The global fight against malaria is at a crossroads with the progress made for almost two decades stalled [
1,
2]. The decline in malaria burden between 2000 and 2015 [
3] is facing serious setbacks, as cases of malaria have consistently increased globally between 2015 and 2017 [
1,
4]. This malaria transmission recurrence, threatening a return to the 2012 levels is a warning sign to the control and elimination efforts of the World Health Organization (WHO) [
5]. The trend suggests that primary regions of interests for pre-elimination need urgent attention; most worrying being the WHO African Region, which accounts for ~ 92% of all malaria-related deaths [
2]. Niger Republic, with a high transmission and increased case incidence (2010–2016), is among countries with the highest per capita rate of malaria fatalities globally [
6]. It alone accounts for ~ 4% of malaria burden in the world [
4]. The Sahelian region of Niger represents the northern limit of malaria endemicity, compared to the north of the country where malaria is more marginal, where population densities are lower, and
Anopheles densities are known to be very low [
7]. The Sahel Region, characterized by a high seasonal malaria transmission [
8], is important for monitoring purposes, to provide enough evidences to support elimination in West Africa. However, generating reliable data on indigenous Sahelian
Anopheles species, their contribution to malaria transmission and monitoring insecticide resistance status over time and space [
4], is a pre-requisite for implementation of evidence-based control measures in this dry region.
The major vectors of malaria in Niger are
Anopheles gambiae sensu lato (s.l.) and
Anopheles funestus [
4,
9,
10], with
Anopheles coluzzii being the dominant species from the Gambiae complex [
11]. Unfortunately, information on the insecticide resistance status of these dominant vector species (DVS) from Niger and the underlying molecular mechanisms driving the resistance in the field is very limited. In addition, there is also a dearth of information on the impact of nationwide distribution of long-lasting insecticidal bed nets on development and/or escalation of resistance. Between 2005 and 2009 more than 6 million LLINs (Permanet
®2.0, Vestergaard, Lausanne, Switzerland) were freely distributed, with 73.4% coverage. Additionally, 11.3 million nets were distributed between 2014 and 2017 [
12]. A study published in 2017 described pyrethroids and DDT resistance in
An. coluzzii from Niger [
9]. However, collection for the study was carried out in 2013 and the link between the presence of the observed 1014F
kdr mutation and the resistance phenotype was not established. Another notable study followed increased frequency of 1014F
kdr in
An. coluzzii following the nationwide mass distribution of bed nets in Niger [
7]. However, pyrethroids/DDT resistance profiling was not conducted on the
Anopheles used in the study prior to genotyping.
To facilitate planning and implementation of evidence-based malaria control in Niger/the Sahel, the role of a major malaria vector An. coluzzii, in malaria transmission in Niger, and its resistance status to the various insecticides in use for public health control was characterized. The underlying molecular mechanisms driving the resistance in the field was also investigated.