Effects of Pathogen-Vector Interactions on the Transmission of Dengue Virus

Viral factors that affect DENV replication and transmission in the mosquito vector

Figure ?. Predicted secondary RNA structures of the 3’ NTR of; a, an American genotype DENV-2 strain and b, a Southeast Asian DENV-2 strain.[15]

The transmission from vector to host for a particular DENV strain is determined by viral infectivty of mosquito cells, and the rate of viral replication in these cells. Dissemination from the heomocoel to the salivary glands affects disease transmission as well but it is tied directly tied to viral replication rates and viral titers in the hemocoel as seen in figure ?[4].

and dissemination of the virus in mosquito tissues. Replication rate and viral titers are both linked to genotypic differences

the genotype of a particular strain

and how easily the virus can disseminate from the midgut to the salivary glands [4]. Infectivity, replication, and dissemination are affected by both the genotype of the infecting virus as well as a variety of mosquito host factors that modulate dengue virus infection.

More virulent strains have fast rates of viral replication as well as higher virus titers in both human host and vector host. It seems as though mutations within the E envelope glycoprotein responsible for virion binding to the host cell receptor increases the infectivity of a strain. Differences in the nontranslated regions of the genome (NTRs) also seem to affect virulence because possible changes in the time it takes to initiate translation because of changes in secondary structure as seen in figure (dengue virus structural… leitmeyer). No specific nucleotide or amino acid differences in either the coding or noncoding region have been correlated with attenuated disease in humans. It is only clear that there are differences at these sights between more virulent strains and less virulent strains.