Historical distribution and molecular diversity of Bacillus anthracis, Kazakhstan.

To map the distribution of anthrax outbreaks and strain subtypes in Kazakhstan during 1937-2005, we combined geographic information system technology and genetic analysis by using archived cultures and data. Biochemical and genetic tests confirmed the identity of 93 archived cultures in the Kazakhstan National Culture Collection as Bacillus anthracis. Multilocus variable number tandem repeat analysis genotyping identified 12 genotypes. Cluster analysis comparing these genotypes with previously published genotypes indicated that most (n = 78) isolates belonged to the previously described A1.a genetic cluster, 6 isolates belonged to the A3.b cluster, and 2 belonged to the A4 cluster. Two genotypes in the collection appeared to represent novel genetic sublineages; 1 of these isolates was from Krygystan. Our data provide a description of the historical, geographic, and genetic diversity of B. anthracis in this Central Asian region.

Phenotypic and molecular characterizations of Yersinia pestis isolates from Kazakhstan and adjacent regions.

Recent interest in characterizing infectious agents associated with bioterrorism has resulted in the development of effective pathogen genotyping systems, but this information is rarely combined with phenotypic data. Yersinia pestis, the aetiological agent of plague, has been well defined genotypically on local and worldwide scales using multi-locus variable number tandem repeat analysis (MLVA), with emphasis on evolutionary patterns using old isolate collections from countries where Y. pestis has existed the longest. Worldwide MLVA studies are largely based on isolates that have been in long-term laboratory culture and storage, or on field material from parts of the world where Y. pestis has potentially circulated in nature for thousands of years. Diversity in these isolates suggests that they may no longer represent the wild-type organism phenotypically, including the possibility of altered pathogenicity. This study focused on the phenotypic and genotypic properties of 48 Y. pestis isolates collected from 10 plague foci in and bordering Kazakhstan. Phenotypic characterization was based on diagnostic tests typically performed in reference laboratories working with Y. pestis. MLVA was used to define the genotypic relationships between the central-Asian isolates and a group of North American isolates, and to examine Kazakh Y. pestis diversity according to predefined plague foci and on an intermediate geographical scale. Phenotypic properties revealed that a large portion of this collection lacks one or more plasmids necessary to complete the blocked flea/mammal transmission cycle, has lost Congo red binding capabilities (Pgm-), or both. MLVA analysis classified isolates into previously identified biovars, and in some cases groups of isolates collected within the same plague focus formed a clade. Overall, MLVA did not distinguish unique phylogeographical groups of Y. pestis isolates as defined by plague foci and indicated higher genetic diversity among older biovars.

Clinical and epidemiological characteristic of tularemia in Kazakhstan.

From 1950 to 1977, 5049 human tularemia cases were registered that had been associated with a large number of non-immunized people coming to Kazakh tularemia endemic areas from different places of Soviet Union to harvest the grain. Since 1978, the number of tularemia patients has considerably decreased and during 1992-2001 thirty-one human cases were reported. Epidemiological analysis showed that infection was transmitted by a variety of routes, including bites of infected arthropod, ingestion of infected food and water, transfer to mouth by contaminated hands and direct contact from skinning musk-rats and hares. The disease presented mainly as glandular-bubonic (62.5%), bubonic (25.0%) or pulmonary (12.5%) forms.

Plague in Kazakhstan at the present time.

Since 1990 to 2002, 19 human plague cases and 2 bacteria-carriers cases were registered in natural plague foci on the territory of the republic. For last 12 years plague in forms of bubonic and bubonic-septic was diagnosed in Kazakhstan. Out of 19 patients (14 men--73.6% and 5 women--26.3%), 13 persons recovered (8.4%), 6 persons died (31.6%). Employment of the treatment in the new scheme sharply lowered lethality from plague. Live attenuated Y. pestis EV vaccine available for human and camel use is applied as a basic preventive measure in plague natural foci. Epidemiological importance of ill camels remains high. At the analyzed period, in 5 cases infection was a result of forced camel slaughter. 11 people (57.8%) were infected through flea bites. Central Asian desert plague focus is still the most active and its potential to start epidemic increases in connection with rising of anthropogenic influence. All these changes occur on the background of epidemiological survey decreasing in natural plague foci.