[Nature-focal rickettsioses in Mongolia. Two decades of Russian-Mongolian scientific collaboration].

The results of many years' studies of nature-focal rickettsioses in Mongolia in collaboration of Soviet (Russian) and Mongolian specialists under leadership of I. V. Tarasevich are represented. Presence of contacts of population, domestic and wild animals with Coxiella burnetii and Rickettsia sibirica on the territory of Mongolia was established. The map of spread of ticks corresponding to their epidemiological significance was developed. Methodological documents for prevention of nature-focal rickettsioses in Mongolia were developed for organs of healthcare and veterinary medicine. Corpuscular inactivated vaccine against Q-fever from immunogenic strains "Dermacentor-Mongol 1". "XY -1958" was prepared.

Prevalence of Sarcocystis infection in horses in Mongolia.

Sarcocystis infection was detected in 93% of horses in Mongolia. Using the compress method, sarcocysts were found in the muscles of the diaphragm, heart and tongue in 40 of the 43 horses that were slaughtered at the Makh Impex Meat Company in Ulaan Baatar in July 1998. The muscle of the tongue showed the highest rate (97.5%) of infection. The distribution of sarcocysts in the muscles was positively correlated with horse age; the rate of detection was significantly lower (p=0.01) in the under 10 year old group than the older group. All horses were apparently healthy and were slaughtered for human consumption.

Prevalence of Sarcocystis infection in meat-producing animals in Mongolia.

A survey of Sarcocystis infection was conducted in Mongolia between June 1998 and July 1999. Samples of muscle were taken from the diaphragm, heart, tongue, esophagus,and intercostal region of cattle, yak, hainag, sheep, horses, and camels. A muscle compress method was used to determine the prevalence of infection: cattle 90.0% (27/30), yak 93.3% (28/30), hainag 100% (30/30), sheep 96.9% (753/777), horses 75% (3/4) and camels 100% (5/5). Of the various muscles, heart was the most commonly infected in cattle (100%), yak (86.7%), and hainag (100%); tongue was most likly to be infected in sheep (100%) and horses (100%).

Detection of antibodies to Hypoderma lineatum in cattle by Western blotting with recombinant hypodermin C antigen.

The cDNA encoding the entire mature hypodermin C (HC) of Hypoderma lineatum was cloned and expressed in Escherichia coli as a glutathione S-transferase fusion protein using pGEX vector. The recombinant HC protein (rHC) was tested by Western blotting to detect antibodies to H. lineatum in cattle. Western blotting with rHC as antigen clearly differentiated between H. lineatum-infested cattle sera and normal cattle sera. Forty-six out of forty-eight serum samples from cattle in Central Mongolia were positive, whereas all 30 serum samples from cows in Hokkaido, Japan, were negative by Western blotting. The result of Western blotting was identical to that of a previously developed enzyme-linked immunosorbent assay. These data demonstrated that Western blotting, with rHC expressed in E. coli, might be a useful method for the diagnosis of cattle hypodermosis.

Detection of Babesia caballi and Babesia equi in Dermacentor nuttalli adult ticks.

Ticks play an important role in human and veterinary medicine particularly due to their ability to transmit protozoan pathogens. In this study we have demonstrated that polymerase chain reaction (PCR) and nested PCR methods enabled detection of Babesia caballi and Babesia equi in field isolates of Dermacentor nuttalli adult ticks from Mongolia. Primers specific for 218 bp fragment merozoite antigen 1 (EMA-1) gene of B. equi successfully amplified products from all samples of D. nuttalli adult ticks while primers for the 430 bp fragment product from BC48 gene of B. caballi amplified products from seven of the 54 samples. Using PCR and nested PCR methods we have found mixed infections with B. equi and B. caballi in the tick vector. The amplified DNA fragment from D. nuttalli ticks was inserted into the EcoRV site of pBluescript SK and sequenced. The sequence of the 430 bp fragment was completely identical to the nucleotide sequence of the USDA strain of B. caballi. These results suggest that D. nuttalli may play an important role as a vector of both B. caballi and B. equi and also may be important in maintaining endemicity of equine piroplasmosis in Mongolia.