A case series of fatal meningoencephalitis in Mongolia: epidemiological and molecular characteristics of tick-borne encephalitis virus

In Mongolia, the incidence and fatality rates of tick-borne encephalitis (TBE) have been increasing. We aimed to identify the epidemiological and molecular characteristics of tick-borne encephalitis virus (TBEV) associated with fatal meningoencephalitis in Mongolia. We conducted a descriptive study of 14 fatal cases of TBE that occurred between 2008 and 2017 in Mongolia. Reverse transcription polymerase chain reaction (RT–PCR) was used to detect viral RNA in brain tissue. RT–PCR products from six patients who died from TBE between 2013 and 2017 were directly sequenced and analysed phylogenetically. Ticks collected from Selenge and Bulgan provinces were also tested for TBEV by RT–PCR. Between 2008 and 2017, there were 14 fatal TBE cases in hospitals in Mongolia. The 14 patients who died reported receiving tick bites in Bulgan or Selenge province; 71.4% of deaths resulted from tick bites in Bulgan province. The TBE case fatality rate was 28.6% for patients in Bulgan province and 2.7% for those in Selenge province. All of the fatalities were men; the median age was 45 ± 12.6 years. Tick bites occurred between April and June in forested areas. In 2013, a 388 base pair fragment of the envelope (E) gene was obtained from a hospitalized patient. The closest relatives of this virus are Far-Eastern TBEV isolates. The case fatality rate differed between two provinces where tick bites occurred. A higher number of TBE cases and the virulent Far-Eastern subtype occurred in patients in Bulgan province. This province should increase vaccination coverage, training, education and investigations

The First Survey of Bovine Babesia Species Infecting Yaks (Bos grunniens) in Mongolia

application/pdfYak (Bos grunniens) farming is an important part of Mongolia's livestock industry. Yaks survive in harsh mountain environments; provide meat, milk, and wool; and serve as a mode of transportation. In Mongolia, yaks are frequently raised alongside other livestock animals such as cattle, Bactrian camels, sheep, goats, and horses. Recently, we demonstrated that Babesia bovis, Babesia bigemina, and Babesia naoakii-parasites with the potential to cause clinical bovine babesiosis-infect not only cattle but also Bactrian camels in Mongolia. However, yaks have never been surveyed for Babesia infections in this country. In the present study, we surveyed yaks in 8 Mongolian provinces: Bayankhongor, Bayan-Ulgii, Khovd, Khovsgol, Omnogovi, Ovorkhangai, Uvs, and Zavkhan. Blood samples were taken and deoxyribonucleic acid (DNA) was extracted from 375 yaks. Furthermore, Giemsa-stained thin smears were prepared from 315 of the 375 blood samples and then examined for the microscopic detection of Babesia parasites. Microscopy revealed that 34 (10.8%) of 315 blood smears were positive for Babesia parasites. All 375 DNA samples were then tested for B. bovis, B. bigemina, and B. naoakii infection using specific polymerase chain reaction assays. We observed that 238 (63.5%) yaks in all surveyed provinces and 8 (2.1%) yaks in 3 provinces (Bayankhongor, Bayan-Ulgii, and Omnogovi) were positive for B. bovis and B. bigemina, respectively. However, all yaks tested were negative for B. naoakii. This epidemiological survey, the first to report Babesia infection in Mongolian yaks, suggests that disease management strategies for yaks in this country should further address bovine babesiosis. © American Society of Parasitologists 2023

Additional file 3: Figure S1. of Isolation, cultivation and molecular characterization of a new Trypanosoma equiperdum strain in Mongolia

The phylogenetic tree of the 18S rRNA and ITS region. A phylogenetic analysis was performed using the T. equiperdum IVM-t1, SITB818, STIB841, STIB842, BoTat1.1, T. evansi Tansui (Accession No. D89527.1), Cairo (AB551922.1), KAI.2 (AY912277), Sam.2 (AY912279.1), T. brucei TREU927 (AC012647), T. b. gambiense DAL972 (FN554966.1), T. b. gambiense Tsuua (AJ009141) and T. b. rhodesiense Utro (AJ009142) sequences. A: A phylogenetic tree based on the 18S rRNA sequence. B: A phylogenetic tree based on the ITS sequence. Figure S2. The maxicircle PCR of the Trypanozoon species. Gel electrophoresis images of the PCR products are shown in A to G, NADH-dehydrogenase subunit 7 (NAD7; 383 bp), Cytochrome oxidase subunit 2 (Cox2; 1747 bp), ATOas subunit 6 (A6; 299 bp), 12S ribosomal RNA (12S rRNA; 1597 bp in T. b. brucei GUTat3.1 strain and T. equiperdum STIB818 strain, 1415 bp in T. equiperdum STIB841, STIB842, BoTat1.1 strains, respectively), NADH-dehydrogenase subunit 7-cytochromeB (ND7-CyB; 1450 bp), Maxicircle unknown reading frame-NADH dehydrogenase subunit 1 (MURF-ND1; 1779 bp) and Maxicircle unknown reading frame 2-cytochrome oxidase subunit 1 (MURF2-Cox1; 1551 bp), respectively. M: the 100 bp and 1 kbp DNA ladders; Lanes 1 to 8 show T. b. brucei GUTat3.1, T. evansi IL3960, T. equiperdum IVM-t1, STIB818, STIB841, STIB842, BoTat1.1 strains and negative control (distilled water), respectively. (PPTX 164 kb