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

Authors

  • Uyanga Baasandavga National Center for Zoonotic Diseases, Ulaanbaatar, Mongolia
  • Burmaajav Badrakh Mongolian Academy of Medical Science, Ulaanbaatar, Mongolia
  • Natsagdorj Burged National Center for Zoonotic Diseases, Ulaanbaatar, Mongolia
  • Otgonsuren Davaajav Institute of Veterinary Medicine, Ulaanbaatar, Mongolia
  • Tungalag Khurelsukh National Center for Zoonotic Diseases, Ulaanbaatar, Mongolia
  • Amber Barnes Duke University, Durham, North Carolina, United States of America
  • Unursaikhan Ulaankhuu National Center for Zoonotic Diseases, Ulaanbaatar, Mongolia
  • Tsogbadrakh Nyamdorj National Center for Zoonotic Diseases, Ulaanbaatar, Mongolia

DOI:

https://doi.org/10.5365/wpsar.2018.9.1.003

Abstract

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.

Author Biography

Uyanga Baasandavga, National Center for Zoonotic Diseases, Ulaanbaatar, Mongolia

Surveillance department

Downloads

Published

27-03-2019

How to Cite

1.
Baasandavga U, Badrakh B, Burged N, Davaajav O, Khurelsukh T, Barnes A, Ulaankhuu U, Nyamdorj T. A case series of fatal meningoencephalitis in Mongolia: epidemiological and molecular characteristics of tick-borne encephalitis virus. Western Pac Surveill Response J [Internet]. 2019 Mar. 27 [cited 2026 Apr. 2];10(1). Available from: https://ojs.wpro.who.int/ojs/index.php/wpsar/article/view/618

Issue

Vol. 10 No. 1 (2019): January – March

Section

Original Research

License

You are free to:

  • Share — copy and redistribute the material in any medium or format for any purpose, even commercially.
  • Adapt — remix, transform, and build upon the material for any purpose, even commercially.
  • The licensor cannot revoke these freedoms as long as you follow the license terms.

Under the following terms:

  • Attribution — You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
  • No additional restrictions — You may not apply legal terms or technological measures that legally restrict others from doing anything the license permits.

Notices:

When the Licensor is an intergovernmental organization, disputes will be resolved by mediation and arbitration unless otherwise agreed.

You do not have to comply with the license for elements of the material in the public domain or where your use is permitted by an applicable exception or limitation.

No warranties are given. The license may not give you all of the permissions necessary for your intended use. For example, other rights such as publicity, privacy, or moral rights may limit how you use the material.