Background: Francisella tularensis, the causative agent of tularemia, is a zoonotic agent that remains across much of the northern hemisphere, where it exists in enzootic cycles. In Ukraine, tularemia has a long history that suggests a need for sustained surveillance in natural foci. To better characterize the host-vector diversity and spatial distribution of tularemia, we analyzed historical data from field collections carried out from 1941 to 2008.
BackgroundFrancisella tularensis, the causative agent of tularemia, is a zoonotic agent that remains across much of the northern hemisphere, where it exists in enzootic cycles. In Ukraine, tularemia has a long history that suggests a need for sustained surveillance in natural foci. To better characterize the host-vector diversity and spatial distribution of tularemia, we analyzed historical data from field collections carried out from 1941 to 2008.FindingsWe analyzed the spatial-temporal distribution of bacterial isolates collected from field samples. Isolates were characterized by source and dominant land cover type. To identify environmental persistence and spatial variation in the source of isolation, we used the space-time permutation and multinomial models in SaTScan. A total of 3,086 positive isolates were taken from 1,084 geographic locations. Isolation of F. tularensis was more frequent among arthropods [n = 2,045 (66.3%)] followed by mammals [n = 619 (20.1%)], water [n = 393 (12.7%)], and farm produce [n = 29 (0.94%)], respectively. Four areas of persistent bacterial isolation were identified. Water and farm produce as sources of bacterial isolation were clustered.ConclusionsOur findings confirm the presence of long-standing natural foci of F. tularensis in Ukraine. Given the history of tularemia as well as its environmental persistence there exists a possibility of (re)emergence in human populations. Heterogeneity in the distribution of tularemia isolate recovery related to land cover type supports the theory of natural nidality and clusters identify areas to target potential sources of the pathogen and improve surveillance.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-014-0453-2) contains supplementary material, which is available to authorized users.
Leptospirosis remains one of the most widespread natural-focal, zoonotic infectious diseases in the world and in Ukraine. Leptospirosis is enzootic in the entire territory of Ukraine. Cases of diseases are registered in all regions of Ukraine. We initiated a study of comparative analysis of territorial distribution of leptospirosis outbreaks among animals and incidence in humans in Ukraine covering the years 2009–2016 inclusive. This study of the incidence of leptospirosis in Ukraine shows a significant circulation of leptospirosis both among humans and animals. Among cattle herds in Ukraine the percentage of positive animals was found to be 4.2% of the surveyed population. The dominant serovars of Leptospira were kabura (12.4%) and polonica (9.5%). Positive reactions with other serovars were observed less frequently: tarassovi – 5.1%, bratislava – 4.9%, copenhageni – 4.1%, grippotyphosa – 2.4%, pomona – 1.1%, canicola – 1.0%. In pigs, the percentage of positive animals amounted to 3.2%, the dominant serovars of Leptospira were bratislava (29.1%) and copenhageni (25.1%). Positive reactions with other serovars were observed less frequently: tarassovi – 4.3%, canicola – 3.0%, pomona – 2.7%, grippotyphosa – 1.3%, polonica – 1.2%, kabura – 0.6%. In horses, the percentage of positive animals amounted to 9.5% of the surveyed population. The serological range of Leptospira in horses was as follows: copenhageni – 14.2%, bratislava – 12.1%, canicola – 6.8%, grippotyphosa – 4.8%, tarassovi – 4.7%, pomona – 2.1%, kabura – 1.4%, polonica – 1.3%. Analysis of the results of research indicates extensive circulation of leptospirosis among humans in Ukraine as evidenced by the percentage of humans positively responding to MAT – 12.1% of the studied samples. The etiological structure of leptospirosis cases includes all the 14 serovars of the diagnostic set. The basis of the etiological spectrum was the serovar copenhageni – 37.3%. The share of other serovars as the etiological factor of leptospirosis in humans was different in different spans of the considered period. Most frequently, those were kabura – 12.3%, grippotyphosa – 11.7%, canicola – 9.5%, pomona – 9.1%. We mapped annual incidence of leptospirosis in animals and humans. Choropleth maps of annual leptospirosis incidence and cluster maps show opposite spatial patterns for animals and humans. The highest human rates were in the western and central parts of the country while the highest animal rates were mainly in the eastern part.
IntroductionAnthrax is an acute especially dangerous infectious disease ofanimals and humans.Bacillus anthracisis a potential bioterrorismtool. In Ukraine, there are favorable natural conditions for the spreadof anthrax. There are 13.5 thousand of constantly anthrax-troubledpoints. Anthrax epidemic situation in Ukraine could be characterizedas unstable. Because of the continuing reform of Ukrainian humanhealth entities, the State Sanitary Epidemiological Service (SSES) haslost its control functions and is remaining in an uncertain state, whichincreases possible risks.MethodsEpidemiological analysis of official data has been performedusing information from the following sources: State SanitaryEpidemiological Service of Ukraine (SSES), State Veterinary andPhytosanitary Service of Ukraine, and analytical materials fromSI UCDCM. Collected papers Distribution and EpidemiologicalCharacteristics of Major Human Infectious Diseases in Ukraine(Kyiv Research Institute of Epidemiology, Microbiology andParasitology, 1976) were also used during the study. Materials werecompiled for the period from 1945 to 2015.ResultsIn the early XX century, more than 10,000 cases of anthrax inhumans were annually registered in tsarist Russia. In 1913, 1,473cases of anthrax in animals were recorded only in Kherson province(currently, Kherson oblast of Ukraine). The morbidity among humansincreased again during the WWII. In the late 40s, massive epizooticanthrax among animals was eliminated and morbidity among peoplesignificantly reduced because of planned government measures,strengthened veterinary, sanitary, and epidemiological surveillance.Since 1950, significant reduction of incidence of human anthrax hasbeen being recorded in Ukraine.Since 1964, certification and mapping of persistent anthrax-troubled points in Ukraine have been being performed.Compulsory vaccination of people against anthrax was cancelledand compulsory vaccination of all livestock was introduced in 1990.The period from 1976 to 1993 is characterized as epidemically safe.Single cases of the disease in human were registered with intensityrates of 0.01 – 0.002 per 100,000 population (excluding 1985).No human cases were registered during the certain years: 1978, 1982,1987, 1988.The epidemic situation complicated during the period 1994-2001. The following outbreaks were registered:Table 1. Total number of disease cases/ including the numberof cases during outbreaks within regionsThe main reason for the complication of the epidemiologicalsituation was weakening of epidemiological and veterinarysurveillance during the economic crisis characterizing this period.Epizootiological outbreaks arose from incomplete anti-anthraxvaccination of agricultural animals and from violation of veterinary-sanitary rules for their keeping as well. More than 80% of humaninfection cases happened resulting compelled cattle slaughtering,while the rest 20% resulted from meat product distribution andconsumption without corresponding sanitary-veterinary expertise.Six human cases of anthrax were registered during 2002-2015.Fig. 1. Dynamics of anthrax cases in humans in Ukraine during1945 – 2015 (absolute numbers)Table 2. Chronology of anthrax epidemiological surveillancemilestones in UkraineConclusionsRelative wellbeing regarding anthrax in Ukraine persists owing tothe implementation of ruled veterinary-sanitary activities and statesanitary epidemiological surveillance in meat- and leather-processingindustries as well as because of active food control.The main risks, which could trigger complication in the currentepidemiological situation with anthrax, are the following:1) Uncertainty in the system of sanitary-epidemiological andveterinary surveillance, which resulted from the reformation of theState Sanitary-Epidemiological and State Veterinary services.2) Existence of favorable conditions for anthrax agent circulation(considerable number of persistent anthrax-troubled points in allregions).3) Economic instability in the country.4) Uncontrolled epidemic situation in the zone of the Anti-terroristoperation (Donetsk and Luhansk oblasts).
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