Detection of Babesia venatorum, Anaplasma phagocytophilum and Candidatus Neoehrlichia mikurensis in Ixodes persulcatus ticks from Mongolia

Information about the prevalence and geographical distribution of tick-borne pathogens Anaplasma phagocytophilum, Candidatus Neoehrlichia mikurensis, and Babesia spp. is still rare in Mongolia. We tested 275 Ixodes persulcatus ticks for A. phagocytophilum, Cand. N. mikurensis and Babesia spp. and 125 Dermacentor nuttalli ticks especially for Babesia spp. using different PCR methods. Ticks were collected from three provinces (Selenge, Arkhangai, Khentii) in Mongolia. DNA of A. phagocytophilum, Cand. N. mikurensis and Babesia spp. were found with a prevalence of 6.2%, 1.5% and 3.3% in each case in I. persulcatus ticks. This is the first time Cand. N. mikurensis was found in ticks from Mongolia. Sequence analysis of Babesia spp.-positive amplicons showed exclusively B. venatorum, which had also not been mentioned in Mongolia before. On the contrary, all D. nuttalli ticks tested negatively for Babesia spp. This study demonstrates that all three zoonotic pathogens are present in I. persulcatus ticks in Mongolia, and justify the need for further investigations of a more detailed genetic characterization of these pathogens.

Sparse evidence for equine or avian influenza virus infections among Mongolian adults with animal exposures

In recent years, Mongolia has experienced recurrent epizootics of equine influenza virus (EIV) among its 2·1 million horses and multiple incursions of highly pathogenic avian influenza (HPAI) virus via migrating birds. No human EIV or HPAI infections have been reported. In 2009, 439 adults in Mongolia were enrolled in a population‐based study of zoonotic influenza transmission. Enrollment sera were examined for serological evidence of infection with nine avian, three human, and one equine influenza virus strains. Seroreactivity was sparse among participants suggesting little human risk of zoonotic influenza infection.

Isolation, preliminary characterization, and full-genome analyses of tick-borne encephalitis virus from Mongolia

Tick-borne encephalitis virus (TBEV) causes one of the most important inflammatory diseases of the central nervous system, namely severe encephalitis in Europe and Asia. Since the 1980s tick-borne encephalitis is known in Mongolia with increasing numbers of human cases reported during the last years. So far, however, data on TBEV strains are still sparse. We herein report the isolation of a TBEV strain from Ixodes persulcatus ticks collected in Mongolia in 2010. Phylogenetic analysis of the E-gene classified this isolate as Siberian subtype of TBEV. The Mongolian TBEV strain showed differences in virus titers, plaque sizes, and growth properties in two human neuronal cell-lines. In addition, the 10,242 nucleotide long open-reading frame and the corresponding polyprotein sequence were revealed. The isolate grouped in the genetic subclade of the Siberian subtype. The strain Zausaev (AF527415) and Vasilchenko (AF069066) had 97 and 94 % identity on the nucleotide level. In summary, we herein describe first detailed data regarding TBEV from Mongolia. Further investigations of TBEV in Mongolia and adjacent areas are needed to understand the intricate dispersal of this virus.

Ecology of influenza virus in wild bird populations in Central Asia

The study provides the results of avian influenza virus surveillance in Central Asia during 2003-2009. We have analyzed 2604 samples from wild birds. These samples were collected in Kazakhstan (279), Mongolia (650), and Russia (1675). Isolated viruses from samples collected in Mongolia (13 isolates) and in Russia (4 isolates) were described. Virological analysis has shown that six isolates belong to the H3N6 subtype and five isolates belong to the H4N6 subtype. Two H1N1 influenza viruses, one H10N7 virus, two H3N8 viruses, and an H13N8 virus that is new for Central Asia have been also isolated. Samples were taken from birds of six orders, including several species preferring water and semiaquatic biotopes, one species preferring dry plain regions, and one more species that can inhabit both dry and water biotopes.

[Detection of leptospirosis infection in certain wild and domestic animals in Mongolia]

AIM

Serological examination for leptospirosis of domestic and certain species of wild animals in Mongolia.

MATERIALS AND METHODS

Collection of material from domestic and wild animals was performed in 2009--2010 in 7 aimags (regions) of Eastern, Central and Southern Mongolia. Serological study of filter paper dried blood samples obtained from 51 specimens of cattle and small cattle, camels, and 545 specimens of rodents of various species was performed in microagglutination reaction (MAR) of leptospirae with 13 reference strains.

RESULTS

There is a presence in certain regions of Mongolia of anthropurgic loci of leptospirosis infection including arid zones where ecological conditions do not favor the development of epizootic process. The results of the study indicate the epizootic significance of Tarassovi serogroup leptospirae in cattle and Sejroe serogroup (probably hardjo serovar) in goats, sheep and camels. Results of serological studies of desert and steppe specimens of wild fauna of Mongolia suggest a possibility of circulation of leptospirae in natural foci.

CONCLUSION

Detection in a significant percent of cases in tarbagan and long tailed ground squirrel blood sera of agglutinins to Pomona (mozdok) leptospirae with negative MAR results for Pomona (pomona) strain suggests a presence of a pathogen of a previously unknown serovar. However final conclusion could be made only after the isolation of cultures of the pathogen and their identification.

[Detection of natural tularemia foci in Mongolia]

AIM

Study of the current spread of natural tularemia foci in Mongolia and its epizootic activity evaluation for consequent substantiation of the recommendations for prophylaxis of this disease.

MATERIALS AND METHODS

Study of 1119 pellet specimens from predatory birds obtained in 6 aimag in Mongolia in 2008--2010 was performed. Tularemia antigen was detected by using antibody neutralization reaction (ANR) and passive hemagglutination reaction (PHR) with tularemia diagnosticums. Tularemia DNA was detected by PCR by using strain specific primers. Presence of plague antigen in PHR with plague immunoglobulin diagnosticum was also studied in all the samples.

RESULTS

Epizootologic monitoring allowed the detection of natural tularemia foci in 5 of the 6 studied aimags in Mongolia. PHR was the most effective study method that allowed to detect tularemia antigen in the environmental objects in high quantities (up to 9.2% of positive samples) and high titers (up to 1:1600). PCR was less effective. Plague antigen was detected in 9 samples in 2010 for the first time, and in 3 cases together with tularemia antigen, which indicates a presence of combined natural foci of tularemia and plague in this territory.

CONCLUSION

In the studied regions of Mongolia natural tularemia foci were detected, their epizootic activity was determined and recommendations for future study tactics of natural tularemia foci were given.

Molecular epidemiological study of Bacillus anthracis isolated in Mongolia by multiple-locus variable-number tandem-repeat analysis for 8 loci (MLVA-8)

The incidence of anthrax, which is caused by Bacillus anthracis, in the human and animal population of Mongolia has increased recently, and control of this infection is a nationwide concern. In this study, 29 isolates obtained from animals and various regions in Mongolia from 2001 to 2007 were analyzed by performing multiple-locus variable-number tandem-repeat analysis for 8 loci (MLVA-8) to understand the genetic relationship between the Mongolian B. anthracis isolates. We found that all the Mongolian isolates can be classified into A3 cluster along with the Japanese and the Chinese B. anthracis isolates. Our data revealed that MLVA-8 is useful for studying the molecular epidemiology of the Mongolian B. anthracis isolates and would help characterize B. anthracis infections in Mongolia.

[Isolation of influenza A virus from wild birds in western part of Mongolia]

AIM

To study circulation of influenza A viruses in western part of Mongolia.

MATERIALS AND METHODS

Isolation and characterization of influenza viruses was performed according to recommendations of WHO.

RESULTS

Circulation of influenza A viruses subtypes H3N6, H4N6, H1N1, H13N8 in different wild bird species in western part of Mongolia was documented.

CONCLUSION

Taxonomic and ecologic heterogeneity of bird species involved in continuous circulation of influenza A viruses was revealed. Subtype H13N8 was isolated for a first time from herring gull on territory of western Mongolia.

[Genetic characteristics of the causative agent of tick-borne encephalitis in Mongolia]

A patient with diagnosed meningoencephalitis and a history of tick bite died in Mongolia in 2008. The purpose of this paper is to characterize the virus causing the ill person's death. The virus was identified using the phylogenetic analysis of the 520-bp fragment of the tick-borne encephalitis virus (TBEV) genome, which codes the fragment of TBEV protein E between 52-223 amino acids. TBEV RNA was detected in the samples of medulla oblongata, cerebral cortex, and pia mater of brain, but not in the cerebellar tissue. The study virus fragment was genetically closest to the representatives of the Far East subtype. Its closest relative was virus 740-84 (GenBank EU878282) isolated from large-toothed redback voles (Clethrionomys glareolus) in Buryatia and greatly differed from the Far East virus Soffin. Two amino acid substitutions (H86R and VI7A) were detected within the study protein E fragment. The paper is the first to describe the causative agent of tick-borne encephalitis on the territory of Mongolia and to discuss the evolution and pathogenicity of TBEV.