Представлен анализ заболеваемости природно-очаговыми инфекционными болезнями бактериальной и вирусной этиологии, отражен объем их лабораторной диагностики на территории Сибири и Дальнего Востока в 2012 г. и прогноз развития эпидемиологической ситуации в 2013 г. Анализ выполнен на основании информации, поступившей в Референс-центр по мониторингу природно-очаговых инфекций при Иркутском научно-исследовательском противочумном институте из учреждений Роспотребнадзора Сибирского, Дальневосточного и Уральского федеральных округов, а также обзоров и прогнозов состояния природных очагов инфекций Алтайской, Тувинской, Читинской, Хабаровской и Приморской противочумных станций.
The review covers the main definitions and criteria for endemicity and enzooticity relating to natural focal zoonotic infections and, in particular, to leptospirosis. Since leptospirosis is widespread, and almost all territories are endemic for this disease, it is proposed to allocate a high, medium and low degree of endemicity on the basis of several criteria, primarily the population morbidity. The unevenness of endemicity is also important in the epidemiological analysis of the leptospirosis situation.
Retrospective epidemiological analysis of hemorrhagic fever with renal syndrome (HFRS) was performed in the Jewish Autonomous Region based on archival, statistical and operational data of 133 HFRS cases. Total 63 mammal samples were examined by ELISA and RT-PCR. Large-scale flooding in 2013 sharpened the epizootological condition and created the preconditions for epidemiological complications. The high increase in HFRS incidence in 2014 was characterized by the epidemiological process intensity displacement from the southern areas to least affected by flooding northern parts of the region and alteration of the seasonality corresponding to the maximum number of carriers in natural foci. Since 2015 a decrease of morbidity is observing. RNA and antigen of Hantaviruses were found in Apodemus agrarius and Microtus maximowiczii. Sequencing of L-gene fragment (334 bp) of RNA-containing samples showed their taxonomic affiliation to the three Hantaviruses: Khabarovsk, Hantaan and Puumala.
Aim of the study was to investigate the features of vaccine prevention of leptospirosis and its influence on morbidity.Materials and methods. The incidence of human leptospirosis in the Russian Federation in 1956–2016, 41 cases of disease in Siberia and the Far East in 2012–2016, official Rossel'khoznadzor data, volumes of laboratory studies and vaccination of animals in Primorsk Territory and Irkutsk Region were analyzed. Blood sera from 7315 humans, 2189 dogs, 481 bovine animals and 50 small cattle, 115 pigs, 88 horses were investigated to pathogenic Leptospira antibodies.Results. Essential significance of vaccinal leptospiroses prevention in farm animals and dogs to decrease the epizootic and epidemic process activities is demonstrated. Currently, the epidemic process in Siberia and at the Far East includes only sporadic cases, the immune stratum of the population is 3,7 ± 0,2%. Postvaccinal antibody titres in dogs, pigs and small cattle rarely exceed 1:100 while in bovine animals and horses it can reach 1:800 without disease signs.Conclusion. Human immunization in the antropurgic foci is impractical at effective specific prophylaxis for animals. The standard base for leptospiroses requires improvement. The concept of absolute and relative diagnostic antibody titer in microagglutination test is offered to use in clinical diagnostics. In veterinary the correction of diagnostic titer depending on the animal species and vaccination time is necessary.
Background. In presence the epizootiological situation on leptospirosis in the territories adjacent to Lake Baikal is not studied well. The showing up of natural focus, discovering of host animal’s species composition and etiological structure of leptospirosis causative agents are essential to plan any epidemiological response and to organize the specific prophylaxis.Aim: to analyze contemporary characteristics of leptospirosis natural foci at the territories adjacent to Lake Baikal.Materials and methods. From 2011 till 2020 the territory of nine Irkutsk Region's administrative districts was investigated. Trapping has been done at four kind of sites (wetland, meadow, forest-shrub, steppificated meadow) and boroughs. 1152 small mammals which belonged to 35 species were collected. Collected samples were studied by complex of methods. Serogroup belonging was detected by micro agglutination and decomposition test, and genomic species – by Microflex LT mass analyzer.Results. A leptospirosis natural foci in the Irkutsk city boundary was newly founded and there were isolated (from small mammals) four pathogenic cultures of leptospiras belonging to Javanica serogroup. Main hosts of causative agents at the territories adjacent to Lake Baikal were defined (insect-eating mammals: tundra shrew, largetoothed Siberian shrew, even-toothed shrew, shrew-mouse, and rodents: root vole, ground vole, narrow-skulled vole, sewer rat). By micro agglutination were defined pathogenic leptospirosis serogroups (Icterohaemorrhagiae, Grippotyphosa, Javanica, Pomona, Sejroe, Autumnalis, Australis), all over 2.4 ± 0.45 % seropositive. Antibody dilution at survey animals ranged from 1 : 20 to 1 : 640. On the grounds of PCR results the mean value of infected animals in studied sample was 16.4 ± 1.14 %. Positive PCR findings were at 19 from 35 animal species.Conclusion. At the territories adjacent to Lake Baikal In the Baikal region, the proportion of animals that have had contact with pathogenic leptospira is quite high. Natural focus of this infection are highly pervasive in this region, they are evolved mainly in dewy sites.
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