Vectors, molecular epidemiology and phylogeny of TBEV in Kazakhstan and central Asia

Abstract

Background In the South of Kazakhstan, Almaty Oblastʼ (region) is endemic for tick-borne encephalitis, with 0.16–0.32 cases/100,000 population between 2016–2018. The purpose of this study was to determine the prevalence and circulating subtypes of tick-borne encephalitis virus (TBEV) in Almaty Oblastʼ and Kyzylorda Oblastʼ. Methods In 2015 we investigated 2341 ticks from 7 sampling sites for the presence of TBEV. Ticks were pooled in 501 pools and isolated RNA was tested for the presence of TBEV by RT-qPCR. For the positive samples, the E gene was amplified, sequenced and a phylogenetic analysis was carried out. Results A total of 48 pools were TBEV-positive by the RT-qPCR. TBEV-positive ticks were only detected in three districts of Almaty Oblastʼ and not in Kyzylorda Oblastʼ. The positive TBEV pools were found within Ixodes persulcatus, Haemaphysalis punctata and Dermacentor marginatus. These tick species prevailed only in Almaty Oblastʼ whereas in Kyzylorda Oblastʼ Hyalomma asiaticum and D. marginatus are endemic. The minimum infection rates (MIR) in the sampling sites were 4.4% in Talgar, 2.8% in Tekeli and 1.1% in Yenbekshikazakh, respectively. The phylogenetic analysis of the generated sequences indicates that TBEV strains found in Almaty Oblastʼ clusters in the Siberian subtype within two different clades. Conclusions We provided new data about the TBEV MIR in ticks in Almaty Oblastʼ and showed that TBEV clusters in the Siberian Subtype in two different clusters at the nucleotide level. These results indicate that there are different influences on the circulating TBEV strains in south-eastern Kazakhstan. These influences might be caused by different routes of the virus spread in ticks which might bring different genetic TBEV lineages to Kazakhstan. The new data about the virus distribution and vectors provided here will contribute to an improvement of monitoring of tick-borne infections and timely anti-epidemic measures in Kazakhstan.

Genomic Determinants Potentially Associated with Clinical Manifestations of Human-Pathogenic Tick-Borne Flaviviruses

“…ticks, but it was reported that Dermacentor reticulatus also might play a relevant role as a TBEV nature reservoir [ 38 ]. Moreover, TBEV was detected in pools of Haemaphysalis punctata [ 39 ] and other Haemaphysalis spp. [ 40 ].…”

Eight Years of Collaboration on Biosafety and Biosecurity Issues Between Kazakhstan and Germany as Part of the German Biosecurity Programme and the G7 Global Partnership Against the Spread of Weapons and Materials of Mass Destruction

“…The sequencing of E-genes of the virus revealed that Kazakh TBEV samples belong to two different clades of the Siberian subtype ( Figure 1D ). Three endemic tick species are responsible for the transmission of the virus ( 18 ). The results of these investigations were recognised by the Ministry of Health in Nur-Sultan.…”

Operationalizing Cooperative Research for Infectious Disease Surveillance: Lessons Learned and Ways Forward

“…Through the German Federal Foreign Office's German Biosecurity Program, the Bundeswehr Institute of Microbiology (BIM) and the Deutsche Gesellschaft für Internationale Zusammenarbeit GmbH (GIZ) have managed a project in Kazakhstan for the past seven years in collaboration with key Kazakh partners including the aforementioned NSCEDI at the CRL and the Research Institute for Biosafety Problems (RIBSP). Under the auspices of the G7 Global Partnership against the Spread of Weapons and Materials of Mass Destruction, the GBP focuses on surveillance, detection and diagnostics, biosafety and biosecurity including work published on Crimean Congo haemorrhagic fever, tick-borne encephalitis virus, Rickettsia and orthohantaviruses (9)(10)(11)(12).…”