[The epizootic characteristics of tularemia in the Crimea].

Cases of tularemia were registered in the Crimea both before and after planned immunization. In 1981-1993 in 4.000 localities 35,100 mammals, 27,400 ectoparasites, 8,800 feces left by birds of prey and foxes and 900 environmental specimens were studied.

[The antigenic differentiation of hantaviruses by using monoclonal antibodies].

85 hantavirus (HV) strains from Russia and other counties were examined by indirect fluorescent antibody test using monoclonal antibodies (MAbs) prepared against hantaviruses: Hantaan (Hantaan 76-118, A-9 strains), Seoul (SR-1, R-22 strains) and Puumala (Hallnas 83-223 strain). 68 HV strains were differentiated into five virus type groups: Hantaan, Puumala, Seoul, Prospect Hill and Belgrade-Dobrava. 17 strains were found to be antigenically closely related but distinct from Hantaan type (4 strains), Puumala (6 strains) and Prospect Hill (7 strains).

[Genetic differentiation of hantaviruses using the polymerase chain reaction and sequencing].

Thirty-two hantavirus strains and 8 samples of lung tissue from rodents collected in different regions of Russia have been examined by molecular biological methods. Two methodological approaches have been employed for the study of genetic relationships between the viruses: nested PCR assay and common RT-PCR with subsequent direct sequencing of 200 and 365 base pair of G2 protein encoding regions of M-segment, respectively, and the resultant sequences were compared with those of the prototype hantavirus. The study revealed a mosaic pattern of distribution of different hantavirus genotypes on the territory of Russia.

Antigenic relationships of hantavirus strains analysed by monoclonal antibodies.

The antigenic relationships among 71 hantavirus strains, isolated from rodent species or humans in several geographic regions, were examined by immunofluorescence assay (IFA) using human patient sera and a panel of 22 monoclonal antibodies prepared against Hantaan, Seoul, and Puumala viruses. The study included virus strains, mainly from the former USSR, for which little or no serological data were available. Fifty-nine of the 71 isolates could be placed into five antigenic groups of hantaviruses, Hantaan (HTN), Puumala (PUU), Seoul (SEO), Prospect Hill (PH), Dobrava/Belgrade (DOB).

[Ixodid ticks in the mountainous part of the Crimea].

About a hundred of patients with tick-borne encephalitis (TBE) were recorded over the latest decade in the Crimea, and 60 TBE virus strains were isolated from the ticks collected on the peninsula. The results of studies carried out in 1986-1990 helped define the borders of 4 local natural foci of TBE, study their acarifauna, detect the principal TBE vector--Ixodes ricinus (with a mean virophority of 0.6%), and distinguish two foci with a combination of TBE and Crimean-Congo hemorrhagic fever.