31 research outputs found

    The deduced evolution history of Omsk hemorrhagic fever virus

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    Omsk hemorrhagic fever (OHF) is a severe disease that emerged in the 1940s in Siberia, Russia. It is caused by the OHF virus (OHFV), belonging to the Flavivirus genus. In wildlife, the principal vector of OHFV is the Dermacentor reticulatus tick. However, humans are mainly infected after contact with an infected muskrat Ondatra zibethicus. The evolutionary history of OHFV is not yet clarified. In an attempt to reconstruct the temporal and spatial phylodynamics of OHFV, a collection of 25 OHFV strains was studied. Maximum likelihood analysis, the Bayesian MCMC approach, and procedures based on continuous-time Markov Chain process, were used for the investigation of OHFV E gene nucleotide sequences. Six statistically supported clusters of OHFV were identified; five of them joined in a main clade A. The first revealed evolutionary event, when OHFV clade A and clade B divided, dated to about 700 years ago. Clusters C, D, and E, within clade A, separated 230 years ago and further evolved during last century. The phylogeographic analysis showed that clade A originated in the Omsk Province, whereas clusters B, C, and E appeared to originate in Kurgan, Novosibirsk, and Omsk Provinces, respectively. In conclusion, OHFV, as a member of the mammalian tick-borne group of flaviviruses, evolved in Western Siberia during the last millennium. When a highly susceptible species, O.zibethicus, was introduced into the region, in the 1930s, OHFV used this species as an amplifying host that lead to numerous fatal epizootics in muskrats and to human OHF outbreaks

    DNA haplotypes of the complement C6 and C7 genes associated with deficiencies of the seventh component; And a new DNA polymorphism in C7 exon 13

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    Eight common DNA polymorphisms have been described for the linked C6 and C7 genes. We now describe a ninth polymorphism in C7 exon 13 which is located in a tight cluster with two previously reported markers. We have used all these markers to investigate the heterogeneity of C7 deficiency. Five of the nine C7 deficient probands (resident in Ireland, South Africa, Russia and Israel) are heterozygous for C6/C7 haplotypes. Seven different C7 deficient haplotypes were found for C7 markers alone, but all the four Israelis share one and three out of four Irish haplotypes share another. The markers appear to be a good guide to the heterogeneity of C7 deficiency and have been useful in choosing homozygous subjects for the investigation of molecular defects.Articl

    High seroprevalence of Borrelia miyamotoi antibodies in forestry workers and individuals suspected of human granulocytic anaplasmosis in the Netherlands

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    Substantial exposure to Borrelia miyamotoi occurs through bites from Ixodes ricinus ticks in the Netherlands, which also transmit Borrelia burgdorferi sensu lato and Anaplasma phagocytophilum. Direct evidence for B. miyamotoi infection in European populations is scarce. A flu-like illness with high fever, resembling human granulocytic anaplasmosis, has been attributed to B. miyamotoi infections in relatively small groups. Borrelia miyamotoi infections associated with chronic meningoencephalitis have also been described in case reports. Assuming that an IgG antibody response against B. miyamotoi antigens reflects (endured) infection, the seroprevalence in different risk groups was examined. Sera from nine out of ten confirmed B. miyamotoi infections from Russia were found to be positive with the recombinant antigen used, and no significant cross-reactivity was observed in secondary syphilis patients. The seroprevalence in blood donors was set at 2.0% (95% CI 0.4–5.7%). Elevated seroprevalences in individuals with serologically confirmed, 7.4% (2.0–17.9%), or unconfirmed, 8.6% (1.8–23%), Lyme neuroborreliosis were not significantly different from those in blood donors. The prevalence of anti-B. miyamotoi antibodies among forestry workers was 10% (5.3–16.8%) and in patients with serologically unconfirmed but suspected human granulocytic anaplasmosis was 14.6% (9.0–21.8%); these were significantly higher compared with the seroprevalence in blood donors. Our findings indicate that infections with B. miyamotoi occur in tick-exposed individuals in the Netherlands. In addition, B. miyamotoi infections should be considered in patients reporting tick bites and febrile illness with unresolved aetiology in the Netherlands, and other countries where I. ricinus ticks are endemic

    A stochastic model for ecological systems with strong nonlinear response to environmental drivers: application to two water-borne diseases

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    Ecological systems with threshold behaviour show drastic shifts in population abundance or species diversity in response to small variation in critical parameters. Examples of threshold behaviour arise in resource competition theory, epidemiological theory and environmentally driven population dynamics, to name a few. Although expected from theory, thresholds may be difficult to detect in real datasets due to stochasticity, finite population size and confounding effects that soften the observed shifts and introduce variability in the data. Here, we propose a modelling framework for threshold responses to environmental drivers that allows for a flexible treatment of the transition between regimes, including variation in the sharpness of the transition and the variance of the response. The model assumes two underlying stochastic processes whose mixture determines the system's response. For environmentally driven systems, the mixture is a function of an environmental covariate and the response may exhibit strong nonlinearity. When applied to two datasets for water-borne diseases, the model was able to capture the effect of rainfall on the mean number of cases as well as the variance. A quantitative description of this kind of threshold behaviour is of more general application to predict the response of ecosystems and human health to climate change

    Combined vaccines in the national prevention immunization schedules for the children in Belarus, Kazakhstan, Russia and Ukraine

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    Еhe announcement of the east European expert group for vaccine prevention presents position of the leading specialists of Russia, Belarus, Ukraine and Kazakhstan on key issues of the national pre vention immunization schedule. the authors examine in detail the aspects of vaccination against hepatitis type b, including optimal term of injection of the first vaccine dose, vaccination tactics for the premature and low weight newborns, safety of recombinant vaccines against hepatitis type в. based on the analysis of the morbidity of h. influenzae type b invasive forms along with the methods recommended by who (HIB RAT), experts recommend introduction of the vaccine against this infection into the prevention immunization schedule. The experts believe the basis for the combined vaccines in pediatrics to be the vaccines with cellfree pertussis component. This class of vaccines allows introducing the additional booster dose of pertussis vaccines for immunization of the preschool children into the immunization schedule, which is dictated by the present epidemic situation with due account for this infection. The experts note the importance of application of the combined vaccines in pediatrics, whose wide implementation into healthcare system practices is in the interests of the parents, medical officers and society.Key words: hepatitis type в, h. influenzae type b, HIB RAT, pertussis, diphteria and tetanus toxoids and pertussis vaccine, poliovaccines, combined vaccines, prevention immunization schedule, children

    Combined vaccines in the national prevention immunization schedules for the children in Belarus, Kazakhstan, Russia and Ukraine

    No full text
    Еhe announcement of the east European expert group for vaccine prevention presents position of the leading specialists of Russia, Belarus, Ukraine and Kazakhstan on key issues of the national pre vention immunization schedule. the authors examine in detail the aspects of vaccination against hepatitis type b, including optimal term of injection of the first vaccine dose, vaccination tactics for the premature and low weight newborns, safety of recombinant vaccines against hepatitis type в. based on the analysis of the morbidity of h. influenzae type b invasive forms along with the methods recommended by who (HIB RAT), experts recommend introduction of the vaccine against this infection into the prevention immunization schedule. The experts believe the basis for the combined vaccines in pediatrics to be the vaccines with cellfree pertussis component. This class of vaccines allows introducing the additional booster dose of pertussis vaccines for immunization of the preschool children into the immunization schedule, which is dictated by the present epidemic situation with due account for this infection. The experts note the importance of application of the combined vaccines in pediatrics, whose wide implementation into healthcare system practices is in the interests of the parents, medical officers and society.Key words: hepatitis type в, h. influenzae type b, HIB RAT, pertussis, diphteria and tetanus toxoids and pertussis vaccine, poliovaccines, combined vaccines, prevention immunization schedule, children
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