THE STRUCTURE OF A NATURAL TULAREMIA FOCUS OF THE FLOOD PLAIN TYPE
ARMY BIOLOGICAL LABS FREDERICK MD
Pagination or Media Count:
The active or elementary foci of tularemia are located on small unflooded areas which are among the extensive territories solidly inundated during the floods. The elementary foci are stable--the tularemia infection is found in them every year. The elementary foci are characterized by their multiple-vector and multiple-host nature. The maintenance and circulation of the infection in them are maintained by two species of ixodial ticks-- Dermacentor marginatus and Rhipicephalus rossicus--and by a number of species of rodents highly sensitive to tularemia--the water rat, meadow vole, house mouse and common hamster. A characteristic feature of the elementary foci is the seasonal concentration of small rodents on their territory, particularly the water rat, which is brought about by the flood. A considerable number of the larvae and nymphs of ixodial ticks feeds on these rodents and is responsible for maintaining the tularemia infection.
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