Aedes mosquitoes in the emerging threat of urban yellow fever transmission

Abstract

This last decade has seen a resurgence of yellow fever (YF) in historical endemic regions and repeated attempts of YF introduction in YF-free countries such as the Asia-Pacific region and the Caribbean. Infected travellers are the main entry routes in these regions where competent mosquito vectors proliferate in appropriate environmental conditions. With the discovery of the 17D vaccine, it was thought that YF would be eradicated. Unfortunately, it was not the case and, contrary to dengue, chikungunya and Zika, factors that cotribute to YF transmission remain under investigation. Today, all the signals are red and it is very likely that YF will be the next pandemic in the YF-free regions where millions of people are immunologically naïve. Unlike COVID-19, YF is associated with a high case-fatality rate and a high number of deaths are expected. This review gives an overview of global YF situation, including the non-endemic Asia-Pacific region and the Caribbean where Aedes aegypti is abundantly distributed, and also proposes different hypotheses on why YF outbreaks have not yet occurred despite high records of travellers importing YF into these regions and what role Aedes mosquitoes play in the emergence of urban YF.

Arthropod-Borne Flaviviruses in Pregnancy

“…Avoidance of mosquito bites through behavioral measures is critical to preventative efforts. Measures include wearing long sleeves and trousers, use of insect repellent, staying indoors when feasible, particularly at dawn and dusk, and use of mosquito nets [ 155 , 156 , 157 , 158 , 159 ]. For ZIKV-infected persons in particular, mosquito bite avoidance during the viremic period has been demonstrated to reduce further transmission to other persons particularly in the first week of illness in endemic areas (or for a three-week period after return to a non-endemic area) [ 136 , 160 , 161 ].…”

Perspectives of vector management in the control and elimination of vector-borne zoonoses

“…In fact, some of these diseases have multiple transmission cycles. For example, Trypanosoma cruzi has an urban transmission cycle involving humans, and sylvatic cycle involving wildlife ( Orozco et al, 2013 ), whereas yellow fever virus has sylvatic, intermediate/savannah and urban transmission cycles ( Valentine et al, 2019 ; Cunha et al, 2020 ; Gabiane et al, 2022 ). Of note, each transmission cycle may involve different vectors with distinct biological properties and behaviors that further complicate transmission blocking via vector control program.…”

Yellow Fever: A Perennial Threat

“…During the past few centuries, there have been geographic expansions and retractions of areas at risk for YF transmission (16)(17)(18)(19)(20)(21). At present, there are 44 countries in Sub-Saharan Africa and the Americas (South and Central America), which are considered by the World Health Organization (WHO) to have intermittent, sylvatic, epizootic, sporadic cases, and urban outbreaks of YF (22)(23)(24).…”