Epidemiology Epidemiology and Control and Control of Zoonotic of Zoonotic Infections Infections www.freelivedoctor.com
Epidemiology Epidemiology and Control of and Control of Zoonotic Zoonotic InfectionsInfections
Epidemiology Epidemiology and Control of and Control of Zoonotic Zoonotic InfectionsInfections
www.freelivedoctor.com
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…