Meeting Abstract

86.5  Monday, Jan. 6 11:00  Dengue Adaptive Evolution: Measuring the Function of Natural Diversity in an Emerging Virus MOH, A.P.*; THONGSRIPONG, P.; BENNETT, S.N.; Virginia Tech; California Academy of Sciences; California Academy of Sciences annapm@vt.edu

Dengue is a tropical to sub-tropical viral disease transmitted through mosquitoes to humans and other primates. The dengue virus is classified as a flavivirus, a fast-evolving RNA virus that relies on an arthropod vector to disperse and transmit itself. There are four serotypes of dengue virus that co-circulate seasonally in many populations, in some years causing intense epidemics. Understanding the evolutionary mechanisms or reasons why some dengue viruses have greater epidemic propensities than others has become imperative in epidemiological and ecological studies of the virus. This study pits pairs of dengue viruses against each other in cell culture to determine their fitness differences in terms of replication rates as a representation of epidemic potential. Strains of dengue viruses from Puerto Rico during the large 1998 epidemic and an earlier lineage from a mild transmission year, 1994, were used to infect mosquito and vertebrate cell lines. In each of three replicates, a 1994 strain was paired with a 1998 strain in the same culture, and the relative dominance of one strain over another was determined. The results of this study reflect viral levels in both co-infections and single infections of the cell lines over seven days using qPCR probes to differentiate between the strains. These findings indicate higher initial levels of the 1994 strain, which appear contrary to the apparent dominance of the 1998 strain’s epidemic spread. The results may only apply to the initial incubation period of the virus, and not necessarily viral levels throughout longer periods of infection. It is likewise possible that the 1994 strain is over-virulent, and therefore prevented its own spread.