ON THE HISTORY OF A DISCOVERY AND BIOCENOSlS STRUCTURE OF THE KOKPAK MESOFOCUS OF PLAGUE
Until quite recently the Kokpak mesofocus of plague was believed to have been discovered in 1947 (Galuzo et al., 1951; Bibikov et al., 1973). However, some documents that have been found by our group make it possible to state that this event took place in 1940.
In 1940 an extremely unique increase in the numbers of house mice for this region was observed in the Tekes valley and was connected with poor harvests of cereals. Doctors Ye.S. Schipakova and V.P. Smirnov, who were sent to the regions to carry out surveys, revealed a plague epizootic among these rodents, and moreover they found a weasel and two domestic cats that had been infected with plague (Smirnov, 1946). The epizootic occured in the autumn-winter season when all marmots were in the state of hibernation, however, V.P. Smirnov made a supposition that the house mice infection had resulted from parasite contact with plague infected burrows of marmots whose habitats in the Tekes valley penetrated into the agricultural area. In 1942 doctors R.F. Dedyukhina and O.V. Krassovski confirmed this hypothesis and were first to isolate four strains of plague from local marmots and one strain from both fleas Oropsylla silantiewi and lice Polyplax collected from these animals.
Nowadays the boundaries of the epizootic area and the biocenosis structure of the Kokpak mesofocus of plague seem to have been studied thoroughly enough. Its territory covering an.area of about 100 thousand hectares is inhabited by 32 mammal species and 37 arthropod species of Siphonaptera, Anoplura and Acarina orders. Through the efforts of numerous researchers it has been found that grey marmots play the main role in the focus as well as their specific fleas O. silantiewi and Rhadinopsylla li ventricosa. This conclusion is confirmed by the fact that only the violation of the spatial structure and significant decrease in marmot populations or their fleas caused a long-term recession in the focus epizootic activity. Other mammals and arthropods were involved in epizootic in certain years (Bibikov et al., l972, 1973; Burdelov et al., 1981; Arakelyanz et al., 1984), their paticipation, however, doesn't seem to play an important role in the plague rooting in the mesofocus.
More than 568 strains of plague microbes have been found during the whole survey period in the Kokpak mesofocus (1940-1996). Spontaneous plague infection has been found in 8 mammal species and l0 species of their arthropod parasites (table).
The data show that the overwhelming number of plague microbe strains has been isolated from grey marmots and their specific fleas. This firmly confirms their leading role in maintaining plague focality. The role of other species in the focus existence has not fully revealed, although some fur-bearing species and those bent for inhabiting human dwellings seem to be a serious epidemiologic danger.
Plague infected species and the number of strains isolated
|Species||Number of strains||Species*, their hosts and the number of strains|
*FLEAS: 1 - Oropsylla silantiewi, 2 - Rhadinopsylla li ventricosa, 3 - Pulex irritans,
4 - Neopsylla teratgra, 5 - N. pleskei, 6 - Citellophylus tesquorum, 7 - not identified
fleas; TICKS: 8 - Ixodes crenulatus, 9 - I. persulcatus; LICE: 10-Polyplax
sp., 11 - Neohaematopinus palearcticus.
** The exact number of strains is not given by V.P. Smirnov
*** The plague contact was found through serological test
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