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Zoonoses are disease and infections of animals Causative agents are transmitted between animals and humans Origin – Not exactly …! Who knows..! Zoonotic diseases have been known since antiquity Bubonic plague and rabies were known since biblical times More than 150 zoonoses have been recognized In recent years several new zoonotic diseases have emerged E.g. KFD, Monkey Pox etc., Apart from morbidity and mortality they cause great economic losses Particularly in animals, meat, milk and other foods and products of animal origin As usual…! Developing countries suffer much severe losses than developed countries Less well developed public health and veterinary services and partly because of their unfavourable climatic and environmental conditions Zoonoses and human health are matters of particular concern in India Because nearly 80% of India’s population is rural and live in close contact with domestic animals and often not far from wild ones Definition Zoonoses have been defined “Those disease and infections (the agents of) which are naturally transmitted between (other) verterbrate animals and man” Zoonoses have been classified in terms of their reservoir hosts, whether these are men or lower vertebrate animals… Classified in terms of their reservoir host... Anthropo-zoonoses: Infections transmitted to man from lower vertebrate animal, eg. Rabies Zooanthroponoses: Infections transmitted from man to lower vertebrate animals However these terms have also been used interchangeably for all diseases found in both animals and man, eg. TB Amphixeonoses: Has been used for infections maintained in both man and lower vertebrate animals that may be transmitted in either direction, eg. Staphylococcal infections Euzoonoses Diseases in which humans are an obligatory host of the agent, eg. Taenia solium and Taenia saginata Classification based upon the type of life cycle of the infecting organism Four categories: 1.Direct Zoonoses: Transmitted from an infected vertebrate host to a susceptible vertebrate host By direct contact, by fomite or by mechanical vector Agent itself undergoes little (or) no propagative changes and no essential developmental change during transmission Examples: Rabies, Trichinosis and Brucellosis 2. Cyclo – zoonoses: Require more than one vertebrate host species No invertebrate host, in order to complete the developmental cycle of the agent Ex: Human taeniases, echinococcosis and pentastomid infections 3.Meta – Zoonoses Transmitted biologically by invertebrate vectors Invertebrate- agent multiplies (or) develops or both and there is always an extrinsic incubation (prepatent) period before transmission to another vertebrate host is possible Ex: Arbovirus, Plague, Schistosomiasis 4.Sapro-zoonoses: Have both vertebrate host and a non-animal developmental site or reservoir Organic matter (including food), soil and plants are considered to be non-animal Ex: Various forms of larva migrants and some of the mycoses Common Zoonotic Diseases Bacteria Anthrax Plague Brucellosis Rickettsia Scrub typhus Murine typhus Tick typhus Leptospiros Q fever is Salmonellos is Virus Parasite Fungus Rabies Taeniasis Yellow fever Japanese encephaliti s KFD Echinococco sis Zoonotic Leishmaniasi dermatophyt s es Toxoplasmos is Chikungun ya Collection of specimens: Specimen are collected according to the site of lesion Laboratory diagnosis tests for bacterial, rickettsial, parasitic and fungal zoonosis Laboratory diagnosis: Lab diagnosis is important for the diagnosis of zoonoses In humans and animals this is based on Isolation Serology Autopsy BACTERIAL Zoonotic Diseases Bacteria Sample Cutaneous anthrax Fluid from eschar Microscopy Gram positive bacilli Pulomonary Sputum anthrax stool Acute brucellosis (Undulent fever) Blood NA –Medusa head BAP-String of pearls McFadyean’s reaction Intestinal anthrax Culture Gram negative coccobacilli Gelatin stabInverted fir tree Casteneda method Serology Others Ascoli’s Lysis by thermoprecipi gammaphage tin ELISA Direct fluorescence antibody test Std agglutination test ELISA, CFT SKIN test BACTERIAL Zoonotic Diseases Bacteria Bubonic plague Sample Microscopy Culture Fluid from Gram NA, BAP buboes negative sputum bacilli, bipolar staining Pneumonic Blood Safety pin Chee broth plague appearance (Stalactitie growth) Salmonellosis Stool Gram MacConkey Food negative agar, wilson bacilli and blair medium Serology Others Passive PCR hemagglutination Widal test BACTERIAL Zoonotic Diseases Bacteria Sample Microscopy Culture Leptospirosis Blood Urine Dark ground microscope, spirochete Tuberculosis Sputum (M.bovis) Acid fast bacilli Karthof’s medium Stuart’s medium Fletcher’s medium L J medium Serology Microscopic agglutination test Others Laboratory procedures for Viral Zoonoses: Disease Sample Microscopy Culture Rabies Antemortem – corneal impression smear, Skin biopsy: Saliva Postmartembrain Blood ImmunoTissue fluorescence culture (WI 38, BHK 21) Negri bodies Yellow fever Japanese Encephalitis KFD CSF Yolk sac of chick embryo Intracerebral inoculation Serology Hemagglutinati on inhibition CFT Immuno- Laboratory procedures for Parasitic Zoonoses: Disease Sampl Microscopy e Taenia Stool Egg Echinococcu Stool s Leishmania Blood Peripheral blood, Amastigote Serology ELISA ELISA Hemagglutination Indirect fluorescent antibody Aldehyde test Antimony test CFT Laboratory procedures for Fungal Zoonoses: Disease Sample Microscopy Culture Zoophilic dermatophytes Microsporumca nis Skin scraping Trichophyton verrucosum Hair clipping T.equinum Nail clipping KOH preparation SDA RICKETTSIAL ZOONOSES Rickettsial diseases 1. Typhus group Agent a. Epidemic typhus R. prowazekii b. Murine typhus R. typhi c. Scrub typhus R. tsutsugamushi 2. Spotted fever group a. Indian tick typhus R. conorii b. Rocky mountain R. rickettsii spotted fever c. Rickettsial pox R. akari 3. Others a. Q fever C. burnetii b. Trench fever Rochalimaea quirttana Vectors Louse Flea mite* reservoirs Humans Rodents Rodents Tick* Tick* Rodents, dogs Rodents, dogs Mite* Mice Nil Louse Cattle, sheep, goats Humans Laboratory procedures for Rickettsial zoonoses: Disease Scrub typhus Sample Blood Culture Serology Yolk sac of Weil-Felix chick embryo test Murine typhus Blood Yolk sac of Weil-Felix chick embryo test Indian Tick Blood typhus Yolk sac of CFT chick embryo
