PARASITOLOGICAL FACTORS IN THE NATURAL FOCI OF TAIGA ENCEPHALITIS
Studies were made in inhabited and wild taiga. In the former, studies of Ixodes persulcatus ticks for the virus of spring-summer (taiga) encephalitis were all negative; in the latter, extensively positive. The same applied to the mammalian hosts. Haemaphysalis concinna ticks were shown to be virus v...
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| Format: | Text |
| Language: | English |
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1962
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| Online Access: | http://www.dtic.mil/docs/citations/AD0291639 http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=AD0291639 |
| Summary: | Studies were made in inhabited and wild taiga. In the former, studies of Ixodes persulcatus ticks for the virus of spring-summer (taiga) encephalitis were all negative; in the latter, extensively positive. The same applied to the mammalian hosts. Haemaphysalis concinna ticks were shown to be virus vectors from nymph to adult stages and to transmit the virus transovarially to their progeny. Spontaneously infected Dermacentor silvarum ticks were also found. Mice can be infected with emulsions of I. persulcatus organs or may, instead, become immune. The same alternatives hold in the case of infected tick bites. Which of the two occurs depends on the quantity of virus inoculated, which, in turn, is related to the number of ticks biting, the degree to which they are infected, the duration of blood-sucking; also important here are the conditions of the virus, the environment and the animal. There is no doubt that the same factors operate when man is bitten by infected ticks. The fact that high serum antibody titers are found in man and cattle in the wild taiga, low titers in the inhabited taiga, and an intermediate situation at a place between the two is cited as proof. |
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