Epidemiology Epidemiology and Control of and Control of Zoonotic Zoonotic InfectionsInfections

Epidemiology Epidemiology and Control of and Control of Zoonotic Zoonotic InfectionsInfections

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1 – Zoonosis Intro & TSE

2 – Rabies

3 – Classic Zoonoses

4 – Bioterrorism

5 – Vector-borne Diseases

6 – Parasitic Zoonoses

7 – Emerging Zoonoses

8 – Foodborne Illnesses

Epidemiology and Control of Epidemiology and Control of Zoonotic InfectionsZoonotic Infections Epidemiology and Control of Epidemiology and Control of Zoonotic InfectionsZoonotic Infections

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Part I: Introduction to Zoonoses

Part II: Transmissible Spongiform Encephalopathies

Intro to ZoonosesIntro to Zoonoses• Definition

• Importance

• Etiologies

• Animal Examples

• Transmission Routes

• Life Cycles

ZoonosesZoonoses

From the Greek:

Zoon: Animal

Noson: Disease

Diseases and infections which are naturally transmitted between vertebrate animals and humans

- WHO 1959

ZoonosesZoonoses

• 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

ZoonosesZoonoses

• > 250 zoonotic diseases

• 60% of US Household have ≥1 pet

• Multiple pets in the home

• Human-animal bond

• Exotic species as pets

Zoonoses: Common DiseasesZoonoses: Common Diseases

Frequency – (CDC, 2003)

Salmonella 39,919

Lyme disease 18,991

West Nile (CNS) 2,862

Trichinosis 4

ZoonosesZoonoses

Spectrum of Disease Severity

Death = rabies

Severe illness = plague

Chronic illness = Q-fever

Mild illness = psittacosis

Zoonoses: ImportanceZoonoses: Importance• Economics

– Zoonotic disease are expensive• Rabies post-exposure prophylaxis

• GI illness due to Salmonella or Campylobacter – lost productivity, medical costs

– Import/Export• BSE – restriction on cattle

• Avian Influenza – restriction on chicken

• Travel/Globalization• Decreased transit time - SARS

• Remote area accessibility

Zoonoses: ImportanceZoonoses: Importance

• Surveillance– Animals are sentinels

• Prevention and Control– Animal = key component– Complications (e.g. Lyme disease)– Unknown reservoirs (e.g. Ebola)

Zoonoses: Etiologic Classification

Zoonoses: Etiologic Classification

• Viral

• Bacterial

• Parasitic

• Mycotic

Zoonoses: Viral ExamplesZoonoses: 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

Zoonoses: Bacterial ExamplesZoonoses: Bacterial Examples

Anthrax* Plague*

Brucellosis* Psittacosis*

Campylobacteriosis* Q fever*

Cat-scratch disease* Relapsing fevers

Leptospirosis* Salmonellosis*

Listeriosis* Tularemia*

Lyme disease* Yersiniosis* indicates covered in lectures

Zoonoses: Parasitic ExamplesZoonoses: Parasitic Examples

PROTOZOAL HELMINTHIC

Trypanosomiasis Baylisascariasis*

Babesiosis Cysticercosis

Cryptosporidiosis* Hydatidosis

Leishmaniasis Schistosome dermatitis

Giardiasis* Trichinosis*

Toxoplasmosis* Visceral larva migrans and toxocariasis*

* indicates covered in lectures

Zoonoses: Mycotic ExamplesZoonoses: Mycotic Examples

Aspergillosis

Blastomycosis

Cryptococcosis*

Dermatophytosis*

Histoplasmosis

Sporotrichosis

* indicates covered in lectures

Zoonoses: Animal SpeciesZoonoses: Animal Species

• Dogs & Cats– Rabies– Roundworm– Ringworm – Lyme Disease (dogs only)– Cat Scratch Disease (cats only)

• Food Animals– Salmonella– E.coli– Brucellosis

Zoonoses: Animal SpeciesZoonoses: Animal Species

• Birds: – Psittacosis– West Nile– Cryptococcus

• Reptiles, Fish, & Amphibians– Salmonella– Mycobacterium

• Wild Animals– Hantavirus– Plague– Tularemia

Routes of TransmissionRoutes of Transmission

• Direct– Droplet or Aerosol– Oral – Contact

• Indirect – Foodborne– Water-borne– Fomite– Vector-borne– Environmental

Zoonoses - Life CycleZoonoses - Life Cycle

ORTHOZOONOSES

– May be perpetuated in nature by a

single vertebrate species

– E.g. rabies, brucellosis, anthrax

Zoonosis: Rabies Life CycleZoonosis: Rabies Life CycleVirus inoculation (bite)

Salivary gland excretion

Zoonoses - Maintenance CycleZoonoses - Maintenance Cycle

CYCLOZOONOSES

– Requires more than one vertebrate species but no invertebrate host

– Most are cestodiases (tapeworm diseases)

• Taenia saginata and T. solium require man to be one of vertebrate hosts

• Others, such as hydatidosis, man is accidentally involved

Life Cycle:

                                                                                  

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Zoonoses - Life CycleZoonoses - 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

Zoonoses: MetazoonosesZoonoses: Metazoonoses• Invertebrate Host: Mosquitoes

• Vertebrate Host: Birds

• Incidental Hosts: – HUMANS, horses, amphibians, other mammals

Risk FactorsRisk 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

Risk FactorsRisk Factors

• Recreational Activities

– Camping & Lyme disease

• Farm Settings

– Sheep & Q-fever

– Cattle & Cryptosporidium

• Travel

– Maylasia & Nipha

– Australia & Hendra

Reportable Diseases of Animals

Reportable Diseases of Animals

• By veterinarian or other individual• Reported to CA Department of Health Services

– Plague – Rabies

• Reportable to the CA Department of Food and Agriculture – Anthrax– Brucellosis– Glanders– Listeriosis– Rabies in livestock– Venezuelan equine encephalomyelitis– West Nile– And more…