Epidemiology and Diversity of Echinococcus spp. in the Republic of Sakha, Russia

• Applicant: Dr. Marion Wassermann
• Subject Area: Medical Microbiology and Mycology, Hygiene, Molecular Infection Biology
• Term: from 2019 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 429483736

Echinococcosis is a worldwide zoonosis and considered by the WHO to be one of the most important “neglected diseases”. Species and genotypes of the causative agents, Echinococcus spp., differ greatly in infectivity and pathogenicity for animals and humans. For two of the most important human pathogenic species, E. multilocularis and E. canadensis, the geographical centre of genetic diversity seems to be in the Asian part of Russia. This hypothesis is based on individual studies with small sample sizes in which it was shown that several divergent genotypes of E. multilocularis occur in this area and neighbouring Mongolia, which indicates a geographic origin of E. multilocularis in this region. The same applies to E. canadensis, where three of the four worldwide known genotypes occur in domestic and wild animals in the Republic of Sakha. The knowledge about echinococcosis in Russia is mainly based on older studies, which are usually not published in international journals. However, it is known that both alveolar and cystic echinococcosis are widespread and frequent in animals and humans, but little information is available on the respective pathogens. In this project, the first systematic study on prevalence of Echinococcus spp. in the Republic of Sakha should be conducted, isolates in relevant sample sizes will be collected and molecularly analysed. E. multilocularis samples shall be collected in various ecological zones in northern and southern Sakha in order to analyse the distribution of genotypes among host species and habitats and to draw conclusions about transmission cycles. The most important hosts are arctic foxes (in the north), red foxes (in the south) and wolves (in the whole area) as final hosts, and various rodent species as intermediate hosts. For E. canadensis, a similar sampling pattern will be carried out, testing the hypothesis of two separate life cycles: a domestic cycle (domestic dog - reindeer) in the north, and sylvatic transmission (wolf - deer species) in the south. Sequence analyses of mitochondrial and selected nuclear genes will allow a comparison of haplotype patterns between geographically or ecologically distinct populations of parasites. In addition, intraspecific variability will be studied and compared with other regions in order to gather information on the geographical origin of the parasites. The investigation of parts of the nuclear genome will provide information on the frequency of hybridization events between sympatric genotypes and thus contribute to clarify the taxonomy of Echinococcus spp.. In addition, the data obtained will help to estimate the infection pressure on humans, since the different genotypes of both Echinococcus species seem to differ strongly in their infectivity and pathogenicity.

• DFG Programme: Research Grants
• International Connection: Russia
• Cooperation Partners: Privatdozentin Dr. Ludmila Mikhaylovna Kokolova, until 3/2022; Professor Dr. Innokentiy M. Okhlopkov, until 3/2022