cdc ppt for bsc nursing unit 1 11

CDC FOR BSC NURSING

BY GUGS A NEMERA

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Learning objective At the end of the session students will be able to:• clearly differentiate between CD and NCD• Define at least five terms those commonly used in CD

and relate it to practical situations • Discuss CD

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UNIT ONE INTRODUCTION

Disease can be communicable or non communicableCommunicable disease in turn classified into several divisions based on

causative organismsclinical presentation or system of body affected

This classification is valuable for Clinician MicrobiologistsEpidemiologists Parasitologsts .

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INTRODUCTION CONT’DCommunicable continues to remain a leading cause of morbidity, disability and mortality worldwide. It accounts for one tenth of deaths in rich countries and six out of ten deaths in poorer countries .for instance annually worldwide

2 m deaths occurs from diarrhea4 m die of LRTI700,000 die from measles 2 m die from TB90% from developing countries

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Definition of common terms (important terms)

Carrier- A person that carries a specific infectious

agent and can transmit to others but has no clinical

sign of infection.

Case - A person identified as having specific health

problem or disease of interest

Case definition- standard criteria for deciding whether

a person has particular disease or health problem.

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Chain of disease transmission: is a logical sequence of

factors or links of a chains that are essential for

development of the infectious agent and progression

of disease

Chemoprophylaxis- Administration of drug to prevent

the development or progression of an infection to

actual disease

Mass chemoprophylaxis

Selective chemoprophylaxis 6

Definition of common terms cont’d

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Chemotherapy: Use of chemicals to treat a clinically manifest disease

Assignment Write at least 250 chemotherapeutic agent those

commonly used in Ethiopia

S.No Drug Dose Route Frequency Duration Indication 1

2

250


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Communicable period: the time during which an

infectious agent may be transferred directly or

indirectly from infected person to susceptible host

Contact - A person or animal that has had an

opportunity to acquire the infection following

association with infected person, animal or

contaminated environment

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Control /Containment – Operation aimed at reducing the prevalence of the disease to a level where it is not a major public health important.

Disinfection: the killing of infectious agents outside the body by direct exposure to physical or chemical agents.

Sterilization – distraction of all forms of life by heat, irradiation, gas or chemical treatment.


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Contamination :The presence of an infectious agent on

the body surface or other inanimate articles or

substances

Note: contamination on body surface does not imply

carrier state

Drug resistance – The ability of infectious agent to

survive despite the administration of antimicrobial in a

dose equal to or higher than the usual recommended

dose10


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Disinfection- the killing of infectious agents outside the body

by direct exposure to physical or chemical agents.

Concurrent disinfection→ application of disinfective

measure as soon as possible of the discharge of infectious

material from the body of an infected person or after the

soiling of material with such infectious discharge.

Terminal disinfection → is the application of disinfective

measures after the pt. has been removed by death or to

hospital, isolation or other partice has been discontinued11


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Sterilization – distraction of all forms of life by heat,

irradiation, gas or chemical treatment.

Disinfestations – The procedure of destroying or

removing undesired small forms of animals particularly

arthropods, rodents, present up on the person,

clothing or in the environments of an individual or

domestic animal using chemicals or physical agents.

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Elimination – eradication of disease from large geographical region or political jurisdiction.

Endemic – Continuous presence (usual prevalence) of a disease or infectious agent with in a geographical area.

Epidemic or outbreak- occurrence of cases of an illness with the frequency that is clearly in excess of what is expected in a given region therefore demanding emergency control.


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Epidemic Thresh hold- The minimum number of

cases indicating the beginning of an out breaks.

Eradication-Termination of all transmission of

infection through surveillance and control.

Host- A person or other living animal that

accommodates infectious agent under normal

conditions.


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Immune individual – A person or animal that has

specific protective antibody and/or cellular immunity

as a result of pervious exposure /infection,

immunization.

Immunity – resistance usually associated with the

presence of antibodies

Immunogenicity: -The ability of an agent to produce

specific immunity.15


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Exposure – meeting with an infectious agent in the way

that may cause disease.

Illness: -Individual or subjective feeling of discomfort.

Disease: -A state of physiological and psychological

dysfunction.

Incubation period – The time interval from the time of

infection to the time of appearance of clinical

manifestation

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Infection – The entry and development of an infectious

agent in the body of humans or animals.

Nosocomial infection → An infection occurring in

patient in hospital and other health facility in whom the

infection was not present or incubating at time of

admission or residual of infection during previous

admission.

Community acquired infection – infection that occurs in

the community (general population.)


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Infectious agent – Bacteria, viruses, Fungi or parasites or

their products that can cause disease.

Infectious individual: A person or an animal from which the

infectious agent can be naturally acquired.

Infestation- The lodgement, development and reproduction

of arthropods on the surface of the body or in the clothing.

This also used for invasion of the gut by parasitic worms.

Inoculums size – The minimum size of infectious agent or its

products that can cause disease.

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Isolation – Keeping infected persons or animals in

separate place for as long as they can transmit

diseaseStrict isolation Contact isolationRespiratory isolation TB. Isolation. Enteric precaution Drainage /secretion precautions-

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Primary or index case- A person who acquires a disease

through exposure and brings it in to population

Notifiable disease – disease for which regular, frequent

and timely information on individual cases is considered

necessary for prevention and control of disease.

Notification – The processes by which cases or out

breaks one brought to the knowledge of the health

authorities.

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Quarantine- Restriction of the activity of well person or animal who have exposed to a case of communicable disease during its periods of communicability.


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Mode of Transmission- any mechanism by

which infectious agent spread from source or

reservoir to a person.

Pollution – The presence of offensive, but not

necessarily infectious matter in the

environment

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Reservoir- Any person, animal, arthropod, plant, soil

etc in which the infectious agent normally lives and

reproduce itself in such a manner that it can be

transmitted to a susceptible host.

Secondary case – A person infected by primary case.

Surveillance- Systematic collection, collation and

analysis of data, dissemination information for

action.

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Susceptible host- person or animal not possessing sufficient

resistance against particular infectious agent to prevent

contracting infectious disease when exposed to it.

Transmission: any mechanism by which infectious agent

spread from source or reservoir to a person.

Direct transmission – immediate transfer of infectious agent to a

suitable portal of entry (direct contact, projection)

Indirect transmission- transfer of infectious agent through

intermediate means (vehicle born, contaminated materials vector

born)

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Transmission cycle -is a cycle which describes

how an organism grows, multiplies and

spreads. In some cases man may be the only

host in which case the infection spreads

directly from man to man. E.g. measles. In

some cases like malaria the transmission cycle

involves man and mosquito

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Absolute or complete quarantine, the limitation of freedom of movement of those exposed to a communicable disease for a period of time not longer than the longest incubation period of that disease in such manner as to prevent effectual contact with those not so exposed.

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Modified quarantine: A selective partial

limitation of freedom of movement of

contacts commonly on the bases of known or

presumed differences in susceptibility and

related to the longer of disease transmission

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Universal precaution – Simple standard procedure to be used

during care of patients at times to minimize the risk of

transmission.

Virulence – The ability of infectious agent to invade and damage

the tissue of the host and cause death.

Zoonoses – An infectious disease that is transmissible under

normal condition from animal to human.

Zonosis – An infection or infectious disease that is transmissible

under normal condition from vertebrate to human.


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Sporadic - A disease that occur in a

population in occasional and irregular

intervals.

Pandemic – worldwide epidemic disease.

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COMMUNICABLE DISEASE/ (infectious disease)

Definitions

A disease due to specific agent or its toxic products

that a rises through transmission of that agent or its

products from infected person, animal or reservoir to

susceptible host either directly or indirectly through an

intermediate plant or animal host, vector or

intermediate environment

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Specific feature of communicable disease

A case may be risk factor

Each infectious disease has its own incubation period

People may be immune

An individual may be a source without being recognized as a

case.

There is some times a need for urgency

Preventive measures (usually) have a good scientific ground

Intervention in infectious disease can have several effects 31BY GN 2013

Classification of communicable disease

It may be classified in several ways i.e. byClinical manifestation Time course Taxonomy of infectious agent Mode of transmission

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Based on C/m or system involved

Diarrhoeal diseaseFebrile illnessRespiratory tract infection Central Nervous system infectionCardiovascular system infection UTICutaneous

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Based on time course

Acute Disease with short durationneeds urgent careRapidly progressive Abrupt on set.

Chronic Indicate duration usually

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Based on taxonomy of infectious agent

Metazoan ProtozoalBacterial Fungal Viral

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Based on mode of transmission ¨ Airborne diseases (respiratory tract as portal of entry and/or exit)

¨ Feco-oral transmitted diseases (GIT as entry and/or exit)

¨ Direct contact (Mucus membranes and/or skin as portal of entry /exit)¨ Direct inoculation¨ Vector bone disease ¨ Inoculation by bite of animal/ contacts with

animal products ( zoonosis ).

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Unit two:Chain of disease transmission (diseases

transmission dynamics)

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Learning objectiveAt the end of the session students will be able to:

1.Describe Chain of disease transmission2.List major effects of agent on the host

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Chain of disease transmission DefinitionsA logical order of events which must occur in

order for disease causing organisms to cause infection.

Series that is essential to the development of the infectious agents and propagation of disease.

There are six successive events implicated in the chain of disease transmission

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Chain of disease transmission cont’d

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1.Infectious Agent

• It can be an organism or its toxin• Infection agents’ needs

MultiplicationSurvival

ReservoirsPersistence Latency Vector Intermediate host

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Multiplication→ two methods – Asexual (almost exact replicas produced →any

natural selection occur on the batches than single individual.

– Sexual- scope of variety are there

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Survival Agent survive by finding suitable hosts Agent prolong the period of survival by different methods ReservoirsSuitable place to store infectious agent Reservoir can be humans, animals, vectors or inanimate

environment (soil, waters)Persistence –Development of special stages by agent to with stand

distraction in adverse environment. E.g. forming cyst (protozoa), eggs (nematodes) spore (bacteria)

•

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Latency –Developmental stage in the environment not

Infective to a new host. –Parasite time of suitable condition

Vector –Parasite use service of arthropods to transmit from

one host to other – It can be part of transmission process (Mosquito)

Intermediate host – some parasite needs intermediate host for

development before they invade the final host.E.g. Schistosoma uses a molluscan

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Effect of the agent on host

If enough agents survive to infect a new host, they will produce a reaction or illness.

The effect of host is determined by VirulenceToxicity Dose response

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2.Reservoir of infection

A living or non living in which an infectious agent normally lives, transforms and multiplies on which it primarily for survival and where it produce itself in such a way that it can be transmitted to new susceptible host.

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Types of reservoir A. Man as the only reservoir

MeaslesGonorrhoeaSyphilisSmall poxTyphoid Meningococcal meningitis

Transmission cycle man to man

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Types of reservoir cont’d

B. Animals as reservoir Infectious disease where animals are primary

reservoirs includes: Bovine Tuberculosis – Cow to man Brucellosis – Cows, pigs and goats to man Anthrax – Cattle, sheep, goats, horse to man Rabies - Dogs, foxes, wild animal to man

Man is not essential part (usual reservoir) of the life cycle

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Types of reservoir cont’d C .Non living thing

Some of the organisms are basically saprophytes i.e. living in soil adapted to live freely in nature and biologically equipped to withstand marked environmental changes. Some of the non living reservoirs are soil, water, food etc Examples Clostridium tetani of tetanus Salmonella typhi of Typhoid fever

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3.Portal of exit

¨ Site on reservoir through which an infectious agent escapes from the reservoir.

¨ Examples GIT – Typhoid fever, Ascariasis dysentery Skin and mucus membrane-syphilis RT – TBC

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4.Made of transmission

Mechanism by which an infectious agent transferred from reservoir or infected host to new host.

Two main type of mode transmission

1. Direct transmission2. Indirect transmission

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Direct transmission

Immediate transfer of infectious agent from infected host or reservoir to an appropriate portal of entry on the susceptible host. Some of the ways of direct transmission are Direct vertical – transpalcental syphilis, HIVDirect contact – contact of if IA with skin, mucosa,

ConjunctivaDirect touching, kissing, sexual intercourseDirect projection – droplets of saliva created by

expiratory activity52BY GN 2013

Indirect Transmission

Airborne transmission Vehicle Borne transmission Vector borne transmission

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5.Route of entry

Site on susceptible host through which an infectious agent get into it

The manner of entry is one of the factors which determine whether or not the infectious agent establishes the infection

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6.Susceptible host-

A person or animal lacking of sufficient resistance to particular pathogenic agent to prevent the disease if or when exposed. In order for transmission to be completed, the existence of susceptible host is necessary

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Level of susceptibility of depends on;

Nutritional status Stress Environment Pre-existing medical condition Immune status Age

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Unit three Determinants of disease and defence

mechanism of hosts

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Learning objective

• At the end of the session the learner will be able to:

1.Describe major determinants of health using epidemiological triad

2.Discuss the defense mechanism of the host

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4.1: determinants of diseaseThe determinants of disease presented by

simply by Epidemiologic triad of host, agent and environment

Host factors DemographicBiologicalsocioeconomic

Agent factors Biological agentsPhysical agentsChemical agents Nutrient agentsMechanical agentsSocial agents

Environment:Physical environmentBiological environmentSocial environment

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4.2 Defence mechanism of the host

1. Non specific resistance or innate or natural immunity.

2. Immune system defences

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Non specific resistance or innate or natural immunity. Are immunity used for either to prevent micro

organisms from entering the body or to eliminate them rapidly

It includesA. Physical barrierB. Chemical (secreted) barrierC. Inflammatory cells or action of white blood cellsD. Inflammatory response

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Physical barrier

External barrier (skin & epithelial tissue) Internal barrier (mm) Prevent the pathogen from entering to body. Filtering and clearing the pathogen – cilia &

sneeze reflex

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Chemical (secreted) barrier

acid in stomach, enzymes in the tear and saliva ,substances in sebaceous and sweat secretion act non specifically for bacteria, fungus

interferon for virus

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Inflammatory cells or action of white blood cells

Acting as phagocyte e.g. Monocyte and macrophages.

Inflammatory responseThe major function of natural immunity

elicited in response to tissue injury or invading organism

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Immune system defences

The body has three means of defending itself when the body invaded by agents. 1st line defence 2nd line of defence 3 rd. line of defence

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1st line defenceThe phagocytic immune response involves WBC

(granulocyte and macrophage) Move to the point of attack and engulf and destroy the

invading agent 2nd line of defence

The humeral response sometimes called antibody response

A class of protein which all anti body belong is called IGAntibodies are produced by a class of lymphocyte called

B.cells3 rd. line of defence (cellular immune response)/Cell mediated

immune response Deals primary with intera-cellular pathogens It also involves lymphocyte

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Unit four

Host parasite interactions (measuring of infectiousness)

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Learning objective

• After completion of this session students will be able to

1.List common measures of infectiousness of CD

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1 Infectivity Ability of the infectious agent to invade and

multiply/produce an infection) in exposed host It can be studied/measured using The speed with which an infectious agent spreads with in a

population of close contacts /secondary attack rate SAR = (# new cases in a group – initial cases) (# of susceptible persons in group – initial cases) Sero-surveys after epidemics to determine the proportion of

persons recently infected. Measuring the progression of an infectious agent from

exposure to infection (infection rate) Infection rate (IR) = total number of infected people x 100 Total no susceptible people Host and environmental factor as well as dose route of entry,

source of infection, strain of agent influence the infectivity of an agent.

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2.Pathogenicity Ability of an agent to produce clinically manifest disease in susceptible host. Measured by the proportion of infections that result in clinically apparent disease Laboratory methods also help full Pathogenicity = total number of clinical cases x 100

Total number of sub-clinical case

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Virulence Ability of an agent to produce severs disease. Measured by proportion of clinical cases

resulting in sever clinical manifestation including squealed

Measure of virulence for human Case fatality rate (CFR) Hospitalization rate Proportion of cases disabled or who have

developed Squeal Proportion of cases that require different kinds of

treatment

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Virulence cont’d Note High infectivity different from High Pathogenicity High Pathogenicity different from High virulence e.g. Rhinovirus infection: High Pathogenicity but low virulence

Measles infection :high Pathogenicity low virulence HIV: High Pathogenicity & high virulence

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Factor determine the degree of infectivity, Pathogenicity and virulence

Strain of the agent e.g. N- Meningitides Dose of the agent e.g. Cholera Route of infection Treatment especially on virulence Season Host factor Age Nutritional status Immune response

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4.AntigencityAbility of the infectious agent to induce immune response and thus an immune state in the host.

5. ToxignocityRefers the ability of agent to produce toxin or Poison

6. Resistance Ability of the agent to resist adverse environmental condition during transmission from one host to another

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7. Disease Prevalence RateNumber of current cases per population at risk

Old: Persistent active disease contracted previously New: Onset of active disease # of EXISTING cases of a specified disease

Point prevalence Prevalence at a specific point in time

Period prevalence Prevalence over a given time interval

Usage Measure amount of illness in the community Determine health care needs of the community

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8. Disease Incidence RateNumber of new disease cases per population at

risk ¨ High incidence implies high disease occurrence ¨ Low incidence implies low disease occurrence ¨ # Of NEW cases of a disease in a period of time¨ Population at risk of developing the disease during

the same period of timeMeasured over a given time interval Usage

Determine probability of developing a specific disease Used to detect etiologic factors

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9: Immunogenicity

Infection’s ability to produce specific immunity in the host e.g. measlesMeasured by serologic surveysDepends on:Amount of antigen formed in the hostSite of multiplicationAgent’s ability to induce lifelong immunity

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Diseases According to Host-related properties

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unit five

Source of infection Learning objectives 1.Explain the three main sources of infection

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Source of infection There are three main sources of infection 1.Humans 2.Environment (inanimate, including food &

water) 3.Other animals

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A) Humans People are colonized by a wide variety of microorganisms most of which can become pathogenic given the right conditions.

Normal body flora of the healthy individual vary from one

person to another depending on age, general health,

temperature and specific local condition such as acidity in

the stomach.If normal conditions are altered, then the normal flora may be destroyed and replaced by harmful organisms .Any individual can be a source of infection although it is traditional to call exogenous infection

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B) The inanimate environment Soil, food and water can harbor organisms which act as a source of injection under the right conditions.For example, soil can contain clostridium species and if a traumatic penetrating injury carries these organisms deep into tissue anaerobic conditions may permit the organism to multiply.

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C) Other animals A variety of diseases can be spread from

animal to man and these are called zoonosis Zoonosis is an infectious disease of animals

that may be transmitted to man.Example Brucellosis, Rabies, Toxoplasmosis

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Unit six Carriers and Infected individuals

Learning objective 1.Explain the four types of carries

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Carries A person or animal that does not have apparent clinical disease but is potential source of infection to other people

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Type of carriers and its role 1.Incubatory carrier or precocious carrier (but not all

disease) Transmitting disease during incubation period i.e. from the

time of 1st shading to manifestation. E.g. Mumps ,measles

2.Convalescent carrier Transmit infection during recovery i.e. from time of recovery

to when agent stops shadingE.g. Typhoid fever ,Diphtheria

3. Asymptomatic carrier (Healthy) Transmitting a disease without ever showing clinical

manifestation High carrier rate e.g. Polio, Ameobiasis, meningo coccus

4.Chronic carrier Transmitting disease for long period/ indefinite transmission E.g. Viral Hepatitis (B, c) , Typhoid fever

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Unit sevenCourse of an infectious disease over time

Learning objective1.Discuss courses of an infectious disease over

time

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Prepatent period ¨ The time interval between infection and the point at which

infection 1st detected(lab method).¨ Between biological onset and the time of first shading of the

agent¨ Measured by the 1st shading of infectious agent by host.

2.Incubation period Time interval between infection and the 1st appearance

of clinical manifestation of disease i.e. between biological and clinical on set.

Used in investigation of disease out break

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3.Communicable period The period during which an infected host can transmit the infection to other Measured by the length of time in which the agent shades by host.Degree of transmissibility does not remain constant throughout the period of communicability as the amount of the agent that shade by infected host is variable at different point in time.

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4 Generation time Onset of infection to maximal communicability

of the host (during or after incubation period) It applies to both apparent and unapparent

infection Focuses on transmission of infection as core

concept.

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5.Latent period The time interval between recovery and the reoccurrence (as a relapse)

6.Prodormal period From onset of symptom to appearance of characteristic manifestation

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Unit eight

Spectrum of infectious disease/ gradient of infection/ Learning objective 1.Mention the possible outcome of infectious

disease

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Spectrum of infectious disease/ gradient of infection/

Spectrum means range of possible option for somethingSpectrum of infection implies the range in the expression of disease be it in terms of the degree of severity or clinical manifestation.The Sequence of event takes place in the host depending on the variety of host response.The sequence of event may be

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Spectrum of infectious disease cont’d

Five type of reaction in spectrum of disease 1. No Reaction No infection 2. Sub clinical or unapparent infection 3. Atypical disease 4. Frank disease 5. Sever disease

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Unit nineNatural history of disease

Learning objective 1.Define natural history of diseases2.Explain the four stages of natural history of

diseases

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Natural history of disease

Definition • A course of disease over time in the absence

of any intervention or unaffected by treatment.

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Natural history cont’d Characteristics Each disease has its own natural history Intervention or treatment modifies the course of

disease through time Helps to understand the intervention measures that

could be under taken in order to prevent or control diseases.

Has four stages 1. Stage of susceptibility 2. Stage of pre-symptomatic disease 3. Clinical stage 4. Stage of disability

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Natural history cont’d

Stage of susceptibility Period of exposure Disease has not yet developed but there are factors that favour occurrence (risk factors)

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Stage of pre-symptomatic disease – sub clinical stagePeriod of latency Period biological onset Disease process has already began but no s/s are detectable Initiation of disease process can be evidenced by investigation methods (lab investigation)

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Natural history cont’d Clinical stage

Sufficient and organ change occur Sign and symptoms of disease appears Severity of a disease is variable depending on the interaction certain factor such as ¨ Nutritional status ¨ Immunity of individuals ¨ Virulence of the agent ¨ Presence or absence of medication ¨ Presence of underlying illness

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Stage of disability or death (outcome) ¨ Disease has occurred and left over damage to

the body ¨ residual long or short duration disability ¨ chronicity ¨ death ¨ Note – Recovery can take place at any stage

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Unit ten Epidemiology and general methods of

prevention and control of communicable diseases

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Introduction to epidemiology of communicable disease

Definition: Epidemiology is the study of the frequency,

distribution and determinants of diseases and other health related events in specified populations

the application of this study to the promotion of health and to the prevention and control of health problems (Last 1983).

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Components of the definition

Population The focus of epidemiology is mainly on the population rather than individuals.

FrequencyShows epidemiology to be mainly a quantitative science It is measured by morbidity rates which quantify the occurrence of illness Mortality rates which quantity the occurrence of death

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Health related conditions conditions with directly or indirectly affect or influence health

DistributionRefers to the geographical distribution of diseases, the distribution in time, or / and distribution by type of persons affected. The part of epidemiology concerned with the frequency and distribution of diseases by time, person and place is named descriptive epidemiology.It asks the questions: - How many? Where? When? What?

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Determinants Are factors which determine whether or not a person will get a disease, or in other words, the causative factors for diseaseThe part of epidemiology dealing with the causes and determinants of diseases is analytical epidemiology It asks the questions. How? Why?

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Importance of Studying Communicable Diseases Epidemiology

Offers insights in to why disease and injury afflict some people more than others why they occur more frequently in some locations and times than in others applied science with direct and practical applicationsFor most effective ways to prevent and treat health problems. Discovery of new infectionsThe possibility that some chronic diseases have an infective origin.

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General methods of prevention and

control of communicable diseases

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Disease prevention

Inhibiting the development of a disease before it occurs or if it occurs interrupting or slowing down the progression of diseases.

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Disease control

Involves all the measures designed to reduce or prevent the incidence, prevalence and consequence of a disease to a level where it cannot be a major public health problem.

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Levels of disease prevention

The different points in the progression of a disease at which one can intervene to prevent further out come.

There are three levels of prevention.¨ Primary ¨ Secondary¨ Tertiary

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Primary prevention Preventing health people before becoming sick by altering susceptibility or reducing exposure for susceptible individuals In order to carry out effective p prevention know first who is most “at risk” of getting disease. Purpose (Objective)Promotion of healthReducing incidence of disease Prevention of exposure Prevention of disease

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Health promotion

Consists of general non specific Interventions those enhance health. Aim at individual, communities, organizations and PoliciesPromotion measures include ¨ Improve socio economic status of the population¨ Good nutrition, clothing, shelters, rest¨ A void risk behaviour ¨ Broad area of health education

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Prevention of exposureAny intervention which prevents the coming

in contact between an infectious agent and a susceptible host.

This includes actions such asProvision of safe and adequate waterproper excreta disposalvector controlsafe environment at home, at school and at work

on the streets

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Prevention of diseaseDuring the latency period between exposure

and the biological onset of the disease. An example for this is immunization.

N.B. Immunization against an infectious

organism does not prevent it from invading the immunized host but prevents it from establishing an infection.

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Prevention of disease cont’d Breast feeding is an example of intervention that

acts at all three levels of primary Prevention.Health promotion: By providing optimal nutrition for a young child, either as the sole diet up to six months of age, or as a supplement in later age.Prevention of exposure: by reducing exposure of the child to contaminated water.Prevention of disease after exposure: by the provision of ant-infective factors, including antibodies, WBCs and others

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Primary prevention cont’d

Target- total population Specific protective measures

Immunization Environmental sanitation Prevention against accidents Prevention of occupational hazards

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Secondary prevention (2preventions)Prevention after biological onset but before permanent

damage occur Include early dictation and prompt treatment of disease in

such a way that it is possible to: ¨ Cure disease (curative medicine) ¨ Slow the progression¨ Prevent complication ¨ Limit disability¨ Reverse communicability¨ Reduce prevalence.

On community-Secondary prevention for the infected individual and p for potential contacts

Target population→ patients (clinical or sub clinical)

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Tertiary prevention

Takes place after permanent damage Important aspect of therapeutic and rehabilitation medicine Aim at treatment to prevent disability and death ¨ New training and especial education to help the

patient to return to some useful work & life in community.

Target- patient: E.g. Physiotherapy

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Principles of communicable disease control

Elimination of Reservoir Immunization Environmental control Vector control Surveillance

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Elimination of Reservoir

Man as reservoir Detection and adequate treatment Isolation Quarantine

Animal as reservoir ¨ Action will be determined by usefulness of the

animal

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Immunization or vaccinations

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Introductions The new born may carries antibodies transmitted

from its mother across the placenta and from early breast feeding which protecting at very vulnerable stage in life

The effect of this antibody wears off after six weeks to six month thereby the child makes their own from natural or artificial infections (immunizations)

Immunization cont’d: Definitions of important terms

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Vaccination: Administrations of any vaccine or toxoids

Immunization: The process of inducing immunity artificially

by administering antigenic substance There are two types of immunizations;

active immunization and passive immunization


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Active immunization: Involves the stimulation of immune system to produce antibodies and cellular immune responses that protect against infections. Example use of vaccine agents

Passive immunization: the process of producing temporary protection through administration of exogenously produced anti body such as Immunoglobulin. Example breast milk


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Toxoids: Modified bacterial toxin that has been made non toxic but retain the capacity to simulate antitoxins

Immunoglobulin: an antibody containing solutions made available for passive immunizations

Antitoxin: an antibody derived from the serum of animals from stimulations with specific antigens which used to provide passive immunity


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Vaccine: a suspension of attenuated life or killed micro-organisms or antigenic portions of these agents presented to potential hosts to induce immunity and prevent disease. Vaccine can be life attenuated, killed organisms and toxoids

Life attenuated; giving actual infection which is the best of all; examples measles, polio, BCG

Killed organisms: used when live attenuated strain is impossible to produce; it should be repeated. example pertussis

EPI target disease in Ethiopia

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Before 2007 øTuberculosis øTetanus øPertussis øDiphtheria øMeasles øPoliomyelitis

After 2007«Tuberculosis «Tetanus «Pertussis «Diphtheria «Measles «Poliomyelitis«Hepatitis B «Haemophilus influenzae B

« Pneumonia «Rota virus

Antigen for immunization

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1. BCG

2. Penta-valent (DPT plus HiB&Hb)

3. Polio

4. Measles

5. Tetanus toxoids( TT)

6. PCV

7. Rota virus

Epidemiological case definitions of vaccine preventable disease

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Measles: any child with fever, red eyes, and generalized rash within three or more days and history of cough, runny nose.Pertusis: any child with history persistent cough for two or more weeks, fits, and cough followed by vomiting Neonatal tetanus: Neonate with history of normal suck and cry in 1st two days of life and onset of illness between 3-28 days of age with inability to suck breast followed by stuffiness and/or convulsions more often deathPoliomyelitis: any child less than 15 years and who have AFP or any child who clinical suspect polio

EPI delivery strategy

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Static: immunization performed as a part of routine activities of the health institution Outreach: is an immunization approach in which the staff of the health unit goes out and administers vaccine for mother and children Mobile: a team of health unit staff go out of the health institutions and provide immunization as Mopping up or house to house mainly for single dose antigens campaign: like as national immunization days

Environmental control ¨ Personal and domestic hygiene¨ Proper preparation, handling ,cooking and

storage of food ¨ Use of safe water source ¨ Proper disposal of wastes and excreta

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Vector control

¨ Adulticids¨ Repellents or detergents¨ Personal protection ¨ Larvicide’s ¨ Biological control ¨ Environmental modification ¨ Insecticides

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AdulticidsKilling of adult mosquito can be done while:

¨ Flying – using knock down spray ¨ Resting- Residual insecticides

Repellents or detergentsApplied on the body in the form of lotion or

smocks Do not kill but deter from biting Made from phyethroids but other insecticide can

be added

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Personal protection Reduce the no of mosquito biteThey are cloths that cover the arms and legs Can be combined with repellents Mosquito nets Larvicide’s Act on mosquito larva by acting on

Breathing apparatus Not effective

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Biological control Use of natural methods to bring about reduction in vector

Environmental modification Making the environment no longer suitable for existence of the vector

E.g. draining of water

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Insecticides Poisons – Paris green Fumigants

Hydrogen cyanides, methyl bromide and ethylformate used on body or clothing to destroy infestation

Knock down – Pyrethrum Residual insecticide Organo chlorines

dichlorodiphenyltrichloroethane (DDT) Benzenehexahloride (RHC) - Dieldrin kill or reduce time of contact

Organophosphate e.g. Malathion inhibits cholinesterase at nerve junction and cause paralysis

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Unit eleven Surveillance and investigation and

management of outbreaks

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Surveillance Surveillance is a continuous collection, analysis, interpretation and dissemination of health information for the purpose of monitoring health events, and using the information for prevention and control of health problems.

Key qualities (elements) of surveillance Its continuous activity Its ability to detect changes in ecology or incidence of disease. The dissemination of pertinent information for action.Although surveillance is applicable to all types of diseases, primary attention should be directed towards disease amenable to effective control

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Methods of surveillance system 1.Active surveillance

2. Passive surveillance

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Active surveillance A collection of data usually on specific disease or health related events for relatively limited period of time by regular outreach on the part of health department personnel. A system in health staff make periodic field visits to health care facilities to identify new cases or death from disease (case finding) Involves Interviewing clinicians and pts Reviewing health records Surveying villages in under developed countries

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Characteristics of Active surveillance ¨ Identify Local outbreak¨ More expensive to maintain and establish as it

require good organization, funds and resources.

¨ More accurate and complete than passive

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Passive surveillance • Surveillance in which either available data on

reportable disease are used or reporting is mandated or requested with the responsibility often failing on health care provider or district health officer.

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Characteristics of Passive surveillance ¨ Problems with under reporting or lack of

completeness ¨ May dilute small out breaks in the total

regional pupation¨ In expensive and easily implemented ¨ Allow for international comparison ¨ Data is analyzed centrally ¨ Wide coverage requiring without specific

arrangement

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Types of passive surveillance Total passive carried out through predetermined reports submitted at regular intervals Simulated passive surveillance

¨ surveillance team request reports from third parties

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Step to be followed in surveillance 1. Collection of data

Name, age, sex address, occupation, vaccination, Treatment, place of infection, source of infection, exposed susceptible e

2. Compilation and analysis of dataanalysis can be made of cases by person, place and time.

3. Formulation of recommendation for action 4. dissemination and feed back

higher authorities Person and institution involved in notification &

control program To the community.

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Out break Occurrences of more cases of disease than expected in a given area among specific group of people over particular period of time.

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Outbreak is:A public, political and economic emergency An unusual event An event requiring rapid action A failure of surveillance An opportunity /for training, Research…)

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Reason to investigate out break Control /prevention Research opportunity TrainingPublic political and legal concern

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Steps in outbreak investigation 1.Preparation for field work A. Investigation

Have appropriate scientific knowledge, supplies and equipment to carry out investigation

Discuss with someone who is knowledgably about the disease.

Review applicable literature.

B. Administration C. Consultation

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2. Establish the existence of our break 3. Varity the diagnosis 4. Establish case definition

Include clinical criteria and restriction by time place and person.

must be applied to all without bias Type

Possible – Fewer of typical clinical features Probable – Typical clinical feature without lab

investigation. Confirmed

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5. Perform descriptive epidemiology. Time- when do they become ill? Place- where do they live Person- who are the cases

5Develop hypothesis source of the agent, made of transmission etc Who is becoming ill? What is a disease What is the source and the vehicle What is the mode of transmission

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6. Test hypothesis Compare with established facts When clinical, lab environmental and/or epidemiological data undoubtedly support hypothesis

8. Refine hypothesis and do additional studies

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9. Implement control measures Control source of pathogen Interrupt transmission (vector

contrle ,personal & environmental sanitation) Modify host response :

Vaccination Prophylaxis Treatment

10. Communicate the findings

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Learning objective1.List at least four diseases under national

regulation 2. list diseases under international regulation

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Unit twelve Notification and health regulation

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Introduction to Notification and health regulationInternational health regulations Require that certain disease are notified

Purpose To warn other countries and intended travellers to the country of health risk involved For assistance

Disease under international health regulation ¨ Plaque, cholera, yellow fever, Ebola

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Disease under surveillance by WHO Louse borne typhus fever RF Paralytic poliomyelitis Malaria Influenza AIDS Small poxDiphtheria, typhoid whooping cough

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National health regulation TBCLeprosy Sleeping sickness Vaccination required for international travel yellow fever

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Integrated disease surveillance and response Functional disease surveillance system is useful for priority setting, planning mobilization and allocation of resources, production and early detection of epidemics, monitoring and evaluation of intervention programs.

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Integrated disease surveillance and response (IDSR) priority disease

1.Epidemic prone Cholera Diarrhoea with b/d (shigella) Measles Meningitis Malariaplague Viral Hemorrhagic Fevers(Ebola) Typhoid fever RF Epidemic typhus

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2. Disease selected for case based surveillance Measles Poliomyelitis Dracunculiasis (Guinea worm)Neonatal tetanus

3 .Other diseases of public health importance Diarrhoea in <5 years of age Pneumonia AIDS Onchocerciasis STITB

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cdc ppt for bsc nursing unit 1 11

Health & Medicine