Tularemia Outbreak Investigation in Kosovo: Case Control and Environmental Studies (original) (raw)
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Virology: Research and Reviews, 2017
Tularemia is a vector-borne zoonosis with a complex epidemiology caused by Francisella tularensis. F. tularensis is a non-motile, obligatory aerobic, facultative intracellular Gram-negative coccobacillus. The bacterium has a broad host range, i.e. mammals, birds and invertebrates. Two types (A, B) and four subspecies (F. tularensis subsp. tularensis (type A), F. tularensis subsp. holarctica (type B), F. tularensis subsp. mediasiatica and F. tularensis subsp. novicida.) are known today. Types A and B are of importance as they cause disease in humans and animals. Type A is present almost exclusively in North America and type B is found all over the Northern hemisphere. F. tularensis is considered to be a class A biological warfare agent, it is notoriously difficult to recognize infections in non-endemic regions and was produced as a weaponized agent by several countries in the 1960ties and 70ties. Humans can acquire tularemia by inhaling dust or aerosols contaminated with F. tularensis bacteria, this type of exposure can result in pneumonic tularemia, one of the most severe forms of the disease. especially farming involving machines that disperse remains of infected animals or carcasses. Rarely, water can become tularemia contaminated through contact with infected animals. Humans who drink contaminated and untreated water may contract oropharyngeal tularemia. The tularemia outbreak in B&H in 1995 showed an unusual number of oropharyngeal cases. As all aspects of this particular tularemia epidemic were not thoroughly investigated and the possible intentional use of agents of biological warfare remained a possibility, we reviewed all available data in order to assess whether the outbreak was natural.
Vector-Borne and Zoonotic Diseases, 2015
Tularemia is a re-emerging bacterial zoonosis, broadly distributed across the northern hemisphere. In Georgia, there is a history of human tularemia outbreaks dating back to the 1940s. In response to outbreaks, health officials initiated long-term field surveillance and environmental monitoring. The objective of our study was to obtain information from 57 years of field surveys to identify species that play a role in the occurrence Francisella tularensis subsp. holarctica in the environment in Georgia. We collected historical data on human outbreaks, field collections, population dynamics of the common vole (Microtus arvalis), and conducted surveys on small mammals and vectors from five regions in Georgia during 1956-2012. Bacterial isolation was conducted using standard culturing techniques, and isolation rates for species were obtained for a subset of years. We used a Spearman rank correlation to test for associations between the density of the common vole and isolation rates. From 1956 through 2012, there were four recorded outbreaks of human tularemia (362 cases). A total of 465 bacterial isolates of F. tularensis subsp. holarctica were obtained from 27 species and environmental samples. The number of isolations was highest in the common vole (M. arvalis; 149 isolates; 32%) and Dermacentor marginatus ticks (132 isolates; 28%); isolation rates ranged between 0-0.91% and 0-0.47%, respectively. Population dynamics of the common vole were not correlated with the isolation rate. Given the history of tularemia re-emergence in Georgia, continued field surveys and environmental monitoring may provide an early indication of outbreak risk in humans. In conclusion, our findings provide evidence of longstanding foci of F. tularensis subsp. holarctica that are likely maintained by the common vole-tick cycle.
The Lancet Infectious Diseases, 2008
Epidemic typhus is transmitted to human beings by the body louse Pediculus humanus corporis. The disease is still considered a major threat by public-health authorities, despite the effi cacy of antibiotics, because poor sanitary conditions are conducive to louse proliferation. Until recently, Rickettsia prowazekii, the causal agent, was thought to be confi ned to human beings and their body lice. Since 1975, R prowazekii infection in human beings has been related to contact with the fl ying squirrel Glaucomys volans in the USA. Moreover, Brill-Zinsser disease, a relapsed form of epidemic typhus that appears as sporadic cases many years after the initial infection, is unrelated to louse infestation. Stress or a waning immune system are likely to reactivate this earlier persistent infection, which could be the source of new epidemics when conditions facilitate louse infestation. Finally, R prowazekii is a potential category B bioterrorism agent, because it is stable in dried louse faeces and can be transmitted through aerosols. An increased understanding of the pathogenesis of epidemic typhus may be useful for protection against this bacterial threat.
Tularemia Outbreak, Bulgaria, 1997–2005
Emerging Infectious Diseases, 2006
The 1997-2005 tularemia outbreak in Bulgaria affected 285 people. Ten strains were isolated from humans, a tick, a hare, and water. Amplified fragment length polymorphism typing of the present isolates and of the strain isolated in 1962 suggests that a new genetic variant caused the outbreak.
Tularaemia: A Re-Emerging Infectious Zoonotic Disease of Public Health Significance
Tularemia is a re-emerging bacterial disease that affects humans, wild animals, and domestic animals. The disease is caused by Francisella tularensis that is found all over the world, but it is most commonly reported in North America, a few Scandinavian and Asian countries. The disease can occur in sporadic and epidemic form. Humans acquire the infection through the handling or ingestion of infected animals, vector bites, interaction with the aquatic environment, and aerosol inhalation. The disease classically manifests by the ulceroglandular, glandular, oculoglandular, oropharyngeal, respiratory and typhoidal forms. A rapid onset of fever, chills, headaches, diarrhea, muscular aches, joint pain, dry cough, and increasing weakening are all common symptoms. Because of its low infectious dose, ability to survive in the environment, and ability to be easily disseminated by aerosol, Francisella tularensis has been designated as a "category A" agent of greatest concern for bioterrorism. Laboratory help that include microbiological, immunological and molecular techniques is needed to make an unequivocal diagnosis of disease. In untreated patients, the fatality may be high. Tularemia can be prevented by using insect repellent, wearing gloves when handling sick or dead animals, thoroughly cooking game meat before eating it and not drinking untreated water. Prophylactic treatment and health education of the high risk groups is imperative.
Tularemia Goes West: Epidemiology of an Emerging Infection in Austria
Microorganisms
The zoonotic disease tularemia is caused by the Gram-negative bacterium Francisella tularensis, with the two major subspecies tularensis and holarctica being responsible for infections in humans and animals. The F. tularensis subspecies holarctica is less virulent and prevalent in Europe and Asia. Over the last few centuries, few epidemic outbreaks and low numbers of infections have been registered in the eastern part of Austria, specifically in the provinces of Lower Austria, Burgenland, and Styria. The reported infections were mostly associated with hunting hares and the skinning of carcasses. Within the last decade, ticks have been identified as important vectors in Tyrol and served as first evidence for the spread of F. tularensis to Western Austria. In 2018, the pathogen was detected in hares in the provinces of Tyrol, Vorarlberg, and Salzburg. We presume that F. tularensis is now established in most regions of Austria, and that the investigation of potential host and vector an...
Tularemia among Free-Ranging Mice without Infection of Exposed Humans, Switzerland, 2012
Emerging Infectious Diseases, 2015
The animals primarily infected by Francisella tularensis are rapidly consumed by scavengers, hindering ecologic investigation of the bacterium. We describe a 2012 natural tularemia epizootic among house mice in Switzerland and the assessment of infection of exposed humans. The humans were not infected, but the epizootic coincided with increased reports of human cases in the area.
Environmental surveillance during an outbreak of tularaemia in hares, the Netherlands, 2015
Eurosurveillance
Tularaemia, a disease caused by the bacterium Francisella tularensis, is a re-emerging zoonosis in the Netherlands. After sporadic human and hare cases occurred in the period 2011 to 2014, a cluster of F. tularensis-infected hares was recognised in a region in the north of the Netherlands from February to May 2015. No human cases were identified, including after active case finding. Presence of F. tularensis was investigated in potential reservoirs and transmission routes, including common voles, arthropod vectors and surface waters. F. tularensis was not detected in common voles, mosquito larvae or adults, tabanids or ticks. However, the bacterium was detected in water and sediment samples collected in a limited geographical area where infected hares had also been found. These results demonstrate that water monitoring could provide valuable information regarding F. tularensis spread and persistence, and should be used in addition to disease surveillance in wildlife.