Tick-borne encephalitis virus and West-Nile fever virus as causes of serous meningitis of unknown origin in Kazakhstan.

Flaviviruses are a family of viruses that cause many diseases in humans. Their similarity in the antigenic structure causes a cross-reaction, which complicates the precise diagnostic of disease causing agents. Tick-borne encephalitis virus (TBEV), a member of the flavivirus family, is the cause of tick-borne encephalitis (TBE). Worldwide the awareness of this disease is raising, however, in many countries such as the Republic of Kazakhstan (KZ) there is a lack of serological investigation of flaviviruses in humans. In our study, we focused on two TBE endemic regions of KZ (East Kazakhstan Oblast (EKO) and Almaty (AO)) and a region where TBE cases were registered only since 2010 (Akmola Oblast (AkO)). In KZ, up to 400 cases of serous meningitis of unknown origin were registered annually in the period from 2017 to 2019. Our goals were to calculate the prevalence of antibodies against TBEV in patients with suspected meningitis. We collected 179 sera and 130 cerebrospinal fluid (CSF) samples from patients and included a questionnaire with focus on socio-demographical factors and observed tick bites. The human samples were tested with TBEV and West-Nile fever virus (WNFV) IgM and IgG ELISA, by immunofluorescence assay using a flavivirus biochip, and TBEV-specific real-time RT-PCR. We found TBEV and WNFV antibodies in 31 samples by serological and molecular techniques. Seven serum samples out of 31 showed TBEV-specific antibodies, and three serum pairs had WNFV antibodies. Correlating the serological results with the information gained from the questionnaires it becomes apparent that the number of tick bites is a significant factor for a TBEV infection. This result has an impact on diagnostic in KZ and physicians should be aware that both flaviviruses play a role for serous meningitis of unknown origin in KZ.

Occurrence of Anti-Rickettsia spp. Antibodies in Hospitalized Patients with Undifferentiated Febrile Illness in the Southern Region of Kazakhstan.

Undifferentiated febrile illness still represents a demanding medical problem all over the world, but primarily in low- and middle-income countries. Scientific and clinical investigations related to undifferentiated febrile illness and rickettsial diseases in Kazakhstan are lacking. This study reflects the investigation of antibodies against spotted fever group (SFG) and typhus group (TG) rickettsiae in patients with undifferentiated febrile illness in the southern region of Kazakhstan (Almaty and Kyzylorda oblasts). Paired serum samples were gathered from 13 hospitals in these two oblasts and explored for the presence of IgM and IgG antibodies against typhus group and IgG antibodies against spotted fever group rickettsiae using ELISA. Patient's questionnaires were statistically analyzed. In total, 802 inpatients from Almaty (N = 9) and Kyzylorda (N = 4) hospitals were included in this research. Based on ELISA results, 250 patients out of 802 (31.2%) from both oblasts had IgG antibodies against SFG rickettsiae. Results from 11 (1.4%) patients indicated acute infection with tick-borne rickettsiosis. Regarding TG rickettsiae (R. typhi), a past infection was detected in 248 (30.9%) febrile patients and acute infection in 22 (2.7%) patients in the two selected oblasts. The data indicated that SFG and TG rickettsioses are present in Kazakhstan. Kazakh physicians should be aware of these emerging diseases in both investigated oblasts because the occurrence of these diseases is not suspected during day-to-day clinical practice. The identification of rickettsial pathogens and implementation of modern laboratory methods for the diagnostics of rickettsioses are in need throughout Kazakhstan.

Monitoring of pathogenic Borrelia burgdorferi sensu lato in the Almaty oblast, Kazakhstan.

Lyme borreliosis (LB) is one of the most common vector-borne diseases transmitted by ticks. It is caused by the Borrelia burgdorferi sensu lato (s.l.) genospecies. The Almaty oblast of Kazakhstan is considered endemic for LB. Nevertheless, there are significant gaps in the tick surveillance for LB agents in the region. We evaluated B. burgdorferi s.l. prevalence in 413 ixodid ticks collected from bitten people and the seroprevalence of antibodies to B. burgdorferi s.l. in 589 residents of the Almaty oblast, Kazakhstan. All samples were collected between 2018 and 2020. Borrelia burgdorferi s.l. DNA was detected in 24 % (9/38) of I. persulcatus ticks that attacked humans in the city of Almaty and the Talgar and Karasay districts. Multilocus sequence typing identified two novel B. afzelii sequence types in I. persulcatus. The seroprevalence of IgG antibodies against B. burgdorferi s.l. in the analyzed population was detected to be 5.8 %. The obtained results confirm active circulation of B. burgdorferi s.l. in the Almaty oblast of Kazakhstan and raise concern regarding LB preventive measures in the region.

Vector-borne and zoonotic infections and their relationships with regional and socioeconomic statuses: An ID-IRI survey in 24 countries of Europe, Africa and Asia.

BACKGROUND: In this cross-sectional, international study, we aimed to analyze vector-borne and zoonotic infections (VBZI), which are significant global threats. METHOD: VBZIs' data between May 20-28, 2018 was collected. The 24 Participatingcountries were classified as lower-middle, upper-middle, and high-income. RESULTS: 382 patients were included. 175(45.8%) were hospitalized, most commonly in Croatia, Egypt, and Romania(P = 0.001). There was a significant difference between distributions of VBZIs according to geographical regions(P < 0.001). Amebiasis, Ancylostomiasis, Blastocystosis, Cryptosporidiosis, Giardiasis, Toxoplasmosis were significantly more common in the Middle-East while Bartonellosis, Borreliosis, Cat Scratch Disease, Hantavirus syndrome, Rickettsiosis, Campylobacteriosis, Salmonellosis in Central/East/South-East Europe; Brucellosis and Echinococcosis in Central/West Asia; Campylobacteriosis, Chikungunya, Tick-borne encephalitis, Visceral Leishmaniasis, Salmonellosis, Toxoplasmosis in the North-Mediterranean; CCHF, Cutaneous Leishmaniasis, Dengue, Malaria, Taeniasis, Salmonellosis in Indian Subcontinent; Lassa Fever in West Africa. There were significant regional differences for viral hemorrhagic fevers(P < 0.001) and tick-borne infections(P < 0.001), and according to economic status for VBZIs(P < 0.001). The prevalences of VBZIs were significantly higher in lower-middle income countries(P = 0.001). The most similar regions were the Indian Subcontinent and the Middle-East, the Indian Subcontinent and the North-Mediterranean, and the Middle-East and North-Mediterranean regions. CONCLUSIONS: Regional and socioeconomic heterogeneity still exists for VBZIs. Control and eradication of VBZIs require evidence-based surveillance data, and multidisciplinary efforts.

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

BACKGROUND: In the South of Kazakhstan, Almaty Oblast' (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 Oblast' and Kyzylorda Oblast'. 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 Oblast' and not in Kyzylorda Oblast'. The positive TBEV pools were found within Ixodes persulcatus, Haemaphysalis punctata and Dermacentor marginatus. These tick species prevailed only in Almaty Oblast' whereas in Kyzylorda Oblast' 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 Oblast' clusters in the Siberian subtype within two different clades. CONCLUSIONS: We provided new data about the TBEV MIR in ticks in Almaty Oblast' 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.

Serological investigation of orthohantaviruses in patients with fever of unknown origin in Kazakhstan.

OBJECTIVE: Orthohantaviruses are geographically widely distributed and present various clinical manifestations from mild symptoms to the severe form of haemorrhagic fever with renal syndrome (HFRS) in Eurasia. Official registration of HFRS in Kazakhstan started in the year 2000. However, the true prevalence of human infections by orthohantaviruses within Kazakhstan is unknown. The aim of this study was to investigate of the seroprevalence of orthohantavirus infections in patients with fever of unknown origin (FUO) in two regions, Almaty and Kyzylorda region. METHODS: Paired serum samples from 802 patients with FUO were screened for the presence of orthohantavirus IgG and IgM antibodies by ELISA. Positive samples were further tested by immunoblotting and indirect immunofluorescence tests (IIFT) to determine the respective orthohantavirus serotypes. Suspected acute serum samples were additionally checked by a RT-PCR to identify viral RNA. RESULTS: In total 178/802 (22.2%) serum samples reacted with orthohantavirus IgG antibodies and 4/802 (0.5%) with IgM antibodies. All positive samples were tested by immunoblotting which resulted in 2.9% positive samples with IgG antibodies against Puumala (PUUV), Hantaan (HTNV) and Dobrava (DOBV) virus serotypes in Almaty region and 5.4% to PUUV and DOBV serotypes in Kyzylorda region, respectively. In the IFFT, 1.9% positive samples from Almaty and 3.1% from Kyzylorda were confirmed for PUUV and DOBV serotypes. Out of four IgM ELISA positive samples only three were positive against PUUV in the immunoblot and showed weak positive reactivity for the Saaremaa (SAAV), PUUV and HTNV serotypes in the IFFT. CONCLUSIONS: This study demonstrates the presence of orthohantavirus infections among patients with FUO in Kazakh regions that were so far considered as non-endemic. The healthcare system needs to be prepared accordingly in order to be capable of detecting cases and providing adequate management of patients.

Prevalence of Rickettsia species in ticks including identification of unknown species in two regions in Kazakhstan.

BACKGROUND: Over 60 years ago clinical patterns resembling tick-borne rickettsioses have been described for the first time in Kazakhstan. Since 1995 the incidence of clinical cases of tick-borne rickettsioses in humans seems to be rising but studies on epidemiological data regarding the occurring etiological agents, tick vector species, prevalence and distribution throughout Kazakhstan are still scarce to date. The aim of the study was molecular investigation of ticks for spotted-fever group rickettsiae in the endemic Kyzylorda region and the so far considered as non-endemic Almaty region. A total of 2341 ticks was collected in the two regions in Kazakhstan and sorted in 501 pools: Ixodes persulcatus (243); Dermacentor marginatus (129); Haemaphysalis punctata (104); Hyalomma asiaticum (17); Dermacentor reticulatus (3); and Rhipicephalus turanicus (5). Pools were tested for Rickettsia spp. using real-time PCR. For positive samples multilocus sequence typing (MLST) was performed. RESULTS: The calculated minimum infection rate (MIR) for rickettsiae in the investigated ticks in Almaty region varied between 0.4-15.1% and 12.6-22.7% in the Kyzylorda region. At least four different Rickettsia species were identified in the two selected regions of Kazakhstan. Two of these are already known to science: Rickettsia raoultii and R. slovaca, the latter being reported for the first time in Almaty region One new form, "Candidatus R. yenbekshikazakhensis", was described by MLST of six gene fragments in Almaty region and one new genotype, "genotype R. talgarensis" was detected using three gene fragments. CONCLUSIONS: Kazakh physicians should be aware of rickettsioses after tick bites in both regions studied. Both, R. raoultii and R. slovaca should be included in the diagnostics. The role for human diseases has further to be investigated for the newly described rickettsiae, "Candidatus R. yenbekshikazakhensis" and "Genotype R. talgarensis".

Seroepidemiological and molecular investigations of infections with Crimean-Congo haemorrhagic fever virus in Kazakhstan.

OBJECTIVES: The aim of this study was to detect the seroprevalence of Crimean-Congo haemorrhagic fever virus (CCHFV) in patients with fever of unknown origin (FUO) in endemic (Kyzylorda) and non-endemic (Almaty) oblasts of Kazakhstan. METHODS: Paired serum samples from 802 patients with FUO were collected. Serum samples were investigated by ELISA to detect IgG and IgM antibodies against CCHFV. Sera with suspected acute infection were further investigated by RT-PCR to detect the viral RNA. RESULTS: IgG antibodies were detected in 12.7% of the sera from both oblasts. Acute infection was shown by IgM ELISA in four patients from Kyzylorda, with only one developing severe CCHF. Viral RNA was found by RT-PCR in the other three patients' sera. Phylogenetic analysis of partial L and S segments revealed CCHFV genotype Asia 2 and a possible reassortment between the genotypes Asia 1/Asia 2. Animal husbandry, such as working with cattle and horses, was significantly associated with CCHFV seropositivity. CONCLUSIONS: The antibodies and viral RNA detected in sera indicate that mild or even asymptomatic CCHFV infections are presented in Kazakhstan. This study describes the circulation of CCHFV in the so far non-endemic Almaty oblast for the first time. In conclusion, physicians treating patients with FUO in Kazakhstan should be aware of mild CCHF.