Climate change is affecting human health worldwide. In particular, changes to local and global climate parameters influence vector and water-borne diseases like malaria, dengue fever, and tick-borne encephalitis. The Republic of Sakha in northern Russia is no exception. Long-term trends of increasing annual temperatures and thawing permafrost have corresponded with the northward range expansion of tick-species in the Republic. Indigenous communities living in these remote areas may be severely affected by human and livestock diseases introduced by disease vectors like ticks. To better understand the risk of vector-borne diseases in Sakha, we aimed to describe the increase and spatial spread of tick-bite cases in the Republic. Between 2000 and 2018, the frequency of tick bite cases increased 40-fold. At the start of the period, only isolated cases were reported in southern districts, but by 2018, tick bites had been reported in 21 districts in the Republic. This trend coincides with a noticeable increase in the average annual temperature in the region since the 2000s by an average of 1 °C. Maps illustrate the northward spread of tick-bite cases. A negative binomial regression model was used to correlate the increase in cases with a number of climate parameters. Tick bite case frequency per district was significantly explained by average annual temperature, average temperature in the coldest month of the year, the observation year, as well as Selyaninov’s hydrothermal coefficient. These findings contribute to the growing literature that describe the relationship between tick abundance and spread in Northern Latitudes and changes in temperatures and moisture. Future studies might use these and similar results to map and identify areas at risk of infestation by ticks, as climates continue to change in Sakha.

The results of the analysis of genetic characteristics for 15 microsatellite loci of the modern population of Yakut cattle of the gene pool enterprise of the State Enterprise of the Republic of Sakha (Yakutia) “Yakut Cattle” are presented. Yakut aboriginal cattle, considered one of the unique local breeds in Russia, are represented by a small population. It is distinguished by exceptionally high frost resistance (down to –60 Cº), unpretentiousness to living conditions and tolerance to insufficient nutrition. A comparative assessment of the allele pool of Yakut cattle was carried out on subpopulations of 7 farms: “Sakkyryr” of the Eveno-Bytantaisky ulus, “Kylys” of the Gorny ulus, “Taastaakh” of the Namsky ulus, “Kullegi” of the Amginsky ulus, “Onkhoi” of the Verkhnevilyuysky ulus, “Akana” of the Nyurbinsky ulus and “ Symakh” Megino-Kangalassky ulus. In total, data on 898 heads of purebred Yakut cattle were analyzed. Based on the results of the analysis, it was established that in all 15 microsatellite loci of Yakut cattle, polymorphism of alleles is widespread from 3 to 10. The most polymorphic is the TGLA53 locus, which has 10 alleles, despite this the number of effective alleles in this locus is only 2.76. Allele 160 (0.534) occurs with the highest frequency at this locus, and 188 (0.009) with the lowest frequency. In loci BM1818, INRA023, the smallest number of alleles was found – 3. Of all the analyzed loci, allele 256 of the SPS115 locus is observed with the highest frequency with an occurrence frequency of 0.733. The rarest alleles occurred with a frequency of 0.002 and 0.004. On average, the number of alleles per locus of indigenous Yakut cattle was 5.91 ± 0.46, which indicates a fairly high consolidation of the population of local purebred Yakut cattle and the lowest genetic diversity of the existing population of local cattle compared to cultivated breeds. A total of 90 alleles were identified in the Yakut cattle population.

The subgenus Megatrypanum Hoare, 1964, with the type species Trypanosoma theileri Laveran, 1902, comprises stercorarian trypanosomes of mammals. A substantial portion of this subgenus consists of T. theileri-like trypanosomes parasitizing cervids and bovids worldwide. Similar to most other members of the genus Trypanosoma that lack obvious economic importance, the biology of T. theileri-like trypanosomes remains poorly understood. In particular, fundamental aspects such as their host specificity, host–parasite interactions, and the morphology of developmental stages have been studied only to a limited extent. In this work, we provide a detailed description of the development and cellular organization of T. theileri-like trypanosomes in the horsefly Hybomitra montana using transmission electron microscopy (TEM). We show for the first time that T. theileri-like trypanosomes possess a well-developed cytostome–cytopharyngeal complex, morphologically similar to those in other stercorarian trypanosomes. This complex is present in the studied trypanosomes at the epimastigote stage and degrades during metacyclogenesis. In the host ileum, epimastigotes and trypomastigotes at different stages of metacyclogenesis are embedded in a fibrillar matrix that isolates them from the gut lumen. This promotes their accumulation in the vector, thereby increasing the efficiency of future infection of the vertebrate host, which occurs via contamination of the oral mucosa.

Цель: изучение видового разнообразия эндобионтной фауны северного домашнего оленя эвенской и чукотской породы. Материалы и методы. Проведены исследования содержимого преджелудков 69 взрослых северных оленей двух пород: чукотской породы из Нижнеколымского района (40 голов) и эвенской породы из Оймяконского района (29 голов). Сбор содержимого преджелудков проводился во время массового забоя домашних северных оленей в ноябре 2022 г. Промежуток времени после забоя оленя до взятия проб составлял не более 20-25 минут. Пробы фиксировали 10% раствором формалина. Определение видов проведено по определителям Догеля В.А., 1929; Корниловой О.А., 2003, 2010. Сравнение видового состава эндобионтных инфузорий фауны животных исследованных пород проведена по коэффициенту сходства Жаккара-Малышева (Kj-m) и индексу общности фаун Чекановского-Сьеренсена (Ics). Результаты. В результате проведенных исследований установлено, что видовое разнообразие эндобионтной фауны домашних северных оленей чукотской и эвенской пород не значительно, но отличается. Определен видовой состав эндобионтных инфузорий на основании морфологических и морфометрических исследований. Всего идентифицировано 18 видов инфузорий, относящихся к 9 родам, в том числе у оленей эвенской породы - 18 видов по 9  родам и у оленей чукотской породы - 13 видов по 6 родам. Основу общих видов инфузорий для оленей чукотской и эвенской пород, разводимых в Якутии, составляют 3 вида Entodinium, 3 вида Epidinium, по 2 вида Diplodinium и Ostracodinium, по 1 виду Polyplastron, Enoploplastron и Dasytricha. Большее видовое разнообразие эндобионтов эвенской породы можно объяснить тем, что эвенская порода относится к таежному типу с более широким многообразием поедаемых кормовых растений, чем у тундровых оленей чукотской породы.

Mammoth fauna found in the permafrost in Yakutia are usually well-preserved, with up to 90% of unique discoveries, including those with soft tissues and fossil animals with intact biological fluids. Despite the exceptional preservationconditions in the deep permafrost, the remains of woolly mammoth have not been used in paleoparasitological research. This article introduces the initial findings of a paleoparasitological investigation conducted on thawed samples obtained from a woolly mammoth. The research material consisted of the gastrointestinal contents of a woolly mammoth found in the Bulunsky district on the Bykovsky Peninsula in 2022. The mammoth’s remains were discovered in permafrost and were consistently frozen until sampling, maintaining their shape well. Traditional helminthological methods, such as native smear and the Fulleborn method, were used. For the first time, eggs and larvae of helminths from the Nematoda class, including the Ascaris eggs from the Ascaridata suborder, family Ascarididae Baird, 1853 were identified in frozen-thawed samples of the woolly mammoth. A total of 13 eggs were found, showcasing excellent preservation that allowed for visualization of eggs at various developmental stages and measurement of eggshell size and thickness. The diameter of the Ascaris eggs from the woolly mammoth (Mammutus primigenus (Blumenbach, 1799)) was 73.25 ± 1.47 microns, with a shell thickness of 4.10 ± 0.20 microns. Additionally, four varieties of whole larvae and larvae fragments of the Nemathelminthes type within the Nematoda class were identified for the first time. These discoveries contribute to our knowledge of ancient fossil animals parasites and require further exploration.