Dengue virus serotype 2 from a sylvatic lineage isolated from a patient with dengue hemorrhagic fever

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.

Figure 1. MCC tree of 58 complete coding sequences of DENV-2.

Horizontal branches are drawn to a scale of estimated year of divergence with tip times reflecting sampling date (year). The tree is automatically rooted due to the assumption of a molecular clock. The coalescent (i.e. divergence) times of some key nodes, as well their 95% HPD values, are shown. Posterior probability values (all 1.0) are shown above nodes. Isolate DKD811 newly determined here is in the grey shaded box. Accession number for DKD811 full genome is FJ467493.