INVESTIGATION OF NORTH-ASIATIC (SIBERIAN) RICKETTSIOSIS IN DERMACENTOR NUTTALLI TICKS COLLECTED IN ONE OF THE KRASNOIARSK REGION FOCI,
NAVAL MEDICAL RESEARCH UNIT NO 3 CAIRO (EGYPT) DEPT OF MEDICAL ZOOLOGY
Pagination or Media Count:
In the North Asiatic rickettsiosis foci in the Krasnoyarsk region Dermacentor nuttalli ticks were collected and examined for natural infestation with the causative agent Dermacentroxenus sibiricus. The transmission of rickettsia in recently molted ticks is reduced, apparently because of the underdevelopment of salivary glands during post moulting period. The feeding of ticks kept fasting for over a year was accompanied with intensive infection of guinea pigs, reaching its peak during repeated letting of them on guinea pigs after artificially interrupted feeding. A causal agent strain T, isolated from the ticks and identified both serologically with a standard antigen and immunologically by repeated inoculations with the Altay strain Net-svetaev, was identified as the causative agent of the North Asiatic rickettsiosis. Following inoculation of guinea pigs with a suspension of larvae hatched from tick eggs collected from cattle, a strain No. 50 was isolated, proving the transovarial transmission of the rickettsiae. Hence in the focus, D. nuttalli appear to be both the vector and the reservoir of infection.