Almas Berdibekov

Orthohantaviruses are zoonotic pathogens that play a significant role in public health. These viruses can cause haemorrhagic fever with renal syndrome in Eurasia. In the Republic of Kazakhstan, the first human cases were registered in the year 2000 in the West Kazakhstan region. Small mammals can be reservoirs of orthohantaviruses. Previous studies showed orthohantavirus antigens in wild-living small mammals in four districts of West Kazakhstan. Clinical studies suggested that there might be further regions with human orthohantavirus infections in Kazakhstan, but genetic data of orthohantaviruses in natural foci are limited. The aim of this study was to investigate small mammals for the presence of orthohantaviruses by molecular biological methods and to provide a phylogenetic characterization of the circulating strains in Kazakhstan. Small mammals were trapped at 19 sites in West Kazakhstan, four in Almaty region and at seven sites around Almaty city during all seasons of 2018 and 2019. Lung tissues of small mammals were homogenized and RNA was extracted. Orthohantavirus RT-PCR assays were applied for detection of partial S and L segment sequences. Results were compared to published fragments. In total, 621 small mammals from 11 species were analysed. Among the collected small mammals, 2.4% tested positive for orthohantavirus RNA, one sample from West Kazakhstan and 14 samples from Almaty region. None of the rodents caught in Almaty city were infected. Sequencing parts of the small (S) and large (L) segments specified Tula virus (TULV) in these two regions. Our data show that geographical distribution of TULV is more extended as previously thought. The detected sequences were found to be split in two distinct genetic clusters of TULV in West Kazakhstan and Almaty region. TULV was detected in the common vole (Microtus arvalis) and for the first time in two individuals of the forest dormouse (Dryomys nitedula), interpreted as a spill-over infection in Kazakhstan.

Omsk haemorrhagic fever virus (OHFV) is the agent leading to Omsk haemorrhagic fever (OHF), a viral disease currently only known in Western Siberia in Russia. The symptoms include fever, headache, nausea, muscle pain, cough and haemorrhages. The transmission cycle of OHFV is complex. Tick bites or contact with infected small mammals are the main source of infection. The Republic of Kazakhstan is adjacent to the endemic areas of OHFV in Russia and febrile diseases with haemorrhages occur throughout the country—often with unclear aetiology. In this study, we examined human cerebrospinal fluid samples of patients with suspected meningitis or meningoencephalitis with unknown origins for the presence of OHFV RNA. Further, reservoir hosts such as rodents and ticks from four Kazakhstan regions were screened for OHFV RNA to clarify if this virus could be the causative agent for many undiagnosed cases of febrile diseases in humans in Kazakhstan. Out of 130 cerebrospinal fluid samples, two patients (1.53%) originating from Almaty city were positive for OHFV RNA. Screening of tick samples revealed positive pools from different areas in the Akmola region. Of the caught rodents, 1.1% out of 621 were positive for OHFV at four trapping areas from the West Kazakhstan region. In this paper, we present a broad investigation of the spread of OHFV in Kazakhstan in human cerebrospinal fluid samples, rodents and ticks. Our study shows for the first time that OHFV can not only be found in the area of Western Siberia in Russia, but can also be detected up to 1.600 km away in the Almaty region in patients and natural foci.

Цель работы. Определение длительности сохранения ДНК чумного микроба в костной ткани грызунов и его количественной динамики во времени под воздействием биотических (ДНК-азы посторонней микрофлоры) и абиотических (изменяющиеся влажность, температура, инсоляция) факторов. Материалы и методы. Невозможность в большинстве случаев провести датировку подобного полевого материала, приводит к снижению его информативности. О длительности сохранения капсульного антигена (FI) чумного микроба, выявляемого серологическим методом, в погадках и костях и динамики его снижения известно из более ранних исследований. После гибели подопытных животных, зараженных вирулентным штаммом чумного микроба, их скелеты освобождали от мягких тканей и помещали в условия, приближенные к естественным. Исследование костных останков на наличие в них фрагментов ДНК чумного микроба проводили непосредственно после гибели животных, а затем дважды в год. Результаты и выводы. Полученные данные позволили все костные останки павших от чумной инфекции млекопитающих условно разделить на три группы: с высоким, средним и низким содержанием бактерий. Дальнейшее их исследование показало, что через полгода в костной ткани животных снижения концентрации ДНК возбудителя чумы не происходит. После одного года зафиксировано резкое снижение (в 100 раз) наблюдаемых разведений материала, при которых еще возможно обнаружение детектируемых плазмид. Через полтора года наблюдений генов чумного микроба в костях экспериментальных животных обнаружить не удалось. С целью увеличения информативности при исследовании такого типа материала предложено воссоздать систему смотровых площадок по сбору погадок и костных останков млекопитающих.