Survey of tick-borne relapsing fever borreliae in southern and southeastern Kazakhstan.

Tick-borne relapsing fever group borreliae (TBRFGB) are spirochetes that cause disease in humans and animals. Little is known about the prevalence of TBRFGB infections in ticks and humans in Kazakhstan. A total of 846 ticks belonging to ten species of the family Ixodidae and three species of the family Argasidae were collected from the vegetation, poultry shelters, domestic ruminants, bitten humans, pigeons, dogs and house walls in four oblasts of the southern and southeastern regions of Kazakhstan. The ticks were subjected to DNA extraction and identification of TBRFGB by conventional PCR using primers targeting flagella subunit B (flaB), glycerophosphodiester phosphodiesterase (glpQ) and P66 porin (P66) genes. The overall infection rate of TBRFGB in the ticks was 6.2 % (46/846). TBRFGB DNA was identified in Ixodes persulcatus (5.5 %; 26/477), Ornithodoros tartakovskyi (6 %; 2/36) and Argas persicus (13.4 %; 18/134) ticks. Partial sequencing of flaB, glpQ and P66 genes identified Borrelia miyamotoi in I. persulcatus and Borrelia anserina in A. persicus. To detect the presence of B. miyamotoi infection in people in the study region, we performed serological analysis of samples collected from 42 patients admitted to hospital with fever of unknown etiology or with a history of a tick bite. The analysis revealed IgM and IgG antibodies against one or several B. miyamotoi antigens in 10 % and 5 % of patients, respectively. The data obtained provide strong evidence of the presence of B. miyamotoi and B. anserina in the southern and southeastern regions of Kazakhstan, underscoring the need for increased awareness of potential infections caused by these borreliae in these regions.

Molecular and seroepidemiological investigation of Сoxiella burnetii and spotted fever group rickettsiae in the southern region of Kazakhstan.

Ticks are involved in the circulation of a number of human pathogens, including spotted fever group (SFG) Rickettsia spp. and Coxiella burnetii. Little is known about the occurrence of these microorganisms in the southern region of Kazakhstan. In 2018-2022, a total of 726 ticks were collected from bitten humans, livestock, and vegetation in four oblasts of the southern region of Kazakhstan and subjected to DNA extraction. The overall infection rate of Coxiella spp. and Rickettsia spp. in the ticks was 3.3% (24/726) and 69.9% (300/429), respectively. Phylogenetic analysis of ompA and gltA genes revealed the presence of three pathogenic SFG rickettsiae: Candidatus R. tarasevichiae, R. aeschlimannii and R. raoultii in ticks collected from bitten humans. In addition, Candidatus R. barbariae was detected in six Rhipicephalus turanicus ticks for the first time in Kazakhstan. To determine the seroprevalence of C. burnetii infection, we performed a serological analysis of samples collected from 656 domestic ruminants (cattle, sheep, and goats) in the region. Overall, 23.5% (154/656) of the animals tested were positive for IgG against C. burnetii. Seroprevalence at the herd level was 54% (28/52). Goats (43%; 12/28; odds ratio (OD) = 28.9, p < 0.05) and sheep (31.9%; 137/430; OD = 18.1, p < 0.05) had higher seroprevalence than cattle (2.5%; 5/198). Among the risk factors considered in this study, age (p = 0.003) and the oblast in which the animals were sampled (p = 0.049) were statistically associated with seropostivity for Q fever in sheep, according to the results of multivariate logistic regression analysis. Seroprevalence ranged from 0% to 55.5% in animals in different districts of the southern region of Kazakhstan. Active C. burnetii bacteremia was detected in four of 154 (2.6%) seropositive animals. The data obtained provide strong evidence of the presence of pathogenic rickettsiae and C. burnetii in the southern region of Kazakhstan and emphasize the need to improve epidemiological surveillance in the region.

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.

Tick-borne pathogens and their vectors in Kazakhstan - A review.

Tick-borne diseases (TBDs), in particular Crimean-Congo hemorrhagic fever (CCHF) and tick-borne encephalitis (TBE), have been found to be expanding beyond their traditional geographic locations in Kazakhstan, which led to increased awareness and concern against TBDs in recent years. The tick fauna of Kazakhstan includes more than 30 species of human-biting ixodid ticks, recognized as carriers of a number of dangerous infectious pathogens that cause CCHF, TBE, tularemia, tick-borne rickettsioses and Lyme borreliosis. This paper presents the current knowledge of the main vectors of tick-borne pathogens (TBP) occurring in Kazakhstan, as well as a review of recent studies of ticks performed with the use of molecular methods being currently developed and widely utilized by Kazakh epidemiologists.