Epidemiology and Control of Zoonotic Infections

7/30/2019 Epidemiology and Control of Zoonotic Infections

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Epidemiologyand Control of

ZoonoticInfections

www.freelivedoctor.com


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1 Zoonosis Intro & TSE

2 Rabies3 Classic Zoonoses

4 Bioterrorism

5 Vector-borne Diseases

6 Parasitic Zoonoses

7 Emerging Zoonoses

8 Foodborne Illnesses


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Part I: Introduction to Zoonoses

Part II: Transmissible Spongiform

Encephalopathies


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Intro to Zoonoses

Definition

Importance

Etiologies

Animal Examples

Transmission Routes

Life Cycles


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Zoonoses

From the Greek:

Zoon: Animal

Noson: Disease

Diseases and infections which are

naturally transmitted betweenvertebrate animals and humans

- WHO 1959


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Zoonoses

Does NOT include

Fish and reptile toxins

Allergies to vertebrates

Diseases in which animal-derived food

serves as a vehicle (e.g. hepatitis A

contaminated deli meat) Experimentally transmitted diseases


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Zoonoses

> 250 zoonotic diseases

60% of US Household have 1 pet

Multiple pets in the home

Human-animal bond

Exotic species as pets


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Zoonoses: Common Diseases

Frequency (CDC, 2003)

Salmonella 39,919

Lyme disease 18,991

West Nile (CNS) 2,862Trichinosis 4


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Zoonoses

Spectrum of Disease Severity

Death = rabies

Severe illness = plague

Chronic illness = Q-fever

Mild illness = psittacosis


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Zoonoses: Importance

Economics Zoonotic disease are expensive

Rabies post-exposure prophylaxis

GI illness due to SalmonellaorCampylobacter

lost productivity, medical costs

Import/Export

BSE restriction on cattle

Avian Influenza restriction on chicken

Travel/Globalization

Decreased transit time - SARS

Remote area accessibility


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Zoonoses: Importance

Surveillance

Animals are sentinels

Prevention and Control

Animal = key component

Complications (e.g. Lyme disease)

Unknown reservoirs (e.g. Ebola)


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Zoonoses: Etiologic

Classification Viral

Bacterial

Parasitic

Mycotic


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Zoonoses: Viral Examples

Colorado tick fever Japanese encephalitis

Ebola Monkeypox*

Equine encephalitides(WEE, EEE, VEE)

Nipah*

Hantaviruses Rabies*

Hendra* Rift Valley fever

Herpesvirus B West Nile virus*

Influenza Yellow fever

* indicates covered in lectures


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Zoonoses: Bacterial Examples

Anthrax* Plague*

Brucellosis* Psittacosis*

Campylobacteriosis* Q fever*

Cat-scratch disease* Relapsing fevers

Leptospirosis* Salmonellosis*Listeriosis* Tularemia*

Lyme disease* Yersiniosis



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Zoonoses: Parasitic Examples

PROTOZOAL HELMINTHIC

Trypanosomiasis Baylisascariasis*

Babesiosis Cysticercosis

Cryptosporidiosis* Hydatidosis

Leishmaniasis Schistosome dermatitis

Giardiasis* Trichinosis*

Toxoplasmosis* Visceral larva migrans

and toxocariasis*



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Zoonoses: Mycotic Examples

Aspergillosis

Blastomycosis

Cryptococcosis*

Dermatophytosis*

HistoplasmosisSporotrichosis



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Zoonoses: Animal Species

Dogs & Cats

Rabies

Roundworm

Ringworm

Lyme Disease (dogs only)

Cat Scratch Disease (cats only)

Food Animals

Salmonella

E.coli

Brucellosis


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Zoonoses: Animal Species

Birds: Psittacosis

West Nile

Cryptococcus

Reptiles, Fish, &Amphibians Salmonella

Mycobacterium Wild Animals

Hantavirus

Plague

Tularemia


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Routes of Transmission

Direct

Droplet or Aerosol

Oral

Contact

Indirect

Foodborne

Water-borne Fomite

Vector-borne

Environmental


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Zoonoses - Life Cycle

ORTHOZOONOSES/DIRECT ZOONOSES

May be perpetuated in nature by a single

vertebrate species

E.g. rabies, brucellosis, anthrax


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Zoonosis: Rabies Life Cycle

Virusinoculation

(bite)

Salivary

gland

excretion


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Zoonoses - Maintenance Cycle

CYCLOZOONOSES

Requires more than one vertebrate

species but no invertebrate host

Most are cestodiases (tapeworm

diseases)

Taenia saginataand T. soliumrequire

man to be one of vertebrate hosts

Others, such as hydatidosis, man is

accidentally involved


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Life Cycle:

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Zoonoses - Life Cycle

METAZOONOSES

Require both vertebrates and

invertebrates to complete transmission

All arboviral infections

West Nile virus, Saint Louis encephalitis

Some bacterial diseases

Plague, many rickettsia Some parasitic diseases

Leishmaniasis, schistosomiasis


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Zoonoses: Metazoonoses

Invertebrate Host: Mosquitoes Vertebrate Host: Birds

Incidental Hosts:

HUMANS, horses, amphibians, other mammals


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Risk Factors

Companion Animal

Dogs & roundworm

Rats & Rat Bite Fever

Occupational

Animal control workers & rabies

Wildlife biologists & hantavirus

Foodborne

Raw meat & E.coli

Unpasteurized dairy & Listeria


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Risk Factors

Recreational Activities

Camping & Lyme disease

Farm Settings Sheep & Q-fever

Cattle & Cryptosporidium

Travel

Malaysia & Nipha

Australia & Hendra

Documents

Epidemiology and Control of Zoonotic Infections