Zoonotic Diseases Training Package Zoonotic diseases Session Title 03/08/2010 Bangkok Zoonotic diseases: Session # LEARNING OBJECTIVES At the end of this module the participant should be able to: • Define terms (zoonosis, emerging disease….) • Classify zoonoses based on host, pathogen, transmission • Understand the importance of zoonoses to One Health • Discuss emerging and re-emerging zoonoses • Understand reasons for disease emergence and re- emergence • Describe selected zoonoses important in their region • Understand the principles of zoonosis prevention and control Slide 02 ZOONOTIC DISEASE RESOURCES This presentation gives an overview of the importance of zoonotic diseases to human and animal health, their ecology and epidemiology, and measures used for their prevention and control. Examples used can be varied by trainers according to the relevance of zoonoses in their regions Further information on zoonotic diseases, e.g. statistical data, can be found in the following websites: http://www.oie.int http://www.who.int http://www.fao.org http://www.cdc.gov 3insert your company logo Zoonotic diseases: Session # DEFINITION Zoonoses are infections which are naturally transmitted between vertebrate animals and people Derived from the Greek ZOON (animals) and NOSES (diseases) People, animals, birds, arthropods and the inanimate environment are all involved in cycles of zoonotic infection Slide 04 Zoonotic diseases: Session # ZOONOSES DEFINITIONS Anthropozoonoses: Zoonoses where the main reservoir of infection is non-human vertebrate animals Most zoonoses are of this type e.g. bovine tuberculosis, rabies, leptospirosis Zooanthroponoses: Diseases that mainly affect people, which may be transmitted to animals, which then act as temporary reservoirs of infection Examples are Mycobacterium tuberculosis in dogs, infectious hepatitis in apes, H1N1 pandemic influenza in pigs Slide 15 Zoonotic diseases: Session # ZOONOSES DEFINITIONS Vector: an organism, often an invertebrate arthropod, that transmits a pathogen from reservoir to host, e.g. mosquito and JEV Reservoir: a long-term host of a pathogen, e.g. mouse and hantavirus (in this instance the host can also be the vector as the virus is transmitted via mouse excreta) Fomite: an inanimate object that can transmit an infectious agent, e.g. medical equipment and Ebola virus Slide 05 Zoonotic diseases: Session # Agent Environment Host Zoonotic diseases are multifactorial and their occurrence is affected by interactions between the host, the agent and the environment Slide 14 Zoonotic diseases: Session # ZOONOSES Approximately 1500 infectious diseases are recognized in humans Of these 60% are due to zoonoses however 75% of recently emerging infectious diseases (EID) have been caused by zoonotic pathogens Slide 05 Zoonotic diseases: Session # EMERGING DISEASES WHO/FAO/OIE definition “An emerging zoonosis is a zoonosis that is newly recognised or newly evolved, or that has occurred previously but shows an increase in incidence or expansion in geographical, host or vector range” Slide 06 Zoonotic diseases: Session # THEREFORE EMERGING INFECTIOUS DISEASES CAN BE… A known agent appearing in a new geographic area A known agent or its close relative occurring in a hitherto unsusceptible species A previously unknown agent detected for the first time Wild animal reservoirs represent a more frequent source of ‘new’ agents Slide 07 Zoonotic diseases: Session # REASONS FOR DISEASE EMERGENCE 1. Factors explaining emergence are complex, e.g. genetic drift and shift (influenza) and modification of the immunological status of populations (change in susceptibility of populations; vaccination) 2. Social and ecological conditions influencing population growth and movement, food habits and the environment may be more important 3. Influence of changing environment on reservoirs, vectors and victim species 4. Population expansion and urbanisation Slide 08 Zoonotic diseases: Session # REASONS FOR ZOONOSIS EMERGENCE 5. Increasing contact between human populations, wild and domestic animals expose people to zoonotic agents by direct or indirect contact 6. Growing population of drug and alcohol impaired and immuno-suppressed people worldwide are at higher risk of zoonoses 7. Many of the common, life threatening infections associated with HIV are zoonoses Slide 09 Zoonotic diseases: Session # RECENT EMERGING ZOONOSES Some diseases associated with changing farming practices, trade and consumer habits (Salmonella Enteritidis, E. coli O:157) Live animal trade introduced screwworm to Libya, Ebola-like virus in monkeys in quarantine in the USA and monkeypox to the USA Epidemics of BSE due to many factors including use of ruminant protein as feed Adaptation of avian influenza strain H5N1 to people is a current cause of concern Slide 17 Zoonotic diseases: Session # VULNERABLE AREAS AND PEOPLE Poverty affected communities People with low population immunity (HIV, age) Areas of altered climate and increased vector range Areas of political unrest and population migration Natural disaster affected areas Areas of deforestation and altered biodiversity People affected by global trade and travel Slide 10 IMPACT OF ZOONOTIC DISEASES • Human health (death and disability) • Animal health (death and disability) • Economic losses due to livestock culling, deaths and decreased production • Cost of control programs • Trade implications • Indirect effects on people due to psychological trauma (loss of pets, culling, loss of valuable animals) and impact on cultural traditions, etc. 15insert your company logo Zoonotic diseases: Session # CLASSIFICATION OF ZOONOSES Type of infectious agent (bacteria, fungus, virus, parasite) Mode of transmission Type of reservoir host Slide 11 Zoonotic diseases: Session # MODE OF TRANSMISSION Transmission of infections may be direct, indirect via arthropod vectors, or from environmental foci Direct zoonosis Cyclozoonosis Metazoonosis Saprozoonosis www.who.int Combination (e.g. direct & metazoonosis) Slide 12 Zoonotic diseases: Session # MODES OF TRANSMISSION Direct and Metazoonosis Cyclozoonosis (e.g. Rift valley fever, JE) indirect Mosquito Leptospira in Taenia solium eggs animal urine Contaminated Pigs water Livestock Mosquitoes Humans Leptospirosis in humans Humans Slide 13 SAPROZOONOSIS Diseases of vertebrate animals which can affect people, the infectious agents of which are either capable of replicating in inanimate sites, or require an inanimate environment for the development of an infectious stage of their life cycle eg. histoplasmosis, Toxocara canis, certain food-borne diseases Zoonotic diseases: Session # TYPE OF RESERVOIR HOST Most zoonoses have more than one reservoir species and can be transmitted to people from many different animal species e.g. salmonellosis, rabies, leptospirosis, Nipah virus however Zoonoses can be referred to by their association with a particular species e.g. zoonoses of cattle, zoonoses of bats Slide 14 Zoonotic diseases: Session # SUMMARY OF SELECTED ZOONOSES BACTERIAL Anthrax Brucellosis Plague Leptospirosis Slide 18 Zoonotic diseases: Session # ANTHRAX Bacillus anthracis, Gram-positive sporing rod Worldwide, Russia, Asia, Africa, South America ‘Hot spots’ in warm humid areas where natural cycles exist All mammals susceptible but pigs, dogs and cats relatively resistant Birds can disseminate spores, chickens resistant, some birds susceptible Slide 19 Zoonotic diseases: Session # ANTHRAX Organisms enter via - Skin (cutaneous anthrax) Lungs (pulmonary anthrax, woolsorter’s disease) Gastrointestinal tract Clinical signs include - Eschar in humans (black necrotic skin lesion) Sudden death in ungulates, blood from the nose and other body orifices; septicemia in humans Slide 20 Zoonotic diseases: Session # ANTHRAX http://www.extension.org/pages/Anthrax Slide 21 Zoonotic diseases: Session # ANTHRAX TRANSMISSION AND HUMAN DISEASE Animal by-products, wool, hides, bone meal, meat, imported curios etc. involved in spore transmission Cutaneous infections most common, inhalation, intestinal, person-to-person rare 1-7d incubation, spores germinate, papules, vesicles, edema, fatal septicemia Agricultural workers, vets, rural communities, travellers etc. Bioterrorism agent – US postal workers affected Slide 22 Zoonotic diseases: Session # BRUCELLOSIS B. melitensis - goats, sheep (cattle, camels, dogs, people). Asia, Africa, Mediterranean and South America B. abortus – bovines, (dogs, people). Worldwide B. suis – pigs (people). South America, Southeast Asia, United States, Australia B. canis - domestic and wild carnivores (people). Many countries worldwide Primary hosts susceptible, disease in other hosts varies in severity Slide 23 Zoonotic diseases: Session # BRUCELLOSIS Vegetative endocarditis in a person, Brucellosis transmitted in milk caused by brucellosis and causing orchitis Ufuk Yetkin 2007 WHO and FAO Slide 24 Zoonotic diseases: Session # BRUCELLOSIS Chronic, long term infections, rarely fatal Ingestion, venereal Concentration of animals during calving, during milking, commoner in dairy cattle Organism persists in cool temperatures Abortion depends on stage of gestation Carnivores, birds aid in spread of fomites Flu-like symptoms in humans, including muscle and joint pains, fever, cough, (rarely endocarditis) Slide 25 Case study for discussion of Brucellosis in India Small Ruminant Research, Volume 14, Issue 2, Pages 161-165 (August 1994), Occurrence of abortions and seroprevalence of brucellosis in goats and sheep, S.V. Singha, N. Singha, M.P. Singhb, H. Shankara, D.D. Lalwanib Abstract Occurrence of abortions, still births and seroprevalence of brucellosis were studied in native, unvaccinated and organised flocks of goats (Barbari, Jamunapari, Sirohi, Kutchi, Jakharana, and Marwari) and sheep (Muzaffaragri) with abortion problems during the period from 1985 to 1990. In 6 years, 8.4% lambs and 13.4% kids were lost due to abortions and still births. Incidence of abortions were recorded as 12.3% and 6.8% and still births 1.0% and 1.6% in goats and sheep, respectively. Serologically, 0.6% goats and 3.6% sheep were found to be positive for brucellosis by standard tube agglutination test (SAT). The regular screening of the flocks for Brucellosis and elimination of positive cases partially helped to lower the incidence of Brucellosis in these flocks. http://www.smallruminantresearch.com/article/0921-4488(94)90106-6/abstract Zoonotic diseases: Session # PLAGUE Yersinia pestis, Gram-negative rod Rodent disease transmitted by fleas (carried by 30- 40 species of rodent, 1500 types of fleas) Complex sylvatic (wild) cycle Rodents act as reservoir and amplifying host Humans accidental hosts Carnivores infected by ingestion Slide 26 Zoonotic diseases: Session # PLAGUE Capture of rats in Indochina to prevent plague www.asnom.org/ en/423_peste.html Slide 27 Zoonotic diseases: Session # PLAGUE Disease of poor living conditions, rats and fleas Spread by fleas, handling plague material Human-human transmission (pneumonic plague) Buboes (cutaneous lymphadenitis), septicemia, pneumonia Buboes in groin CDC.gov Slide 28 Bubonic plague in Mongolia, October 4, 2004, a case study for discussion There have been several cases of Bubonic Plague (also know as Black Plague, Black Death, Pestilence) in Mongolia recently, resulting in two deaths so far this year. According to D. Tserennorov, vice director for the Center for Infectious Diseases with Natural Foci, two people in the Darbi Soum of Gobi-Altai Aimag were infected. One of the victims died on September 18th and 62 others who have had, or may have had direct contact with the man are now quarantined. On September 19, 2004, a woman from Ilbenkh in the Bayankhongor Aimag was infected after skinning a marmot. Seventy people who have had, or may have had direct contact with her have not shown any symptoms of the disease so far. The Mongolian government has declared a state of emergency in these, and surrounding areas. The State Disaster Protection Agency warns people not to hunt or eat marmots. The Plague is transmitted via several methods. They include: Bites from rodent fleas Exposure to humans with the pneumonic form of the plague Handling infected carcasses Scratches or bites from infected domestic cats Exposure to aerosols (small air-borne particles breathed in from infected animals and humans) (http://mongolia.usembassy.gov/tw_10042004.html) Zoonotic diseases: Session # LEPTOSPIROSIS Disease described in dogs in 1850 Weil’s disease described in people in 1880 Organism first isolated in Japan in 1914 - now 7 pathogenic species & over 200 serovars recognised By 1940 leptospirosis established as a major animal and public health problem Occupational disease Associated with natural disasters e.g. floods Slide 29 Zoonotic diseases: Session # LEPTOSPIROSIS Direct anthropozoonosis (or via fomites) Host-adapted serovars in maintenance hosts which act as reservoirs, inapparent infections in these animals Herbivores long shedding, carnivores short Severe infections in secondary hosts (non-reservoir) All serovars capable of infecting any animal. Dominant serovars vary between regions, e.g. serovar Autumnalis in Thailand Moist environmental conditions favor survival outside hosts, endemic zones worldwide Slide 30 Zoonotic diseases: Session # LEPTOSPIROSIS Occupational hazard: in rice-growing communities, e.g. July 2008 578 infections, 15 dead in Thailand. Cattle, pigs and rodents possible reservoirs, via urine contaminating paddy fields. Recreational risks: Sabah, Malaysia, 2000 Eco-challenge race – 50 out of 80 athletes contracted leptospirosis Natural disasters: Typhoon Ketsana, Manila, Philippines in 2009, approx 170 deaths, hundreds infected, 1 million doses of prophylactic doxycycline, hospitals coped poorly Slide 31 Zoonotic diseases: Session # LEPTOSPIRA AND HUMAN DISEASE Contact with infected urine or contaminated water, seasonal spring/summer in cooler climates Entry via intact mucous membranes, aerosols or skin abrasions, occupational disease Anicteric (without jaundice) disease is common form in Australia, vague symptoms, flu-like, fever, headache, myalgia Icteric disease very severe, more common in Asia, rodent hosts of serovars Person-person transmission rare, dead-end hosts Slide 32 LEPTOSPIROSIS IN KAMPHAENG PHET, THAILAND (case study to discuss) Am. J. Trop. Med. Hyg., 76(1), 2007, pp. 135–8 Kamphaeng Phe Province (gray (www.ajtmh.org/cgi/reprint/76/1/135.pdf) area) Zoonotic diseases: Session # SUMMARY OF SELECTED ZOONOSES VIRAL LYSSAVIRUSES (RABIES) FLAVIVIRUSES (JAPANESE ENCEPHALITIS) NIPAH VIRUS INFLUENZA VIRUSES SARS Slide 33 Zoonotic diseases: Session # LYSSAVIRUSES Family Rhabdoviridae, Genus Lyssavirus 1. Classical rabies 2. Lagos bat virus 3. Mokola virus 4. Duvenhage virus 5. European bat virus 1 6. European bat virus 2 7. Pteropus Lyssavirus (Australian bat lyssavirus) Slide 34 Zoonotic diseases: Session # CLASSICAL RABIES Virulent rabies spread from Europe to Asia and other regions by infected dogs; many countries worldwide Dogs most important domestic hosts, cats, cattle and other domestic animals commonly involved Many wild reservoirs which differ between regions; principally canids (foxes, wolves, jackals) but also mongooses, skunks, raccoons, bats Some countries free by eradication e.g. UK Direct zoonosis – bites, mucosal exposure, other routes e.g. corneal transplants Slide 36 Zoonotic diseases: Session # PATHOGENESIS OF RABIES infection of neurons Furious spread to death neurons in ganglia or Dumb spinal cord, spread to brain clinical signs 2-3 days spread to salivary glands, skin Virus shedding Slide 37 Zoonotic diseases: Session # RABIES Transmission to people mainly by bites via virus in saliva, aerosol transmission extremely rare Aerosol transmission, found in bat saliva in zoos Incubation 4 days – 6 years, depends on bite site Clinical rabies invariably fatal Prodromal period (behavioural changes) Excitative period (hydrophobia, aerophobia in people); a dog in India bit 40 people/9 dogs in 4 hours Paralytic period (dumb rabies) Slide 38 Zoonotic diseases: Session # BAT-ASSOCIATED LYSSAVIRUSES Haematophagous (blood sucking), insectivorous and frugivorous (fruit eating) bats all can transmit rabies and related viruses Spread by bites and scratches from infected animals Neurological signs in bats and humans similar to classic rabies Cases reported in Australia, Europe and USA Vampire bats are reservoirs of classical rabies, South America Slide 35 Zoonotic diseases: Session # OTHER BAT-ASSOCIATED ZOONOSES Pteropus spp. fruit bats are known reservoirs of a number of other zoonotic viruses worldwide, including Nipah virus, Hendra virus, Ebola and SARS Slide 47 HENIPAVIRUSES The genus Henipavirus is a newly described genus including 2 newly emerged viral agents, Nipah virus and Hendra virus, first identified in Malaysia and Australia respectively Slide 50 Zoonotic diseases: Session # HENDRA VIRUS Named for a suburb in Brisbane, infected 23 horses and 3 people in Queensland in 1994 Survey identified infected fruit bats; postulated that bat to horse contact had occurred due to habitat changes Occupational hazard, with infections in veterinarians and horse-associated workers Disease has killed four of the seven people infected since its discovery Slide 51 Zoonotic diseases: Session # NIPAH VIRUS Malaysia and Singapore 1998/9 Mild disease in pigs Encephalitis & respiratory infections in people, cats and dogs in contact with pigs Malaysia 257 human cases/105 deaths; Singapore 11/1 1.1m pigs slaughtered Pteropus spp. bats implicated, closely related to Hendra virus Seasonal, may be linked to bats ‘birthing’ www.abc.net.au, AFP: Raul Arboleda Slide 52 Zoonotic diseases: Session # NIPAH VIRUS Eight outbreaks in Bangladesh and India since 1998 have been associated with bats contaminating fresh date palm juice, collected overnight to make palm sugar (255 cases/136 deaths) Bats have been seen to drink from the containers used to collect the raw juice, contamination Humans commonly drink the raw juice in the villages associated with the industry Fruit bats are ‘anthropophilic’ in India and Bangladesh (live in close proximity to humans) Slide 53 Case study of Nipah outbreak in Bangladesh The Daily Star, Wednesday, January 20, 2010 Nipah virus claims 3 in Faridpur Three members of a family under Bhanga upazila of the district died within a week after they contracted encephalitis caused by Nipah virus. Faridpur Civil Surgeon Dr Bashirul Islam stating the report of Institute of Epidemiology, Disease Control and Research and National Influenza Centre, Bangladesh (IEDCR) yesterday confirmed the death of the three from Nipah virus that spread from the swab of bats. The dead were identified as Karuna Biswas, 30, of Algi village under Bhanga upazila, her daughter Dipti Biswas, 11, and nephew Sanu Biswas, 10. All the three drank raw date juice before they contracted the disease, the family sources added. On information, a special team of the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDRB) led by Faridpur Civil Surgeon Dr Bashirul Islam visited the village on Saturday and collected the sample of blood of the three. After examining the blood sample the IEDCR authorities identified the disease as encephalitis, says Dr Bashirul, adding that the disease originated from raw date juice contaminated by the swab of bats. All people of the district were advised to collect date juice covering the mouth of jars with nets so that bats cannot sink their tongues into the jar, he said. While talking to The Daily Star, Director of the IEDCR Prof Mahmudur Rahman said this is the first incidence of death due to Nipah virus this year. Last year encephalitis broke out in Rajbari and Manikganj. But very few people died because of the government's early detection programme. Under the programme a regular surveillance has been in place in Faridpur, Rajbari and Madaripur since 2006. The major outbreak took place in Faridpur in 2004 causing death to at least 17 people of Laxmipur village under Sadar upazila. www.thedailystar.net/newDesign/news-details.php?nid=122688 Zoonotic diseases: Session # SEVERE ACUTE RESPIRATORY SYNDROME Outbreak in China in November 2002 SARS coronavirus Flu-like symptoms Case fatality rate in humans of almost 10% Related to trade in wild animals, civet cats (which had been in contact with bats in the farms), market hygiene Humans infected via processing, cleaning Human-to-human transmission, 8096 cases, 774 deaths Disease control by quarantine, thermal imaging used to detect cases early in disease at airports Slide 54 SARS outbreak – discuss origins, spread, ecological and economic implications Severe Acute Respiratory Syndrome CBC News Online | Updated April 22, 2004 Origin of the crisis: Health officials declared in July 2003 that the global epidemic of severe acute respiratory syndrome was over, but in December 2003 and January 2004, China confirmed four new cases of SARS in southern Guangdong province. Those patients recovered, but on April 22, 2004, China confirmed two more suspected cases of the disease, one in Beijing and one in Anhui, a province in eastern China. The first case of SARS appeared in November 2002. It killed 800 people around the world, including 44 in Toronto. The disease killed 350 in China. That country later ordered the killing of some 10,000 civet cats, suspected to be carriers of SARS. The weasel-like mammals are considered a delicacy in Guangdong and are served in wild-game restaurants. Two inquiries into the political and medical reaction to the SARS outbreak released reports in April 2004. Both reports focused on the need to improve public health spending on infectious disease prevention, identification, control and containment – and the importance of clear communication and cooperation among all levels of government and health care providers. www.cbc.ca/news/background/sars/ 52insert your company logo Zoonotic diseases: Session # FLAVIVIRUSES Approximately 60 viruses, of which 29 are human pathogens Yellow fever, Japanese encephalitis, Murray Valley encephalitis, West Nile virus, Chikungunya virus Important causes of viral encephalitides All are zoonoses (although dengue and yellow fever are now adapted to humans in urban cycles) Slide 39 Zoonotic diseases: Session # JAPANESE ENCEPHALITIS Distributed throughout Asia, world’s most important cause of epidemic encephalitis Maintained in nature in a complex cycle involving many species of birds, mammals and insect vectors Transmission cycles depend on human practices such as rice cultivation (for mosquito habitat) and livestock production Night heron Slide 44 Zoonotic diseases: Session # JAPANESE ENCEPHALITIS Certain water birds, e.g. egrets, cormorants and herons play a role as reservoirs Pigs are the primary amplifying hosts of JEV; susceptible pigs infected during seasonal epidemics coinciding with rainy season Pigs sustain viremia sufficient to infect mosquito vectors Cattle, chickens, humans are dead end hosts Slide 43 Zoonotic diseases: Session # JAPANESE ENCEPHALITIS Human disease: fever, nausea, vomiting, seizures, coma, CNS signs; 20% case mortality; estimated 50,000 cases/year; 20% case disability rate; universal infection by 15years old in rural areas Control difficult due to extensive mosquito breeding areas in rice fields Immunisation of humans the only option, possibly barriers/traps round villages 11 more succumb to Japanese Encephalitis in India, toll reaches 311. www.MyNews.in Slide 45 Zoonotic diseases: Session # JAPANESE ENCEPHALITIS 28 species of mosquito can be infected with JEV but not all are competent vectors, mainly the Culicoides group Pigs and horses affected clinically, abortion in sows and encephalitis in horses Birds introduce virus into virus-free areas by migrating while viremic Piglets affected soon after start of rains Slide 46 Evolution of JE control in Thailand Case study for discussion http://www.path.org/projects/JE_in_depth.php Zoonotic diseases: Session # HANTAVIRUS First recognized in the Korean war in the 1950s along the Hantan river New strain causing Hantavirus cardiopulmonary syndrome recognized in America in 1993 Rodent reservoir www.kuleuven.be/ rega/mvr/research.html Slide 55 Zoonotic diseases: Session # HANTAVIRUS RNA viruses of the Bunyaviridae family Spread by aerosolized rodent excreta or rodent bites No human-to-human transmission Endemic in China, SE Asia, America and Europe Renal and (cardio)pulmonary syndromes Control by controlling rodent populations, do not stir up dust when cleaning rodent-infected areas Slide 55 Zoonotic diseases: Session # INFLUENZA VIRUSES Highly contagious acute respiratory disease, high mortality, low mortality Type A viruses are the only zoonotic ones, H5N1 and H1N1 are 2 newly emerged virus strains of global concern Humans, pigs, horses and avians are commonly affected, other animals rarely (cattle, mink, seals) Poultry and pigs are the main source of infection for humans, occupational exposure Slide 56 H1N1 INFECTIONS IN HUMANS AND PIGS Disease in humans self-limiting, uncomplicated respiratory illness with fever; severe disease and deaths have occurred Pigs also affected, initially via contact with infected humans or infected fomites, then via direct contact with secretions and feces May 2nd 2009 virus isolated from pigs in Alberta, Canada; to the end of 2009 14 countries had reported the pandemic strain in pigs to the OIE Slide 60 H1N1 INFECTIONS IN BIRDS AND ‘MIXING VESSELS’ Chickens appear refractory to infection, however commercial turkeys have shown some signs, mostly decrease in egg production in breeding flocks; older turkeys more susceptible to infection; turkey infections reported from Canada, USA and Chile Turkeys are unique in that, like pigs, they have receptors for both avian and mammalian influenza A receptors in their tissues; they are commonly infected with strains from wild birds and pigs; role of turkeys in the epidemiology of pandemic H1N1 unclear Slide 62 H1N1 INFLUENZA TIMELINE April 21st 2009 – novel strain identified in Mexico and the USA, first called ‘Swine Flu’, now named Pandemic (H1N1) 2009 virus This ‘triple reassortant strain’ contains a unique combination of gene segments donated by viruses originating from 3 species (humans, pigs, birds) and 2 hemispheres Each segment has been nested in well-established swine influenza lineages for over 10 years; ancestors circulated undetected for over 10y before emerging in humans The strain has developed strong ‘mammalian-like’ hemagglutinin (HA) receptor specificity, and can no longer replicate in aquatic waterfowl, their historic natural reservoir Slide 58 June 11th 2009 – WHO raised the influenza alert level to Level 6 – pandemic! 2009-2010: Pandemic (H1N1) 2009 Influenza spread to many countries worldwide; virus disseminated worldwide in just a few weeks Feb 2010: >213 countries reported lab confirmed cases, at least 16,500 deaths, the majority in Europe and the Americas – underrepresentation as many deaths are never tested or recognised as influenza related. Activity in Africa reported but low, circulation continuing in South and SE Asia Seasonal Influenza B viruses now predominant in S. Asia; Global Influenza Surveillance Network monitors global circulation of viruses including pandemic, seasonal and others Slide 59 H1N1 INFECTIONS IN HUMANS AND PIGS Clinical signs in pigs mild: fever, slight cough, sneezing, nasal discharge Clinical signs in humans usually mild: fever, slight cough, sneezing and nasal discharge; vomiting and diarrhea in up to 38% of cases H1N1 infections in pigs similar in duration to other influenza viruses Sampling by nasal swab: virus shed for up to 20d post-clinical signs; pig herds rapidly clear the virus post-infection Slide 61 Global concern is that H1N1 viruses might acquire virulence markers by reassorting with viruses such as H5N1 that cause severe disease in humans Such reassortments are more likely to occur in ‘mixing vessels’ (pigs, turkeys) than in humans; risk highest in pigs Slide 63 OIE RECOMMENDATIONS Pigs infected with pandemic (H1N1) 2009 virus should be managed similarly to herds infected with any other swine influenza virus; control outbreaks with bio-safety measures, avoiding dissemination to humans and animals Thus, restrictions of trade or slaughter of pigs as a public health intervention are irrational actions (statement from Canadian scientists – alluding to the slaughter of all pigs in the country by Egyptian authorities, with subsequent loss of livelihood for small, poor communities) Countries should implement vigilant surveillance for, and monitor for changes in the structure and behavior of, the virus Slide 64 Zoonotic diseases: Session # HIGHLY PATHOGENIC AVIAN INFLUENZA Avian influenza less host-specific than mammalian strains, many avian species infected; both low pathogenic (LPAI) and highly pathogenic (HPAI) strains are recognised in poultry HPAI A/H5N1 was isolated from chickens and humans in Hong Kong in 1997, causing 6 human deaths. Following this a larger outbreak occurred in Hong Kong in 1999 Aggressive virus eradication was used in HK, with millions of chickens being culled, also in-contact dogs and cats Slide 65 • Further outbreaks in SE Asia in 2003/4/5 may have been spread via migratory ducks, probably originating from China, and then locally via live bird markets • Other HPAI strains have occasionally caused human infections (H7 and H9 strains) Slide 66 H5N1 IN 2010 – discuss importance of H5N1 Peak in poultry in 2006 – 63 countries infected in Europe, Asia and Africa April 2010: 493 human cases/292 deaths (in 15 countries); 260m poultry culled; estimated $20bn economic damage worldwide; devastated livelihoods at the family farm level. Now endemic in poultry in 5 countries: Egypt, Indonesia, Vietnam, China and Bangladesh; sporadic outbreaks in: Bhutan, Cambodia, Laos, India, Myanmar, Nepal Slide 67 HUMAN MORBIDITY/MORTALITY BY COUNTRY (APRIL 2010) Iraq 3/2 Turkey 12/4 Azerbaijan 8/5 Cambodia 10/8 Thailand 25/17 China 38/25 Egypt 109/34 Vietnam 119/59 Indonesia 163/135 Other 6/4 500th human case reached in July 2010 Slide 68 Endemic factors: tens of millions of free- ranging ducks; significant broiler production; live bird markets; high human and animal densities H5N1 sero-conversion has occurred rarely in pigs, virus has not been isolated www.birdflu.org.au/ Slide 69 CONTROL MEASURES FOR HPAI IN POULTRY Vaccination used in all those countries except Bangladesh; all other countries have a slaughter policy (e.g. Thailand, Europe) Other policies: improved poultry biosecurity, enhanced surveillance capacities; prompt reporting to OIE World Animal Health Information System (WAHIS) UN proposed framework for sustaining momentum; three streams of work for national, regional and global authorities • prevention and control of HPAI • adoption of One Health approaches • readiness for response to influenza pandemics Slide 70 PARASITIC DISEASES ECHINOCOCCUS spp. Dogs are the primary host of E. granulosus Eggs are ingested by intermediate hosts including people and sheep Cysts transmitted from sheep to dogs by eating offal Onchospheres penetrate intestine and travel to liver and lungs; grow slowly into hydatid cysts; may reach 20cm in diameter; surgery required to remove cysts Control programs aimed at treating dogs for tapeworms and breaking transmission cycle 75insert your company logo Hydatid disease Hydatid cyst in human liver Cyst in child’s brain Cyst removal Hydatid Disease Control in Nepal – case study Butchering in Nepal is generally done by the people of lower caste, who are usually less educated. It is common practice to slaughter animals in open air, mainly near water sources like the bank of a river, streams, ponds and public taps where meat and viscera can be washed conveniently. Sometimes, household yards and near by streets are used as slaughter and selling site. The discarded offal and slaughter by products are then usually left as such in the slaughter site or disposed near by. In the countryside, animals are usually slaughtered and sold during periodic local markets, or during religious ceremonies. Once the animal is slaughtered, all the meat is usually consumed immediately as there is no access of ordinary people to refrigeration. The situation is somewhat different in the cities, but there is virtually no infrastructure to accommodate the slaughter and sale of meat. A large number of stray dogs occur in Nepal, mainly in the cities, besides owned dogs by individuals or the community. The dogs survive on garbage and remain wandering in search of food, mainly around the slaughter site. Butchers often throw inedible meat pieces, viscera or bones to these dogs or the dogs have easy access to the slaughter wastes, which if contains cyst of Echinococcus infects them. As the dogs are freely roaming, they defecate on wherever they wish, commonly on the river bank or any other free space which is often used as playground or foraging ground, and thus re-infect man and animals. This is assumed to be the most common mode of transmission throughout Nepal. http://shrawanbhandari.com/index.php/blog/28-prospects-of-hydatid-disease-control-in-nepal.html 77insert your company logo Zoonotic diseases: Session # SURVEILLANCE AND CONTROL OF ZOONOSES Historically the task of veterinarians – now One Health National and international eradication programmes e.g. rabies, TB, brucellosis, HPAI Slaughter inspection of food animals Prophylactic vaccinations mainly in animals Therapy of animals with zoonotic diseases Vector and reservoir population control (arthropods, rodents) Surveillance for diseases of importance in the region e.g. Japanese encephalitis, rabies, HPAI Slide 71 Zoonotic diseases: Session # OTHER CONTROL MEASURES Breaking cycles of transmission Enhancement of host resistance e.g. vaccination, nutrition Destruction of infectious agents Prevention of environmental degradation to reduce disruption of natural balances among hosts, agents and the environment Integration of medicine and veterinary medicine in approaches to control One Health Slide 72 Zoonotic diseases: Session # ZOONOSES PREVENTION Sensible personal hygiene • Wash hands after handling animals • Wash hands before eating or drinking • Disinfect and dress wounds as soon as possible • Wash eyes if urine splashed Necropsy • Wear gloves and a face mask if unsure Working with sick wildlife • Take special precautions e.g. Personal protective equipment (PPE) Slide 73 Zoonotic diseases: Session # EXAMPLES OF ZOONOSIS CONTROL MEASURES Anthrax Brucellosis Plague Leptospirosis Rabies Avian Influenza Slide 74 Zoonotic diseases: Session # CONTROL OF BRUCELLOSIS Surveillance, quarantine, movement control Serological testing - card test, Rose Bengal test, milk ring test, slaughter positives Segregation at parturition, sanitation Vaccination - S19 (live), 45/20 (killed) No vaccines for pigs or dogs Slide 75 Zoonotic diseases: Session # CONTROL OF PLAGUE Rodent control (cover feed, alter habitats) Flea control in rodents and pets Effective diagnosis, early warning, treatment and quarantine Avoid handling or eating meat from sick animals Slide 76 Zoonotic diseases: Session # CONTROL OF LEPTOSPIROSIS Vaccination of cattle, pigs, deer, dogs Need virulent, local serovars in vaccines, little cross- immunity, killed vaccines, annual re-vaccination Protective clothing, e.g. boots, eye protection, gloves in abattoirs Avoid contact with animal urine Control of wild reservoirs e.g. Rodents Differential diagnosis - brucellosis, meningitis, hepatitis, influenza Slide 77 Zoonotic diseases: Session # CONTROL OF RABIES Strict quarantine laws for imported dogs plus pre-entry vaccination Other laws in endemic areas - limit dog ownership, destruction of unregistered dogs Pre-exposure (humans), cell culture vaccine, 1ml on day 0, 7 and 21 Animal vaccines use attenuated live virus or recombinant orthopox virus incorporating the virus glycoprotein gene Oral administration in wild animals (foxes, raccoons) via bait stations has been highly successful in Europe and the USA Human post-exposure vaccination very effective, can also use hyper-immune serum if unvaccinated Slide 78 Discuss methods of control for rabies in Bali Poisoned darts are being used to kill stray dogs in Bali The beautiful resort and formerly rabies-free Indonesian island of Bali is under siege from the deadly virus. The outbreak that was initially publicized in late 2008 continues to this day with the human death toll up to 78, and probably many other deaths are going unreported. The problem has got to the point where rabies vaccine supplies on the island are running low and may soon not be available. The Australian-based Bali Street Dog Fund has vaccinated thousands of dogs to help curb the outbreak and the Bali government has even used controversial methods like picking out strays for killing. Since the beginning of the outbreak, 200,000 dogs have been killed, though many find this an ineffective method to control rabies. Rabies is an acute viral infection that is transmitted to humans or other mammals usually through the saliva from a bite of an infected animal. It is also rarely contracted through breaks in the skin or contact with mucous membranes. The only treatment for human exposure to rabies is rabies-specific immune globulin and rabies immunization. Appropriate treatment started soon after the exposure will protect an exposed person from the disease. http://www.examiner.com/x-7707-Infectious-Disease-Examiner~y2010m8d8-The-rabies-problem-in-Bali-continues Rabies – case study for discussion Indian man eats dog’s heart to “prevent rabies” A stray street dog that had terrorized an Indian village last week biting at least seven people found its most bizarre fate. His latest victim, a 30 year old laborer from a village on the outskirts of Ranchi decided to make sure he wouldn’t get rabies from the dog in the most unusual manner— eating the dog’s heart. According to reports, the man went after the dog and killed it by throwing rocks at it. After the dog died, he removed the dog’s heart with a pair of scissors and ate it raw. The man after being questioned by local media about seeking medical care responded that he didn’t need medical help since he treated himself by eating the dog’s heart. Not only is rabies transmitted by animal bites but also by the butchering of rabies- infected or sickly animals where the virus could get into the persons eyes or mouth. http://www.examiner.com Zoonotic diseases: Session # CONTROL OF BAT LYSSAVIRUSES Australian, African and European bat lyssaviruses Similar to rabies Spread by bites and scratches from infected animals Prevention: avoid being bitten by bats, handle animals with care and protective clothing. Wash wounds thoroughly with soap and water Vaccination with rabies vaccine Slide 79 Zoonotic diseases: Session # CONTROL OF AVIAN INFLUENZA Control by biosecurity, quarantine, closed flocks, movement control, vaccination, live bird market improvements, hygiene, cancelling shows etc. Eradication of virulent viruses by slaughter programs Control of the disease in wild birds impractical, may be a source of infection via migration for non- endemic areas; flock biosecurity important Human H5N1 vaccines currently being tested Slide 80 Zoonotic diseases: Session # SUMMARY Zoonotic diseases pose global epidemic health risks Increased risk of disease due to increased contact between humans and animals, wild and domestic Zoonotic diseases most likely to originate in SE Asia, Africa and China Air travel allows disease to spread rapidly around the world Future control of emerging infectious diseases will rely on the adoption of One Health principles Slide 82 Zoonotic diseases: Session # LEARNING OBJECTIVES At the end of this module the participant should be able to: • Define terms (zoonosis, emerging disease….) • Classify zoonoses based on host, pathogen, transmission • Understand the importance of zoonoses to One Health • Discuss emerging and re-emerging zoonoses • Understand reasons for disease emergence and re- emergence • Describe selected zoonoses important in their region • Understand the principles of zoonosis prevention and control Slide 02 Zoonotic Diseases Training Package Thank you Training resources Zoonotic diseases: Session # MULTIPLE CHOICE QUESTIONS Are the following statements true or false? a) Zoonotic diseases are easy to control and eradicate from populations b) Humans are often incidental hosts of zoonotic diseases c) Zoonoses are not important today because we have antibiotics and other drugs to control them d) Zoonotic diseases can only be transmitted by wild animals Zoonotic diseases: Session # SHORT ANSWER QUESTIONS 1. Why have trade and travel played important roles in the spread of zoonoses? 2. Name and describe 3 recently emerged zoonoses 3. What is the difference between an emerging and a re-emerging disease? 4. List 5 reasons for disease emergence Zoonotic diseases: Session # LONGER QUESTIONS 1. Draw the lifecycle of a direct, indirect, cyclo- and meta-zoonosis. 2. Name 3 arboviral infections in Asia and discuss the similarities and differences in their epidemiology. What information would you need to formulate a control program for each of these? 3. Following heavy flooding in Asia, name 3 zoonoses that could occur and what could be done to control, prevent or prepare for them? Zoonotic diseases: Session # NEWSPAPER CLIPPINGS Look at the newspaper clipping from the Bangkok Post 1st October 2009 and answer the following questions: 1. Explain why zoonotic disease outbreaks often occur after natural or man-made disasters. 2. What conditions are likely to exacerbate the disease outbreaks? 3. What would you need to do to minimize the risk of disease outbreaks related to emergency situations such as these? Zoonotic diseases: Session # Further case studies http://www.vwb-vsf.ca/english/documents/OHOWCompendiumCaseStudies_001.pdf See page 67 for Asian case studies on: Brucellosis H5N1 (“Avian Influenza”) Severe Acute Respiratory Syndrome (SARS) Nipah Virus Hydatid Disease/ Cystic Echinococcosis 99insert your company logo Zoonotic diseases: Session # ACTIVITIES Games can be developed and played to highlight important or relevant information Card games Quiz games Board games Memory games Crosswords etc.
Pages to are hidden for
"Zoonotic diseases presentation.ppt - Wikispaces"Please download to view full document