48-hour surveillance of Aedes aegypti activity along an urbanisation gradient reveals substantial nocturnal and outdoor biting in Burkina Faso

Tuesday, November 12, 2024

3:48 PM – 4:00 PM MST

Location: Phoenix Convention Center, 222 A

Presenting Author(s)

AB

Athanase Badolo, Ph.D.

Professor of Medical Entomology
Université Joseph Ki-Zerbo
Ouagadougou, Kadiogo, Burkina Faso

Co-Author(s)

AS

Aboubacar Sombié

Université Joseph Ki-Zerbo
Ouagadougou, Kadiogo, Burkina Faso
KT

K. Hyacinthe Toé

Université Joseph Ki-Zerbo
Ouagadougou, Kadiogo, Burkina Faso
AG

Awa Gnémé

Université Joseph Ki-Zerbo
Ouagadougou, Kadiogo, Burkina Faso
WO

W. Mathias Ouédraogo

Université Joseph Ki-Zerbo
Ouagadougou, Kadiogo, Burkina Faso
AT

Alfred Tiono

Groupe de Recherche Action en Santé
Ouagadougou, Kadiogo, Burkina Faso
FR

Franck Remoué

Institut National de la Recherche Agronomique (INRAe)
Montpellier, Midi-Pyrenees, France
CC

Carlo Costantini

Institut National de la Recherche Agronomique (INRAe)
Dakara, Dakar, Senegal

Aedes aegypti transmits several arboviruses, including dengue. Its bionomics understudied in Africa, is gaining interest over the past decades in response to increased dengue cases. As Ae. aegypti behaviour is required to guide disease control, we investigated its biting patterns along an urbanisation gradient in Burkina Faso to assess daily variation in blood-feeding and the locations where biting activity occurs.

In 2023, we evaluated biting rates using Human Landing Catches for 48 hours, weekly, both indoors and outdoors, for three months, during the rainy season in urban, peri-urban, and rural areas.

A total of 4,684 Ae. aegypti were caught over 144 days x sites x localities. Their distribution varied between indoor and outdoor sites, as well as day and night periods, depending on the location. Number of bites per person peaked at ~1,000 every 48 hours in the urban locality outdoors and decreased to a minimum of ~100 bites indoors. Contrary to the paradigm that Ae. aegypti activity is only diurnal, we found biting occurred continuously throughout the 24-hour period with two peaks: one between 5 AM and 9 AM, and another between 4 PM and 7 PM. Moving from urban to rural localities, decrease in biting rates is observed and a change in daily biting patterns. The evening biting peak remained consistent across localities, but the morning peak vanished in the rural locality.

The reasons behind these unusual and varying behaviours, further investigations are needed. We are exploring whether there is a connection between genomic variants and behavioural differences.