater distances than the limitsof their normal home range (rats 100-150 feet,

9

mice 10-30 feet) as, for example, their annualmovement from fields to buildings in the falland then back to the fields in the spring; andtheir migrations when their usual sources offood are cut off, or when they are flooded outor burned out.

LIMITING FACTORS

The factors that control the balance betweenreproduction, mortality, and movement of ro-dents are: the physical environment, predationand parasitism, and competition.

The physical environment is comprised ofthree main elements : (1) food and water, (2)harborage, and (3) climate. Improperly handledfoods, garbage, and field crops often are majorsources of rodent food. (Favorite foods andharborage for rodents are listed on page 4 under"Description and Habits of Domestic Rats andMice.") Climate directly affects the number ofrodents able to survive outdoors but has littleor no effect on those living in heated buildings.A given environment can support only a certainnumber of animals. Generally speaking, areaswith warm, moist climates are favorable, whilethose with dry, cold climates are unfavorable.Man can reduce rodent populations and keepthem low by permanently eliminating their food,water, and harborage.

Competition, whether between members of thesame species or between two or more species, isone of the most important factors limiting ratpopulations. Norway rats compete intensely withroof rats and have replaced them over largeareas, particularly in many cities where bothonce were found. Competition among membersof the same species is very c!osely associatedwith the social organization of a population. Adefinite social order, or hierarchy, exists amongrats and mice. This social order is determinedlargely by fighting, and the most aggressiveanimals in a population are dominant. Othersare killed or are forced to move. Those thatmove may suffer even higher mortality frompredators and resident rodents in the new areas.The strife caused by increased population pres-

sure lowers reproduction, increases mortality,and decreases the population.

The effect of predators and parasites on re-duction of rodent populations appears to betemporary. This includes the predatory activ-ities of man, dogs, cats, foxes, rats, birds, snakesand other foes, and the parasitic activities of

bacteria, rickettsia, spirochetes, protozoa, andworms.

In summary, the most lasting control can beachieved by increasing corn' etition and preda-tion through permanent alterations of the physi-cal environment. In other words, environmentalsanitation is the first and foremost requirementfor rodent control.

LIMITING FACTORS actingth h

POPULATION FORCES == POPULATION CHANGESroug

physical environment

lin rt.; itilvily.

predation

=41111V

competition

10

population size

SANITATION FOR RAT AND MOUSE CONTROL

Improper storage of refuse (garbage andrubbish) and of food in the home and in busi-ness establishments invites rats to infest blocksand nc.t,hborhoods. Rat and mouse populationsare controlled by the use of garbage grinders orthe storage of all refuse in rodent-proof con-tainers, the satisfactory collection and disposalof refuse, and the proper storage of usable ma-terials. Structural harborage, such as small pro-tected enclosures under cabinets, shelves, andstairs, should be eliminated. Permanent removalof harborage and sources of food will eliminateexisting rat and mouse populations.

STORAGE OF REFUSE

Refuse storage facilities should includeenough containers to hold all garbage and rub-bish that normally accumulates between col-lection days. A good refuse container should be:

1. Rustresistant

2. Watertight

3. Tightly covered

4. Easy to clean

5. Easily handled

by one man

6. Of rat- and damage-

resistant construction

(heavy.duty)

7. With a recessed bottom

11

Recommended container capacity:

For garbage only

For combined garbage and rubbish

5.12 gallons

20.32 gallons

I12

12

_j__

Fifty-five-gallon drums should not be usedfor refuse containers. When filled they are tooheavy and too clumsy to handle, and they eitherhave no lids or the lids are not tight.

Recently, units using suspended single-service paper bags for refuse storage have beentested in various communities. Since new bagsare used for each collection period, sanitation isimproved, collection labor is reduced, and addi-tional bags can be used to handle unusual quan-tities of refuse.

12

Some communities have inaugurated refusecollection systems utilizing rat-proof storagecontainers with a capacity of several yardseach. These containers are regularly emptiedinto a large compactor vehicle, which transportsthe refuse from several containers to a sanitary

landfill or an incinerator. They are available invarious sizes appropriate for use in markets,apartments, schools, and other large food-handling establishments. Some of the largerunits are equipped with mechanical compactorsto reduce the volume of refuse and therebyincrease their capacity. A special truck is re-quired for servicing these units mechanically.

*NA

1.47-7811firifaiPoil

Draining and wrapping household garbagebefore placing it in refuse containers:

1. Reduces fly breeding

2. Reduces odors

3. Prevents garbage from sticking or freezing to the sides of

the container, thus avoiding damage to cans (from bump.

ing to loosen garbage)

4. Reduces cleaning frequency

5. Adds to the useful life of the container.

The practice of wrapping garbage is not prac-tical for all food-handling establishments. How-ever, special low-cost, waterproof garbage bagsdesigned to fit standard-size containers are avail-able commercially.

All containers should be washed or steamcleaned often enough to prevent fly and odorproblems.

STORAGE OF USABLE MATERIALS

Proper storage of usable materials reducesthe food and harborage available to rodents toa minimum. All packaged bulk foodstuffs shouldbe stacked 12 to 18 inches off the floor. Unlessused promptly, foods removed from commercialpackaging should be stored in covered glass ormetal containers. All food scraps left aftermeals should be collected and placed in acovered refuse container.

Sweeping floors at frequent intervals helpsto reduce rodent food and permits ready detec-tion of fresh rodent signs. In food-handlinglocations, a white band 6 inches wide paintedalong the floor next to the wall speeds the dis-covery of rodent droppings, rodent tracks, andother signs indicating the presence of rats andmice.

Thorough inspections should be made reg-ularly to detect any new evidence of rodent in-festation. Remember, effective and permanentcontrol of rats and mice can be attained onlythrough a continuous sanitation program.

6" WHITEBAND

If I 1111

///

13

COLLECTION OF REFUSE

Good refuse storage practices are dependentupon efficient refuse collection service. Twice-weekly collection of residential garbage, or ofcombined garbage and rubbish, is recommendedto prevent the overloading of individual storagefacilities, which provides exposed food for ratsand a breeding medium for flies. Daily collec-tion of refuse is recommended for businesssections.

Four garbage storage and collection systemswere studied in California, and the percentagesof containers producing excessive numbers offlies were found to be as follows: 67%, withmetal cans and once-a-week collection; 25%,

with disposable paper bags and once-a-weekcollection; 10%, with metal cans and twice-a-week collection; and almost to fly productionwith disposable bags and twice-a-week collec-tion. An economic evaluation of these systems,based on a time-and-motion study of pickupservice in four comparable areas, showed a man-power savings of up to 30% when paper bagswere substituted for metal cans. However, un-less the collection system is actually designedaround the concept of paper bags, the savingsin time does not equal the cost of the paperbags.

Compactor-type trucks are the equipment ofchoke for collection, because they: (1) preventcontents from blowing or spilling o_c, (2) areleakproof, and (3) are easy to load and unload.

14

DISPOSAL OF REFUSE

Refuse dumps and areas where hogs are fedon garbage are major producers of flies and rats,which migrate from these unsatisfactory dis-posal sites to adjacent cities and farms. Whenthe rats' daily source of food at such a site iscut off, as by a snowstorm or a refuse-collectors'strike, great numbers of the rats soon migrateelsewhere. Unfortunately, many cities have in-sanitary, rat-infested, burning dumps. Until asanitary method of disposal is instituted, it isoften necessary to poison rats periodically toreduce the population and attempt to preventmigrations (see page 17).

The sanitary landfill and incineration methodsof refuse disposal can be operated so that con-ditions favorable to rat production do not de-velop. At a properly operated sanitary landfill,garbage and rubbish are compacted and coveredwith earth daily. Local officials must demon-strate continuing interest in and support of amodel operation by providing adequate financ-ing, by visiting it frequently, and by makingit a showplace for visiting officials. Modern

incinerators operating at high temperaturescompletely burn combined refuse, thus leavinga residue that does not furnish food for rats.

Where sewer systems are adequate, electricgarbage grinders provide sanitary disposal ofgarbage. However, this leaves other rubbishsuch as cans and bottles, which must be collectedregularly.

Research has shown that composting munici-pal wastes is feasible and that it can meet publichealth requirements for sanitary disposal. Costsof composting are higher than with the sanitarylandfill but lower than with the incineratoroperation. Composting permits the salvage ofsome noncompostible materials such as metalsand rags, and produces an end product, humus,that can be sold as a soil-conditioner supple-ment to fertilizers. However, / composting isprimarily a method of sanitary refuse disposalrather than a source of income or a method ofsatisfying an agricultural need. Despite consid-erable investment anci the application of ad-vanced techniques, no large-scale compostingplant has operated economically for a longenough time in the United States to indicatesuccess.

Is

REFUSE AND SEWER RATS

Rats often enter sewers at outlets mid throughmanholes, catch basins, broken pipes, or drains.They nest in earth at or near such locations. Inthe sewers, the rats feed on floating organicmatter or that stranded or adhering to the bot-tom or sides of pipes, especially during periodsof low sewage flow. The problem is usuallygreatest where storm and sanitary sewers are

16

combined, The domestic sewage of an averagecommunity furnishes ample food for sizablerat populations. The number of rats in sewerswill probably increase in this country as theexpanding use of garbage grinders increases thefood content of inadequate sewers. However,the net effect of garbage grinders is to reducerats and improve community sanitation.

,

RODENT KILLING

RELATION TO OTHER CONTKOLPROCEDURES

In the community rodent-control program,rodent killing is an important adjunct to im-provements in sanitation and other environ-mental factors. However, timing is of greatimportance; and control through killing alonedoes not endure. For these reasons, killingmethods can be applied most effectively:I. Before sanitation or cleanup programs are begunto prevent

mass movement and spread of rodents.

2. After dusting with 10percent MT or other insecticide recom-

mended for flea controlto reduce rodent populations,

which are the reservoirs of plague and murine typhus.

3. During and after, or together with, ratproofing worktoeradicate rodents in buildings.

4. hay in community programsto stimulate public interest inrodent control.

Rat killing without environmental improve-ments, particularly good sanitation, is ineffectivebecause:I. Rats and mice rapidly regain the original population level

through their high birth rate and the greater survival ofyoung as a result of less competition,

2. A continuous killing program is necessary, which is costlyin terms of labor and materials.

3. Continued use of most poisons can result in bait shyness.

POISONS AND BAITS*

POISONS AND THEIR MODES OF ACTION

The anticoagulants, red squill, and zinc phos-phide are the rodenticides generally recom-mended for use by health departments and bythe public. These rodenticides are availablecommercially and are the ones with which theuntrained individual is the least likely to ex-perience difficulties.

The anticoagulant rodenticides, such as war-farin, Pival, Fumarin, and diphacinone, kill in aradically different manner from the older acute(single dose) poisons. They must be ingestedfor several consecutive days before they becomeeffective. This provides a definite safety factorfor a child or an animal that may eat a singlelarge portion of anticoagulant bait. The anti-coagulant poisons cause internal hemorrhages,so the poisoned rodents literally "bleed todeath." Even when weakened, the rats appar-ently do not associate their condition with thefood supply and will return again and again tofeed on anticoagulant-treated baits. So the prob-lem of bait shyness commonly associated with

*See pages li Rol 19 for table or rodenticidts.

17

SOME CHARACTERISTICS

POISONSri ,.-7°7. lei.._1

D

274, a....

.0 Ygi, vi,L.,0

tu

1.4

1cu.

0>47.

i.la

g 1:4g I-.5 a1 g i

E..0

0 a03

.8 .c

E a...c.s

ANTICOAGULANTS

Warfarin

Furnarin

Pival 1' .025 Good Good Good Yes No None Slight

i

None

ANTICOAGULANT

Diphacinone 0.5' .005 Good Good Good Yes No None Slight None

ANTU 8' 1.5 Good Good Poor No Yes Slight Medium Slight

ARSENIC 100' 3.0 Fair Fair Fair No Yes None Medium' None

rtUOROACETAM IDE

(1081) 15-Norway51-1.0ce 2.0 Good Good Good No No None Slight Slight

PHOSPHORUS,

YELLOW a 1.7 .054 Good Good Fair No No Strong Strong Fast

RED SQUILL 0 10.0 Fair Fair Poor No No Medium Strong' Medium

SODIUM

FLUOROACETATE

(1080)

5-Norway2-Roof R.

10-Mke1/2 0:. /Gat.2 Oz /28 tbs. Good Good Good No No None Slight Slight

STRYCHNINE

(Medd) a 6 0.6 Fair Fair Poor No Yes None Stroce Slight

STRYCHNINE

(Sulfate) 8 0.8 Fair Fair Poor No Yes None Strong' Slight

ZINC PHOSPHIDE 40 1.0 Good Good i Good No No Strong Strong Fast

gresoloof Rims Rats otaill aaria! lamas Rats aiid

floof Res[Ratko isalosf Noma lab. Roof hats. sod Novo Mies

s000 Mica asIv

I. Mon of law tottossbo doses novena he 510 tars of vow.2. Nonni fob oil. , It ant atiesaro.J. Poetic% gm of USP rides nry eider woo aorta parks last is folth os w 11/

isictiottod it 2$ Mg.: IOW focoomoodoll, at I S vomitC. Coloaforsiol Int.otaboos rut from 14% is pasta fors. rte is labia directs.

18

OF COMMON RODENTICIDES

SolubilityType of Bait

MixturesACTION

(Cause ofDeath)

Relation to humansand to Other Animals

ANTIDOTES°t tg.3 ..E.

''S .g

v, cp.

.1 ill

Q 5

0Z '.0

a x.4g re,

t.c,, 1 .

g

Yes Yes Yes No Yes

Inhibits clotting of blood;causes internalhemorrhage. I

Yes No Slight

Vitamin It and transfusionsof whole brood.

No Yes Yes No No

Inhibits clotting of blood;cones Internalhemorrhages. Yes No Slight

Vitamin K and transfusionsof *bole blood.

No No Yes Yes NoPlural effusion (ow.producticn of fluid In thelungs),

No No Medium Hone

Yes Na No Yes YesKidney destructino; Castroenteritis; Contra! nervoussystem offectod. II

No No' Mediumsilk of Illbtftell, milk, andiirsior; Ctsid of kn.

Yes No No Yes Yes

Simile, to Wispfluoroseetste (1080). Ile

Yes No' Extreme

None

No Yes Yes No No

Heel paralysis; Castro.Westin! end liverdonde. II No No Medium

Copper sulfate befog emetic;Cathartic en oafs. Avoidfats and oils (as milt).

Yes Yes Yes Yes Yes Newt pe:alysle. No No Slight Acts stows 'milk toanimals usable of vomiting.

Yes No

i

No Yes Yes

Paralysis of hurt end thecontrol nervosa system

Yes No; Extreme

ethylNONE. MINIMUM orskohol and acetic andrecommended.

EE

Yes No Yes No No

Convulsions doe t antistimulatems et WM, Nye-tem; eskiesties; asakors.

111 III

No No Medium

file untie env 10 miring,.Canton Is meter no soda.tin; Km la dart nom.

Ya No Yes No No

Convulsion en te neetimoletin of moven errtow astmostioa; Ssplemli.

11 II IINo No Medium

No emetic after 10 *inns.Cltarnal II webs sod soda.thm; Keep is lark room.

No Yes Yes Yes No same es hesehss. No No Medium Sant es pliontsens.

$10 kensrest 'dist

II II M Very hat Keg

I. Minims somptabla Intl; we teak spills gin bettor nouns.. ffermelly blecnortnle lo rob.. Cat be inn tbroegli tots or breaks Is The *la; also gager el initiog lens powder.. t: refs wall oi Ant sill non el pen; spool Is 'snail; 1 Uneven If sail lo a

gins of warm motor Is nutty effective; an a Pliwsktos IMI104001.

Modified from U. S. Dept. cif Interior, Fish end Wildlife Sennee Leaflet #337, Revised Dec. IBS,

19

"one shot" poisons is largely overcome. Non-fatal doses of acute poisons are often painful,whereas anticoagulants apparently cause no pain.

Red squill has a bitter taste and a natural emeticaction, factors that contribute to its safe use asa rodenticide. Rodents, unlike humans and mostdomestic animals, are unable to vomit and aretherefore not protected by the emetic qualityof red squill, which kills them by paralyzingthe heart. This poison is not well accepted byroof rats and house mice, but it can be usedeffectively against Norway rat populations ifexposed in a very attractive bait at the start of akilling campaign. However, because of redsquill's bitter taste, bait shyness may soon be-come a problem.

Commercial squills vary considerably instrength, so it is important to buy only afortified squill. Red squill fortified to an LD.-,0of 500 mg/kg has given high percentage killswhen thoroughly mixed 10% by weight with afresh attractive bait material. A more toxic squill(LDno of 250 mg/kg), mixed similarly at 5% byweight, is recommended to increase acceptanceand enhance results.

Red squill is hygroscopic, that is, it absorbs

water from the atmosphere, so if it is exposedto the air it becomes caked and hard. Therefore,red squill should be protected by storing it intightly sealed containers.

ANTU (Alpha-naphthylthiourea), if usedproperly, is effective as a quick-acting poisonfor the Norway rat. It causes an overproductionof fluid in the lungs of the rat, and the poisonedanimal dies by drowning, usually within 48hours. As with red squill, it is not effective forthe control of roof rats or mice. Rats arestrongly reluctant to accept repeated doses ofANTU, and they develop a marked tolerancefor it. Consequently, this poison should not beused against the same rat populations more oftenthan once a year. Therefore, the single annualbaiting must be thorough. ANTU has a goodsafety record where humans are concerned, butdogs, cats, and hogs are readily poisoned by it,so great care in placement of baits is necessary.

The offensive odor and unattractive color ofthe more toxic zinc phosphide serve as safetyfactors for it. Despite these characteristics, Nor-way rats, roof rats, and house mice seem to likethe taste and pungent odor of the phosphorus.It kills them by causing heart paralysis and gas-trointestinal and liver damage. Although most

20

ZINCPHOOPHIDE

well-fed domestic animals will not touch baitsprepared with zinc phosphide, it is nonethelessa hazard to all animals and should be used withcare.

Sodium lluoroacetale, 1080 (CRYCOONa), is verypoisonous and very fast acting, usually produc-ing symptoms in rats in 20 minutes or less andkilling them within 1 to 8 hours. It is extremelydangerous to use, and its use is therefore re-stricted almost entirely to bonded professionaloperators. Rats poisoned with 1080 may developconvulsions from its action on the nervous sys-tem, but death usually results from heart failure.

fluoroacetamide, 1081 (FCH2COHN2), a rodenti-cide closely related to sodium fluoroacetate(1080), has been registered with the U. S. De-partment of Agriculture for poisoning rats insewers. British researchers consider it safer tomanufacture and handle and more efficient inuse than 1080. They found it an effective andwell accepted rodenticide for R. rattus, R.norvegicub, and M. musculus when mixed 1 or2 percent in water or feed baits.

The period of onset of warning symptomswith 1081 is longer than with 1080, with theresult that rats consumed from 18 to 100 lethaldoses before becoming distressed. Thereforefluoroacetamide is believed less likely than 1080to lead to poison-shy rats because sublethalamounts of bait are ingested. Fluoroacetamide isavailable from the manufacturer as a water baitand as a ready-to-use dry bait. Although it is lesstoxic than 1080, it is nonetheless a highly toxic

compound and the same handling precautionsfollowed for 1080 apply to flu ,roacetamide.

Sodium fluoroacetatn. (1080) and fluoroaceta-mide (1G81) are the most effective and thefastest acting rodenticides. Because of theirextreme toxicity to man and animals, theyshould be used only on certain types of premisesand only by competent specialists. These pro-fessional operators know the precautions andthe very strict limitations to be observed in theuse of these poisons.

SUGGESTED BAIT FORMULAS

Anticoagulants (warfarin, Pival, and Fumarin0.025'; ; diphacinone 0.005';0 are effective ina variety of simple, inexpensive, meal-type baitssuch as yellow corn meal, rolled oats, or a com-bination of the two. Advantages of these baitmaterials are: (1) low cost, (2) ready acceptanceby rodents, and (3) good keeping qualities.

Materials Parts by Weight Amount

Poison (0.5% concentrate) 1 pad 11b.

Yellow corn meal 19 parts 19 lbs.

Where rodents do not accept this formula,replace 7 parts of the yellow corn meal with 5parts of rolled oats, 1 part of granulated sugar.and 1 part of corn oil. This mixture is moreexpensive but should increase acceptance byrodents. A discoloring agent such as charcoalmay also be added. The chances of failure incontrol of mice, which nibble when they feed.can be reduced by using relatively high dosages

21

.igesmiiiitilloimilinli It

If

of anticoagulant, by weight: 1 part concentrateto 9 parts corn meal (0.5% concentrate whenusing warfarin, Pival, or Fumarin, but 0.1%concentrate when using diphacinone).

Anticoagulants are available as water-solublebaits, which should be mixed according to in-structions on the label. Field trials in Englandsuggest that the combined use of anticoagulantsolution baiting stations surrounded by a dustof anticoagulant concentrate is a valuable addi-tional method of controlling house mice, par-ticularly those living in warm, dry environments.

Single-Dose Poisons

Red Squill 5% or 10%Poison (fortified)

SOO mg/kg250 mg/kg

Bait: ground fresh meat, bacon,fresh or canned fish, grains,cereals, selected fresh fruitsor vegetables, or combina-tions of these (see p. 24).

with SOO mg/kg squillwith 250 mg/kg squill or up to

Bireler (optional) as required tohold bait together (see page 24)

Discoloring agent (optional)

Amount

1 lb.1 lb.

Note:

Rats and mice are attracted to sweets. Asmall amount of sugar, molasses, syrup,raisins, or sweetened fruits will increaseacceptance when added to food or waterbaits. However, this also increases theattractiveness of baits to ants and otherinsects and may thereby reduce their ac-ceptability to rodents.

Zinc Phosphide 1%PoisonBait: (Same selection as for

Red Squill)Tartar emetic

Amount4 oz.

25 lbs.11/2 oz.

Zinc phosphide is often used to coat 1/2-inch9 lbs. cubes of sweet potato or apple for use as bait3.

19 lbs. To mix, put the freshly cut, moist cubes in awide pan with the poison, then using a longhandled spoon, mix until all of the poison hesbeen taken up by the cubes.

22

ANTU 1.5%PoisonBait: (Same selection as for

Red Squill)Discoloring agent (optional)

Amount8 oz.

33 lbs.

Strychnine (for house mouse control only)Poison is available from manufacturers as aprepared product consisting of colored wheatgrains or canary seed coated or impregnatedwith strychnine.

DDT (50%, finely powdered) dusted alongrunways is effective for mouse control. Caremust be taken that foodstuffs do not becomecontaminated.

Paraffin FormulationsFor poisoning rats insewers and other humid areas, sufficient meltedparaffin is added to coat anticoagulant or single-dose poison-grain mixtures. When solidified,such bait mixtures shed water, resist mildew andinsect infestation, and keep bait fresh for severalweeks.

--.!: il

23

In formulating these baits, add up to 11/2

pounds (maximum) of mel:ed paraffin to 23/4pounds of a grain-and-poison mixture in a con-tainer suitable as a mold, for example, a dis-carded paper milk carton, which can be tornaway after the mixture has set. Let one end of ashort piece of wire hang in the mixture as itsolidifies, and make a small loop, or eye, in theother end so that additional wire can be added,as needed, to permit lowering the bait blockinto the sewer and securing it there.

In dry locations, rodent acceptance of theseparaffin bait formulations may not be as goodas with conventional mixtures. However, reportsindicate good results in the use of rodenticide-bait-paraffin mixtures to control rats in sewerswhere conventional mixtures cannot be used.

Some grains, such as oats, and some rodenti-cides, such as Ptval, are reported to inhibitmildew. Also, preservatives such as 0.025 per-cent DuPont DDPD and 0.1 percent 2,4,5-trichlorophenylacetate have been added to baitsto extend the period of overall acceptability, butthey also reduce the taste acceptability to ro-dents. British workers found no evidence thatpoisoning treatments improved through use ofmold-inhibiting substances.

PREPARATION OF BAITS

Suggested materials for baits include: fresh,frozen, or canned meats, fish, or pet food; bacon,yellow corn meal, cracked corn, hulled oats,rolled oats, canary seed (for mice), apple, sweetpotato, melon, tomato, peanut butter, nutmeats,and butter.

Fresh baits are the most acceptable to rats andmice, so mix only enough bait for current needs.

A binder of molasses or of vegetable, mineral,or fish oil is often used in cereal or dry baits tohold the poison and the dry bait together and toaid in mixing.

An emetic, usually tartar emetic, is mixedwith zinc phosphide and other more toxic baitformulations to protect animals other than ro-dents, even though acceptability of such baitsto the rodents is thereby reduced. Rats areamong the few animals that are unable to vomit.

Mix bait as directed. Too much poison maygive the bait a strong taste or odor. Too littlewill not kill but may result in "bait shyness."Excessive amounts of poison increase the dangerto man and to domestic animals.

Mix baits well. Poor mixing results in, non-uniform baits and poor kills, and speeds de-velopment of bait shyness. Mechanical bait-mixing equipment is necessary where largequantities of bait are mixed routinely.

CAUTION: Clearly label poisons and mixing equipment. Do

not use bait-mixing equipment for other purposes. Lock uppoisons and mixing equipment when not in use.

24

CAUTION: Treat all poisons with respect. Read and follow

all label instructions. Avoid inhaling powders or getting poisons

on hands, clothes, or utensils from which they may reach themouth. Wear rubber gloves when handling poisons. Always mix

poisons in a well-ventilated place, particularly when mixing dry

ingredients.

BAIT PLACEMENT

Aaticoagulant Bolts. Anticoagulants are not"one-shot" poisons, so they require a differentmethod of use from other rodenticides (see page17). Bait mixtures are frequently placed inpaper, metal, or plastic pie plates or in perma-nent bait stations. The number of pie plates orbait stations would vary with the infestation.Small pie plates will hold 1/4 to 1/4 pound,whereas permanent bait stations often hold over

a pound of bait mixture. Be liberal in baiting.Anticoagulant bait mixtures are usually exposedfor a minimum of two weeks; but where reinfes-tation is likely, a few bait stations may be main-tained on a permanent basis. For anticoagulantsto be fully effective, repeated doses must beconsumed by every rodent at a given locationfor a period of five or more consecutive days.

Therefore, observe the following instructions:1. Protect animals other than domestic rodents, and shield baits

from the weather under shelter or with bait boxes, boards,

pipes, or cans.

2. Note locations of all bait containers so that inspections can

be made rapidly and the bait that has been consumed can

be quickly replaced. (Note: Bait consumption is generally

heavy right after initial placement, making daily inspection

and replacement advisable for the first 3 days after regular

feeding begins.)

3. At each inspection, smooth the surface of the baits so that

new signs of feeding will show readily.

4. Replace moldy, wet, caked, or insect-infested baits withfresh ones.

5. If a bait remains undisturbed for several successive inspec-tions, move it to an area showing fresh rodent signs.

3-p

71;gr.ze..41

Use shallow bait containers fastened to thefloor, or containers of sufficient weight to pre-vent the rodents from overturning them ordragging them to their burrows. A roofing tackdriven through metal or fiber containers into thefloor reduces spillage.

23

Poisoned Water. When poisoned water is used,place it only where other animals cannot getto it. Use containers that will not spill, such asglass caster cups or low metal or water-resistantpaper cups. Chicken founts are satisfactory forpermanent stations. Note: Water baits are mosteffective where other sources of water are lim-ited or can be eliminated, as in feed mills orgranaries. British workers report that the use ofanticoagulant dust concentrate placed in a patcharound anticoagulant poison water stations iseffective in mouse control.

"kr

Single-Dose Poisons. Wrap one-shot poisonfood baits in 4" x 4" paper squares to form"torpedoes" about the size of a large olive.One pound of bait will make about 80 to 90 suchtorpedoes. These may be tossed readily intootherwise inaccessible places. Rats prefer tocarry their food to their harborage to tat it insafety. If several types of bait such as meat,fish, or cereal are to be distributed at the sametime, a different color of paper should be usedfor each of the various types of bait.

Be generous with baits. Remember, rodentshave a limited "home range," usually less than150 feet for rats and 30 feet for mice. Too fewbaits, or poorly placed baits, may miss manyrodents. Bait liberally where signs of rat activityare numerous and recent. In light or moderateinfestations, torpedoes containing a single-dosepoison, such as red squill, have given goodcontrol when applied at a minimum rate of 20baits per private residence and 40 per small busi-ness establishment. As many as 100 to 200 baitsmay be required for premises with heavy rodentinfestations. Place baits in hidden sites out ofreach of children and pets. Inspect and rebaitas needed, using another poison and anotherbait material when the rats become shy of theoriginal baits.

"Throw Bags," which are bags of paper,moisture-resistant paper, or plastic, each con-taining about 1/4 pound of anticoagulant orsingle-dose poison bait mixture, can be throwninto heavily infested sewers and into burrowsand other inaccessible areas. Some operatorspierce the bags in place to make the contentsmore accessible to rats. However, this makes itmore difficult to determine the amount of baitconsumed.

26

Prebaiting. When single-dose poisons are tobe used, prebaiting for several nights with threeor more kinds of unpoisoned baits can increasesubsequent acceptance of the poison bait, par-ticularly when rats evidence bait shyness. How-ever, it is too costly a practice for large-scaleuse. As with poisoned baits, a distinguishingcolor of paper wrapper should be used for eachtype of .. unpoisoned bait material. Prebaitingwith distinctively-colored torpedoes of threekinds of baitfor example: meat, fish, andgrainwill show the preferred bait material andat the same time indicate how many baits areneeded, and where.

Poisoning at Dumps. Open dumps, with theircontinuously replenished supply of food andharborage suitable for rodents, comprise aspecial problem in the rodent-control program(see page 15). Until sanitary disposal of refuseis instituted, poisoning may be the only effectivemeans of controlling rats at these sites.

Fifty to a hundred pounds or more of poisonedbait may be required to bait a single heavily in-fested dump. Good results have been obtainedby using the following techniques:

1. Wait about a day after the last load of refuseis deposited at the dump. Provide drinkingwater if none is available.

2. Using a single-dose poison, bait heavily forseveral nights. If -rodent ectopart sites orcockroaches are a problem, power dust witha recommended insecticide.

3. On the day following the last night of single-dose poisoning, establish a number of anti-coagulant rodenticide bait stations and serv-ice them regularly until all signs of ratfeeding cease.

4. Level the dump and cover with earth to adepth of two feet after compaction.

Poisoning In Sewers. In sewer systems, as atopen dumps, rodents find safe harborage and aconstantly replenished supply of food ; and, likethe open dump, an infested sewer serves as acontinuous source of reinfestation for nearbyneighborhoods. Unless and until permanent con-trol of sewer rodents is undertaken, by majorrenovation of old sewers or construction of new,a poisoning program is the only effective meansof control. But results of poisoning are short-lived, and sewers must be re-treated periodi-cally. Field trials suggest that two to fourtreatments per year against rats in sewers givesatisfactory control.

The most satisfactory effective formulationfor use in humid sewers is the paraffin-poison-bait mixture described earlier (page 23), usingeither an anticoagulant rodenticide or zincphosphide as a single-dose poison. An especiallyprovided wire, when attached to the ladder orother suitable point near the top of the manhole,prevents the bait block or bait container fromlodging in the sewer and simplifies inspection ofthe bait station. Paraffin baits to be placed insewers subject to overflow may be nailed orotherwise fastened to boards of sufficient sizeto float the can or carton of bait.

CAUTION: Sewer manholes can serve as reservoirs of pois-

onous gases and carbon dioxide. A worker should never enter a

manhole unless he has a rope tied as a lifeline around his body

and helpers present to lift him to the surface, immediately, ifnecessary.

27

TRAPPING .

Traps are useful when poisons fail or theiruse is too risky, where the odor of unrecovereddead rodents would be a problem, and whenlive-trapped rodents are desired in order tocollect rodent ectoparasites and bloods for usein disease studies. For the latter purpose, steeltraps and cage-type traps should be used,

The snap trap is one of the most effectivedevices for killing rats and mice, particularlymice. An attractive bait should be fastened se-curely to the trigger, For rat control, the triggermay be expanded with cardboard or screen wireand used unbaited. Steel traps (Oneida-Victor

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size #0 or equivalent) are effective for catchingrats alive. Set the trap with the jaws openacross the runway and fasten the chain securely.Cage or bcx traps are usually less convenientand are not as efficient as steel traps, but theycatch the rodent uninjured. Placing cage trapsin dark places or covering them with materialsuch as burlap bags will increase catches. A"choker"-type trap, properly set, may catchseveral mice per night.

Boiling traps after use to remove the humanodor is not necessary. Rats live so close to manthat his odor is part of their everyday expe-rience.

expanded trigger

Fasten securely awayfrom trap

Ile DIRECTION OFRAT RUN

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28

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GASSING

Gassing of burrows is used as a supplemen-tary measure for killing rodents. It should notbe attempted by untrained operators. Severalmaterials are available for this purpose, onebeing calcium cyanide. Cyanide dust ("A"-dust*or equivalent) is effective when it can be blowninto a burrow system where rodents are con-centrated. However, calcium cyanide dust is noteffective when the ground is extremely dry.Some moisture is needed in either the soil orthe air to convert the dust to gas.

A foot pump is an effective means of blowingcalcium cyanide dust into rodent burrows. Afterinserting the pump hose an appreciable distance

Menufaciured by American Cyanamid Co.. New York, N. Y.

30

dow:1 the burrow entrance, the operator turnsthe veve to "dust "and pumps 2 to 6 strokes withthe handle, which blows the dust into the bur-row system. Then he turns the valve to "air"and pumps an additional 10 strokes or so, whichforces the dust throughout the system. Hewatches the ground nearby for escaping dustto show him where there are other openingsto the burrow system, then quickly closes andseals these auxiliary openings to prevent escapeof the gas or of the rodents it is meant to kill.When a foot pump is not available for dis-pensing the dust, the operator can use a handduster or a long-handled spoon. However, hemust be sure to place the dust at least 8 inchesdown inside the burrow.

Burrows may be reopened by rats shortlyafter they have been gassed. This representseither a failure of the gassing operation or anew rodent infestation and indicates a need forre-treatment.CAUTION: Cyanide fumes are highly toxic and rapidly fatal. Avoid

inhaling dust or fumes. Cyanide gas is lighter than air. Therefore,

burrows that may lead under occupied buildings must rot be

gassed. Indoor fumigation with this gas must be done only bythoroughly trained professional fumigators.

OTHER KILLING METHODS

Carbon monoxide gas from an automobilemotor left running may sometimes be used forgassing rodent burrows. The fumes from themotor are piped through a hose running fromthe auto's exhaust pipe into the burrow system.All burrow entrances other than the one to beused for introducing the gas should be searchedout and tightly sealed in advance of the opera-tion, thus preventing the escape of the rodentsand avoiding dilution of the gas.

This technique is extremely hazardous, how-ever, since the fumes may be forced back throughthe exhaust system, and any leak in the systemcould let the deadly gas enter the auto andovercome the occupants. To safeguard againstthis danger, all car doors and windows must beleft open while the motor is running.

Flooding burrows may be a productive tech-nique and is applicable where there are tightclay soils. Water under pressure, as from agarden hose, can be used to drown rodents intheir burrow or to drive them out where theycan be clubbed to death.

RELATED PROBLEMS

ECTOPARASITE CONTROL

Control of ectoparasites (fleas, lice, mites, andticks) is vital in order to prevent transfer ofrodent diseases to man. Ectoparasites feed onthe blood of their rodent hosts and may therebybecome infected. When such hosts are killedthrough trapping or poisoning, their ectopara-sites may, by chance, select man as a temporaryhost, and if they are diseased, may infect himwith the organisms. When disease is thought tobe present in a population of rodents, theectoparasites must be killed before rodent eras'ication measures are begun.

To treat a building or an area for control ofectoparasites:1. Inspect for signs of rat or mouse activity, especially for rub-

marks at the base of walls, and for evidence of runways and

burrows.

2. Treat all runways, burrow entrances, and nests with lf) per-

cent DDT dust or other recommended insecticide. Dust the

vertical surfaces against which the rodents may brush by

using a dust gun, hand shaker, or scoop, or by hand.throwing

the insecticide.

Rats that come in contact with insecticidedust carry it on their feet and fur to their bur-rows and nests. This gives ectoparasite controlin areas beyond the reach of normal dustingactivities.

As determined in past extensive county-widedusting programs, residential premises requireabout 21/2 pounds of 10% DDT dust per treat-ment and business establishments require about4 pounds per treatment.

In controlling plague or murine typhus, themodern approach is to dust with 10% DDT tokill infected ectoparasites, particularly theoriental rat flea. The dusting operations shouldbegin at those locations where the cases ofplague or murine typhus were acquired, or aresuspected of having been acquired. Treatmentsshould then be extended to adjoining areas, asneeded. For fleas resistant to DDT, 2% Diazinon,5% malathion, or 10% carbaryl dusts can betried.

31

DEADRODENT ODORS

Dead rodents should be removed, if possible.However, when they die in inaccessible places,the following measures may give partial orcomplete relief from offensive odors:1. The use of fans will increase air circulation.

2. To mask unpleasant odors, such products as isobornylacetate, Neutroleum Alpha, quaternary ammonium com-pounds, Styamine 1622, Zephiran chloride, and Bactine can

be used as an aerosol, a mist spray, or in a bowl or bottlewith a cotton wick.*

32

3. Oil of pine, oil of peppermint, oil of wintergreen, formalin,

anise, or activated charcoal can also be used as maskingagents or deodorants. For exampIP 10 drops of pine oil in agallon of water can be applied with an atomizer or with afine-mist sprayer.

4. If the dead rodent can be located, as by fixing its position

between partitions or walls, a pint water mixture of one ofthe masking agents listed in #2 above may be pouredthrough a small hole bored Into the wall a few inches above

the floor level and as close to the source of the dead-ro

dent odor as passible. This treatment usually dispels odors

rapidly. When the precise location of a rat carcass Is difficultto determine, one or more blue bottle flies (Catliphoraspp.) released into the room can help. Guided by the odor,they will fly unerringly to the spot where the dead rat isbehind the wall.

CARCASS DISPOSAL

The carcasses of all rats recovered from thepoisoning, trapping, and gassing operations andall uneaten poison baits should be buried orburned. Anyone handling the dead rodentsshould wear rubber gloves.

*Isobornyl acetate is manufactured by E. I. du Pont de Nemours& Co., Wilmington, Del.; Neutroleum Alpha, by Fritasche Bros.,New York, N. Y.; Styamine 1622 by Rohm & Hass, Philadelphia,Penn.

RATPROOF1NG

Ratproofing or vent stoppage consists ofchanging structural details to prevent entry ofrodents into buildings. Openings as small as ahalf inch will admit young rats. Where onlyNorway rats are encountered, such openings asground floor windows, sidewalk gratings, base-ment vents, utility pipe openings, and founda-tion walls are normally ratproofed; but whereroof rats are found, ratproofing must alsoinclude wires, vertical pipes, and openings toupper floors and roofs. Where only Norwayrats are encountered, the stoppage work, in orderto be economically feasible, is confined to themore likely points of entry and not to everypossible entrance.

DEVICES

1. The cuff and channel for wooden doors to side and backentrances prevent rats from gnawing under or around the

doors. The front doors of most establishments are less ex-

posed to rats and are generally protected with a kick plate.

Wooden door jambs can be flashed with sheet metal toprotect them from rat 7qawing. Because open doors provide

ready entry for rodents, both screen doors and wooden doors

to foodhandling establishments should be equipped withreliable selfclosing devices.

2. Vents and windows can be made secure against rat entry by

screening them with heavy wire mesh, preferably in a sheet-

metal frame. If desired, fly screening can be incorporated

into the frame also. Wooden surfaces exposed to gnawing

must be covered by the frame.

3. Metal guards of suitable construction should be placedaround or over wires and pipes to prevent rats from using

them to gain entrance into a building.

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4. Openings around pipes or conduits should either be covered

with sheet metal patches or filled wit concrete or brick andmortar.

5. The use of concrete for basement floors and for foundations

not only prevents rat entry but also increases the value ofthe property.

6. Floor drains, transoms, letter drops, and fan openings must

receive stoppage consideration.

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1. l7.gauge, 2" x 2" (1/4inch mesh) galvanized hardware cloth

for screening against rats; 19-gauge, 4" x 4" (1/4inch mesh)

for mice.

2. 18gauge galvanized expanded metal for screening where ex.posure to damage is greater than normal.

3. 24 to 26.gauge galvanized sheet metal.

4. 14inch brass or aluminum for kick plates.

5. Concrete, brick and mortar, glass, tile, and other building

materials.

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33

As an adjunct to vent stoppage, buildingsshould be planned or modified to avoid deadspaces such as double walls, double floors, andenclosed areas under stairways.

Rubbish piles or other materials stackedagainst buildings should be removed. They pro-vide the means by which rats and mice canbypass otherwise effective stoppage measures.

After buildings have been completely rat-proofed, measures should be taken to eradicatethe rodents that have been trapped within.

Inspections should be made at regular inter-vale to make sure that rats have not been re-introduced in incoming shipments and that theratproofing work remains intact.

As a general guide in planning preventionmeasures, it will be assumed that rats can dothe following:

1. Gain entrance through openings larger than 1/2.inch square.

2. Climb both horizontal and vertical wires.

3. Climb the Inside of vertical pipes 11/z to 4 Inches in dian.eter.

4. Climb the outside of vertical pipes and conduits with diam

eters up to 3 Inches.

34

5. Climb the outside of vertical pipes and conduits of any sire

if within 3 inches of a wall.

6. Crawl horizontally on any type of pipe or conduit.

7. Jump vertically as much as 36 inch ,s from a flat surface.

8. Jump horizontally 48 inches if on a flat surface.

9. Jump horizontally at least 8 feet from an elevation 15 feetabove the finish point.

10. Reach about 18 Inches horizontally or vertically.

11. Drop 50 feet without being killed.

NEW CONSTRUCTION

All new buildings should be so designed thatthey are ratproof, Building codes of commun-ities should be revised, if necessary, to requirethat new construction be ratproof. Codes shouldalso specify that modifications and repairs bemade to existing buildings to render them rat-proof.

ORGANIZATION OF COMMUNITY RAT-CONTROL PROGRAMS

In any community, careful planning mustprecede inauguration of a rodent-control pro-gram. As a basis for planning, a survey must bemade to determine the degree and extent ofinfestation and to pinpoint problem areas, whichin essence determines the type and size of pro-gram required. Survey results must be conciselysummarized in a form suitable for presentationto local officials. This might be as a brief reportsupported by attractive and meaningful mapsand graphs, and by 2" x 2" color slides and anyother essential materials or documents thatsummarize and illustrate the problem and em-phasize the need for a rodent-control program.

Based on the survey results, tentative esti-mates of space, material, and personnel require-ments can then be made. The proposed role ofprivate pest-control firms should be given, alongwith other proposed plans for the program.When local officials have approved and budgetedthe rodent-control program, complete details ofplans, facilities, and operations can then bedeveloped and implemented. After the programis operational, additional surveys are made

periodically to measure progress. Rat-surveymethods are described in detail in the publica-tion "Urban Rat Surveys."

ORGANIZATIONAL STRUCTURE

A workable organizational structure forrodent control in a community develops some-what as follows:I. The health department or other local agency employs staff to

control rats In blighted residential areas, in sew and in

public buildings on a permanent basis. Some cities contract

this work out to private firms.

2. Local health agencies or departments of public works provide

community-wide inspection and enforcement services. In

many communities these services now are inadequate or

non-existent, particularly in blighted areas, because of ashortage of funds, equipment, and personnel.

3. Private pestcontrol firms contract to control rats in privatebusiness establishments and in residences.

4. State and Federal health agencies offer limited consultation,

training, and research in rodent control.

35

INFORMATION AND EDUCATIONPROGRAM

The major element needed for a successful,long-lasting rodent-control project in a com-munity is a strong, continuous educational pro-gram in environmental sanitation. It is essentialthat refuse (garbage and rubbish) handlingfacilities be improved, particularly in ailblighted areas of the community, which invar-iably are the areas most heavily infested withrats. Proper storage of food and of refuse mustbe achieved neighborhood-by-neighborhood,block-by-block, residence-by-residence. Jointaction of all concerned is essential.

Before refuse storage can be satisfactory, thelocal government MUST provide adequaterefuse collection service (twice weekly to res-idences and daily to businesses is recommended).If refuse collection is not frequent and regular,householders cannot be expected to store refuseproperly. Ordinances and timely enforcementare needed for those who refuse to obey regula-tions. Carelessness and indifference of any ofthe people are formidable foes to a successfulrodent-control program, particularly in blightedareas. These attitudes must be fought with acontinuous educational effort and with consist-ent, fair, resolute law-enforcement activity ona continuing basis.

Each year, the essentials of rodent controlshould be taught in the schools to all studentsof a receptive age group. Educational and pro-

36

motional programs should be presented to com-munity organizations such as Chambers of Com-merce, Lions Clubs, Garden Clubs, and RotaryClubs, and these groups should be invited tosponsor community projects to promote im-provements.

For a rat-control program to be successful,educational and promotional work must reachthe neighborhood or block levels. Oftentimesneighborhood garden or improvement clubs willassume leadership. In blighted areas, where theproblem is greatest, resident block leaders mustbe found to spearhead needed improvements intheir blocks on a continuous basis. In theneighborhood effort, Boy Scouts, Girl Scouts,and other youth groups are often of great help.Needless to say, the cooperation of all busi-nesses, and particularly those handling food, isvital to the success of a rat-control program.

Stimulating neighborhood meetings must beheld periodically to gain and to maintain neigh-borhood and block enthusiasm and support. Newideas or "gimmicks" must occasionally be in-corporated into motivational efforts in order tosustain citizen interest.

Publicity through mass media (newspapers,radio, television, exhibits, leaflets, etc.) is help-ful, particularly in the middle and high socio-economic areas. However, these media often donot reach the majority of the householders inblighted areas where the need is greatest. There,personal contact, usually door to door, is re-quired.

SUMMARY

Rats are filthy and destructive. They arewidely feared and despised, and they spreaddisease and cause great economic losses.

Control of rats requires: (a) environmentalsanitation to eliminate their food and harbor-age, (b) effective ratproofing, and (c) efficientkilling programs. These control measures mustbecome a way of life in the community if ratpopulations are to be kept low or eliminated.

Controlling rat populations, not individualrats, is the key to a successful rodent-controlprogram in a community.

37

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Brooks, Joe E.: The presence of the roof rat, Rattusrattus, in sewers in California. Calif. Vector Views

38

10(11): 71-72 (1963).Brooks, Joe E.: Fluoroacetamide -a new British-de-

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39

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Storer, T. I.: How to control rats and mice. Calif.Agr. Exper. Sta., Univ. of Calif., Berkeley, Calif., 28pp., 1960.

Storer, T. I., ed.: Pacific Island rat ecology. BishopMuseum Bull. 225, 274 pp., 1962.

Szaber, T.: The effectiveness of some anticoagulantrodenticide dusting powders. J. Hyg. Epidem. 8:332-337 (1964).

40

U. S. Fish and Wildlife Service: Rat control methods.Circular No. 13, U. S. Government Printing Office,Washington, D. C., 16 pp., 1948.

U. S. Fish and Wildlife Service: Characteristics ofcommon rodenticides, Department of the Interior,Leaflet WL-337, Washington, D. C 4 pp., 1952.

Ward, J. C.: The functions of the Federal Insecticide,Fungicide, and Rodenticide Act. Amer. J. PublicHealth SS: 27-31, July 1965.

Weinburgh, H. B.: Field rodents, rabbits, and hares.U. S. Department of Health, Education, and Wel-fare, Public Health Service, Atlanta, Ga., 87 pp.,1966.

Wolf, H. W.: Resistance of bituminous fiber pipe topenetration by rats. Public Health Rep. 77: 806-808,September 1962.

World Health Organization: Insecticide resistanceand vector control. Thirteenth report of the ExpertCommittee on Insecticides. WHO Technical Re-port Series No. 265: 1.227 (1963).

SUGGESTED AUDIOVISUAL AIDS FILMSTRIPS AND FILMOGRAPHS*

The following films and filmstrips are avail-able on short-term loan within the United States.Requests should be addressed to:

National Medical Audiovisual CenterChamblee, Georgia 30005

Letters requesting these training aids shouldindicate exact dates that films are to be usedand allow ample time for shipment.

MOTION PICTURES

M -3 7.1 a

M-37.1b

AI-37.1c

M-37.1d

M-37.1e

M-37.141)

M-37.1f(2)

M-37,1g

4-116

4-049,1

M.4

M-228

M-1161

The Rat Problem, B&W, Sound, 16min., 573 ft., 1954.

The Norway RatHabits and Char-acteristics, B&W, Sound, 18 min.,636 ft., 1953.

The Roof RatHabits and Char-acteristics, B&W, Sound, 8 min.,296 ft., 1954.

Sanitation Techniques in Rat Con-trol, B&W, Sound, 12 min., 432ft., 1954.

Ratproofing, B&W, Sound, 10 min.,355 ft., 1954.

Rat Killing, B&W, Sound, 13 min.,476 ft., 1954.

Area Poisoning, B&W, Sound, 9min., 309 ft,, 1954.

Rat Ectoparasite Control, B&W,Sound, 8 min., 292 ft., 1954.

Rural Rat Control, B&W, Sound,16 min., 572 ft., 1951.

Epidemiology of Murine Typhus(Rev.), B&W, Sound, 18 min., 670ft., 1953.

Sanitary Storage and Collection ofRefuse, Color, Sound, 19 min., 671ft., 1952.

Refuse Disposal by Sanitary Land-fill, Color, Sound, 13 min., 472 ft.,1936.

It Must be the Neighbors, Color,Sound, 14 min., 1966.

00VUINMIL1117 11110,41010 OIncr. isst-vok 1 p

41

5-068 Rat Eradication Measures on Rat-proofing Projects, B&W, Sound,12 min., 78 fr., 1947.

5-067 Ratproofing of Existing Buildings,B&W, Sound, 14 min., 80 fr.,1947.

M-1574 Field Recognition of Domestic RatSigns, Color, Sound, 7 min., 16mm., filmograph, 1968.

F-111 Recognition of Domestic RodentSigns, Color, Sound, 7 min., 58 ft.,1952.

F-229a The Sanitary Landfill: Part I.Operating Procedures, Color,Sound, 7 min., 59 fr., 1957.

F-229b The Sanitary Landfill: Part II,Small Community Laud fills,Color, Sound, 6 min., 41 fr., 1956.

M-474 Use of Anticoagulants in RodentControl, Color, Sound, 11 min.,1961.

F-298 Use of Anticoagulants in RodentControl, Color, Sound, 10 min.,76 fr., 1961.

'Filmography are filmstrips on 16 mm. motion picturefilm with a sound track.