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Zoonoses and Veterinary Public Health DVM, PHD, OKAMOTO Karoku Prof. Veterinary Public Health, Dep. Veterinary Medicine, Fac. Agriculture, Kagoshima University Approximately 75% of recently emerging infectious diseases affecting humans are diseases of animal origin; approximately 60% of all human pathogens are zoonotic. Quoted from CDC, USA Examples of emerging infectious disease (Pathogen, Year, Natural reservoir) BSE 1986/1993 Cow SARS 2003 palm civet et.al HPAI H5N1 1997/2003 Water bird HPS 1993 Rodentia HPS: Hantavirus Pulmonary Syndrome SARS: Severe Acute Respiratory Syndrome West Nile 1999 Bird/Mosquito Ebola 1976 Monkey H1N1 Pandemic 2009 Swine/Bird Lassa 1969 Rodentia Nipah virus 1998 Megabat/Swine E. Coli O157 1982 Cow/Food Hendra virus 1994 Megabat/Horse VzHF 1991 Rodentia BzHF 1994 Rodentia Venezuelan & Brazilian Hemorrhagic Fever International Health Regulations(2005): IHR 2005 Annex 2 Decision instrument for the assessment and notification of events Event detected by national surveillance system National IHR Focal Point Small pox ● Poliomyelitis(wild type) ● Influenza(new subtype) ● Severe acute respiratory syndrome (SARS) ● Each State Party shall notify WHO within 24 hours of assessment. ● Cholera Plague ● Yellow fever ● Viral haemorrhagic fevers(Ebola, Lassa, Marburg) ● ● West Nile fever ● Others(Dengue fever, Rift Valley fever) DOES THE EVENT MEET AT LEAST TWO OF THE FOLLOWING CRITERIA? I. Is the public health impact of the event serious? II. Is the event unusual or unexpected? III. Is there a significant risk of international spread? IV. Is there a significant risk of international travel or trade restrictions? Diseases in the red are zoonoses. Event shall be notified to WHO under the International Health Regulations Many of zoonoses have the potential to spread through various means over long distances and to become global problems. Calvin W. Schwabe(1927 – 2006) Veterinary Epidemiology, UC Davis Classification of Zoonoses Dr. Schwabe provided the following classification system of zoonoses based on the type of life cycle of the pathogen. Direct zoonoses are transmitted from an infected vertebrate host to another host by direct contact, fomite or mechanical vector. The pathogen does not undergo developmental change or propagation during the transmission. Cyclozoonosis requires more than one vertebrate host but no invertebrate host is needed. An example is echinococcosis. Metazoonoses does require an invertebrate host where the pathogen multiples or develops before it can infect a vertebrate host. Saprozoonoses are diseases transferred through a non-animal reservoir, such as a plant, or through the abiotic environment, such as through water or soil. Direct zoonoses an vertebrate host Avian influenza, Rabies, Hantavirus, Psittacosis, Bovine tuberculosis, Brucellosis, E. coli O157, Anthrax Cyclozoonosis more than one vertebrate host Echinococcosis, Cysticercosis, Toxoplasmosis, Trichiniasis Saprozoonoses Metazoonoses an invertebrate host West Nile fever, Yellow fever, Rift Valley fever, Plague, Anisakiasis non-animal reservoir Tetanus, Botulism, Aspergillosis, Histoplasmosis, Toxocariasis, Fascioliasis, Anthrax The World Health Organization Expert Committee on Zoonoses came up with the classification system of zoonoses provided by Dr. Schwabe. Calvin Schwabe One Health Project A CENTER OF EXCELLENCE AT THE INTERSECTION OF HUMAN, ANIMAL, AND ENVIRONMENTAL HEALTH Our Mission To strengthen the UC Davis School of Veterinary Medicine's commitment to the One World-One Health movement by educating veterinarians of the future to integrate human, animal, and ecosystem protection into their professional lives. The Calvin Schwabe One Health Project fosters a diverse and sustainable planet, with the goal of encouraging a new generation of veterinary expertise in the integration of better health for humans, animals, and their environment. To that end, One Health expands career pathways for veterinary students in disciplines such as public practice, wildlife and ecosystem health, food safety, herd health, disaster preparedness, rural health, and zoonotic disease threats. Metazoonoses West Nile fever Life cycle of West Nile virus (WNV) 1.WNV is spread by the bite of an infected mosquito (vector). 2.Mosquitoes become infected when they feed on infected birds(Reservoir). 3.WNV can cause most clinical cases in humans and horses that does generally not allow transmission to others(Dead-end host). Dead-end host Vector Mosquito Bird Human Equine Reservoir host Other animals Many of zoonoses have the potential to spread through various means over long distances and to become global problems. West Nile fever suddenly occurred in the New York in 1999 . A mosquito traveled by air? ★ Endemic area of Japanese encephalitis and West Nile fever WNV Positive ratio of dead birds WNV Positive mosquito Human case Newark Liberty International Airport Kennedy International Airport A mosquito arrived at this terminal. Spread of West Nile virus in New York City in 1999 No. of patients 10000 8000 WNV amplification between birds and mosquitoes took three years. 6000 4000 2000 62 0 21 66 fatality rate(%) Initial high fatality rate may 20 due to the following reasons. 1. Diagnostic and treatment 18 system were not prepared. 16 2. The number of patients in 14 mild was increased with the 12 progression of surveillance. 10 3. Acquisition of immunity. 8 6 4 2 0 Progression of West Nile fever in USA(1) No. of death 300 Why the number of death in 2002 was more than in 2003 when the number of patients peaked. No. of State affected 60 250 50 200 40 150 30 100 20 50 WNF occurred in almost all Sates in 2002, and many people acquired immunity. 0 10 0 Progression of West Nile fever in USA(2) Small pox Smallpox is an infectious disease unique to humans(not zoonosis), caused by Variola virus. The fatality rate for flat-type is 90% or greater and nearly 100% is observed in cases of hemorrhagic smallpox. Smallpox is believed to have emerged in human populations about 10,000 BC. In the early 1950s an estimated 50 million cases of smallpox occurred in the world each year. To eradicate smallpox, each outbreak had to be stopped from spreading, by isolation of cases and vaccination of everyone who lived close by. This process is known as "ring vaccination". The global program on smallpox eradication initiated by WHO in 1958 and intensified since 1967. The global eradication of smallpox Hemorrhagic-type smallpox. was certified by a commission of eminent scientists on December 1979. Virus families not assigned to an order(65 Families) Family: Poxviridae Orthopoxvirus is a genus Subfamily: Chordopoxvirinae of poxviruses that includes Genus: Orthopoxvirus many species isolated from Camelpox virus mammals. Although Variola Cowpox virus virus infects only human, Ectromelia virus some Orthopoxviruses have Monkeypox virus the ability to infect non-host Raccoonpox virus species, such as monkeypox Taterapox virus virus. Vaccinia virus I now offer a few topics Variola virus related with small pox Volepox virus eradication. Genus: Parapoxvirus Bovine papular stomatitis virus Orf virus Parapoxvirus of red deer in New Zealand Pseudocowpox virus Monkeypox was first found in 1958 in laboratory monkeys. African squirrels might be the common host for the disease. Rats, mice, and rabbits can get monkeypox, too. Direct zoonoses Monkeypox Seven years old girl in Republic of Zaire Human monkeypox Six months later, she healed but many pockmark remained. Monkeypox is an exotic infectious disease caused by the monkeypox virus, and is usually transmitted to humans from rodents, pets, and primates through contact with the animal's blood or through a bite. Human monkey pox can be difficult to distinguish clinically from smallpox. Case-fatality ratios in Africa have ranged from 1% to 10%. It is assumed that vaccination against smallpox would provide protection against human monkeypox infection. Since the eradication of smallpox in 1979, human case increase gradually. Endemic Human Monkeypox, Democratic Republic of Congo, 2001–2004 Emerg Infect Dis. 2007 Among 136 patients, 51 (37.5%) had laboratory-confirmed MPX infection, 61 (44.8%) had laboratory-confirmed chickenpox virus infection, and 1 (0.7%) had coinfection. Age and sex distribution of patients with monkeypox Age male female <4 5–14 15–24 25–34 >35 8/12 12/22 5/17 2/9 1/6 7/21 9/19 8/13 0/8 1/7 Total 28/66 24/68 Monkeypox positive/No. cases investigated Distribution of 52 confirmed cases of human monkeypox. 762 rodents Movement of imported African rodents to pet shops and distribution of prairie dogs from a pet shop associated with human cases of monkeypox, in 2003 USA. MMWR 2003 Rodents and prairie dogs contacted with each other. African rodents were resell to Japan, but 15 already dead before arrival and lived two rodents was not infected. All 35 human cases of monkeypox were associated with prairie dogs. Cowpox and Pseudocowpox virus Milker's nodules In 1796, Dr Edward Jenner used “cowpox virus” to inoculate a patient to prevent them from contracting smallpox. Discovery of virus is in 1892(tobacco mosaic disease), so it is not as clear what virus he used for vaccine 100 years ago. In fact, milker's What is cowpox? nodule is usally caused by a parapox virus(Pseudocowpox), not by cowpox virus. Nowadays, cowpox is a rare disease. It mostly occurs in Great Britain and some European countries. Cows are no longer the main carrier of the virus; instead woodland rodents are the natural hosts of the virus who then pass it on to domestic cats. Feline cowpox virus infection Cowpox Virus Transmission from Pet Rats to Humans Germany: Outbreak including 5 patients caused by infected pet rats from the same litter in 2009. Human cowpox infections seem to be increasing. One obvious reason for an increase might be the fading cross-protective immunity to cowpox after the cessation of small pox vaccination. Human cowpox is a disease of young people, with half of all cases occurring in individuals younger than 18 years, because of their not having been vaccinated for smallpox, which may confer some protection against cowpox. 16 years old boy VARV: Variola virus CPXV: cowpox virus VACV: vaccinia virus Brazilian Vaccinia Viruses and Their Origins VACV species imported to Brazil in 1804, when human vaccine arrived at a port on the arms of slaves returning from Portugal. The species was maintained in this manner(arm to arm) and in 1887 the first animal vaccine was produced in calves. In 1963, Brazilian VACVs(Group 1, 2) was isolated from the blood of a rice rat captured near the edge of Amazon rain forest. Since then, those virus were naturally isolated from a wild rodent. In 1999, exanthematous outbreaks affecting dairy cattle and their handlers were reported. Brazilian VACVs existed before the beginning of the WHO smallpox eradication vaccination campaigns. Original animal vaccine strein imported in 1887 The virus that Dr. Edward Jenner used for vaccination derived from milker's nodule in 1796 may be Brazilian VACVs. Voyages of Christopher Columbus(1492-1504) Cyclozoonosis Skunk, liver. The inner surface of the cyst is lined by hydatid sand, and the cyst is surrounded by a thick capsule of fibrous connective tissue Iowa Sate Univ.: CFSPH Echinococcosis (Hydatid Disease) Human, liver. Multiple thinwalled hydatid cysts project from the capsular surface of the liver. WHO: Echinococcosis Echinococcus granulosus Oral intake Humans are accidental intermediate hosts and are not able to transmit the disease. There are areas of high endemicity in southern South America, Mediterranean coast, southern part of Russia, Middle East, south-western Asia, northern Africa, Australia, Kenya, New Zealand and Uganda. Relate to wool industry Echinococcus multilocularis Definitive Host Fox Dog Cat ingesting eggs shed in the feces predatism Intermediate Host Rodent E. multilocularis is found primarily in the northern hemisphere. It is widely distributed in continental Europe, and also occurs in much of northern and central Eurasia eastward to Japan (where it is found only on the island of Hokkaido), and in North America, where it primarily occurs in Canada, Alaska and the north central U.S. from Montana to central Ohio. CFSPH: Echinococcosis Rebun island For the production of fur, red foxes were imported in Rebun island in 1924. First patient with hydatid cyst was detected in 1937, after a in 1965 lapse of 2 years reaching 129 patients. Hokkaido authorities gave instructions to destroy all foxes and stray dogs. Although the outbreak resolved, a hydatid patient was detected in east area of Hokkaido in 1965, and infection of Ezo red foxes were confirmed diffusely. Since then, about 10 patients each year continues to suffer the disease. Several monkeys, gorillas and orangutans died by hydatid desease in 2 zoological gardens in 1992 and 1994. By this circumstance, the Zoo were forced to shut. Since 1999, anthelmintic pellet including Praziquantel(Biltricide: effective against flatworms) were put in place widely where foxes are ranging. Before After キツネの駆虫に関するガイドライン 参考資料 1989-98 2000-05 199 Nuber of points captured Nuber of foxes captured 5,157 313 Nuber of positive foxes Positive rate(%) 6.1 148 3,840 18 0.5 80 70 No. of foxes captured: 25,358 No. of hydatid foxes: 5,174 Positive rate: 20.4% No. of stray dogs : 9,945 No. of hydatid dogs: 99 Positive rate: 1.0% 8 7 北海道におけるエキノコックス症対策の経緯 6 60 Fox 50 5 40 4 30 3 20 2 Dog 10 1 0 0 1966 1971 1976 1981 1986 1991 1996 2001 2006 Progression of prevalence of Echinococcosis in the foxes and dogs at Hokkaido through 1966-2008. 0.3 0.25 0.2 Echinococcus specific PCR using Cox1 primer 0.15 0.1 北海道におけるエキノ コックス症対策の経緯 0.05 0 Number of pigs slaughtered: 27,321,373 Number of hydatid pigs: 31,253 Positive rate: 0.11% Progression of prevalence of Echinococcosis in the pig slaughtered at Hokkaido through 1983-2008. Saprozoonoses Anthrax In May 1881 Louis Pasteur performed a public experiment to demonstrate his concept of vaccination. The trial was held under the supervision of two graziers and three government officials at Junee Junction in Australia during September and October 1888. The trial was undertaken on 39 sheep and 6 cattle. It was a complete success: all vaccinated animals remained in very good health, whereas all 19 Pasteur's Vaccine of Anthrax unprotected sheep and one of in Australia: as a preventative the two non-vaccinated cows against Cumberland Disease died within a few days. in sheep, cattle and horses. When conditions are not conducive to growth and multiplication of the vegetative bacilli, B. anthracis tends to form spores. These spores are extremely resistant to inactivation by heat or chemicals, and can survive in the environment for decades. Capsulated B. anthracis in the blood of an animal that has died of anthrax. Rain and other agents can disperse the spores to other locations. Heavy rains, alternating with dry periods, may concentrate the spores and result in outbreaks among grazing animals. Spores and vegetative cells of B. anthracis Virtually all mammals and some birds can contract anthrax, but susceptibility varies widely and most clinical cases occur in wild and domesticated herbivores. Cattle, sheep, and goats are considered to be highly susceptible; horses somewhat less so. Pigs, other omnivores, and carnivores are more resistant to disease, but they may become ill if the dose is high. Birds are highly resistant. Enlarged spleen has a ‘blackberry jam’ consistency. Bloody discharges from the nose, mouth, and anus Louisiana State Univ.: World Anthrax Site 20,000-100,000 cases estimated globally/year Human case rates for anthrax are highest in Africa and central and southern Asia. Where the disease is infrequent or rare in livestock, it is rarely seen in humans. 300 Number of cases 250 200 150 100 50 It was revealed that the application of Cow bone meal was very effective to crop growth in Kagoshima Prefecture consisting of volcanic ash soils in the middle of Edo period. The bone meals imported from China and Korea in Meiji period Equine were contaminated with Anthrax spores. Human 0 Occurrence of Anthrax in Kagoshima prefecture through 1908-1932 30 In Japan, only one animal-Anthrax case in several years was reported recently. The spores still may be distributed in the soil, the number of them do not reach the onset dose. By the oral route, minimum infectious dose for sheep was 3.5 x 10 4 spores and that the dose needed to ensure lethal infection in sheep, horses and cattle was 5 x 108 spores. 20 WHO: Anthrax in humans and animals 60 Number of cases 50 40 10 0 Numer of cattles with Anthrax in Japan, 1960-2000 400 Number of deaths 350 300 During the first documented outbreak of anthrax, in the summer of 1962, 281 bison died in the eastern Slave River Lowlands. Outbreaks soon became widespread, extending during the course of the next few years to as far south as bison herds in the Sweet Grass area. Number of Bisons in National Park 250 200 150 100 50 No cases of human anthrax have been diagnosed in the last two decades in Canada. Wood Buffalo National Park Slave River Lowlands Mackenzie Bison Liard River Valley (Nahanni) Wood Bison in the NWT 0 4500 1800 1555 400 Wood bison is designated as the Status of Endangered Wildlife in Canada Number of bisons died of anthrax in Canada Anthrax in U.S. Cutaneous anthrax Early 1900s: 200 cases annually Late 1900s: 6 cases annually Inhalational anthrax 20th century: 18 cases/16 fatal Outbreaks of anthrax in wild animals including bison were a public health threat in United States, formerly. CDC: Epizootiology and Ecology of Anthrax Distribution by decade of 75 cases of anthrax in humans in Texas, 1935 to 2001. 2001 Anthrax Letters 2001 anthrax attacks The second letter dated at 9 November Who did it for • 22 cases what purpose? – 11 cutaneous The truth has – 11 inhalational not been • 5 deaths (all inhalational) revealed until now. – Index case in Florida – 2 postal workers in Maryland – Hospital supply worker in New York City – Elderly farm woman in Connecticut Aum Shinrikyo • Japanese religious cult • 1993 – Unsuccessful attempts at biological terrorism – Released anthrax from office building • Vaccine strain used – not toxic – No human injuries • Successful attempt in 1995 – Sarin gas release in Tokyo subway – 1,000 injured – 12 deaths A group behaving fanatically would exist in any country. It is an unavoidable phenomenon resulting from the mentally suffering society. Guru in the cult The International Health Regulations (2005) provide not only the ability of the world community to cope with public health emergencies affecting more than one country, but they have important implications for biosecurity, including the response to transborder incidents involving the accidental or deliberate release of biological or chemical agents or radiological materials.