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.

[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.

Mongolian and Japanese Joint Conference on "Echinococcosis: diagnosis, treatment and prevention in Mongolia" June 4, 2009

The first Mongolian-Japanese Joint Conference on "Echinococcosis: diagnosis, treatment and prevention in Mongolia" was held in Ulaanbaatar on June 4^th, 2009. It was the first chance for Mongolian experts (clinicians, pathologists, parasitologists, biologists, epidemiologists, veterinarians and others working on echinococcosis) joined together. Increase in the number of cystic echinococcosis (CE) cases year by year was stressed. CE in children may be more than adult cases. Alveolar echinococcosis was suspected chronic malignant hepatic tumors or abscesses. Main discussion was as to how to introduce modern diagnostic tools for pre-surgical diagnosis, how to establish the national system for the data base of echinococcosis with the establishment of a network system by experts from different areas. The importance of molecular identification of the parasites in domestic and wild animals was also stressed.

Rabies in the Mongolian steppes

Historically, rabies in Mongolia has been connected to the specific steppe and forest-steppe landscapes, known as the Mongolian steppes. The main reservoirs of the rabies virus (RABV) are the wolf, red fox and corsac fox. Fox rabies has been reported in Mongolia since the early 1960s. Eleven human rabies cases (0.4 per million inhabitants) were reported in Mongolia from 1994-2004. Wild animals predominated as a source of human infection: five people died following wolf bites, two were exposed to foxes, and four to dogs. From 1996-2004, 1,273 rabid animals were reported (about 140 per year). Cattle consisted of more than 80% of all reported cases. The Mongolian steppes continue into the Chita region of Russia and the Republics of Buryatia, Tyva and Altai. Four RABV isolates from the western part of Mongolia were sequenced and compared with available isolates from Russia, China and other countries. The isolates from Mongolia belonged to the "steppe" phylogenetic clade, which includes viruses circulating in vast territories, from Southeast Europe to Tyva, West Siberia and Kazakhstan. However, RABV isolates from Mongolian-type steppes in the east (Chita region, Russia) belong to the eastern group of arctic-like viruses.

[Results of two-year-old inspection of the presence of infuenza virus in wild birds in Western Mongolia]

The results of virology inspection of the wild birds living in territory of the Western Mongolia, carried out in 2003-2004 are presented. For the specified period influenza viruses H3 and H4 subtype hemagglutinins are isolated from birds. It is revealed taxonomic and ecological heterogeneity of the birds involved in maintenance of circulation of influenza viruses in the given territory. Influenza viruses are isolated from birds of 5 special groups; among them there are preferring water and nearwater biotops, a species preferring dry plain region, and also a species which habitat does not depend from water's territories.