Susceptibility of mosquito vectors of the city of Praia, Cabo Verde, to Temephos and Bacillus thuringiensis var israelensis

Abstract

Many vector-borne diseases circulate in the Republic of Cabo Verde. These include malaria during the colonization of the archipelago by the Portuguese explorers and several arboviruses such as yellow fever (now eradicated), dengue and zika. To control these vector-borne diseases, an integrated vector control program was implemented. The main targeted mosquito vectors are Aedes aegypti and Anopheles arabiensis, and in a lesser extent the potential arbovirus vector Culex pipiens s.l. The main control strategy is focused on mosquito aquatic stages using diesel oil and Temephos. This latter has been applied in Cabo Verde since 1979. Its continuous use was followed by the emergence of resistance in mosquito populations. We investigated the current susceptibility to Temephos of the three potential mosquito vectors of Cabo Verde through bioassays tests. Our results showed various degrees of susceptibility with 24h post-exposure mortality rates ranging from 43.1% to 90.9% using WHO diagnostic doses. A full susceptibility was however observed with Bacillus thurigiensis var israelensis with mortality rates from 99.6% to 100%.

A next generation targeted amplicon sequencing method to screen for insecticide resistance mutations in Aedes aegypti populations reveals a rdl mutation in mosquitoes from Cabo Verde

“…In 2009, more than 21,000 cases of dengue fever were diagnosed and in 2015 an epidemic of Zika caused at least 7,580 reported cases. To prevent vector-borne disease, Cabo Verde has a history of applying several strategies to combat Anopheles , Aedes and Culex vectors, including the past use of DDT (organochlorine) and recent spraying of temephos (organophosphate) and deltamethrin (pyrethroid) insecticides [ 29 ]. Compared to Anopheles mosquitoes, little is known about Aedes insecticide resistance and associated mutations, in both Cabo Verde, and in Africa as a whole [ 30 ].…”

First Report of the L1014F kdr Mutation in Wild Populations of Anopheles Arabiensis in Cabo Verde, West Africa

“…More recently, temephos resistance was reported in An. arabiensis from the City of Praia [53], collected at the same time and at the same locations, which suggest a possible selective pressure for resistance to insecticides due to their greater use (frequency and quantity). Unfortunately, there is currently no public data on the use of pyrethroids by location to estimate the possible association between the use of chemical compounds in the island and the reported resistance data.…”

Population Genetics of Anopheles pretoriensis in Grande Comore Island

“…The species name is based on the location of its discovery in Pretoria, South Africa. This species’ geographic distribution is widespread in Africa, being present in over 30 continental countries [ 22 , 23 ] and in islands such as Cape Verde [ 24 ], Comoros [ 8 ], Madagascar [ 25 ] and Mayotte [ 26 ]. Anopheles pretoriensis has also been reported in Saudi Arabia [ 27 ] and Yemen [ 28 ].…”