Pathogenesis of Dengue Vaccine Viruses in Mosquitoes.
Final scientific rept. 1 Jun 79-30 Jun 82,
YALE UNIV NEW HAVEN CONN SCHOOL OF MEDICINE
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Techniques were developed and improved for the study of dengue virus in the mosquito vector. A technique for oral infection of mosquitoes using freshly prepared virus stocks proved to be efficient. An improved in vitro assay for transmission of dengue parent and vaccine viruses was deployed and is being assessed. Using an oil-charged capillary feeding system, saliva can rapidly and reliably be collected from even moribund mosquitoes. This technique will greatly facilitate studies on the assessment of vector competence. The dengue-2 vaccine virus S-1 and its parent virus PR 159 were compared for their ability to infect orally, to replicate in, and subsequently to be transmited by Aedes aegypti mosquitoes. The vaccine virus was markedly less efficient in its ability to infect mosquitoes orally. After ingesting infectious bloodmeals containing 3.7 to 8.2 log 10 TCID50ml of the respective viruses, 56 220396 of the mosquitoes became orally infected with the parent virus contrasted to 16 66397 for the vaccine virus. None of the 16 infected mosquitoes transmitted the vaccine virus, while 14 322 of the mosquitoes transmitted the parent virus. The vaccine virus remained temperature sensitive 39 C after orally infecting and replicating in Ae. aegypti mosquitoes.
- Medicine and Medical Research