Seroprevalence of tularemia in wild bears and hares in Japan

Tularemia is a zoonotic disease caused by Francisella tularensis. The distribution of the pathogen in Japan has not been studied well. In this study, seroprevalence of tularemia among wild black bears and hares in Japan was determined. Blood samples collected from 431 Japanese black bears (Ursus thibetanus japonicus) and 293 Japanese hares (Lepus brachurus) between 1998 and 2009 were examined for antibodies against F. tularensis by micro-agglutination test (MA) or enzyme-linked immunosorbent assay. By subsequent confirmatory tests using western blot (WB) and indirect immunofluorescence assay (IFA), eight sera from Japanese black bears were definitely shown to be seropositive. All of these eight bears were residents of the northeastern part of main-island of Japan, where human tularemia had been reported. On the other hand, no seropositive Japanese hares were found. These results suggest that Japanese black bears can serve as sentinel for tularemia surveillance and may help understand the distribution of F. tularensis throughout the country. This is the first report on detection of antibody to F. tularensis in black bears of Japan.     

Prairie dogs: vectors and victims

Prairie dogs (Cymonys spp.) are native to North America. They have proved to be a relatively popular pet in North America and in multiple countries around the world. All or the vast majority of prairie dogs sold in the pet trade are wild caught. Two zoonotic diseases that naturally occur in wild prairie dogs are tularemia and plague. Epizootics of both of these diseases have occurred in recently captured prairie dogs intended for the pet trade. The lot containing prairie dogs with tularemia was widely distributed within the United States and internationally before the disease was recognized. Recently, prairie dogs intended for the pet trade were exposed to monkeypox as the result of close contact with several species of wild caught African rodents. Infected prairie dogs developed a systemic disease with cutaneous manifestations. Prairie dogs were distributed to six states before the disease was recognized. As many as 76 people developed monkeypox from exposure to these prairie dogs. The last reported case was in June 2003. Currently, it is illegal to buy, sell, trade, or transport prairie dogs in the United States. However, veterinarians are still permitted to treat them.     

Epizootic of tularemia in an outdoor housed group of cynomolgus monkeys (Macaca fascicularis)

Tularemia is a highly contagious infectious zoonosis, transmissible by inoculation, ingestion, or inhalation of the infectious agent Francisella tularensis. The disease is perpetuated by infected rodents, blood-sucking arthropods, and by contaminated water. Therefore, nonhuman primates housed outdoors may be at risk for exposure. An epizootic of F. tularensis occurred in an indoor/outdoor-housed group of cynomolgus monkeys (Macaca fascicularis) at the German Primate Center. Tularemia was diagnosed in 18 out of 35 animals within a period of 2 years. Six animals died with unspecific clinical symptoms; 12 animals developed seroconversion and were still alive. Pathologic findings were similar in all monkeys that died and resembled the clinical picture of the human disease, including an ulceroglandular syndrome with local lymphadenopathy, gingivostomatitis, and systemic spread, with manifestations such as subacute necrotizing hepatitis, granulomatous splenitis, and pneumonia. Tularemia was diagnosed by culture, real-time polymerase chain reaction, and ELISA techniques. This is the largest outbreak in nonhuman primates and the first report of tularemia in cynomolgus monkeys. An overview of the recent literature about tularemia in nonhuman primates is given.     

Tularemia

Tularemia is a rare but potentially fatal disease that develops in numerous wild and domestic animals, including lagomorphs, rodents, cats, and humans. The disease occurs throughout much of the United States and should be considered in the differential diagnosis of acute febrile illness, particularly when risk factors such as contact with wild mammals or tick exposure are present. Veterinarians may be at increased risk of acquiring tularemia from contact with infected animals, but standard precautions should greatly reduce this risk. Outbreaks of tularemia warrant investigation, especially given the possibility of the use of F tularensis as an agent of bioterrorism.     

An endemic case of tularemia in the mountain hare (Lepus timidus) on the island of Stora Karls?

In September 1983, an epizootic of unknown cause broke out among the mountain hares on the island of Stora Karls?, which is located outside the coast of Gotland. One hare was sent in the National Veterinary Institute for post-mortem examination. The hare showed lesions in liver, spleen, and bone-marrow typical for tularemia. The specimens were positive for Francisella tularensis with fluorescent-antibody test. Tularemia has not been observed earlier in this part of Sweden. It is supposed that the disease might have been spread to Stora Karls? with migrating birds from Finland, where there was an epizootic of tularemia during the summer 1983.     

Tularemia as a cause of fever in a squirrel monkey

CASE DESCRIPTION: A 3-year-old female squirrel monkey (Saimiri sciureus sciureus) was examined because of sudden onset of lethargy and fever. CLINICAL FINDINGS: On initial examination, the monkey was weak and febrile and had petechiae on both thoracic limbs. Following collection, blood samples were slow to clot. During the next week, the monkey developed anemia and thrombocytopenia; Francisella tularensis was isolated from blood samples. TREATMENT AND OUTCOME: Treatment with gentamicin resulted in the monkey's gradual return to health, but inguinal lymphadenopathy developed after drug administration was discontinued. Francisella tularensis was isolated from a fine-needle aspirate of an enlarged lymph node. Treatment with streptomycin resulted in resolution of infection. By use of biochemical and molecular tests, the microbial isolate was characterized as F tularensis subsp holarctica. Results of a microagglutination assay confirmed that the monkey had developed serum antibodies against F tularensis. CLINICAL RELEVANCE: With timely diagnosis, treatment of tularemia in the squirrel monkey was successful. Francisella tularensis is the cause of a highly infectious zoonotic disease, and infection with this microorganism is enzootic in wildlife throughout the Northern Hemisphere. Tularemia should be considered in the differential diagnosis of febrile disease in animals of any species. Even limited or indirect exposure of humans or other animals to outdoor environments in which reservoir hosts and arthropod vectors are present can lead to transmission of F tularensis. Francisella tularensis is a class A agent of bioterrorism, and all cases of tularemia (regardless of species) should be reported to public health officials.     

Tularemia,plague, yersiniosis,and Tyzzer’s disease in wild rodents and lagomorphs in Canada: A review

Information related to infection of wild rodents or lagomorphs in Canada by Francisella tularensis, Yersinia pestis, other Yersinia spp., and Clostridium piliforme was searched for this study. Reports on tularemia in humans linked to these species came from diagnostic databases, literature, wildlife health specialists, and public health agencies. Tularemia has been diagnosed in 8 species of wild rodent and 2 species in the genus Lepus in Canada. Tularemia occurred in wild animals, or in humans associated with these species, in all jurisdictions except the Yukon and Nunavut. Tularemia was diagnosed most frequently in beaver, muskrats, and snowshoe hares, and although tularemia is closely linked to cottontail rabbits in the USA, it has not been reported in cottontails in Canada. Tularemia in humans was associated with muskrats and hares more commonly than with beaver. Plague was diagnosed in bushy-tailed woodrats in British Columbia in 1988. Based on surveys, Y. pestis may occur enzootically in southern Alberta, Saskatchewan, and British Columbia. Infection with Yersinia pseudotuberculosis and Y. enterocolitica has been diagnosed in beaver, muskrats, and snowshoe hares in many provinces. Tyzzer’s disease has been diagnosed in muskrats in British Columbia, Saskatchewan, Ontario, and Quebec and in snowshoe hares in Ontario. Infection with these bacteria is likely much more frequent than indicated by diagnostic records.     

Tularemia in range sheep: an overlooked syndrome?

Abortion and death caused by Francisella tularensis were well recognized in range flocks of domestic sheep in Idaho, Montana, and Wyoming in the first 6 decades of the 20th century. The current report describes 4 episodes of tularemia in 3 range flocks in Wyoming and South Dakota in 1997 and 2007 (1 flock was affected twice). Flock owners reported that ticks were unusually numerous and commonly present on sheep during outbreaks. Tularemia presented as late-term abortions (3 episodes) or listlessness and death in lambs and, to a lesser extent, ewes (1 episode). Lesions were multifocal pinpoint necrotic foci in tissues, particularly spleen, liver, and lung. An immunohistochemical procedure demonstrated F. tularensis, particularly in necrotic foci. The diagnosis was corroborated by bacterial isolation and, in individual cases, by serology, fluorescent antibody assay, and/or polymerase chain reaction detection of F. tularensis. Diagnosticians in endemic areas should include tularemia as a differential diagnosis when investigating late-term abortions or outbreaks of fatal illness in young lambs, particularly in years of high tick activity and when characteristic necrotic foci occur in spleen, liver, and lung.     

An outbreak of tularemia in mink

An outbreak of tularemia in farm raised mink is reported. Twenty-six of approximately 5000 mink succumbed within a 10 day period. Prodromal signs were minimal. Necropsy revealed necrotic nodules scattered in the parenchyma of the lungs, liver, spleen, and mesenteric lymph nodes. Francisella tularensis was isolated from spleens, livers and lungs.     

Tularemia in a group of nonhuman primates.

In an episode of tularemia in a Canadian zoologic garden, three black and red tamarins (Sanguinus nigricollis) and one talapoin (Cercopithecus talapoin) died. A second talapoin developed abscesses in the tongue and submandibular area; this animal recovered with treatment. Francisella tularensis was isolated from lung, liver, and spleen from each dead monkey and from pus collected from the tongue abscess of the sick talapoin. The attending veterinarian contracted the disease from a tamarin bite. The source of the disease was identified as wild ground squirrels, and the causative organism was recovered from the liver and spleen of one squirrel and from fleas found on it.     

Tularemia in Alaska, 1938 - 2010

Tularemia is a serious, potentially life threatening zoonotic disease. The causative agent, Francisella tularensis, is ubiquitous in the Northern hemisphere, including Alaska, where it was first isolated from a rabbit tick (Haemophysalis leporis-palustris) in 1938. Since then, F. tularensis has been isolated from wildlife and humans throughout the state. Serologic surveys have found measurable antibodies with prevalence ranging from < 1% to 50% and 4% to 18% for selected populations of wildlife species and humans, respectively. We reviewed and summarized known literature on tularemia surveillance in Alaska and summarized the epidemiological information on human cases reported to public health officials. Additionally, available F. tularensis isolates from Alaska were analyzed using canonical SNPs and a multi-locus variable-number tandem repeats (VNTR) analysis (MLVA) system. The results show that both F. t. tularensis and F. t. holarctica are present in Alaska and that subtype A.I, the most virulent type, is responsible for most recently reported human clinical cases in the state.     

Pathogenesis of tularemia in immune and nonimmune rats.

Pathogenesis of tularemia in nonimmune rats given (intraperitoneal inoculation) virulent strain (SCHU S4) or vaccinal strain (LVS) of Francisella tularensis and in immune rats given SCHU S4 is described. Both LVS and SCHU S4 caused pyogranulomas in liver and spleen of nonimmune rats. Nonimmune rats given 10(4) SCHU S4 organisms did not survive beyond 72 hours, but immune rats given challenge inoculum of 10(8) SCHU S4 organisms developed lesions and survived. Larger doses of LVS resulted in earlier onset of characteristic hepatitis and splenitis in nonimmune rats. Periportal lymphocytic infiltrates were present in the liver 48 hours after SCHU S4 challenge inoculation of immune rats and 96 hours after inoculation of LVS in nonimmune rats and were associated with intense macrophage aggregation. These changes indicate that the pathogenesis of tularemia is a result of the interdependency of the dose and virulence of the causative agent with the immune status of the host and that cellular immunity has a significant role in the response of the rat to tularemia.     

Equine gastric ulcer syndrome in adult horses: a review

In recent years, gastric ulceration has been recognised as a common, possibly performance-limiting disease of adult horses. Here, we aim to provide the reader with a useful review of recent literature covering all aspects of equine gastric ulcer syndrome (EGUS) in adult horses. The anatomy and physiology of the stomach, with particular reference to secretion of acid and mucosal protective mechanisms, are reviewed, as are the differing theories relating to the aetiopathogenesis of gastric ulceration. We also explore the possible influence of various management factors on development of the disease. The prevalence of the disease in racehorses has been reported to be as high as 100%. In general, horses that are in active training for racing tend to have a prevalence of around 90%, whereas pleasure horses in full work have a reported prevalence of approximately 60%. Emerging diagnostic tests which could obviate the need for gastroscopy are introduced and current recommendations for treatment are summarised, focussing on proton pump inhibitors, in particular omeprazole, administered orally. The oral administration of omeprazole has been shown to be effective in both treating horses with gastric ulceration and at preventing re-occurrence whilst the horses are in training, provided that daily dosing is maintained.     

Immunohistochemical demonstration of Francisella tularensis in lesions of cats with tularemia.

An immunohistochemical test was developed and validated for detection of Francisella tularensis antigen in tissues of cats with fatal tularemia. Ten cases of naturally occurring tularemia in cats were positive both by isolation of F. tularensis and immunohistochemical identification of F. tularensis antigen. Nine additional cases with lesions typical of tularemia were positive for F. tularensis antigen, although bacterial cultures were not performed. Immunohistochemical identification of F. tularensis in formalin-fixed tissue is valuable for establishing a rapid etiologic diagnosis under circumstances where fresh tissues may not be available for isolation and identification of the organism.     

Localized cutaneous infection with Francisella tularensis resembling ulceroglandular tularemia in a cat.

A chronically draining subcutaneous mass was removed from the ventral cervical region of a 6-year-old spayed female Domestic Shorthair cat. The histopathologic diagnosis was severe locally extensive pyogranulomatous and necrotizing cellulitis. Bacterial culture yielded Francisella tularensis subsp. tularensis as the causative agent. Immunohistochemical evaluation of sections for F. tularensis was negative. One year later, the cat was euthanized because of progressive lethargy found to be due to hypertrophic cardiomyopathy with pulmonary thromboembolism. No evidence of cutaneous or systemic infection by F. tularensis was found at necropsy. This case appears to be a localized form of tularemia resembling the ulceroglandular form of tularemia in humans and suggests that bacterial culture may be more sensitive than immunohistochemistry in detecting organisms in cases of localized F. tularensis infection.     

West Nile virus infection of horses

West Nile virus (WNV) is a flavivirus closely related to Japanese encephalitis and St. Louis encephalitis viruses that is primarily maintained in nature by transmission cycles between mosquitoes and birds. Occasionally, WNV infects and causes disease in other vertebrates, including humans and horses. West Nile virus has re-emerged as an important pathogen as several recent outbreaks of encephalomyelitis have been reported from different parts of Europe in addition to the large epidemic that has swept across North America. This review summarises the main features of WNV infection in the horse, with reference to complementary information from other species, highlighting the most recent scientific findings and identifying areas that require further research.     

Isolation of Neisseria ovis and a Colesiota conjunctivae-like organism from cases of kerato-conjunctivitis in reindeer in northern Norway.

Eye inflammation in reindeer seems to be a condition frequently observed in many reindeer herding areas. Bergmann (1912) reported outbreaks of the condition in Scandinavia already at the beginning of this century, and it spread like a contagious disease. The aetiology seems to be complex, as Bergmann found many different kinds of bacteria in his material. In a recent publication, Rehbinder (1970) reported the occurrence of larvae of the reindeer nostril fly (Cephenomyia trompe) in affected eyes. In Norway, eye inflammation in reindeer has also been observed, although outbreaks of the disease seem to be rare.     

Francisella tularensis survey among ranchers and livestock in western Iran

Tularemia is a zoonotic disease that transmitted to humans and domestic animals by wildlife, especially rodents. There are some evidences of the circulation of F. tularensis in rodents, livestock, human populations, and surface waters in western parts of Iran. In this study, we investigated the exposure of livestock and ranchers to F. tularensis in the endemic regions of western Iran. Blood samples were collected from 289 sheep, 103 cattle, and 51 ranchers in 2018. Animal sera were tested by standard tube agglutination method. The specific IgGs against F. tularensis were evaluated by ELISA in human sera. Moreover, the extracted DNAs from 50 sheep spleen samples were evaluated using TaqMan real-time PCR for the presence of ISFtu2 and FopA genes. All animal sera and spleen samples were negative for tularemia. Of the 51 human samples, two samples were seropositive and one sample showed a borderline status for tularemia. Serologic evidence of F. tularensis in the ranchers but negative results in the livestock indicates different transmission routes in human populations and domestic animals in western Iran. Therefore, drinking contaminated water, contact to wildlife or rodents and arthropod bite should be considered as probable routes in the suspicious areas.     

Tularemia

Tularemia is a potentially fatal multi-systemic disease of humans and other animals caused by the bacterial pathogen Francisella tularensis. The disease can be transmitted by ticks, biting flies, water exposure, food, and aerosols and occurs around the northern hemisphere including North America, Europe, and Asia. There are several defined species and subspecies, including F. tularensis subsp. tularensis (Jellison Type A) which is pathogenic for rabbits and occurs in North America, F. tularensis subsp. holarctica (Type B) and mediaasiatica which are less pathogenic for rabbits, and F. tularensis subsp. novicida which has been regarded sometimes as the separate species F. novicida. Because it can have a high aerosol-related infection rate, low infectious dose, and ability to induce fatal disease, F. tularensis is considered a potential agent of biological warfare and is classified by the US Department of Health and Human Services as a List A select agent. We discuss microbiological, clinicopathological, epidemiological, and ecological aspects of tularemia.