Challenges in surveillance and Challenges in surveillance and control of rabies in the Pacific control of rabies in the Pacific

Northwest Northwest

Mira J. Leslie, DVM, MPHMira J. Leslie, DVM, MPH

Todays TopicsTodays Topics

• Rabies:Rabies: Brief Background and ecology Describe surveillance in animals

(PNW) Epidemiology in humans Ongoing challenges in rabies

surveillance and control in PNW

ETIOLOGYETIOLOGY

• Rabies is caused by RNA viruses in the family Rhabdoviridae, genus Lyssavirus

• At least 7 Lyssavirus species or genotypes cause rabies (disease)

• Recently, 4 new Lyssaviruses collected from Eurasian bats have been described

RabiesRabies

• Acute, progressive viral (Genus Lyssavirus) encephalitis

• Highest case fatality of any infectious disease• One of the oldest diseases described• Model zoonosis

RabiesRabies

•

                                                      

                                                                                   

                                                      

                                                                                  

Global Disease

Estimated >55,000 deaths annually

N= 6940

N=229

Reportable disease

•US: 6500-9500 rabid animals recognized annually in all states except Hawaii; 92% wild

•Canada: 220-280 rabid animals reported annually; 77% wild

Animal Rabies in Animal Rabies in North AmericaNorth America

Rabies surveillance is mostly passive and strategies vary greatly among localities.

In 2006, the range of rabid animal reports/state was 0 (Hawaii) to 890 (Texas).

http://www.cdc.gov/rabies/docs/rabies_surveillance_us_2006.pdf

Confirmed cases of rabies in animals do not approximate the true incidence of disease.

Rabies

• All warm-blooded vertebrates are susceptible to experimental infection

• Reservoirs are Carnivora (canids, skunks, raccoons, mongoose, etc.) and Chiroptera (bats)

Rabies Reservoirs:-terrestrial and non-terrestrial

Molecular Epi: Rabies Virus Variants

Geographic distribution

Wildlife reservoirs maintain rabies and infection is transmitted among wildlife and to other species.

Surveillance infrastructure

Large variability among jurisdictions

• Laboratory capacity• Citizen density and awareness– reporting of

sick and dead wildlife, pet-wildlife interaction.• Local capacity for response to citizen reports• Resources and systems for transport of animal

heads New IHC test can be done in field

Enzootic rabies surveillance: sampling strategies

• Laboratory testing of potentially rabid animals that have exposed people wildlife that exposes pets. all reported sick (abnormal behavior) and freshly dead

carnivores and chiroptera without obvious trauma animals that are neurologically impaired or exhibiting

unusual behavior (except rodents and rabbits)

• Testing of healthy animals is ineffective road-kill (except in the face of ongoing epizootic) trapped, hunted or nuisance animals

Pacific Northwest(OR, WA, BC) Bat reservoirs of

rabies

• No terrestrial rabies reservoirs

• Spillover infection from bats into other mammalsOther wildlife and pets

Rabies in Bats

• Appear injured• Found flapping or dead

on ground• Flying during the day• When in urban area,

often expose human and/ or pets Found in pets mouth Child finds bat

Affects many speciesBig brown (E. fuscus), Mexican free-tail, Myotis….

Solitary species (13%)> colonial species (5%)

Rabies in tested bats

OR 136/1368

9.8%

WA 317/4584

6.9%

BC 110/1802

6.1%

This is a skewed population of sick and injured bats; less than 1% of healthy bats are infected with rabies.

Spillover infections

• Bat rabies virus variants BC: 2003-2007 / 1 human, 4 skunks, 1 cat WA: 1992-2007/ 1 horse, 1 llama, 2 humans, 1 cat Oregon: 1990-2007 / 19 foxes, 4 cats, 1 dog, 1 cow

In Alaska there are regular spillover infections from rabid Arctic and red foxes to dogs.

Animal Rabies – Alaska,Animal Rabies – Alaska,Jan 1, 1999 – Dec 31, 2007Jan 1, 1999 – Dec 31, 2007

9

35

49

27

9 11

4

18

45

0

10

20

30

40

50

60

1999 2000 2001 2002 2003 2004 2005 2006 2007

Epizootic activity: “Of the 39 animals evaluated for rabies from December 15, 2005 through March 10, 2006 at the Alaska State Virology Laboratory in Fairbanks, 10 were positive. Four were foxes and six were dogs…

Terrestrial wildlife submissions

0

5

10

15

20

25

30

35

2000 2000 2001 2002 2003 2004 2005 2006 2007

squirrel N=70 raccoon N=51 skunk N=57 red fox N=3

WA: No wildlife spillover detected<3 skunk/year (27/10yrs)<10 raccoon/year (91/10 yrs)< 4 coyote, fox, bobcat/year (34/10yrs)

OR: 19/68 (28%) tested foxes are rabid

British Columbia

Rabies surveillance challenges

• Difficulty in monitoring wildlife Animals don’t die (of rabies) in groups Wildlife habitat is mainly in areas with

little or no human population Short clinical period before death Need fresh brain tissue- specialized testing

• Threat of introduction of rabies to naïve, susceptible population

• A change in the epidemiology of rabies in an area may not be recognized early.

Rabies: Evolving Epidemiology

• Importation and interstate movement of animals

• Development and use of diagnostics and vaccines

• Surveillance for new reservoirs

• Clinical survivor

Animal factors: • Population fluctuations• Susceptibility and

immunization• Distribution of

reservoirs• Evolutionary

adaptation of virus in new hosts

Coyote RVV: Texas to Florida 1994 Raccoon RVV: Florida to Virginia, 1978 HuntersCoyote RVV: Texas to Alabama (1993) E. fuscus Canada to Germany (1986)E. fuscus Massachusetts to Denmark (1994) ResearchersE. fuscus MI/CA car container to Hawaii, (1991)

Rupprecht CE, Smith JS, Fekadu M, Childs JE. The ascension of wildlife rabies: a cause for public health concern or intervention? Emerg Infect Dis 1995;1:107--14.

[1995-2000: AZ- 2 steers with deriengue (Mexico-separate incidents); Dairy cow, horse from midwest]

Rabies translocation events

March 2007March 2007

• New Delhi, India• Veterinarian from WA state: volunteer at animal

shelter• Adopts 2 street puppies

Unvaccinated (> 12 weeks old) Unknown health histories Acting normally at time of rescue Reports of puppy being “picked on” by other street dogs

Source: http://www.rbe.fli.bund.de/About_Rabies/Epidemiology.aspxSource: http://www.rbe.fli.bund.de/About_Rabies/Epidemiology.aspx

Timeline

14 15 16 19 20 21 14 15 16 19 20 21

22 23 22 23

March, 2007 March, 2007

Taken to Olympic

Penninsula

Pup 1 begins to regurgitate

Bites vet & 2nd puppy

Pup 1 gnaws on kennel,

losing multiple deciduous

teeth

Flown to Juneau

Pup 1 adopted & certified for

interstate travel

2 pups and vet arrive in Seattle,

pass through US

Customs

Neuro Neuro signs signs

noticednoticed

Dies. Rabies test positive

Imported rabid puppy, 2007

• Second pup euthanized and tested

• 8 people received PEP• Customs protocols reviewed• Health certificate for interstate

travel should not have been given

Importation of rabid dogs/cats Importation of rabid dogs/cats to USto US

• 1986 – New York – Dog, 4 months old, West Africa (http://www.cdc.gov/mmwr/preview/mmwrhtml/00000874.htm)

• 1987 – New Hampshire – Dog, 5 months old, Mexico (http://www.cdc.gov/mmwr/preview/mmwrhtml/00001275.htm)

• 1987 – California – Cat, unknown age, Mexico (http://www.cdc.gov/mmwr/preview/mmwrhtml/00001275.htm)

• 1995 – California – Dog, 4 weeks old, Mexico• 2004 – California – Dog, 3 months old, Thailand• 2004 – Massachusetts – Dog, 3 months, Puerto Rico• 2007 – WA and Alaska –Dog, 3 months, India

ABC NEWS: Oct 24, 2007

300,000 Imported Puppies Prompt Rabies ConcernsCDC, After Declaring Canine Rabies Eradicated, Now Looks at New, Stricter Rules

By SUSAN DONALDSON JAMESOct. 24, 2007 Just last month the Centers for Disease Control and Prevention declared victory over canine rabies in the United States -- a fatal virus that kills 55,000 people a year globally. That declaration may have been premature.“

By Alan Gomez ,USA Today: Oct 21, 2007

When animal shelters started going overseas to fill their emptying kennels, some worried the imported strays would bring foreign diseases

and even rabies into the USA.

Dog imports raise fears of a resurgence of diseaseDog imports raise fears of a resurgence of disease

Imported Pets a Growing Business in U.S.

• The Border Puppy Task Force in California estimates that 10,000 puppies entered San Diego County from Mexico in just one year. These puppies are sold in shopping center parking lots, on the street, and in pet stores.

Dec. 17, 2007 The Associated Press

The Internet is full of sites that claim to be selling healthy local puppies, but actually deal in imports from Eastern Europe, Russia, Asia, and Central America. 

Rabies surveillance and Rabies surveillance and control in humanscontrol in humans

Many animal bites/exposures, little disease

• Species?• Bite? Non-bite?• Place of exposure

Foreign travel? Other US, local

• How was the animal acting?• Provoked/unprovoked?• Is animal available for

observation- (domestic animal)or testing (wild)?

Challenges: •Infinite variety of exposure scenarios; many gray areas that do not cleanly fit algorithms. •PEP: Expensive, limited availability• Requires PH and medical resources 24/7

Human Rabies

• Human rabies is rare and is reportable in all jursidictions

• Human rabies is preventable (est >30,000 PEP series annually in US)

• >70% cases in US associated with insectivorous bat rabies virus variants

• Challenge: reduce unnecessary PEP

Human Rabies Exposures

Often are preventable

Educate public not to handle bats or other wildlife and stray animals, vaccinate pets,

Pre-exposure prophylaxis veterinarians, wildlife biologists, rehabilitators, foreign travel…

Standard precautions HCW

Standardize criteria in mass exposure events

Mass exposure events

• 465 PEP: County fair- goat, NYS, 1996• 665 PEP: Pet shop kitten, NH 1994 • >100 PEP: Petsmart puppy, AZ 2002• >450 PEP: BC human case- health care workers, family• >120 PEP: Raw milk- dairy cows, OK 2005, MA 1996 and 1998• Tennessee Walking Horse competition, 2006, (only 24)• Rabid kitten softball tournament 2007 (37 PEP)• Toronto flea market puppy, 2007

Schools, day care, roadside zoo, campgrounds...

0

1

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7

8

9 Transplant

Raccoon

BatForeignDog

WA cases

BC cases

Human rabies death

US, Canada

Human Rabies Via Transplanted Organs/TissuesHuman Rabies Via Transplanted Organs/Tissues

20 yr M Donor

Lung

Liver

Kidney

Kidney

Arterial Graft

(died during surgery)

Dec 2004-2005: Germany, 26 yr F donor exposed to rabid dog in India. Transplant lung, kidneys, pancreas = 3 rabies deaths

May/June 2004,TX

Slide adapted from C. Rupprecht original

Human Rabiessurveillance and control challenges

Difficult to recognize clinically Surveillance for unexplained critical illness and

death- rapidly progressive encephalitis Often diagnosed post mortem, may be missed if

no autopsy on brain Often no clear history of animal bite (esp. bat) Variable incubation period No established treatment HCW may be exposed

Rabies PEP

Not reportable in all jurisdictions

In WA: approx 150/yr

In BC: 200/yr Under-

reported?

• Only 2 vaccine (and 2 RIg) products

• Vaccine recalls, shortages

• Unpredictable need (mass exposures)

• Workgroup to develop guidance for restricted use during shortages

The interface:The value of animal rabies

surveillance

• Animal rabies data is foundation for PEP recommendations in absence of animal available for testing/observation.

• Early detection of epizootics resulting from disease introduction, evolution/adaptation, natural cycles.

• Provides information to target and implement appropriate public health interventions.

Rabies Guidelines

ACIP Human Rabies Prevention, 1999 http://www.cdc.gov/MMWR/preview/mmwrhtml/00056176.htm

ACIP clear on raccoon, skunk, coyote, fox bites wild mammal bites referred for PEP? Is there adequate epi information?

Rabies Compendium 2008http://www.nasphv.org/Documents/RabiesCompendium.pdf

Rabies compendium clear on need for vaccination in pets Movement to reduce vaccines in pets- Is this a vulnerability?

RABIES: Ongoing challenges

• Threat of disease introduction: Global and national movement of pets and other

animals; feral, stray, wild animals, hunting stock, stow-away exotic animal trade pet shelters zoos research food animalsrecreational animals

RABIES: Ongoing challenges

• How do we maintain awareness (of bat and spillover rabies infections) among public, physicians and veterinarians? Vaccinate pets, teach children Level of suspicion in encephalitis

• How can we assure availability of biologicals for individual and potential mass exposures? Reduce unnecessary PEP

AcknowledgementsAcknowledgements

• Louisa Castrodale, Alaska DHSS• Reena Gulati, EIS- SPHKC• Rebecca Baer, WDOH• Emilio DeBess, OR DHS• Eleni Galanis, BCCDC • Public health rabies laboratories• CFIA, CDC