Intensity of pyrethroid resistance in Anopheles gambiae before and after a mass distribution of insecticide-treated nets in Kinshasa and in 11 provinces of the Democratic Republic of Congo

Watsenga, Francis; Agossa, Fiacre; Manzambi, Émile Zola; Illombe, Gillon; Mapangulu, Tania; Muyembe, Tamfum; Clark, Tiffany M.; Niang, Mame; Ntoya, Ferdinand; Sadou, Aboubacar; Pluciński, Mateusz M.; Li, Yikun; Messenger, Louisa A.; Fornadel, Christen; Oxborough, Richard M.; Irish, Seth R.

doi:10.1186/s12936-020-03240-6

Cited by 20 publications

(32 citation statements)

References 41 publications

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“…This is in line with the study of Wat’senga et al . for which they performed pyrethroid resistance intensity tests in 11 provinces in DRC and confirmed pyrethroid resistance, with in general higher resistance levels to permethrin than to deltamethrin [ 39 ]. It is debatable whether this resistance can be explained by the presence of kdr mutations.…”

Section: Discussionmentioning

confidence: 99%

Identification of main malaria vectors and their insecticide resistance profile in internally displaced and indigenous communities in Eastern Democratic Republic of the Congo (DRC)

Loonen

Dery

Musaka³

et al. 2020

Malar J

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Background Malaria remains a major public health concern in the Democratic Republic of the Congo (DRC) and its control is affected by recurrent conflicts. Médecins Sans Frontières (MSF) initiated several studies to better understand the unprecedented incidence of malaria to effectively target and implement interventions in emergency settings. The current study evaluated the main vector species involved in malaria transmission and their resistance to insecticides, with the aim to propose the most effective tools and strategies for control of local malaria vectors. Methods This study was performed in 52 households in Shamwana (Katanga, 2014), 168 households in Baraka (South Kivu, 2015) and 269 households in Kashuga (North Kivu, 2017). Anopheles vectors were collected and subjected to standardized Word Health Organization (WHO) and Center for Disease Control (CDC) insecticide susceptibility bioassays. Mosquito species determination was done using PCR and Plasmodium falciparum infection in mosquitoes was assessed by ELISA targeting circumsporozoite protein. Results Of 3517 Anopheles spp. mosquitoes collected, Anopheles gambiae sensu lato (s.l.) (29.6%) and Anopheles funestus (69.1%) were the main malaria vectors. Plasmodium falciparum infection rates for An. gambiae s.l. were 1.0, 2.1 and 13.9% for Shamwana, Baraka and Kashuga, respectively. Anopheles funestus showed positivity rates of 1.6% in Shamwana and 4.4% in Baraka. No An. funestus were collected in Kashuga. Insecticide susceptibility tests showed resistance development towards pyrethroids in all locations. Exposure to bendiocarb, malathion and pirimiphos-methyl still resulted in high mosquito mortality. Conclusions This is one of only few studies from these conflict areas in DRC to report insecticide resistance in local malaria vectors. The data suggest that current malaria prevention methods in these populations are only partially effective, and require additional tools and strategies. Importantly, the results triggered MSF to consider the selection of a new insecticide for indoor residual spraying (IRS) and a new long-lasting insecticide-treated net (LLIN). The reinforcement of correct usage of LLINs and the introduction of targeted larviciding were also included as additional vector control tools as a result of the studies.

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Section: Discussionmentioning

confidence: 99%

Identification of main malaria vectors and their insecticide resistance profile in internally displaced and indigenous communities in Eastern Democratic Republic of the Congo (DRC)

Loonen

Dery

Musaka³

et al. 2020

Malar J

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“…The haplotype is a strongly predictive marker of high-level resistance to pyrethroids, is easily screened with a single diagnostic assay and we suggest should be used for both insecticide resistance monitoring strategies and for informing LLIN selection. [6, 29, 46].…”

Section: Discussionmentioning

confidence: 99%

“…Democratic Republic of Congo Anopheles gambiae s.s . were obtained from the President’s Malaria Initiative supported entomological surveillance project [29] and from collections conducted by Lynd et al [30]. Mosquitoes were collected by human landing catch or pyrethrum spray collection from 15 locations between 2013 and 2018.…”

Section: Methodsmentioning

confidence: 99%

Identification of a rapidly-spreading triple mutant for high-level metabolic insecticide resistance inAnopheles gambiaeprovides a real-time molecular diagnostic for anti-malarial intervention deployment

Njoroge

Oruni

et al. 2021

Preprint

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Insecticide resistance provides both an increasingly pressing threat to the control of vector-borne diseases and insights into the remarkable capacity of natural populations to show rapid evolutionary responses to contemporary selection. Malaria control remains heavily dependent on deployment of pyrethroid insecticides, primarily in long lasting insecticide treated nets (LLINs), but resistance in the major malaria vectors has increased over the last 15 years in concert with dramatic expansion of LLIN distributions. Identifying genetic mechanisms causing high-level resistance in mosquitoes, which may almost entirely overcome pyrethroid efficacy, is crucial for the development and deployment of potentially resistance-breaking tools. Using the Anopheles gambiae 1000 genomes (Ag1000G) data we identified a very recent selective sweep in Ugandan mosquitoes which localized to a cluster of cytochrome P450 genes, including some frequently implicated in resistance. Further interrogation revealed a haplotype involving a trio of mutations, a nonsynonymous point mutation in Cyp6p4 (I236M), an upstream insertion of a partial Zanzibar transposable element (TE) and a duplication of the Cyp6aa1 gene. The mutations appear to have originated recently in An. gambiae from the Kenya-Uganda border region around lake Victoria, with stepwise replacement of the double-mutant (Zanzibar TE and Cyp6p4-236M) with the triple-mutant haplotype (including Cyp6aa1 duplication), which has spread into the Democratic Republic of Congo and Tanzania. The triple-mutant haplotype is strongly associated with increased expression of genes able to metabolise pyrethroids; is strongly predictive of resistance to pyrethroids most notably deltamethrin, a commonly-used LLIN insecticide, but importantly, appears less effective against LLINs co-treated with the synergist piperonyl butoxide (PBO). Frequencies of the triple-mutant haplotype remain spatially variable even within countries, suggesting an effective marker system to guide deployment decisions for limited supplies of PBO-pyrethroid co-treated LLINs across African countries. Duplications of Cyp6aa1 gene are common in An. gambiae across Africa and are likely to be a useful diagnostic for high levels of pyrethroid resistance.

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“…However, in the recent past, pyrethroids were the single insecticide class used for impregnation of LLINs, owing to their rapid action, excitorepellent effects, effectiveness at low doses and low toxicity to humans [61]. Unfortunately, pyrethroid resistance in malaria vectors has emerged and spread rapidly in Côte d'Ivoire [62] and several parts of Africa [63][64][65]. Therefore, efforts should be made to evaluate the effectiveness of insecticide-treated LLINs with different modes of action to which there is no cross-resistance and to evaluate promising tools to be used in combination with LLINs in highly endemic areas.…”

Section: Despite Repeated Mass Distribution Of Llins Malaria Transmimentioning

confidence: 99%

Assessing Anopheles Vector Species Diversity and Transmission of Malaria in Cross-Border Areas of Côte d'Ivoire

Yokoly

Zahouli

Small

et al. 2020

Preprint

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Background Although malaria and Anopheles mosquito vectors are highly prevalent in Côte d'Ivoire, data are still lacking on disease transmission dynamics in cross-border areas. To address this lack of information, we assessed the Anopheles mosquito vector species diversity, the An. gambiae complex members and the transmission of malaria in four cross-border areas of Côte d'Ivoire.Method From July 2016 to December 2017, we collected adult Anopheles mosquitoes in four cross-border health districts of Côte d’Ivoire (Aboisso, Bloléquin, Odienné and Ouangolodougou) using standardized window exit trap (WET) and pyrethrum knockdown spray collection (PSC) methods. We identified collected mosquitoes morphologically at species level and An. gambiae complex members using short interspersed nuclear element-based polymerase chain reaction (SINE-PCR). We analyzed An. gambiae, An. funestus and An. nili specimens for malaria Plasmodium parasite infection using the cytochrome oxidase I gene (COX-I), and malaria prevalence among human population through local Ministry of Health (MoH) statistical yearbooks.Results In total, 281, 754, 1,319 and 2,443 specimens of Anopheles adult females were collected in Aboisso, Bloléquin, Odienné and Ouangolodougou, respectively. We found seven Anopheles species dominated by An. gambiae s.l. (94.8%-99.1%), followed by An. funestus (0.4%-4.3%) and An. nili (0%-0.7%). Among An. gambiae s.l., An. coluzzii predominated in Aboisso (89.2%) and Bloléquin (92.2%), while An. gambiae s.s. was present at the highest frequency in Odienné (96.0%) and Ouangolodougou (94.2%). The Plasmodium sporozoite infection rate in An. gambiae s.l. was highest in Odienné (11.0 %; n = 100) followed by Bloléquin (7.8%, n = 115), Aboisso (3.1%; n = 65) and Ouangologoudou (2.5%; n = 120). In An. funestus, P. falciparum sporozoite infection rate was estimated at 6.2% (n = 32) in Bloléquin, 8.7% (n = 23) in Odienné. No An. funestus specimens were found infected with P. falciparum sporozoite infection in Ouangolodougou and Aboisso. No P. falciparum sporozoite was detected in An. nili specimens in the four health districts. Among the local human populations, malaria prevalence rate was higher in Odienné (39.7%; n = 45,376) and Bloléquin (37.6%; n = 150,205) compared with that in Ouangolodougou (18.3%; n = 131,629) and Aboisso (19.7%; n = 364,585).Conclusion In cross-border health districts of Côte d’Ivoire, Anopheles vector species diversity and abundance and Plasmodium sporozoite infection were high, thus resulting in high transmission of malaria to local populations. An. gambiae and An. funestus were found to be highly Plasmodium-infected in the health districts of Bloléquin and Odienné where malaria prevalence among humans was particularly high. This study provides important information that can be used to guide national malaria control programme strategies in Côte d’Ivoire, mainly in cross-border settings.

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Intensity of pyrethroid resistance in Anopheles gambiae before and after a mass distribution of insecticide-treated nets in Kinshasa and in 11 provinces of the Democratic Republic of Congo

Cited by 20 publications

References 41 publications

Identification of main malaria vectors and their insecticide resistance profile in internally displaced and indigenous communities in Eastern Democratic Republic of the Congo (DRC)

Identification of main malaria vectors and their insecticide resistance profile in internally displaced and indigenous communities in Eastern Democratic Republic of the Congo (DRC)

Identification of a rapidly-spreading triple mutant for high-level metabolic insecticide resistance inAnopheles gambiaeprovides a real-time molecular diagnostic for anti-malarial intervention deployment

Assessing Anopheles Vector Species Diversity and Transmission of Malaria in Cross-Border Areas of Côte d'Ivoire

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