Evaluation of Toxorhynchites splendens (Diptera: Culicidae) as a bioassay host for dengue viruses
Watts, D.M.; Harrison, B.A.; Nisalak, A.; Scott, R.M.; Burke, D.S.
Journal of Medical Entomology 19(1): 54-59
ISSN/ISBN: 0022-2585 PMID: 6126591 DOI: 10.1093/jmedent/19.1.54
T. splendens, a nonhematophagous mosquito was evaluated as a bioassay host for the detection and propagation of dengue viruses. All dengue virus serotypes and strains attained titers in T. splendens comparable to those observed for 2 strains of Aedes aegypti. Peak virus titers occurred in T. splendens .apprx. 6 days postinoculation; specific fluorescence for all viruses was not observed in 100% of mosquito heads until 12 days postinoculation. A 100% correlation was noted between specific fluorescence in T. splendens heads and the recovery of virus from corresponding thorax-abdomens. The volume of inoculum tolerated by T. splendens was .apprx. 5 times greater than that injected into A. aegypti. Thus, for a given volume of inoculum, the number of T. splendens required for virus assays was appreciably less than that needed for A. aegypti. The overall survival rate for T. splendens following intrathoracic inoculation with dengue viruses was 92%, compared to 41 and 42% for 2 strains of male A. aegypti. Thus, T. splendens appears to be more efficient than A. aegypti as a laboratory assay host for detecting dengue viruses in blood of infected patients and for use in experimental investigations.