Features of Multiplication of Different Clones of Venezuelan Equine Encephalomyelitis Virus in Aedes Aegypti Mosquitoes
ARMY MEDICAL RESEARCH INST OF INFECTIOUS DISEASES FORT DETRICK MD
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Multiplication in Aedes aegypti mosquitoes of clones of Venezuelan equine encephalomyelitis virus VEE with varying pathogenicity for white mice, as well as their capacity to accumulate in salivary glands and be transmitted by bite were studied comparatively. Natural virulent variants of VEE virus, in contrast to induced mutants avirulent for white mice, multiplied intensively in Aedes aegypti mosquitoes, accumulated in salivary glands and were transmitted by bite. The distinctive property of virulent variants consisted also in their capacity to cause intensive viremia. The experimental evidence suggests that these biologic properties of virulent variants may ensure their permanent circulation in nature and prevalence in the natural population of VEE virus. Induced mutants avirulent for white mice are not adapted to existence under natural conditions since during multiplication in vectors they do not penetrate into salivary glands and are not transmitted by bite, and during multiplication in mice their amount in the blood is not sufficient for infection of vectors. Low viremia also limits circulation of spontaneous mutants with low pathogenicity.