Dr. V. I. BishorResearch Assistant

Research & Development WingInstitute of Animal Health & Veterinary Biologicals

Palode, Trivandrum

www.vbikerala.nic.in

ZOONOSES

History of Zoonoses• Zoonoses have affected human health throughout times• A possible epidemic of bubonic plague was described in the Old Testament, in the First Book

of Samuel. The so called Black Death emerged in the 14th century and caused vast lossesthroughout Asia, Africa, and Europe. The epidemic, which originated in the Far East, killedapproximately one third of Europe’s population

• Rabies was described in Mesopotamia, in hunting dogs, as early as 2,300 BC. Recognizabledescriptions of rabies can also be traced back to early Chinese, Egyptian, Greek, and Romanrecords

• Ancient accounts and modern hypotheses suggest that Alexander the Great, who died inBabylon in 323 BC, died of encephalitis caused by West Nile virus, a virus that has a wild birdreservoir.

WHO defines Zoonoses“Those diseases and infections which are naturally

transmitted between vertebrate animals and man” According to Taylor et al. who in 2001 cata-logued 1,415 known human pathogens, 62%were of zoonotic origin.most emerging infectious diseases in humansare zoonoses

Zoon: Animals , Noses : Diseases.

Rudolf Virchow was the first to usethe term in his Handbook ofCommunicable diseases.

In India 80 % of the population residing in approximately 575000 villages andthousands of small towns.Have close contact with domestic /wild animals population owing to theiroccupation. Stand at greater chance of acquiring zoonoses.

Zoonoses Vs Major Killer diseases

Disease Death in Millions

Pneumonia & RespiratoryInfectionsAIDSDiarrhoeal DiseasesTuberculosisMalariaMeasles

3.5

2.32.21.51.10.9

Disease Death

RabiesYellow feverJEEbolaMonkey Pox

40000300001000010001000

Classification of zoonosesDirect Zoonoses: Single vertebrate host: Rabies

Cyclozoonoses: More than one vertebrate host: Taeniasis, Hydatid disease

Metazoonoses: Requires both vertebrate and invertebrate host Eg. Arbovirus

Saprozoonoses: Inanimate reservoirs and vertebrate host. eg:Histolasmosis.

Anthrapozoonoses:: Animals to manZoo anthroponoses: Man to Man

Eg : Human TB, Amoebiasis

Amphizoonoses: Man AnimalsEg: Streptococcal infections

Animals

Factors affecting Disease emergence.

1. Introduction of a new host species in to an ecosystem.

2. Introduction of infected host in to new ecosystem.eg : Marburg Disease

3. Change in population dynamic

4. Ecological changes that bring two previously sepearted ecosystem into contact. Eg. Trypansomiasis.

5. Change in habits including the food habits.

6. Technical changes brought about by man . Eg : Anisakiasis.

7. Mutation /genetic recombination of infectious agents . Eg Influenza.

Role of wild animals and BirdsThe ecologic changes influencing the epidemiology of zoonoses with a wildlife reservoir can be of natural oranthropogenic origin.These include, but are not limited to,Human population expansion and encroachment, reforestation and other habitat changes, pollution, andclimatic changes.The movement of pathogens, vectors, and animal hosts: Such movement can, for example,occur through hu-man travel and trade, by natural movement of wild animals including migratory birds, and by anthropogenicmovement of animals.Movement of infected wild and domestic animals is an important factor in the appearance of rabies in newlocationsMicrobial changes or adaptation : These changes include mutations, such as genetic drift in viruses; activationand silencing of genes; genetic recombinations, such as genetic shift in viruses; and conjugation, transforma-tion, and transduction in bacteria. Natural selection and evolution also play a role.Severe acute respiratory syndrome (SARS) is a current example of likely microbial adaptation. This viral respi-ratory illness, caused by SARS-associated coronavirus, is believed to have emerged in Guangdong, China, inNovember 2002. SARS was first reported in Asia in February 2003, and over the next few months, the illnessspread to a global epidemic before it was contained. According to the World Health Organization, 8,098 cases,including 774 fatalities, have occurred. The virus has an unknown reservoir, but wildlife is a likely source ofinfection.Natural infection has been demonstrated in palm civet cats in markets and also in raccoon dogs, rats,and other animals indigenous to the area where SARS likely originated.the live market and Restaurants inchina sold small carnivors and several species of civet cat.Bush meat in Africa: a serious problem for the emergence of infection. (eg Ebola infection from Chimpanzee,Incidence of HIV 2 from sooty mangabeys)New Brucella spp. from marine mammals: The pathologic role of marine Brucella spp. in animals remains unclear, asdoes their zoonotic potential. In 2003, two human cases of community-acquired granulomatous central nervoussystem infections caused by marine Brucella spp. were reported

Important Zoonoses

Prevalent in most countries.In India annual loss of Rs 350 Milliondue to brucellosis.

ControlTest and slaughter policyImmunisation: S19 Vaccine, RB-51 ,45/20 vaccine, Rev 1,Treatment in man

Anthrax20000-100000 human cases per year in the world.90-99 % are cutanious anthrax.Potential Bioweapon( Pulmonary form of Anthrax).Common in southern part of India.

Control in animals.Immunisation

Proper carcuss disposalCare in handling livestock

Management

Control in ManImmunisation

Animal Industry hygiene and managementMedical care and management.

Suitable disinfectant3 % peracetic acid.

3-5 % formaldehyde.

Brucella abortus/suis: occupational diseaseBrucella melitensis: Foodborne.

Vaccination and brucellosis.S19 vaccine is infective. Avoid accidental inoculation.RB-51 lacks LPS; so undetectable by common labtests. This strain is Rifampicin resistant, which is thedrug of choice in humans. Infection followed by theaccidental inoculation of RB 51 have reported in US.

Brucellosis

TuberculosisMost common infectious cause of death in theworld.The disease kills 3 million people a year,with 7.3 million new cases annually.In india about 40 % of the population is infectedwith TB. 2 out of 5 TB cases are found in india.About 5 lakh people in india die every year of TB,more than 1000 every day- a patient per minute.

Leptospirosis

Plague

In india TB prevalent among cattle, Buffaloes andpigs. only 0.1 % of total cases are due to M. Bovis(USA). Data not avialble in India.

Organism isolated from almost allfree living species of animals.In india disease is wide spread inAndaman, AP, Karnataka, Kerala,Tamil Nadu, W. Bengal.In Kerala L. grippotyphosa appearedto be the common serotype.

Primarly a disease of animals.Man is the Dead-End host., also actas a reservoir.Rodents and mammals acts as natu-ral reservoir.They excreate leptospira for about 1year in rodents and weeks -monthsin other animals.

ControlRodents control

sanitationproper management of

AnimalsImmunisation

Personal hygiene andprotection

Health education

Reemerging in many part of India.Primarly a disease of Rodents.

Low temperature and High humidityfavour the pathogen.Dogs acts as sentinel animals.

TransmissionDomestic rodents-rat flea-man

Wild rodent-flea/direct contact -manWild rodent-flea-domestic rodent-flea-

manMan-human flea-man

Mycobacterium tubeculosis which is virulentfor humans but not for cattle.

M. bovis in infective to man.Infection of cattle by human strain is usuallyself limiting and no cow-to-cow or cow-to-mantrasmission.M. Bovis can infect other animals as well as man.Man may also act as a reservoir for bovine bacilli.and can transmit to cattle.

RabiesObstacles in Rabies control

1. Absence or insufficient enforcement of existinglegislation on animal rabies control( especiallyfor dog vaccination and control of dogmovementand population)2. Lack of affordable and high quality biologicalsfor both humans and animals.3. lack of cooperation between the variousnational sectors/agencies/disiplines concernedwith Rabies control and lack of involvement ofNGOs which could contribute to rabies control4. Lack of facilities and trained staff for the treat-ment of bitten and rabid patients.

Control of Animal Rabies

Control of Human Rabies1. Government should allocate sufficient funds to procurement of human rabies vaccine andimmunoglobulins to be given at no cost to indigent risk bite cases.2. Revised national guideline for pre and post exposure treatment based on WHO recom-mendation should be issued.3. Training for health personals for post exposure treatment and handling of rabid patientsshould be provided, including health education with emphasis on precautionary measures tobe taken to prevent potential transmission within family members when a rabid patient iscared for at home.4. Pre exposure treatment of Children which may easily come in contact with dogs and catsof unknown origin when the family can afford it , sholud be considered

1. Immunisation of dogs should reach atleast 80 %of thepopulation in higly endemic areas identified through agood surviellance system based on a network of diagnos-tic laboratories2. Responsible pet ownerships including dog registrationand dog population control such as sterilisation, use ofhormones, elimination of unwanted dogs .3. The status of certain Rabies -free areas should bemaintained through strict implementation of nationaland international regulations on animal movement.4. Community participation through the establishmentof community funds, mobilisation of communityvolunters during vaccination campaign should be pro-moted.

Japanese EncephalitisMost important cause of viral encephalitis ineastern and southern Asia.30000-50000 cases reported annually.Of these about 25-30 % are fatel and 50 % reuslts inpremanent neuropsychiatric sequelae.

The virus exists in a zoonotic transmission cyclebetween mosquitoes and pigs and /or water birds.Human get infection by the bite of mosquitoes andare dead-end host.

Major vector: Culex tritaeniorhynchus.

A disease of rural population. withculex Tri. breeding in rice paddies andpigs providing the main source of bloodmeal.

Control1. MOSQUITO CONTROL

2. AVOIDING HUMAN EXPOSURE3. IMMUNISATION

Inactivated mouse brain vaccine, in china a live attenuated vaccine SA 14-14-2 strain isavilable.

Parasitic ZoonosesToxoplasma gondii : Possibly the most wide spread & prevalent protozoan parasite on earth.In manycountries the seroprevalence for women of child bearing age ranges between 30 and 45%. Seroprevalence isreported from almost all animals. Beef is not a major source of infection to humans. In US studies shows that25% of the house cats were seropositive for toxoplasms.Sarcocystiosis: Herbivors are the intermediate host and carnivors and humans are the definitive host. Hu-man get infection by the consumption of uncooked beef or pork.Giardiosis: infect 2-5 % of the people. companion animals may be a good sourse of infection.Cryptosporidiosis: only C. parvum is zoonotic. An emerging problem in HIV patient . Sourse of infectionmay be calves, sheep, goat, deer, horses, dogs, cats and turkeys.1n 1993 a severe outbreak in USA : more than403000 cases were reported. 12-27 % prevalence in HIV patients worldwide.

Trematodes:F. hepatica, liver fluke of cattle affects about 2.4 million people worldwide.Clonorchis human liver flukes, a parasite of fish affects about 20 million people world wide , mainly infar east Asia.

Cestodes:Taeniosis is a common problem in Asia and Africa. Neurocysticercosis alone causes more than 50000 deathsannually.Echinococcosis, where the humans are the intermediate host

NematodesTrichinella: a cosmopoliten helminth zoonosis. infection from meat of infected pigs, wild boars, horses, dog.Anisakiasis: larvae of Psedoterranova decipiens, a nematode parasite of marine manmmal.also with larvae of Anisakis. which infect sea fish. Tingling sore throat syndrome and ulceration of gut.

Food-borne zoonosesMajor cause of human intestinal diseases.Can be Infection/IntoxicationInfections: Salmonellosiss, Brucellosis,Camphylobacter , Listeriosis,E. coliIntoxication: Bacillus cereus, Botulism,

The inability of the non-industrialisedcountries to keep pace with the populationgrowth, migration to rural to urban areasand the demand for clean safe drinkingwater and proper sanitation are the rea-sons for food borne infections

Consumption of raw or undercookedmeat, crustaceans and fresh waterfish and veghetables facilitatetransmission of food borneinfections.

1. Through heating and rapid cooling of food2.Avoid raw or undercooked foods3.Pasteurise milk and avoid post

pasteurisation contamination4.Proper sanitation at the farm and also in

the processing plant5.Water sanitation6.Sanitary disposal of faeces7.Avoid toxin containing fishes like puffer

fish8.Refrigerate fish immediately after catch9.Proper surveillance of food poisoning10. Public education

Control of food borneinfections

Emerging Zoonoses• Influenza: Mainly by Influenza A virus causes pandemic in humans. Usually the transmis-

sion of avian or Animal influenza to man require a reassortment between human and avian influ-enza viruses.Such events occured in 57 and 68. in 1997, Hong Kong, new sub type H5 noticed inwhich all the genes of the virsus were derived from chicken influenza virus that was apparantlycirculating among the chicken market of Hong Kong. Again in 1999 another outbrake withanother type of Chicken influenza virus in man occured.The virus is of great concern in view of the potential for reassortment with a human influenzavirus which will produce a virus with high human transmissibility which is compleate novel to

the world. The recent (2004) infections are caused by H5N1 avian virus.

• Filovirus: Ebola and Marburg, human infections from monkeys.

• Hendra : First reported in Horses in 1994 in Australia. Bats may act as

reservoir.

• Nipha (Barking Pig Syndrome): ( Named after village Sungai nipha inMalaysia) reported in pigs from Malaysia during 1998 causing viral encephalitis inhumans ( 265 cases and 105 death.).Pigs, dogs and humans were infected.

• Hantavirus: HFRS, HPS. Rodent reservoir, aerosol transmission, reported from Asia and

Americas

BSE-nvCJD CrisisBovine spongiform encephalopathy (BSE) in the United Kingdom may provide

more lessons than any other recent emergent zoonotic disease episode.The disease was first diagnosed in the United Kingdom in 1986; as of 1997, more

than 170,000 cattle had been reported as infected, but modern statistical meth-ods have indicated that about one million cattle had been infected, roughly halfof which entered the human food chain in the United Kingdom

In 1995, the BSE agent was reported to be the cause of a new human zoonotic dis-ease, new-variant Creutzfeldt-Jakob disease. By 1997, 26 cases had been re-ported in the United Kingdom and one in France.

A recent report from The Royal Society states that there is now a compelling caseregarding new-variant Creutzfeldt-Jakob disease as the human manifestation ofBSE. With such a small number of cases, it is impossible to predict future num-bers of cases of the human disease,

BSE may be instructive in other ways, especially in its extension into the worlds ofmacroeconomics, international trade, political science, and even global gover-nance

Zoonoses and Immune status

Xenotransplantations and ZoonosesXenotransplantations is the use of animalorgans, tissues or cells for transplantation intohumans to treat a variety of medical conditions.Domestic pigs are considered the most likelysources for transplantable organs, tissues andcells.The risk factors1. The systemic presence of agents.2. The latent sequestration of agents in axenotransplanted organ( Salmonella ,Mycobacterium)3. Agents contamination of a xenotransplantduring harvesting procedure.Eg: Toxoplasma, Trichinella, Cryptiosporidium,Viruses like Influenza .

Management

1. Development of Xenotransplant-gradeanimals which meet the exacting microbialagent status.2. The implementation of a comprehensivehealth surveillance and clinical investigationprogramme for timely detection and responseto infectious diseses occuring in xenotransplantsource of animals and colonies.3. Strict application and monitoring ofhusbandry and biosecurity practices.4. Support the development and refinement ofdiagnostic procedures.

Immunocompromised persons , Elderly people, HIV patients, Patients under cancer treatment aremore suceptible to zoonotic infection.

Enteric infections by Salmonella, Camphylobactor and Cryptosporidia may result in lifethreatning Diarrhoea in these group.

Systemic infections like Toxoplasmosis, Tuberculosis, Cryptococcosis, Q fever and Cat ScratchFever may lead to fatel encephalitis and /or Pneumonia.

Always seek the advice of a Veterinarian while selecting a pet

Zoonosis -An International problem

Most tremendous impact on evolution of man especially on societies/culture thatdomesticated and bred animals for food and clothing.

Most frequent and dreaded risk to mankind.

Transcend natural boundries, occur world wide

Impact on global economy and Health

Global surveillance in necessary

Inter relationship among countries has led to the internationalisation of control effort totechnical, Economical and Social fields.

International movementImportation of diseaseBan on animals and Animal products

Zoonoses Control: General StrategiesProcure personels

Procure facilities

Procure equipment, material

Establish/modify regulations

Ensure awareness of high risk people

Alter agricultural practices

Improve inspections

Epidemiological conditions

Human factors

Intesectoral

International/regional

Public

Training, allocation

LawOrdinences

Hygiene in animal productionDisposal/recycling animal wastesWater supply/irrigationType of Husbandry

Helath certificationMovement/shipment conditionsMarketsExport/importSeverity of unrecognised, untreated diseases

Prevalence/incidence of diseasesImportance of carriers, subclinical infections

Routs of Transmission

Density, composition, activityLand use

Literacy rateSocial norm

Economic values of AnimalsSocial value of Animal

Medial/public healthVeterinary/agricultural/wild life

Information ExchangeAgrement/codes/Technical cooperation

Educationmotivation

Control of Zoonoses: strategies and tactices for control in Animals

Control of animalpopulations.

Reduction ofsuceptibles.

Maintain Disease freestatus

Infected/contact animals

Uncontrolled , owned suceptibleanimals

Stray suceptible animals

Wild vertebrate reservoir

Vectors

prophylactic treatment

change conditions, populationrequirement

quarantine of animals/products/feeds

protect animals at risk

quarantinetreatdestroy

identificationcontrol

capture / euthanize

consider if pests or commensalHunt, trap, poison,antifertilityagents, predation

Treat animalsControl animal movementControl factors of environment

Entry to disease free area.

environmental/ecological control

chemical/biological agents/fertilty control

ImmunisationChemotherapy

Alter environmentChange Husbandry

Control of Zoonoses: strategies and tactices to Control vehicles of Transmission.

Establish foodhygiene.

Ensure safety of otheranimal products(wool,hide, horn, bones, fat)

Safe disposal or use ofanimal carcusses andwastes.

Hygiene in animalproduction

Decontaminate/disinfect:sites/vehicles/persons

Hygiene at slaughter

Hygiene in handling andprocessing foodstuffs

Hygiene during collection, storage,processing, transport

Animal Carcuss disposal

Excreta/garbage disposal

control risk factors associatedwith water, feeds, land, presonal.

proper use of drugs,biologicals, pesticides

Develop and follow proper meatinspection, judgement, and Hy-giene

safe collection of milk, eggs,, seafood

safe handling, processingstorage, marketing of foods.

Safe collection systems,rendering plant operations,product safety

Ensure safe disposal by burningor burial

Control hazards to water supplies.

Recycle safely as fertilizer, fuel,feed

Control of Zoonoses: strategies and tactices applicable to man

PreventandTreatMan

Prevent infection

Diagnoseinfection

Treat disease

Protect high riskgroups

Prevent spread by man

Educate medical/Veterinarypersonnel

Improve diagnosticservices

Establish facilities andtherapeutic regimens

1.Health education2. Immunisation, chemoprophylaxis.3. Monitoring health status, includingoccupational health program

1. Medical intervention, isolation2. Prevent environmental contamination3. Prevent food contamination4. Prevent animal contact

1. Imrove diagnosis2. Laboratory diagnosis3. Feedback to epidemiological andcontrol services4. Referral capability

1. Referral capability2. Monitor treatment outcome3. Feedback to epidemiological services.

Role of Public helath Veterinarians.

1. Diagnosis, treatment, control and erradication of zoonotic diseases of major human health importance.2. Use of biologicals(vaccines/sera) for prevention /control of zoonotic diseases.3. Development and testing of newer drugs for important zoonotic diseases’ treatment.4. Preparation of strategies and methods for the surveillance and control of important zoonotic diseases.5. Development of suitable animal models for important zoonotic diseases.6. Supervision of food hygienic practices in slaughterhouses, dairy frams and other food processing establishment.7. Production of wholesome and safe foods of animal and non-animal origin.8. Investigation of food borne and other zoonotic disease.9. Statistical reporting of morbidity and mortality of food borne and other zoonotic diseases.10. Epidemiological studies on zoonotic and food borne diseases.11. Participation in environmental health programs.12. Notification to higher authorities about a notifiable disease/exotic disease.13. Health education to public about the source of infection, mode of transmission, personal hygiene, environmental hygiene and control measure against commonly occuring zoonoses.14. Collaboration in medical relief during calamities and diseses.15. Maintain close coordination with medical and public health department.16. Conduct periodic meeting to review situation on the prevalence of zoonotic diseases in an area.

Public Health Implications of emerging Zoonoses.

Large out break : Tip of the iceberg : gross under reporting of infections through out the world.for eg only 10-30 % of the salmonella infections are reported even in developed countries.Invisible Diseases: Some disease may not be recognised as Zoonotic at the outset. these diseasecan spread undetected from many years particularly if the incubation period is too long or thenumber of cases in human or animals is too small, as happend in case of BSE/CJD and Nipha Virus.

Influences on public health practices and structure.The threat of communicable Disease: Threat of spreading infection like Ebola from rural areas tolarger cities. Risk of introduction of infections in other continents- a threat whole world. The Ebola virusattack contributed greatly to promoting the concept of emerging communicable disease among publichealth officials, stressing the renewed importance of microbes and the need of surveillance.A strong support to the opinion that the emergence of a killer disease in avery remote area of the world representas threat for all humans, therby reinforcing the sense of belonging to the same world.Pandemic planning: Sharing and cross over of animal pathogens can cause a pandemic as we learnedfrom the Influenza outbreak in Hong Kong.Global Alert and Response: Regarding the new infections and reservoirs. WHO/FAO/OIE/PAHO/

Uncertain Risks and precautionary Principle: for eg BSE Crisis changed the feeding method ofAnimals, introduced major rearrangement in the food safety issues, questioned the safety of using animaltissues for the production of human biologicals and medical devices( remember our sheep brain vaccine),This particular disease has led to the renewal of an old concept” The precautionary principle”Intersectoral collaboration for the control of zoonoses.: Need of high leval of Governmentalcommitment for the containment of infections and Co-ordination between Medical and Veterinary healthservices .

Morbidity and Mortality of new, emerging zoonoses

Finally..............................

Who will be the world’s expert on Zoonotic diseases?

THANK YOU

16/06/2005

bishorvi@yahoo.co.in | ww.vbikerala.nic.in