Variation in vector competence and extrinsic incubation period for dengue virus between Aedes aegypti populations from Florida and East Africa

On-Demand

Presenting Author(s)

XW

Xiaodi Wang

PhD Student
University of Florida
Vero Beach, Florida

Co-Author(s)

Jovana Bozic

Postdoctoral Fellow
Pennsylvania State University
State College, Pennsylvania
Derrick Mathias

Assistant Professor
University of Florida
Vero Beach, Florida
TS

Tanise Stenn

University of Florida
Vero Beach, Florida
VN

Vincent Nyasembe

University of Florida
Gainesville, Florida
RD

Rhoel D. Dinglasan

Professor
University of Florida
Gainesville, Florida
BN

Billy Ngasala, M.D.,Ph.D.

Professor
Muhimbili University of Health and Allied Sciences
Dar Es Salaam, Dar es Salaam, Tanzania

Approximately half the world’s population lives in a location suitable for dengue virus (DENV) transmission, a mosquito-borne virus that causes ~ 400 million cases annually. The global footprint of DENV closely matches the range of its primary vector, the yellow fever mosquito Aedes aegypti. This species is a highly efficient transmitter of DENV, although geographic variation in vectorial capacity among populations and subspecies is well-documented. For transmission to be perpetuated, virus particles ingested when feeding must infect the midgut epithelium, propagate within, and disseminate to the salivary glands. Recent dengue outbreaks along the Tanzanian coast prompted a study of Ae. aegypti vector competence (VC) and extrinsic incubation period (EIP) in a population from Bagamoyo, Tanzania. We orally challenged mosquitoes from Tanzania and Florida (5-7 days post-emergence) with DENV-2 and found that those from Florida had significantly greater midgut infection rates than mosquitoes from Tanzania at days 7 and 10 post-feeding. We also estimated median times to disseminated infection (DI₅₀) as 12.19 days for Florida and 14.64 days for Tanzania, suggesting that DENV-2 disseminates more slowly in Tanzanian Ae. aegypti. In combination, lower midgut infection rates and slower dissemination may cause a relatively lower vectorial capacity for DENV-2 in this population. Although preliminary genetic analyses indicate that the Bagamoyo population is similar to other populations from East Africa, it is unclear if its vectorial capacity reflects that of Ae. aegypti from Dar es Salaam and Tanga, locations where outbreaks in 2017 were the most intense.