Insecticide resistance in the malaria vector Anopheles arabiensis in Mamfene, KwaZulu-Natal

Abstract The control of malaria vector mosquitoes in South Africa’s affected provinces is primarily based on indoor spraying of long-lasting residual insecticides. The primary vectors in South Africa are Anopheles arabiensis and An. funestus. South Africa’s National Malaria Control Programme has adopted a malaria elimination agenda and has scaled up vector control activities accordingly. However, despite these plans, local transmission continues and is most likely because of outdoor feeding by populations of An. arabiensis. An outdoor Anopheles surveillance system has been set up in three sections of the Mamfene district in northern KwaZulu- Natal in order to assess the extent of outdoor resting An. arabiensis in Mamfene and to assess the current insecticide susceptibility status of this population. According to WHO criteria, the An. arabiensis samples tested showed evidence of resistance to deltamethrin (pyrethroid), DDT (organochlorine) and bendiocarb (carbamate), and full susceptibility to the organophosphates pirimiphos-methyl and fenitrothion. Pre-exposure to piperonyl butoxide completely nullified the deltamethrin resistance otherwise evident in these samples, supporting previous studies implicating monooxygenase-based detoxification as the primary mechanism of pyrethroid resistance. The data presented here affirm the presence of pyrethroid and DDT resistance previously detected in this population and also indicate the comparatively recent emergence of resistance to the carbamate insecticide bendiocarb. These data show that special attention and commitment needs to be given to the principles of insecticide resistance management as well as to investigations into alternative control techniques designed to target outdoor-resting An. arabiensis in northern KwaZulu-Natal.

Download Full-text

Multiple insecticide resistance target sites in adult field strains of An. gambiae (s.l.) from southeastern Senegal

Parasites & Vectors ◽

10.1186/s13071-020-04437-z ◽

2020 ◽

Vol 13 (1) ◽

Author(s):

El hadji Diouf ◽

El hadji Amadou Niang ◽

Badara Samb ◽

Cheikh Tidiane Diagne ◽

Mbaye Diouf ◽

...

Keyword(s):

Insecticide Resistance ◽

Indoor Residual Spraying ◽

National Malaria Control Programme ◽

Control Programme ◽

Molecular Techniques ◽

Target Site ◽

Malaria Control Programme ◽

Insecticide Susceptibility ◽

High Coverage ◽

Pyrethroid Insecticides

Abstract Background High coverage of long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) are the cornerstones of vector control strategy in Senegal where insecticide resistance by the target vectors species is a great of concern. This study explores insecticide susceptibility profile and target-site mutations mechanisms within the Anophelesgambiae complex in southeastern Senegal. Methods Larvae of Anopheles spp. were collected in two sites from southeastern Senegal Kedougou and Wassadou/Badi in October and November 2014, and reared until adult emergence. Wild F0 adult mosquitoes were morphologically identified to species. Susceptibility of 3–5-day-old An. gambiae (s.l.) samples to 11 insecticides belonging to the four insecticide classes was assessed using the WHO insecticide susceptibility bioassays. Tested samples were identified using molecular techniques and insecticide resistance target-site mutations (kdr, ace-1 and rdl) were determined. Results A total of 3742 An.gambiae (s.l.) were exposed to insecticides (2439 from Kedougou and 1303 from Wassadou-Badi). Tests with pyrethroid insecticides and DDT showed high level of resistance in both Kedougou and Wassadou/Badi. Resistance to pirimiphos-methyl and malathion was not detected while resistance to bendoicarb and fenitrothion was confirmed in Kedougou. Of the 745 specimens of An.gambiae (s.l.) genotyped, An.gambiae (s.s.) (71.6%) was the predominant species, followed by An.arabiensis (21.7%), An.coluzzii (6.3%) and hybrids (An. gambiae (s.s.)/An.coluzzii; 0.4%). All target site mutations investigated (Vgsc-1014F, Vgsc-1014S, Ace-1 and Rdl) were found at different frequencies in the species of the Anophelesgambiae complex. Vgsc-1014F mutation was more frequent in An.gambiae (s.s.) and An.coluzzii than An.arabiensis. Vgsc-1014S was present in An.gambiae (s.l.) populations in Wassadou but not in Kedougou. Ace-1 and rdl mutations were more frequent in An.gambiae (s.s.) in comparison to An.arabiensis and An.coluzzii. Conclusions Resistance to all the four insecticide classes tested was detected in southeastern Senegal as well as all target site mutations investigated were found. Data will be used by the national Malaria Control Programme.

Download Full-text

Malaria vectors diversity, insecticide resistance and transmission during the rainy season in peri-urban villages of south-western Burkina Faso

Malaria Journal ◽

10.1186/s12936-020-03554-5 ◽

2021 ◽

Vol 20 (1) ◽

Author(s):

Dieudonné Diloma Soma ◽

Serge Bèwadéyir Poda ◽

Aristide Sawdetuo Hien ◽

Moussa Namountougou ◽

Ibrahim Sangaré ◽

...

Keyword(s):

Insecticide Resistance ◽

Burkina Faso ◽

Urban Areas ◽

Resistance Management ◽

National Malaria Control Programme ◽

Control Programme ◽

Malaria Control Programme ◽

Organophosphate Insecticide ◽

High Susceptibility ◽

Entomological Data

Abstract Background This study reports an updated description on malaria vector diversity, behaviour, insecticide resistance and malaria transmission in the Diébougou and Dano peri-urban areas, Burkina Faso. Methods Mosquitoes were caught monthly using CDC light traps and pyrethrum spray catches. Mosquitoes were identified using morphological taxonomic keys. PCR techniques were used to identify the species of the Anopheles gambiae complex and insecticide resistance mechanisms in a subset of Anopheles vectors. The Plasmodium sporozoite infection status and origins of blood meals of female mosquitoes were determined by ELISA methods. Larvae were collected, breed in the insectary and tested for phenotypic resistance against four insecticides using WHO bioassays. Results This study contributed to update the entomological data in two peri-urban areas of Southwest Burkina Faso. Anopheles populations were mostly anthropophilic and endophilic in both areas and exhibit high susceptibility to an organophosphate insecticide. This offers an alternative for the control of these pyrethroid-resistant populations. These data might help the National Malaria Control Programme for decision-making about vector control planning and resistance management. Conclusions This study contributed to update the entomological data in two peri-urban areas of Southwest Burkina Faso. Anopheles populations were mostly anthropophilic and endophilic in both areas and exhibit high susceptibility to an organophosphate insecticide. This offers an alternative for the control of these pyrethroid-resistant populations. These data might help the National Malaria Control Programme for decision-making about vector control planning and resistance management.

Download Full-text

Multiple insecticide resistance target sites in adult field strains of An. gambiae (s.l.) from southeastern Senegal

10.21203/rs.3.rs-44879/v4 ◽

2020 ◽

Author(s):

El hadji Diouf ◽

El hadji Amadou Niang ◽

Badara Samb ◽

Cheikh Tidiane Diagne ◽

Mbaye Diouf ◽

...

Keyword(s):

Insecticide Resistance ◽

Indoor Residual Spraying ◽

National Malaria Control Programme ◽

Control Programme ◽

Molecular Techniques ◽

Target Site ◽

Malaria Control Programme ◽

Insecticide Susceptibility ◽

High Coverage ◽

Pyrethroid Insecticides

Abstract Background: High coverage of long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) are the cornerstones of vector control strategy in Senegal where insecticide resistance by the target vectors species is a great of concern. This study explore insecticide susceptibility profile and target-site mutations mechanisms within the Anopheles gambiae complex in southeastern Senegal. Methods: Anopheles larvae were collected from Kedougou and Wassadou/Badi, two sites from southeastern Senegal, in October and November 2014, and reared until adult emergence. Wild Fo Adults mosquitoes were morphologically identified to species. Susceptibility of 3-5-day old An. gambiae (s. l.) samples to eleven (11) insecticides belonging to the four insecticide classes was assessed using WHO insecticide susceptibility bioassays. Tested samples were identified using molecular techniques as well as detection of insecticide resistance target-site mutations (kdr, ace-1 and rdl).Results: A total of 3,742 An. gambiae (s.l.) were exposed to insecticides (2,439 from Kedougou and 1,303 from Wassadou-Badi). Tests with pyrethroid insecticides and DDT showed high level of resistance in both Kedougou and Wassadou/Badi. Pirimiphos-methyl and Malathion resistance were not detected while Bendoicarb and Fenitrothion resistance were confirmed in Kedougou. Of the 745 specimens of An. gambiae (s.l.) genotyped, An. gambiae (s.s.) (71.6%) was the predominant species, followed by An. arabiensis (21.7%), An. coluzzii (6.3%) and hybrids (An. gambiae (s.s.) /An. coluzzii; 0.4%). All target site mutations investigated (Vgsc-1014F; Vgsc-1014S, Ace-1 and Rdl) were found at different frequencies in the species of the Anopheles gambiae (s.l.). Vgsc-1014F mutation is more frequent in An. gambiae and An. coluzzii than An. arabiensis. Vgsc-1014S was present in An. gambiae (s.l.) populations in Wassadou but not in Kedougou. Ace-1 and rdl mutations were more frequent in An. gambiae (s.s.) in comparison to An. arabiensis and An. coluzzii. Conclusions: Resistance to all the four insecticide classes tested was detected in southeastern Senegal as well as all target site mutations investigated were found. Data will be used by the national Malaria Control Programme.

Download Full-text

Therapeutic efficacy of artemether–lumefantrine and artesunate–amodiaquine for the treatment of uncomplicated Plasmodium falciparum malaria in Mali, 2015–2016

Malaria Journal ◽

10.1186/s12936-021-03760-9 ◽

2021 ◽

Vol 20 (1) ◽

Author(s):

Youssouf Diarra ◽

Oumar Koné ◽

Lansana Sangaré ◽

Lassina Doumbia ◽

Dade Bouye Ben Haidara ◽

...

Keyword(s):

Plasmodium Falciparum ◽

Uncomplicated Malaria ◽

Artemisinin Resistance ◽

National Malaria Control Programme ◽

Plasmodium Falciparum Malaria ◽

Control Programme ◽

Malaria Control Programme ◽

Pre Treatment ◽

Better Than

Abstract Background The current first-line treatments for uncomplicated malaria recommended by the National Malaria Control Programme in Mali are artemether–lumefantrine (AL) and artesunate–amodiaquine (ASAQ). From 2015 to 2016, an in vivo study was carried out to assess the clinical and parasitological responses to AL and ASAQ in Sélingué, Mali. Methods Children between 6 and 59 months of age with uncomplicated Plasmodium falciparum infection and 2000–200,000 asexual parasites/μL of blood were enrolled, randomly assigned to either AL or ASAQ, and followed up for 42 days. Uncorrected and PCR-corrected efficacy results at days 28 and 42. were calculated. Known markers of resistance in the Pfk13, Pfmdr1, and Pfcrt genes were assessed using Sanger sequencing. Results A total of 449 patients were enrolled: 225 in the AL group and 224 in the ASAQ group. Uncorrected efficacy at day 28 was 83.4% (95% CI 78.5–88.4%) in the AL arm and 93.1% (95% CI 89.7–96.5%) in the ASAQ arm. The per protocol PCR-corrected efficacy at day 28 was 91.0% (86.0–95.9%) in the AL arm and 97.1% (93.6–100%) in the ASAQ arm. ASAQ was significantly (p < 0.05) better than AL for each of the aforementioned efficacy outcomes. No mutations associated with artemisinin resistance were identified in the Pfk13 gene. Overall, for Pfmdr1, the N86 allele and the NFD haplotype were the most common. The NFD haplotype was significantly more prevalent in the post-treatment than in the pre-treatment isolates in the AL arm (p < 0.01) but not in the ASAQ arm. For Pfcrt, the CVIET haplotype was the most common. Conclusions The findings indicate that both AL and ASAQ remain effective for the treatment of uncomplicated malaria in Sélingué, Mali.

Download Full-text