Background
Mosquitoes of the
Anopheles gambiae
complex are the main malaria vectors worldwide. Due to the lack of a vaccine to prevent malaria, the principal way to reduce the impact of this disease relies on the use of chemical insecticides to control its vectors. However, the intensive use of such compounds has led to the emergence of insecticide resistance in several
Anopheles
populations in Africa. This study aimed to investigate the presence of resistance alleles in an
Anopheles arabiensis
population from the City of Praia, capital of the Archipelago Cabo Verde, one of the countries on the World Health Organization list of countries that are on a path to eliminate local transmission of malaria.
Methods
Larvae from the
Anopheles
genus were collected using a one-pint dipper in three areas of City of Praia. Larvae were fed and maintained until the emergence of adult mosquitoes, and these were morphologically identified. In addition, molecular identification was performed using IGS markers and all
An. arabiensis
samples were subjected to PCR to screen for mutations associated to resistance in the
Ace
-
1
,
Na
v
and
GSTE2
genes.
Results
From a total of 440 mosquitoes collected, 52.3% were morphologically identified as
An. gambiae
sensu lato (s.l.) and 46.7% as
Anopheles pretoriensis.
The molecular identification showed that 100% of the
An. gambiae
s.l. were
An. arabiensis.
The mutations G119S in the
Ace
-
1
gene and L119F in the
GSTE2
gene were screened but not found in any sample. However, sequencing analysis for
GSTE2
revealed the presence of 37 haplotypes, 16 polymorphic sites and a high genetic diversity (π = 2.67). The L1014S mutation in the
Na
v
(voltage-gated sodium channel gene) was detected at a frequency of 7.3%.
Conclusion
This is the first study to investigate the circulation of insecticide resistance alleles in
An. arabiensis
from Cabo Verde. The circulation of the L1014S allele in the population of
An. arabiensis
in the city of Praia suggests that pyrethroid resistance may arise, be quickly selected, and may affect the process of malaria elimination in Cabo Verde. Molecular monitoring of resistance should continue in order to guide the development of strategies to be used in vector control in the study region.