Despite the emergence of resistance and environmental concerns, chemical insecticide application remains the most common method for mosquito vector control [
1]. Recent evidence suggests that progress in global malaria control has stalled, with an estimated 241 million malaria cases during 2020 among 85 malaria endemic countries, and an increase in malaria incidence in the region of Africa [
2]. This stagnation and regression in disease control correlates with increasing reports of insecticide resistance, which poses a growing challenge to malaria vector control programmes. Comprehensive and integrated global, regional and national plans will need to be developed and implemented to manage insecticide resistance [
1,
2]. However, as important as insecticide resistance management programme are, it is crucial to develop new vector control tools as soon as possible that will provide additional options for vector management. In the past decade, there has been intense interest in the use of biological control strategies, which aim to suppress insect vector populations by introducing endobiotic bacteria into wild populations [
3‐
6]. A number of approaches are focused on the development of naturally-occurring or genetically engineered microorganisms as biological control agents to either block the development of the malaria parasite within the
Anopheles vector [
7‐
9], or to kill the vector itself [
8,
10,
11]. Despite intensive efforts to develop entomopathogenic microorganisms as biocontrol agents against malaria vectors, most of these efforts have failed to meet expectations due to functional or practical limitations [
12]. For example, bacteria such as
Bacillus
thuringiensis var. israelensis (Bti) and
Bacillus sphaericus (Bs) show no residual persistence post-application [
13]. Interestingly, new and promising microbe-based approaches such as the use of the bacteria
Wolbachia spp. and some eukaryotic
Microsporidia (MB) are under investigation for malaria control [
14‐
17]. A major caveat for translating these results from laboratory to the field involves several development steps that need to be completed before they can be used for malaria control.
Among the promising microbe-based vector control tools are bacteria in the genus
Chromobacterium, such as
Chromobacterium vaccinii [
7] and
Chromobacterium sp. Panama (
Csp_P), which have insecticidal activity across different species of mosquitoes, including
Aedes aegypti and
Anopheles gambiae sensu stricto (
s.s.) [
8]. Additionally, Caragata et al
., [
9] demonstrated that a non-live preparation of
Csp_P was a highly effective larval mosquito biopesticide. Despite efforts to develop entomopathogenic
Chromobacterium as biocontrol agents against malaria vectors, most of the strains under investigation were isolated outside of endemic regions of Africa. Our strategy has been focused on the development of Chromobacterium as a biological control agent based on the assumption that local isolates are adapted to kill local mosquitoes and have evolved to survive local conditions. (i.e. rainy season heat, sunlight and humidity).
A new strain of
Chromobacterium sp., formerly but incorrectly identified as
Chromobacterium violaceum, was isolated in Burkina Faso [
10]. The laboratory infection of insecticide‑resistant malaria vector
Anopheles coluzzii with this new strain of
Chromobacterium resulted in high mortality, reduced mosquito blood feeding propensity, and almost eliminated fecundity [
10]. Whole genome sequence and molecular phylogeny place this strain within the genus
Chromobacterium, but outside any recognized species of
Chromobacterium. For the purposes of the current study, the isolate is referred to as Chromobacterium anophelis sp. nov. strain IRSSSOUMB001. In the present study, the mosquitocidal properties of C. anophelis sp. nov. IRSSSOUMB001 against the larval stages of malaria vector Anopheles coluzzii were further explored, along with an investigation into its impact on reproductive traits within adult mosquitoes and its transgenerational impacts on mosquito fitness.