IDENTIFICATION OF THEILERIA EQUI IN HORSE BLOOD IN THE IRKUTSK REGION

This paper describes the detection of Piroplasmida DNA in the blood of horses. 166 blood samples of horses from five districts of the Irkutsk region were studied. The high piroplasms infection rate in horses (69 %) was found. For six positive samples nucleotide sequences were determined. The comparison of determined 18S rRNA gene sequences with previously published sequences showed that all revealed piroplasms DNA samples are Theileria equi. The data are presented on the lethal cases of equine piroplasmosis in the Irkutsk region in 2008

Epizootic Situation on Anaplasmosis of Small Ruminants in the Irkutsk Region

Anaplasmosis of ruminants is a group of natural focal infections caused by bacteria from the genus Anaplasma of the Anaplasmataceae family. The main etiological agent of anaplasmosis in sheep, goats, and wild ruminants is Anaplasma ovis, which parasitizes in the erythrocytes of these animals. The purpose of this study was the finding and identification of Anaplasma spp. in the blood of small ruminants using genetic methods and obtaining data on the distribution of anaplasmosis in the Irkutsk region. 20 goat blood samples, 611 sheep blood samples and 209 Dermacentor nuttalli ticks from 12 districts of the Irkutsk region were examined for the presence of Anaplasma spp. Only one type of anaplasma, A. ovis, was found among the genotyped samples. A. ovis was found in the blood of sheep and goats in all of the studied districts of the Irkutsk region. The proportion of sheep blood samples containing anaplasma DNA varied from 30 % to 85 %, in goats – from 10 % to 100 % in different districts, and averaged 57.8 % in sheep and 55,0 % in goats. Frequency of infection of D. nuttalli ticks with A. ovis was 5.7 %. The nucleotide sequences of the samples detected in the blood of small ruminants on the territory of the Irkutsk region differed from each other by a single nucleotide substitution and were identical to the sequences of the type strain Haibei, as well as the sequences of A. ovis previously found in the blood of sheep from Mongolia, deer from China, and Dermacentor niveus and Dermacentor nuttalli ticks from China. These sequences were also identical to the sequences previously found in the blood of sheep from Altai and in Dermacentor nuttalli ticks from Tuva, which indicates the wide distribution of these A. ovis genovariants in Siberia and the probable role of D. nuttalli as a carrier of the agent of anaplasmosis of small ruminants in the Irkutsk region

Identification of the etiological agent of equine piroplasmosis in Western and Eastern Siberia

Equine piroplasmosis is a natural tick-borne infection caused by hemoprotozoan parasites of the order Piroplasmida, Babesia caballi and Theileria equi. Animals that recover from piroplasmosis remain persistently infected carriers and can transmit pathogens to vector ticks. Cases of equine piroplasmosis are periodically observed in Siberia, however, no agent of equine piroplasmosis has yet been genetically characterized in Russia. The aim of this work was studying the prevalence of the infectious agents of piroplasmosis in horses from Siberia and genotyping the detected agents. Blood samples from 155 horses were examined for the presence of Babesia and Theileria DNA by nested PCR with the subsequent sequencing of positive samples. DNA of T. equi was found in blood samples from 57.9 %, 38.5 % and 65.0 % of horses from Novosibirsk province, Irkutsk province, and the Republic of Altai, respectively. T. equi DNA was found in the samples from almost all sampling sites included in this study, indicating that most of the studied sites are endemic for equine theileriosis. Surprisingly, DNA of B. caballi was not found in any of the samples examined, even though this agent had previously been detected in many regions in Russia, including Altai. The analysis of the determined 18S rRNA gene sequences demonstrated that T. equi samples belonged to two genetic groups, which differed significantly by the sequences of the variable (V4) region of the gene. All T. equi sequences from group B were identical and corresponded to T. equi sequences found in the blood of horses from China and Korea, while T. equi sequences from group A differed by 1–5 nucleotide substitutions and were identical to the sequences from the blood of horses from India and Brazil or differed from them by single mismatches. Notably, in this study the presence of etiological agent of piroplasmosis in blood samples from horses in Russia was genetically confirmed for the first time

Pollen productivity estimates of key European plant taxa for quantitative reconstruction of past vegetation: a review

International audienceInformation on the spatial distribution of past vegetation on local, regional and global scales is increasingly used within climate modelling, nature conservancy and archaeology. It is possible to obtain such information from fossil pollen records in lakes and bogs using the landscape reconstruction algorithm (LRA) and its two models, REVEALS and LOVE. These models assume that reliable pollen productivity estimates (PPEs) are available for the plant taxa involved in the quantitative reconstruc -tions of past vegetation, and that PPEs are constant through time. This paper presents and discusses the PPEs for 15 tree and 18 herb taxa obtained in nine study areas of Europe. Observed differences in PPEs between regions may be explained by methodological issues and environmental variables, of which climate and related factors such as reproduction strategies and growth forms appear to be the most important. An evaluation of the PPEs at hand so far suggests that they can be used in modelling applications and quantitative reconstructions of pastvegetation, provided that consideration of past environmental variability within the region is used to inform selection of PPEs, and bearing in mind that PPEs might have changed through time as a response to climate change. Application of a range of possible PPEs will allow a better evaluation of the results

Development of A Hyperparameter Optimization Method for Recommendatory Models Based on Matrix Factorization

Many advanced recommendatory models are implemented using matrix factorization algorithms. Experiments show that the quality of their performance depends significantly on the selected hyperparameters. Analysis of the effectiveness of using various methods for solving this problem of optimizing hyperparameters was made. It has shown that the use of classical Bayesian optimization which treats the model as a «black box» remains the standard solution. However, the models based on matrix factorization have a number of characteristic features. Their use makes it possible to introduce changes in the optimization process leading to a decrease in the time required to find the sought points without losing quality. Modification of the Gaussian process core which is used as a surrogate model for the loss function when performing the Bayesian optimization was proposed. The described modification at first iterations increases the variance of the values predicted by the Gaussian process over a given region of the hyperparameter space. In some cases, this makes it possible to obtain more information about the real form of the investigated loss function in less time. Experiments were carried out using well-known data sets for recommendatory systems. Total optimization time when applying the modification was reduced by 16 % (or 263 seconds) at best and remained the same at worst (less than 1-second difference). In this case, the expected error of the recommendatory model did not change (the absolute difference in values is two orders of magnitude lower than the value of error reduction in the optimization process). Thus, the use of the proposed modification contributes to finding a better set of hyperparameters in less time without loss of qualit

Influence of Specific Leptospirosis Prevention to Epidemic Process

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

Lessons learnt from measures taken to prevent rabies introduction and spread into a long rabies free territory (case study of the Irkutsk Oblast)

Rabies is endemic on the considerable part of the Russian Federation, and it is associated with current natural outbreaks of the infection. The highest animal morbidity rates are reported in the central and southern regions of the European part of Russia and in the southern part of Western Siberia. The Irkutsk Oblast is among the few regions of our country, which are rabies free for several decades. The research was aimed at the analysis of factors aiding to the maintenance of the rabies free status of the region. Retrospective study of archive and previously published reports on human and animal rabies cases in the Irkutsk Oblast starting from 1954 was performed. Epidemics of urban rabies ceased in the region in 1970s. Sporadic rabies cases in dogs, reported in 1976 and later, could be imported or could result from the infection from bats. Diagnostic errors were also possible. Rabies is reported in foxes in the Subjects bordering the Irkutsk Oblast: Krasnoyarsk Krai and Republic of Buryatia. It is supposed that in case of the infection introduction the forest-steppe agricultural areas near the Angara River are likely to be affected due to high population of foxes. Relative geographic isolation of the Irkutsk Oblast favors to the long animal rabies freedom of this territory. The vast area of mountain taiga with low fox population serves as an ecological barrier. In 2007–2009 and in 2019, barrier oral vaccination was carried out along the border with the Krasnoyarsk Krai and on the west coast of Baikal Lake. Measures for anti-rabies vaccination of dogs and cats were intensified. Active virological monitoring is performed on a regular basis. The paper demonstrates cartograms of fox and wolf population density along with designation of sites, where oral vaccination of wild carnivores was performed

Veget Hist Archaeobot (2008) 17:461–478 DOI 10.1007/s00334-008-0148-8 REVIEW Pollen productivity estimates of key European plant taxa

for quantitative reconstruction of past vegetation: a revie