Rise and fall of vector infectivity during sequential strain displacements by mosquito‐borne dengue virus

摘要: Each of the four serotypes mosquito-borne dengue virus (DENV-1-4) comprises multiple, genetically distinct strains. Competitive displacement between strains within a serotype is common feature DENV epidemiology and can trigger outbreaks disease. We investigated mechanisms underlying two sequential displacements by DENV-3 in Sri Lanka that each coincided with abrupt increases haemorrhagic fever (DHF) incidence. First, post-DHF strain displaced pre-DHF 1980s. have previously shown more infectious than for major vector, Aedes aegypti. Then, ultra-DHF evolved situ from its ancestor 2000s. predicted would be Ae. aegypti but found infected significantly lower percentage mosquitoes post-DHF. therefore hypothesized had effected disseminating rapidly post-DHF, this was not borne out time course mosquito infection. To elucidate shape these virus-vector interactions, we tested impact RNA interference (RNAi), principal defence against DENV, on replication three Replication all similar cells dysfunctional RNAi, functional suppressed relative to other Thus, differences susceptibility RNAi may account infectivity underlie difference ultra-DHF.