Dengue Virus Serotype 2 from a Sylvatic Lineage Isolated from a Patient with Dengue Hemorrhagic Fever

Open Access
Publisher Website
Google Scholar
Abstract
Dengue viruses circulate in both human and sylvatic cycles. Although dengue viruses (DENV) infecting humans can cause major epidemics and severe disease, relatively little is known about the epidemiology and etiology of sylvatic dengue viruses. A 20-year-old male developed dengue hemorrhagic fever (DHF) with thrombocytopenia (12,000/ul) and a raised hematocrit (29.5% above baseline) in January 2008 in Malaysia. Dengue virus serotype 2 was isolated from his blood on day 4 of fever. A phylogenetic analysis of the complete genome sequence revealed that this virus was a member of a sylvatic lineage of DENV-2 and most closely related to a virus isolated from a sentinel monkey in Malaysia in 1970. This is the first identification of a sylvatic DENV circulating in Asia since 1975. Dengue viruses are mosquito-borne RNA viruses that cause a spectrum of illness from mild disease to life-threatening dengue hemorrhagic fever (DHF). Dengue viruses exist in two separate cycles in nature, circulating in either non-human primates or humans. The viruses that are endemic in humans today most likely evolved from non-human primate dengue viruses a few hundred years ago and have since established themselves as four distinct serotypes in human populations, causing periodic epidemics and severe disease. During the course of routine surveillance for dengue transmission in Malaysia during 2008, a sylvatic dengue virus type 2 was isolated from a young human male with DHF. The complete genome sequence of the virus was determined and found to be closely related to that isolated from a monkey in a similar region of Malaysia in 1970. This is the first sylvatic dengue virus isolated in Asia for more than 30 years.