Fever from the forest: prospects for the continued emergence of sylvatic dengue virus and its impact on public health

Abstract

The four dengue virus (DENV) serotypes that circulate among humans emerged independently from ancestral sylvatic progenitors that were present in non–human primates, following the establishment of human populations that were large and dense enough to support continuous inter-human transmission by mosquitoes. This ancestral sylvatic–DENV transmission cycle still exists and is maintained in non-human primates and Aedes mosquitoes in the forests of Southeast Asia and West Africa. Here, we provide an overview of the ecology and molecular evolution of sylvatic DENV and its potential for adaptation to human transmission. We also emphasize how the study of sylvatic DENV will improve our ability to understand, predict and, ideally, avert further DENV emergence.

Impact of Climate and Mosquito Vector Abundance on Sylvatic Arbovirus Circulation Dynamics in Senegal

“…Knowledge of the sylvatic cycle is especially important given evidence of recent introductions of sylvatic DENV into human populations. 1,[36][37][38] The current study is another step forward in the understanding of the determinants of sylvatic DENV transmission dynamics.…”

“…Mosquito-borne dengue (DENV), chikungunya (CHIKV), yellow fever (YFV), and Zika (ZIKAV) viruses all circulate periodically in sylvatic cycles in the forests of Senegal, 1 are transmitted predominantly by Aedes mosquitoes, and put those people living around or working in the forests at direct risk for infection. These sylvatic cycles have been confirmed by isolation of virus from mosquitoes captured in gallery forests 2 and detection of antiviral antibodies and isolation of sylvatic viruses from non-human primates and humans.…”

Genetic characterization of dengue viruses prevalent in Kerala State, India

“…Kerala has an abundant Ae. albopictus population (Kumar et al, 2011), an established vector for dengue fever in Asia (De Figueiredo et al, 2010;Vasilakis et al, 2011), and restricted prevalence of Ae. aegypti in urban situations.…”

Discovery of fifth serotype of dengue virus (DENV-5): A new public health dilemma in dengue control

“…This ancestral sylvatic-DENV transmission cycle still exists and is maintained in non-human primates and Aedes mosquitoes in the forests of South East Asia and West Africa. 6 The exact reason for emergence of DENV-5 is not clear. The new serotype has only been found in forests of Sarawak.…”

“…6 The replication profiles of low-passage DENV-2 strains representing all major genotypes were evaluated in two surrogate models e human monocyte-derived dendritic cells (moDCs) and severe combined immunodeficient (SCID) mice xenografted with human hepatoma (Huh-7) cells. It was observed that though the strains differed in their replication profiles, there was no marked difference between sylvatic and human strains.…”