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Muhoro AM, Ochomo EO, Kinyua IN, Kosgei JJ, Rasaki LA, Farkas E. A study on the effectiveness of (+)-usnic acid as oral toxic sugar bait against adult male and female Anopheles gambiae. Malar J 2024; 23:311. [PMID: 39420395 PMCID: PMC11487889 DOI: 10.1186/s12936-024-05141-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2024] [Accepted: 10/11/2024] [Indexed: 10/19/2024] Open
Abstract
BACKGROUND Despite the application of various tools for the control of vectors of Plasmodium falciparum, malaria remains the major killer disease in sub-Saharan Africa accounting for up to 90% of deaths due to the disease. Due to limitations of the useage of chemical insecticides such as resistance, negative impact on the environment and to nontarget organisms, the World Health Organization (WHO) requires that affected countries find alternative vector control tools. This study evaluated the effectiveness of ( +)-usnic acid (UA) as an insecticide through oral administration to male and female Anopheles gambiae as an alternative or additional active ingredient to be used in toxic sugar bait. METHODS ( +)-usnic acid was diluted using acetone at 5, 10, and 15 mg/ml concentrations in three replicates. A 5 ml mixture of 2% food dye and 10% sugar using chlorine-free water mixed with the dilutions of the ( +)-usnic acid and negative control was made containing 2% food dye and 10% sugar solution. The preparations were soaked on a ball of cotton wool and placed over the net of a cup. 5 male and 5 non-blood-fed female newly hatched starved An. gambiae Kisumu strain were introduced together into a cup and monitored for knockdown and mortalities after 4, 24 48, and 72 h. The data were analysed using a multiple linear regression model using the lm function, a base R function and a posthoc test were conducted on the significant main effects and interaction terms using the emmeans function from the emmeans R package. All analyses were performed in RStudio using base R (version 4.3.3). RESULTS There was high mortality of both male and female An. gambiae after ingestion of the toxic sugar bait. 15 mg/ml usnic acid caused the highest mortality (50%) within the first 4 h compared to 5 and 10 mg/ml ( +)-UA. There was a decline in the mortality rate with increased exposure time from 24 to 72 h, however, there was a significant difference in mortality at 5, 10 and 15 mg/ml. Acute toxicity was associated with ingestion of 15 mg/ml after 24 h. 72 h post-mortality was lower in all concentrations than in the control. High mortality was observed among females over the first 4 h (60%) compared to males (40%) due to higher feeding rate of the toxic agent. The proportion of dead males and females was equal after 24 h while after 48 h, the proportion of dead males was high.There was a significantly lower mortality rate after 72 h for both males and females (0 to 13.3%). Compared to all the treatments, high mortality of males was observed. CONCLUSIONS The results of this study indicate that ( +)-UA when administered as oral sugar bait to An. gambiae has insecticidal properties and is a suitable ingredient to be used as a toxic agent in the novel attractive toxic sugar bait for the control of malaria vectors. ( +)-UA may be an alternative active ingredient as toxic bait in the effort to reduce and eliminate the transmission of Plasmodium falciparum in Africa.
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Affiliation(s)
- Arthur Macharia Muhoro
- Doctoral School of Biological Sciences, Hungarian University of Agriculture and Life Sciences, Páter K. U. 1, 2100, Gödöllő, Hungary.
- Kenya Medical Research Institute-Centre for Global Health Research (KEMRI-CGHR), P.O. Box 1578, Kisumu, 40100, Kenya.
| | - Eric Odhiambo Ochomo
- Kenya Medical Research Institute-Centre for Global Health Research (KEMRI-CGHR), P.O. Box 1578, Kisumu, 40100, Kenya
| | - Isaac Njangiru Kinyua
- Institute of Pharmacodynamics and Biopharmacy, University of Szeged, Eötvös U. 6, 6720, Szeged, Hungary
| | - Jackline Jeruto Kosgei
- Kenya Medical Research Institute-Centre for Global Health Research (KEMRI-CGHR), P.O. Box 1578, Kisumu, 40100, Kenya
| | - Laide Abbas Rasaki
- Department of Crop Sciences, North Carolina State University, Raleigh, NC, 27695, USA
| | - Edit Farkas
- HUN-REN Centre for Ecological Research, Institute of Ecology and Botany, Alkotmány u. 2-4, 2163, Vácrátót, Hungary
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Bartilol B, Babu L, Garama K, Karisa J, Kamau A, Mwandawiro C, Wanjiku C, Mbogo C, Maia M, Mwangangi J, Rono MK. Molecular xenomonitoring reveals Anopheles funestus and An. rivulorum as the primary vectors of lymphatic filariasis in coastal Kenya. Parasit Vectors 2024; 17:425. [PMID: 39385178 PMCID: PMC11462847 DOI: 10.1186/s13071-024-06513-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2024] [Accepted: 09/26/2024] [Indexed: 10/11/2024] Open
Abstract
BACKGROUND Lymphatic filariasis (LF) is an infectious neglected tropical disease caused by mosquito-borne nematodes such as Wuchereria bancrofti, Brugia malayi, and Brugia timori. Globally, LF affects 51 million people, with approximately 863 million at risk in 47 countries. In Kenya, filariasis is endemic along the entire coastal strip, and more recently, at the Kenya-Ugandan border. The World Health Organization (WHO) recommends mass drug administration to reduce disease transmission and morbidity. Monitoring the effectiveness of such interventions relies on robust surveillance, achieved through microscopic examination of microfilariae in nighttime blood, detection of circulating filarial antigens (CFA), and molecular xenomonitoring. We focused on molecular xenomonitoring along the Kenyan coast due to its noninvasive nature and the opportunity to identify new vectors. METHODS In 2022, mosquitoes were collected from Kilifi, Kwale, and Taita-Taveta counties located within the LF endemic region in Kenya. Subsequently, genomic deoxyribonucleic acid (gDNA) was extracted from these mosquitoes for speciation and analysis of Wuchereria bancrofti infection rates. The impact of sociodemographic and household attributes on infection rates was assessed using generalized estimating equations. RESULTS A total of 18,121 mosquitoes belonging to Culicinae (63.0%, n = 11,414) and Anophelinae (37.0%, n = 6707) subfamilies were collected. Morphological identification revealed that Anopheline mosquitoes were dominated by An. funestus (45.4%, n = 3045) and An. gambiae (42.8%, n = 2873). Wuchereria bancrofti infection rates were highest in Kilifi (35.4%; 95% CI 28.0-43.3%, n = 57/161) and lowest in Taita Taveta (5.3%; 95% CI 3.3-8.0%, n = 22/412). The major vectors incriminated are An. rivulorum, An. funestus sensu stricto, and An. arabiensis. Mosquitoes of the An. funestus complex were significantly associated with LF transmission (OR 18.0; 95% CI 1.80-180; p = 0.014). Additionally, a higher risk of transmission was observed outdoors (OR 1.74; 95% CI 1.08-2.82; p = 0.024) and in homesteads that owned livestock (OR 2.00; 95% CI 1.09-3.66; p = 0.025). CONCLUSIONS In this study, we identified An. funestus s.l. sibling species, An. rivulorum and An. funestus s.s., as the primary vectors of lymphatic filariasis along the Kenyan coast. These findings also highlight that a significant portion of disease transmission potentially occurs outdoors where indoor-based vector control tools, including long-lasting insecticidal nets and indoor residual spray, may not be effective. Therefore, control measures targeting outdoor resting mosquitoes such as zooprophylaxis, larval source management, and attractive sugar baits may have potential for LF transmission reduction.
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Affiliation(s)
- Brian Bartilol
- KEMRI-Centre for Geographic Medicine Research Coast, Kilifi, Kenya.
- Eastern and Southern Africa Centre of International Parasite Control, Nairobi, Kenya.
| | - Lawrence Babu
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Karisa Garama
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | - Alice Kamau
- Liverpool School of Tropical Medicine, Liverpool, UK
| | - Charles Mwandawiro
- Eastern and Southern Africa Centre of International Parasite Control, Nairobi, Kenya
| | | | - Charles Mbogo
- Pan-African Mosquito Control Association, Nairobi, Kenya
| | - Marta Maia
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
- Centre for Global Health and Tropical Medicine, University of Oxford, Oxford, UK
| | - Joseph Mwangangi
- KEMRI-Centre for Geographic Medicine Research Coast, Kilifi, Kenya
| | - Martin Kibet Rono
- KEMRI-Centre for Geographic Medicine Research Coast, Kilifi, Kenya.
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.
- Pwani University Bioscience Research Centre, Kilifi, Kenya.
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Tenywa FC, Musa JJ, Musiba RM, Swai JK, Mpelepele AB, Okumu FO, Maia MF. Sugar and blood: the nutritional priorities of the dengue vector, Aedes aegypti. Parasit Vectors 2024; 17:26. [PMID: 38246994 PMCID: PMC10800037 DOI: 10.1186/s13071-023-06093-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 12/11/2023] [Indexed: 01/23/2024] Open
Abstract
BACKGROUND Sugar-feeding behaviour is essential for mosquito survival and reproduction, and has been exploited to develop new control strategies, such as the attractive targeted sugar baits (ATSB). This study examined the sugar-feeding habits of the dengue vector, Aedes aegypti, in semi-field conditions to determine the optimal timing (age) of sugar meals and whether the availability of sugar sources could affect blood-feeding by these mosquitoes. METHODS A series of paired-choice assays were conducted in which mosquitoes were allowed to choose between a sugar meal or a blood meal directly from a rabbit. Female 1-day-old mosquitoes were given meal choices in cages I-V and observed for feeding choice in only one cage every day for 5 days starting with cages I to V. The preference of Ae. aegypti to feed on sugar or blood and the effect of sugar source availability on blood-feeding was assessed at different chronological and physiological ages. RESULTS In the first 5 days post-emergence, there was no significant difference in mosquito preference for sugar or blood meals. However, after the first gonotrophic cycle, they had a greater preference for blood over sugar (odds ratio, OR [95% confidence interval, CI] = 9.4 [6.7-13.0]; P < 0.001). Nulliparous Ae. aegypti females (≤ 5-day-old mosquitoes) were less likely to blood-feed if both sugar and blood sources were concurrently available (OR = 0.06 [0.02-0.16]; P < 0.001). CONCLUSIONS Newly emerged females of Ae. aegypti mosquitoes were equally likely to choose a sugar meal or a blood meal. However, after the first gonotrophic cycle, they had a greater preference for blood over sugar. Additionally, nulliparous female mosquitoes were less likely to blood-feed when both sugar and blood sources were available. These findings provide insights into the sugar-feeding behaviour of Ae. aegypti and can inform the development and optimization of new control strategies such as using ATSB.
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Affiliation(s)
- Frank Chelestino Tenywa
- Environmental Health and Ecological Sciences Thematic Group, Ifakara Health Institute, P.O. Box 74, Bagamoyo, Tanzania.
| | - Jeremiah John Musa
- Environmental Health and Ecological Sciences Thematic Group, Ifakara Health Institute, P.O. Box 74, Bagamoyo, Tanzania
- The Nelson Mandela African Institution of Science and Technology: School of Life Science and Bio-Engineering, P.O. Box 447, Arusha, Tanzania
| | - Revocatus Musyangi Musiba
- Environmental Health and Ecological Sciences Thematic Group, Ifakara Health Institute, P.O. Box 74, Bagamoyo, Tanzania
- School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, 1.485 Stopford Building, Manchester, M13 9PL, UK
| | - Johnson Kyeba Swai
- Environmental Health and Ecological Sciences Thematic Group, Ifakara Health Institute, P.O. Box 74, Bagamoyo, Tanzania
| | - Ahmad Bakar Mpelepele
- Environmental Health and Ecological Sciences Thematic Group, Ifakara Health Institute, P.O. Box 74, Bagamoyo, Tanzania
| | - Fredros Oketch Okumu
- Environmental Health and Ecological Sciences Thematic Group, Ifakara Health Institute, P.O. Box 74, Bagamoyo, Tanzania
- The Nelson Mandela African Institution of Science and Technology: School of Life Science and Bio-Engineering, P.O. Box 447, Arusha, Tanzania
- Faculty of Health Science, School of Public Health, University of the Witwatersrand, Johannesburg, South Africa
| | - Marta Ferreira Maia
- KEMRI Wellcome Trust Research Programme, Centre for Geographic Medicine Research -Coast, PO Box, Kilifi, 230-80108, Kenya
- Centre for Global Health and Tropical Medicine, Nuffield Department of Medicine, University of Oxford, Old Road Campus Roosevelt Drive, Oxford, OX3 7FZ, UK
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Kumar S, Sharma A, Samal RR, Verma V, Sagar RK, Singh SP, Raghavendra K. Development of Deltamethrin-Laced Attractive Toxic Sugar Bait to Control Aedes aegypti (Linnaeus) Population. J Trop Med 2024; 2024:6966205. [PMID: 38223354 PMCID: PMC10787649 DOI: 10.1155/2024/6966205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 12/23/2023] [Accepted: 12/28/2023] [Indexed: 01/16/2024] Open
Abstract
Background The attractive toxic sugar bait (ATSB) is a promising strategy for controlling mosquitoes at the adult stage. The strategy is based on the use of a combination of fruit juice, sugar, and a toxin in order to attract and kill the adult mosquitoes. The selection of the components and optimization of their concentrations is significant for the formulation of an effective ATSB. Methods The present study formulated nine ATSBs and evaluated their efficacy against two laboratory strains (AND-Aedes aegypti and AND-Aedes aegypti-DL10) and two wildcaught colonized strains of Aedes aegypti (GVD-Delhi and SHD-Delhi). Initially, nine attractive sugar baits (ASBs) were prepared using a mixture of 100% fermented guava juice (attractant) with 10% sucrose solution (w/v) in 1 : 1 ratio. ATSBs were formulated by mixing each ASB with different concentrations of deltamethrin in the ratio of 9 : 1 to obtain final deltamethrin concentration of 0.003125-0.8 mg/10 mL ATSB. Cage bioassays were conducted with 50 mosquitoes for 24 h in order to evaluate the efficacy of each ATSB against the four strains of Ae. aegypti. The data were statistically analyzed using PASW software 19.0 program and 2-way ANOVA. Results The ATSB formulations registered 8.33-97.44% mortality against AND-Aedes aegypti and 5.15-96.91% mortality against AND-Aedes aegypti-DL10 strains of Ae. aegypti, while GVD-Delhi strain registered 2.04-95.83% mortality and SHD-Delhi strain showed 5.10-97.96% mortality. The administration of 0.8 mg of deltamethrin within 10 mL of attractive toxic sugar bait (ATSB) has led to the maximum mortality rate in adult mosquitoes. Conclusions The ATSBs formulated with guava juice-ASB and deltamethrin (9 : 1) showed toxin dose-dependent toxicity by all the four strains of Ae. aegypti. Most effective dosage was found as 0.8 mg deltamethrin/10 mL ATSB which imparted 96% to 98% mortality in adult mosquitoes. The investigations demonstrated the efficacy of deltamethrin-laced ATSB formulations against Ae. aegypti and highlighted the need for conduct of structured field trials and investigating the impact on disease vectors and nontarget organisms.
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Affiliation(s)
- Sarita Kumar
- Department of Zoology, Acharya Narendra Dev College, University of Delhi, Kalkaji, New Delhi 110 019, India
| | - Aarti Sharma
- Department of Zoology, Acharya Narendra Dev College, University of Delhi, Kalkaji, New Delhi 110 019, India
| | - Roopa Rani Samal
- Department of Zoology, Acharya Narendra Dev College, University of Delhi, Kalkaji, New Delhi 110 019, India
| | - Vaishali Verma
- ICMR-National Institute of Malaria Research, Sector 8, Dwarka, New Delhi 110 077, India
| | - Ravinder Kumar Sagar
- Department of Zoology, Acharya Narendra Dev College, University of Delhi, Kalkaji, New Delhi 110 019, India
| | - Shri Pati Singh
- ICMR-National Institute of Malaria Research, Sector 8, Dwarka, New Delhi 110 077, India
| | - Kamaraju Raghavendra
- ICMR-National Institute of Malaria Research, Sector 8, Dwarka, New Delhi 110 077, India
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Ominde KM, Kamau Y, Karisa J, Muturi MN, Kiuru C, Wanjiku C, Babu L, Yaah F, Tuwei M, Musani H, Ondieki Z, Muriu S, Mwangangi J, Chaccour C, Maia MF. A field bioassay for assessing ivermectin bio-efficacy in wild malaria vectors. Malar J 2023; 22:291. [PMID: 37777725 PMCID: PMC10542238 DOI: 10.1186/s12936-023-04718-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 09/13/2023] [Indexed: 10/02/2023] Open
Abstract
BACKGROUND Ivermectin (IVM) mass drug administration is a candidate complementary malaria vector control tool. Ingestion of blood from IVM treated hosts results in reduced survival in mosquitoes. Estimating bio-efficacy of IVM on wild-caught mosquitoes requires they ingest the drug in a blood meal either through a membrane or direct feeding on a treated host. The latter, has ethical implications, and the former results in low feeding rates. Therefore, there is a need to develop a safe and effective method for IVM bio-efficacy monitoring in wild mosquitoes. METHODS Insectary-reared Anopheles gambiae s.s. were exposed to four IVM doses: 85, 64, 43, 21 ng/ml, and control group (0 ng/ml) in three different solutions: (i) blood, (ii) 10% glucose, (iii) four ratios (1:1, 1:2, 1:4, 1:8) of blood in 10% glucose, and fed through filter paper. Wild-caught An. gambiae s.l. were exposed to 85, 43 and 21 ng/ml IVM in blood and 1:4 ratio of blood-10% glucose mixture. Survival was monitored for 28 days and a pool of mosquitoes from each cohort sacrificed immediately after feeding and weighed to determine mean weight of each meal type. RESULTS When administered in glucose solution, mosquitocidal effect of IVM was not comparable to the observed effects when similar concentrations were administered in blood. Equal concentrations of IVM administered in blood resulted in pronounced reductions in mosquito survival compared to glucose solution only. However, by adding small amounts of blood to glucose solution, mosquito mortality rates increased resulting in similar effects to what was observed during blood feeding. CONCLUSION Bio-efficacy of ivermectin is strongly dependent on mode of drug delivery to the mosquito and likely influenced by digestive processes. The assay developed in this study is a good candidate for field-based bio-efficacy monitoring: wild mosquitoes readily feed on the solution, the assay can be standardized using pre-selected concentrations and by not involving treated blood hosts (human or animal) variation in individual pharmacokinetic profiles as well as ethical issues are bypassed. Meal volumes did not explain the difference in the lethality of IVM across the different meal types necessitating further research on the underlying mechanisms.
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Affiliation(s)
- Kelly M Ominde
- Department of Biosciences, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.
- Department of Biological Sciences, and Pwani University Biosciences Research Centre, Pwani University, Kilifi, Kenya.
| | - Yvonne Kamau
- Department of Biosciences, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Jonathan Karisa
- Department of Biosciences, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
- Department of Biological Sciences, and Pwani University Biosciences Research Centre, Pwani University, Kilifi, Kenya
| | - Martha N Muturi
- Department of Biosciences, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | - Caroline Wanjiku
- Department of Biosciences, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Lawrence Babu
- Department of Biosciences, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Festus Yaah
- Department of Biosciences, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Mercy Tuwei
- Department of Biosciences, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
- Department of Biological Sciences, and Pwani University Biosciences Research Centre, Pwani University, Kilifi, Kenya
| | - Haron Musani
- Department of Biosciences, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Zedekiah Ondieki
- Department of Biosciences, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Simon Muriu
- Department of Biosciences, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
- Department of Biological Sciences, and Pwani University Biosciences Research Centre, Pwani University, Kilifi, Kenya
| | - Joseph Mwangangi
- Department of Biosciences, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Carlos Chaccour
- ISGlobal, Barcelona, Spain
- Ciberinfec, Madrid, Spain
- Faculty of Medicine, Universidad de Navarra, Pamplona, Spain
| | - Marta F Maia
- Department of Biosciences, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.
- Centre for Global Health and Tropical Medicine and Nuffield Department of Medicine, University of Oxford, Oxford, UK.
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Pullmann-Lindsley H, Bartlett-Miller A, Pitts RJ. Diols and sugar substitutes in attractive toxic sugar baits targeting Aedes aegypti and Aedes albopictus (Diptera: Culicidae) mosquitoes. JOURNAL OF MEDICAL ENTOMOLOGY 2023; 60:1022-1029. [PMID: 37348932 DOI: 10.1093/jme/tjad072] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 04/27/2023] [Accepted: 06/08/2023] [Indexed: 06/24/2023]
Abstract
Around the world, mosquitoes continue to transmit disease-causing pathogens and develop resistance to insecticides. We previously discovered that a generally regarded as safe (GRAS) compound, 1,2-propanediol, reduces adult mosquito survivorship when ingested. In this study, we assess and compare 5 more chemically related compounds for mosquito lethality and 8 GRAS sugar substitutes to determine toxicity. We conducted a series of feeding assays to determine if ingesting the compounds influenced mosquito mean survivorship in locally collected lab-reared populations of Aedes aegypti (Diptera, Culicidae, Linnaeus, 1762) and Aedes albopictus (Diptera, Culicidae, Skuse, 1894) mosquitoes. Our results indicate that 1,2-propanediol, 1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, 2-methyl-1,3-propanediol, DL-dithiothreitol, acesulfame potassium, allulose, erythritol, sodium saccharin, stevia, and sucralose significantly reduced the mean survivorship of one or both species. Short-term trials with the most toxic compounds revealed that they could substantially affect survivorship after 24 h. We also found that there were different responses in the 2 species and that in several experimental conditions, male mosquitoes expired to a greater extent than female mosquitoes. These findings indicate that several of the compounds are toxic to mosquitoes. Further study is required to determine their effectiveness in attractive toxic sugar baits (ATSBs) as a potential component of population control strategies.
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Affiliation(s)
| | - Ava Bartlett-Miller
- Department of Biology, Baylor University, 101 Bagby Avenue, Waco, TX 76706, USA
| | - Ronald Jason Pitts
- Department of Biology, Baylor University, 101 Bagby Avenue, Waco, TX 76706, USA
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Sagna AB, Zéla L, Ouedraogo COW, Pooda SH, Porciani A, Furnival-Adams J, Lado P, Somé AF, Pennetier C, Chaccour CJ, Dabiré RK, Mouline K. Ivermectin as a novel malaria control tool: Getting ahead of the resistance curse. Acta Trop 2023; 245:106973. [PMID: 37352998 DOI: 10.1016/j.actatropica.2023.106973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 06/14/2023] [Accepted: 06/16/2023] [Indexed: 06/25/2023]
Abstract
Reduction in malaria clinical cases is strongly dependent on the ability to prevent Anopheles infectious bites. Vector control strategies using long-lasting insecticidal nets and indoor residual spraying with insecticides have contributed to significantly reduce the incidence of malaria in many endemic countries, especially in the Sub-Saharan region. However, global progress in reducing malaria cases has plateaued since 2015 mostly due to the increased insecticide resistance and behavioral changes in Anopheles vectors. Additional control strategies are thus required to further reduce the burden of malaria and contain the spread of resistant and invasive Anopheles vectors. The use of endectocides such as ivermectin as an additional malaria control tool is now receiving increased attention, driven by its different mode of action compared to insecticides used so far and its excellent safety record for humans. In this opinion article, we discuss the advantages and disadvantages of using ivermectin for malaria control with a focus on the risk of selecting ivermectin resistance in malaria vectors. We also highlight the importance of understanding how ivermectin resistance could develop in mosquitoes and what its underlying mechanisms and associated molecular markers are, and propose a research agenda to manage this phenomenon.
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Affiliation(s)
- André B Sagna
- MIVEGEC, University of Montpellier, IRD, CNRS, Montpellier, France.
| | - Lamidi Zéla
- Centre International de Recherche-Développement sur l'Elevage en zone Subhumide, Bobo-Dioulasso, Burkina Faso
| | - Cheick Oumar W Ouedraogo
- Institut de Recherche en Sciences de la Santé, Direction Régionale de l'Ouest, Centre National de Recherche Scientifique et Technologique, Bobo-Dioulasso, Burkina Faso
| | - Sié H Pooda
- Centre International de Recherche-Développement sur l'Elevage en zone Subhumide, Bobo-Dioulasso, Burkina Faso; Université de Dédougou, Dédougou, Burkina Faso
| | | | | | - Paula Lado
- Center for Vector-borne Infectious Diseases, Colorado State University, Fort Collins, CO, USA
| | - Anyirékun F Somé
- Institut de Recherche en Sciences de la Santé, Direction Régionale de l'Ouest, Centre National de Recherche Scientifique et Technologique, Bobo-Dioulasso, Burkina Faso
| | - Cédric Pennetier
- MIVEGEC, University of Montpellier, IRD, CNRS, Montpellier, France
| | - Carlos J Chaccour
- ISGlobal, Barcelona Institute for Global Health, Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Infecciosas, Madrid, Spain; Universidad de Navarra, Pamplona, Spain
| | - Roch K Dabiré
- Institut de Recherche en Sciences de la Santé, Direction Régionale de l'Ouest, Centre National de Recherche Scientifique et Technologique, Bobo-Dioulasso, Burkina Faso
| | - Karine Mouline
- MIVEGEC, University of Montpellier, IRD, CNRS, Montpellier, France
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Njoroge TM, Hamid-Adiamoh M, Duman-Scheel M. Maximizing the Potential of Attractive Targeted Sugar Baits (ATSBs) for Integrated Vector Management. INSECTS 2023; 14:585. [PMID: 37504591 PMCID: PMC10380652 DOI: 10.3390/insects14070585] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 06/23/2023] [Accepted: 06/24/2023] [Indexed: 07/29/2023]
Abstract
Due to the limitations of the human therapeutics and vaccines available to treat and prevent mosquito-borne diseases, the primary strategy for disease mitigation is through vector control. However, the current tools and approaches used for mosquito control have proven insufficient to prevent malaria and arboviral infections, such as dengue, Zika, and lymphatic filariasis, and hence, these diseases remain a global public health threat. The proven ability of mosquito vectors to adapt to various control strategies through insecticide resistance, invasive potential, and behavioral changes from indoor to outdoor biting, combined with human failures to comply with vector control requirements, challenge sustained malaria and arboviral disease control worldwide. To address these concerns, increased efforts to explore more varied and integrated control strategies have emerged. These include approaches that involve the behavioral management of vectors. Attractive targeted sugar baits (ATSBs) are a vector control approach that manipulates and exploits mosquito sugar-feeding behavior to deploy insecticides. Although traditional approaches have been effective in controlling malaria vectors indoors, preventing mosquito bites outdoors and around human dwellings is challenging. ATSBs, which can be used to curb outdoor biting mosquitoes, have the potential to reduce mosquito densities and clinical malaria incidence when used in conjunction with existing vector control strategies. This review examines the available literature regarding the utility of ATSBs for mosquito control, providing an overview of ATSB active ingredients (toxicants), attractants, modes of deployment, target organisms, and the potential for integrating ATSBs with existing vector control interventions.
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Affiliation(s)
- Teresia Muthoni Njoroge
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN 46617, USA
- Eck Institute for Global Health, The University of Notre Dame, Notre Dame, South Bend, IN 46556, USA
| | - Majidah Hamid-Adiamoh
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN 46617, USA
- Eck Institute for Global Health, The University of Notre Dame, Notre Dame, South Bend, IN 46556, USA
| | - Molly Duman-Scheel
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN 46617, USA
- Eck Institute for Global Health, The University of Notre Dame, Notre Dame, South Bend, IN 46556, USA
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Muyaga LL, Meza FC, Kahamba NF, Njalambaha RM, Msugupakulya BJ, Kaindoa EW, Ngowo HS, Okumu FO. Effects of vegetation densities on the performance of attractive targeted sugar baits (ATSBs) for malaria vector control: a semi-field study. Malar J 2023; 22:190. [PMID: 37344867 DOI: 10.1186/s12936-023-04625-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 06/16/2023] [Indexed: 06/23/2023] Open
Abstract
BACKGROUND Attractive targeted sugar baits (ATSBs) control sugar-feeding mosquitoes with oral toxicants, and may effectively complement core malaria interventions, such as insecticide-treated nets even where pyrethroid-resistance is widespread. The technology is particularly efficacious in arid and semi-arid areas. However, their performance remains poorly-understood in tropical areas with year-round malaria transmission, and where the abundant vegetation constitutes competitive sugar sources for mosquitoes. This study compared the efficacies of ATSBs (active ingredient: 2% boric acid) in controlled settings with different vegetation densities. METHODS Potted mosquito-friendly plants were introduced inside semi-field chambers (9.6 m by 9.6 m) to simulate densely-vegetated, sparsely-vegetated, and bare sites without any vegetation (two chambers/category). All chambers had volunteer-occupied huts. Laboratory-reared Anopheles arabiensis were released nightly (200/chamber) and host-seeking females recaptured using human landing catches outdoors (8.00 p.m.-9.00 p.m.) and CDC-light traps indoors (9.00 p.m.-6.00 a.m.). Additionally, resting mosquitoes were collected indoors and outdoors each morning using Prokopack aspirators. The experiments included a "before-and-after" set-up (with pre-ATSBs, ATSBs and post-ATSBs phases per chamber), and a "treatment vs. control" set-up (where similar chambers had ATSBs or no ATSBs). The experiments lasted 84 trap-nights. RESULTS In the initial tests when all chambers had no vegetation, the ATSBs reduced outdoor-biting by 69.7%, indoor-biting by 79.8% and resting mosquitoes by 92.8%. In tests evaluating impact of vegetation, the efficacy of ATSBs against host-seeking mosquitoes was high in bare chambers (outdoors: 64.1% reduction; indoors: 46.8%) but modest or low in sparsely-vegetated (outdoors: 34.5%; indoors: 26.2%) and densely-vegetated chambers (outdoors: 25.4%; indoors: 16.1%). Against resting mosquitoes, the ATSBs performed modestly across settings (non-vegetated chambers: 37.5% outdoors and 38.7% indoors; sparsely-vegetated: 42.9% outdoors and 37.5% indoors; densely-vegetated: 45.5% outdoors and 37.5% indoors). Vegetation significantly reduced the ATSBs efficacies against outdoor-biting and indoor-biting mosquitoes but not resting mosquitoes. CONCLUSION While vegetation can influence the performance of ATSBs, the devices remain modestly efficacious in both sparsely-vegetated and densely-vegetated settings. Higher efficacies may occur in places with minimal or completely no vegetation, but such environments are naturally unlikely to sustain Anopheles populations or malaria transmission in the first place. Field studies therefore remain necessary to validate the efficacies of ATSBs in the tropics.
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Affiliation(s)
- Letus L Muyaga
- Department of Environmental Health, and Ecological Science, Ifakara Health Institute, Morogoro, United Republic of Tanzania.
- School of Biodiversity, One Health & Veterinary Medicine, University of Glasgow, Glasgow, UK.
| | - Felician C Meza
- Department of Environmental Health, and Ecological Science, Ifakara Health Institute, Morogoro, United Republic of Tanzania
| | - Najat F Kahamba
- Department of Environmental Health, and Ecological Science, Ifakara Health Institute, Morogoro, United Republic of Tanzania
- School of Biodiversity, One Health & Veterinary Medicine, University of Glasgow, Glasgow, UK
| | - Rukiyah M Njalambaha
- Department of Environmental Health, and Ecological Science, Ifakara Health Institute, Morogoro, United Republic of Tanzania
| | - Betwel J Msugupakulya
- Department of Environmental Health, and Ecological Science, Ifakara Health Institute, Morogoro, United Republic of Tanzania
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Emmanuel W Kaindoa
- Department of Environmental Health, and Ecological Science, Ifakara Health Institute, Morogoro, United Republic of Tanzania
- School of Life Sciences and Biotechnology, Nelson Mandela African Institution of Science and Technology, Arusha, United Republic of Tanzania
- Faculty of Health Sciences, School of Pathology, Centre for Emerging Zoonotic and Parasitic Diseases, Wits Research Institute for Malaria, University of the Witwatersrand, National Institute for Communicable Diseases, Johannesburg, South Africa
| | - Halfan S Ngowo
- Department of Environmental Health, and Ecological Science, Ifakara Health Institute, Morogoro, United Republic of Tanzania
- School of Biodiversity, One Health & Veterinary Medicine, University of Glasgow, Glasgow, UK
| | - Fredros O Okumu
- Department of Environmental Health, and Ecological Science, Ifakara Health Institute, Morogoro, United Republic of Tanzania.
- School of Biodiversity, One Health & Veterinary Medicine, University of Glasgow, Glasgow, UK.
- School of Life Sciences and Biotechnology, Nelson Mandela African Institution of Science and Technology, Arusha, United Republic of Tanzania.
- School of Public Health, University of the Witwatersrand, Johannesburg, South Africa.
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Yalla N, Polo B, McDermott DP, Kosgei J, Omondi S, Agumba S, Moshi V, Abong'o B, Gimnig JE, Harris AF, Entwistle J, Long PR, Ochomo E. A comparison of the attractiveness of flowering plant blossoms versus attractive targeted sugar baits (ATSBs) in western Kenya. PLoS One 2023; 18:e0286679. [PMID: 37279239 DOI: 10.1371/journal.pone.0286679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 05/19/2023] [Indexed: 06/08/2023] Open
Abstract
Attractive Targeted Sugar Baits (ATSB) have been demonstrated to result in significant reductions in malaria vector numbers in areas of scarce vegetation cover such as in Mali and Israel, but it is not clear whether such an effect can be replicated in environments where mosquitoes have a wide range of options for sugar resources. The current study evaluated the attractiveness of the predominant flowering plants of Asembo Siaya County, western Kenya in comparison to an ATSB developed by Westham Co. Sixteen of the most common flowering plants in the study area were selected and evaluated for relative attractiveness to malaria vectors in semi-field structures. Six of the most attractive flowers were compared to determine the most attractive to local Anopheles mosquitoes. The most attractive plant was then compared to different versions of ATSB. In total, 56,600 Anopheles mosquitoes were released in the semi-field structures. From these, 5150 mosquitoes (2621 males and 2529 females) of An. arabiensis, An. funestus and An. gambiae were recaptured on the attractancy traps. Mangifera indica was the most attractive sugar source for all three species while Hyptis suaveolens and Tephrosia vogelii were the least attractive plants to the mosquitoes. Overall, ATSB version 1.2 was significantly more attractive compared to both ATSB version 1.1 and Mangifera indica. Mosquitoes were differentially attracted to various natural plants in western Kenya and ATSB. The observation that ATSB v1.2 was more attractive to local Anopheles mosquitoes than the most attractive natural sugar source indicates that this product may be able to compete with natural sugar sources in western Kenya and suggests this product may have the potential to impact mosquito populations in the field.
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Affiliation(s)
- Nick Yalla
- Entomology Department, Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya
| | - Brian Polo
- Entomology Department, Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya
| | - Daniel P McDermott
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | - Jackline Kosgei
- Entomology Department, Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya
| | - Seline Omondi
- Entomology Department, Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya
| | - Silas Agumba
- Entomology Department, Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya
| | - Vincent Moshi
- Entomology Department, Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya
| | - Bernard Abong'o
- Entomology Department, Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya
| | - John E Gimnig
- Division of Parasitic Diseases and Malaria, Centre for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
| | - Angela F Harris
- Innovative Vector Control Consortium, Liverpool, United Kingdom
| | | | - Peter R Long
- Department of Biological and Medical Sciences, Oxford Brookes University, Gipsy Lane, Oxford, United Kingdom
| | - Eric Ochomo
- Entomology Department, Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya
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11
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Kumar S, Sharma A, Samal RR, Kumar M, Verma V, Sagar RK, Singh SP, Raghavendra K. Laboratory evaluation of the efficacy of deltamethrin-laced attractive toxic sugar bait formulation on Anopheles stephensi. Malar J 2023; 22:92. [PMID: 36899429 PMCID: PMC10007731 DOI: 10.1186/s12936-023-04524-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 03/06/2023] [Indexed: 03/12/2023] Open
Abstract
BACKGROUND Attractive toxic sugar bait (ATSB) is a promising "attract and kill"-based approach for mosquito control. It is a combination of flower nectar/fruit juice to attract the mosquitoes, sugar solution to stimulate feeding, and a toxin to kill them. Selecting an effective attractant and optimizing concentration of toxicant is significant in the formulation of ATSB. METHODS Current study formulated an ATSB using fruit juice, sugar and deltamethrin, a synthetic pyrethroid. It was evaluated against two laboratory strains of Anopheles stephensi. Initial studies evaluated comparative attractiveness of nine different fruit juices to An. stephensi adults. Nine ASBs were prepared by adding fermented juices of plum, guava, sweet lemon, orange, mango, pineapple, muskmelon, papaya, and watermelon with 10% sucrose solution (w/v) in 1:1 ratio. Cage bioassays were conducted to assess relative attraction potential of ASBs based on the number of mosquito landings on each and the most effective ASB was identified. Ten ATSBs were prepared by adding the identified ASB with different deltamethrin concentrations (0.015625-8.0 mg/10 mL) in 1:9 ratio. Each ATSB was assessed for the toxic potential against both the strains of An. stephensi. The data was statistically analysed using PASW (SPSS) software 19.0 program. RESULTS The cage bioassays with nine ASBs revealed higher efficacy (p < 0.05) of Guava juice-ASB > Plum juice-ASB > Mango juice-ASB in comparison to rest of the six ASB's. The bioassay with these three ASB's ascertained the highest attractancy potential of guava juice-ASB against both the strains of An. stephensi. The ATSB formulations resulted in 5.1-97.9% mortality in Sonepat (NIMR strain) with calculated LC30, LC50, and LC90 values of 0.17 mg deltamethrin/10 mL, 0.61 mg deltamethrin/10 mL, and 13.84 mg deltamethrin/10 mL ATSB, respectively. Whereas, 6.12-86.12% mortality was recorded in the GVD-Delhi (AND strain) with calculated LC30, LC50, and LC90 values of 0.25 mg deltamethrin/10 mL, 0.73 mg deltamethrin/10 mL and 10.22 mg deltamethrin/10 mL ATSB, respectively. CONCLUSION The ATSB formulated with guava juice-ASB and deltamethrin (0.0015625-0.8%) in 9:1 ratio showed promising results against two laboratory strains of An. stephensi. Field assessment of these formulations is being conducted to estimate their feasibility for use in mosquito control.
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Affiliation(s)
- Sarita Kumar
- Department of Zoology, Acharya Narendra Dev College, University of Delhi, Kalkaji, New Delhi, 110 019, India.
| | - Aarti Sharma
- Department of Zoology, Acharya Narendra Dev College, University of Delhi, Kalkaji, New Delhi, 110 019, India
| | - Roopa Rani Samal
- Department of Zoology, Acharya Narendra Dev College, University of Delhi, Kalkaji, New Delhi, 110 019, India
| | - Manoj Kumar
- Department of Zoology, Acharya Narendra Dev College, University of Delhi, Kalkaji, New Delhi, 110 019, India
| | - Vaishali Verma
- ICMR-National Institute of Malaria Research, Sector 8, Dwarka, New Delhi, 110 077, India
| | - Ravinder Kumar Sagar
- Department of Zoology, Acharya Narendra Dev College, University of Delhi, Kalkaji, New Delhi, 110 019, India
| | - Shri Pati Singh
- ICMR-National Institute of Malaria Research, Sector 8, Dwarka, New Delhi, 110 077, India
| | - Kamaraju Raghavendra
- ICMR-National Institute of Malaria Research, Sector 8, Dwarka, New Delhi, 110 077, India.,H. No. 28 B, Block ED, Pitampura, Delhi, 110 088, India
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Dias ACA, Teixeira AV, Lima Bezerra F, Andriolo A, Silva ADA. Sugar Bait Composition Containing Ivermectin Affect Engorgement and Mortality of the Mosquito Aedes aegypti (Diptera: Culicidae). JOURNAL OF MEDICAL ENTOMOLOGY 2023; 60:159-164. [PMID: 36440696 DOI: 10.1093/jme/tjac181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Indexed: 06/16/2023]
Abstract
Toxins and attractants have been studied and used in sugar baits for mosquitoes. However, little importance has been given to the combination of sugar concentration, bait composition, and their relationship with mosquito engorgement and mortality. Therefore, the present study evaluated the effects of three concentrations of sucrose on baits with and without an attractant (concentrated guava juice), on engorgement and mortality rates of adult Aedes aegypti (Linnaeus, Diptera: Culicidae). Toxic sugar baits (TSB) and attractant toxic sugar baits (ATSB) containing 10, 50, and 70% sucrose and 100 ppm ivermectin (IVM) were prepared to assess engorgement and mortality rates. Subsequently, different concentrations of IVM (0.312-100 ppm) in TSB and ATSB were prepared with sucrose concentrations of 10 and 70% to determine the lethal concentrations (LC50 and LC90) values. Engorgement on the baits was observed under a stereomicroscope, and mortality was followed up to 48 h after feeding. In general, more mosquitoes engorged on TSB regardless of the sugar concentration, while higher concentrations of sugar in ATSBs resulted in higher numbers of mosquitoes engorging. A large increase in the LC90 of IVM was observed for females feeding on ATSBs and TSBs with 70% sucrose relative to those feeding on baits with lower sugar concentrations. No such effect was observed for males.
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Affiliation(s)
- Alyne Cunha Alves Dias
- Programa de Pós-Graduação em Biologia Experimental, Universidade Federal de Rondônia, Porto Velho, RO, Brasil
| | - Aurea Vieira Teixeira
- Programa de Pós-Graduação em Biologia Experimental, Universidade Federal de Rondônia, Porto Velho, RO, Brasil
| | - Flaviana Lima Bezerra
- Laboratório de Bioecologia de Insetos, Universidade Federal de Rondônia, Porto Velho, RO, Brasil
| | - Aline Andriolo
- Programa de Pós-Graduação em Conservação e uso de Recursos Naturais, Universidade Federal de Rondônia, Porto Velho, RO, Brasil
| | - Alexandre de A Silva
- Programa de Pós-Graduação em Biologia Experimental, Universidade Federal de Rondônia, Porto Velho, RO, Brasil
- Laboratório de Bioecologia de Insetos, Universidade Federal de Rondônia, Porto Velho, RO, Brasil
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13
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Kumar G, Pasi S, Yadav CP, Kaur J, Sharma A. Potential of ivermectin as an active ingredient of the attractive toxic sugar baits against the Indian malaria vectors Anopheles culicifacies and Anopheles stephensi. PEST MANAGEMENT SCIENCE 2023; 79:474-480. [PMID: 36176013 DOI: 10.1002/ps.7217] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 09/26/2022] [Accepted: 09/29/2022] [Indexed: 06/16/2023]
Abstract
BACKGROUND Attractive toxic sugar bait (ATSB) is a novel vector control tool that exploits the sugar feeding behavior of mosquitoes. The current study aims to evaluate the efficacy of ivermectin-based ATSB against insecticide susceptible and resistant strains of major Indian malaria vectors - Anopheles culicifacies and Anopheles stephensi. ATSB with different concentrations of ivermectin were tested against mosquito vectors under standard laboratory conditions. RESULTS Dose-response analysis of ivermectin-ATSB showed 7.8 and 19.8 ppm as 50% and 90% lethal concentration (LC50 and LC90 ) values for insecticide susceptible An. culicifacies. In the case of insecticide susceptible An. stephensi, the LC90 value was 35 ppm which was significantly higher in comparison to the LC90 for An. culicifacies. The LC50 of insecticide-resistant An. culicifacies and An. stephensi were 10.6 and 15.9 ppm respectively whereas LC90 values were 36.9 and 61.0. Ivermectin-ATSB resulted in 99 ± 0.8% mortality of An. culicifacies and 93 ± 3.8% mortality of An. stephensi at an ivermectin concentration of 25 ppm. In another set of experiments, the ATSB solution containing standardized dose of ivermectin was sprayed on Allysum plant and mortality of both Anopheline vectors was recorded. Here, we observed > 90% mortality in both An. stephensi and An. culicifacies. CONCLUSION Our study demonstrates the potential of ivermectin-based ATSB in killing Indian malaria vectors irrespective of the method of application. Further field trials with ivermectin containing ATSB may pave the way for its usage in the national vector control program. © 2022 Society of Chemical Industry.
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Affiliation(s)
- Gaurav Kumar
- National Institute of Malaria Research, New Delhi, India
| | - Shweta Pasi
- National Institute of Malaria Research, New Delhi, India
| | | | - Jaspreet Kaur
- National Institute of Malaria Research, New Delhi, India
| | - Amit Sharma
- National Institute of Malaria Research, New Delhi, India
- Molecular Medicine Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
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14
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Karisa J, Ominde K, Muriu S, Munyao V, Mwikali K, Babu L, Ondieki Z, Bartilol B, Tuwei M, Wanjiku C, Maia M, Midega J, Rono M, Peshu N, Mbogo C, Mwangangi JM. Malaria vector bionomics in Taita-Taveta County, coastal Kenya. Parasit Vectors 2022; 15:430. [DOI: 10.1186/s13071-022-05527-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 10/05/2022] [Indexed: 11/17/2022] Open
Abstract
Abstract
Background
Estimation of the composition and densities of mosquito species populations is crucial for monitoring the epidemiology of mosquito-borne diseases and provide information on local vectors to public health officials and policy-makers. The aim of this study was to evaluate malaria vector bionomics in ecologically distinct sites in Taita-Taveta County, Kenya.
Methods
Adult mosquitoes were collected using backpack aspirators and paired indoor/outdoor CDC light traps in 10 randomly selected households in six villages with distinct ecologies over a study period of 3 years. All Anopheles mosquitoes were morphotyped, and sibling species of Anopheles gambiae sensu lato (An. gambiae s.l.) were identified and separated by PCR analysis of extracted ribosomal DNA. All female anophelines were tested for sporozoite infectivity, with engorged females screened for blood-meal sources using the enzyme-linked immunosorbent assay technique. A subsample of those testing positive and those testing negative for Plasmodium in the ELISA were subjected to PCR assay.
Results
A total of eight different Anopheles species were collected both indoors and outdoors. Anopheles gambiae s.l. (82.6%, n = 5252) was the predominant species sensu lato, followed by Anopheles coustani sensu lato (An. coustani s.l.; (10.5%, n = 666) and Anopheles funestus sensu lato (An. funestus s.l.; 5.6%, n = 357). A subset of 683 mosquito samples representing An. gambiae s.l. (n = 580, approx. 11.0%) and An. funestus s.l. (n = 103, approx. 28.9%) were identified by molecular diagnostic assays into sibling species. The An. gambiae s.l. complex was composed of Anopheles arabiensis (62.5%, n = 363/580), An. gambiae sensu stricto (An. gambiae s.s.; 0.7%, n = 4/580), Anopheles merus (0.7%, n = 4/580) and Anopheles quadriannulatus (0.2%, n = 1/580), with the remaining samples (35.5%, n = 206/580) unamplified. Anopheles funestus s.l. was composed of An. rivulorum (14.6%, n = 15/103) and An. leesoni (11.6%, n = 12/103); the remaining samples were unamplified (73.8%, n = 76/103). A total of 981 samples were subjected to PCR analysis for malaria parasite detection; of these 16 (1.6%) were confirmed to be positive for Plasmodium falciparum. The overall human blood index was 0.13 (32/238).
Conclusions
Anopheles gambiae, An. funestus and An. coustani are key malaria vectors in the Taveta region of Kenya, showing concurrent indoor and outdoor transmission. All of the vectors tested showed a higher propensity for bovine and goat blood than for human blood.
Graphical Abstract
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15
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Muema JM, Bargul JL, Obonyo MA, Njeru SN, Matoke-Muhia D, Mutunga JM. Contemporary exploitation of natural products for arthropod-borne pathogen transmission-blocking interventions. Parasit Vectors 2022; 15:298. [PMID: 36002857 PMCID: PMC9404607 DOI: 10.1186/s13071-022-05367-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 06/16/2022] [Indexed: 11/26/2022] Open
Abstract
An integrated approach to innovatively counter the transmission of various arthropod-borne diseases to humans would benefit from strategies that sustainably limit onward passage of infective life cycle stages of pathogens and parasites to the insect vectors and vice versa. Aiming to accelerate the impetus towards a disease-free world amid the challenges posed by climate change, discovery, mindful exploitation and integration of active natural products in design of pathogen transmission-blocking interventions is of high priority. Herein, we provide a review of natural compounds endowed with blockade potential against transmissible forms of human pathogens reported in the last 2 decades from 2000 to 2021. Finally, we propose various translational strategies that can exploit these pathogen transmission-blocking natural products into design of novel and sustainable disease control interventions. In summary, tapping these compounds will potentially aid in integrated combat mission to reduce disease transmission trends.
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Affiliation(s)
- Jackson M Muema
- Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology (JKUAT), P.O. Box 62000, Nairobi, 00200, Kenya.
| | - Joel L Bargul
- Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology (JKUAT), P.O. Box 62000, Nairobi, 00200, Kenya.,International Centre of Insect Physiology and Ecology (Icipe), P.O. Box 30772, Nairobi, 00100, Kenya
| | - Meshack A Obonyo
- Department of Biochemistry and Molecular Biology, Egerton University, P.O. Box 536, Egerton, 20115, Kenya
| | - Sospeter N Njeru
- Centre for Traditional Medicine and Drug Research (CTMDR), Kenya Medical Research Institute (KEMRI), P.O. Box 54840, Nairobi, 00200, Kenya
| | - Damaris Matoke-Muhia
- Centre for Biotechnology Research Development (CBRD), Kenya Medical Research Institute (KEMRI), P.O. Box 54840, Nairobi, 00200, Kenya
| | - James M Mutunga
- Department of Biological Sciences, Mount Kenya University (MKU), P.O. Box 54, Thika, 01000, Kenya.,School of Engineering Design, Technology and Professional Programs, Pennsylvania State University, University Park, PA, 16802, USA
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Attractive Sugar Bait Formulation for Development of Attractive Toxic Sugar Bait for Control of Aedes aegypti (Linnaeus). J Trop Med 2022; 2022:2977454. [PMID: 35832334 PMCID: PMC9273391 DOI: 10.1155/2022/2977454] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 05/26/2022] [Indexed: 11/17/2022] Open
Abstract
Background Attractive toxic sugar bait (ATSB), based on “attract and kill” approach, is a novel and promising strategy for mosquito control. Formulation of an attractive sugar bait (ASB) solution by selecting an efficient olfaction stimulant and preparation of an optimized sugar-attractant dosage is a significant component for the success of the approach. Methods Current study evaluated relative potential of nine ASBs, formulated by combination of sugar and fresh fruit juices (guava, mango, muskmelon, orange, papaya, pineapple, plum, sweet lemon, and watermelon) in attracting Aedes aegypti adults. Freshly extracted and 48-hour-fermented juices were combined with 10% sucrose solution (w/v) in 1 : 1 ratio. Cage bioassays were conducted against two laboratory strains (susceptible: AND-Aedes aegypti; deltamethrin-selected: AND-Aedes aegypti-DL10) and two field-collected strains (Shahdara strain of Aedes aegypti: SHD-Delhi; Govindpuri strain of Aedes aegypti: GVD-Delhi). Each of the nine ASBs was assayed, individually or in groups of three, for its attraction potential based on the relative number of mosquito landings. The data were analysed for statistical significance using PASW (SPSS) software 19.0 program. Results The prescreening bioassay with individual ASB revealed significantly higher efficacy of ASB containing guava/plum/mango juice than that containing six other juices (p < 0.05) against both the laboratory and field strains. The bioassay with three ASBs kept in one cage, one of the effective ASBs and two others randomly selected ASBs, also showed good attractancy of the guava/plum/mango juice-ASB (p < 0.05). The postscreening assays with these three ASBs revealed maximum attractant potential of guava juice-sucrose combination for all the four strains of Ae. aegypti. Conclusion. Guava juice-ASB showed the highest attractancy against both laboratory and field-collected strains of Ae. aegypti and can be used to formulate ATSB by combining with a toxicant. The field studies with these formulations will ascertain their efficacy and possible use in mosquito management programs.
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Tenywa FSC, Musa JJ, Musiba RM, Swai JK, Mpelepele AB, Okumu FO, Maia MF. Evaluation of an ivermectin-based attractive targeted sugar bait (ATSB) against Aedes aegypti in Tanzania. Wellcome Open Res 2022; 7:4. [PMID: 37409221 PMCID: PMC10318376 DOI: 10.12688/wellcomeopenres.17442.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/21/2021] [Indexed: 10/02/2023] Open
Abstract
Background The control of vector borne arboviral diseases such as Dengue is mainly achieved by reducing human-vector contact and controlling the vectors through source reduction and environmental management. These measures are constrained by labour intensity, insecticide resistance and pro-active community participation. The current study intended to develop and test an ivermectin-based attractive-targeted sugar bait (ATSB) against Aedes aegypti. Methods The 48hour lethal concentration (LC90) of ivermectin against Ae. aegypti was determined through serial dilution experiment where five 30cm x 30cm x 30cm cages were set; into each, a 10% sugar solution treated with ivermectin were introduced. 40 Ae. aegypti were released into each cage and observed for mortality after 4, 8, 24 and 48 hours. The ivermectin-based ATSB was evaluated in a semi field system where ATSB and attractive sugar bait (ASB) were deployed into each compartment of the semi field and 100 female Ae. aegypti were released every day and recaptured the next day through human land catch and Bio-gent sentinel trap. The developed and semi-field tested ATSB was further tested in the field by deploying them in garages. Results The ivermectin 48hr LC90 of male and female Ae. aegypti was found to be 0.03% w/v. In the semi field system, the ATSB significantly reduced a free-flying population of Ae. aegypti within 24 hours (incidence rate ratio (IRR) = 0.62; [95% confidence interval (95%CI); 0.54-0.70] and p-value < 0.001). However, in the field, the ATSBs required the addition of yeast as a carbon dioxide source to efficiently attract Ae. aegypti mosquitoes to feed. Conclusion Ivermectin is an active ingredient that can be used in an ATSB for Ae. aegypti depopulation. However, further research is needed to improve the developed and tested ATSB to compete with natural sources of sugar in a natural environment.
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Affiliation(s)
- Frank Sandra Chelestino Tenywa
- Environmental Health and Ecological Sciences Thematic Group, Ifakara Health Institute, Bagamoyo, Pwani, 0000, Tanzania
- Vector Biology, Swiss Tropical and Public Health Institute, Basel, Basel, CH-4002, Switzerland
- Science, University of Basel, Basel, Basel, CH-4002, Switzerland
| | - Jeremiah John Musa
- Environmental Health and Ecological Sciences Thematic Group, Ifakara Health Institute, Bagamoyo, Pwani, 0000, Tanzania
| | - Revocatus Musyangi Musiba
- Environmental Health and Ecological Sciences Thematic Group, Ifakara Health Institute, Bagamoyo, Pwani, 0000, Tanzania
| | - Johnson Kyeba Swai
- Environmental Health and Ecological Sciences Thematic Group, Ifakara Health Institute, Bagamoyo, Pwani, 0000, Tanzania
- Vector Biology, Swiss Tropical and Public Health Institute, Basel, Basel, CH-4002, Switzerland
- Science, University of Basel, Basel, Basel, CH-4002, Switzerland
| | - Ahmad Bakar Mpelepele
- Environmental Health and Ecological Sciences Thematic Group, Ifakara Health Institute, Bagamoyo, Pwani, 0000, Tanzania
| | - Fredros Okech Okumu
- Environmental Health and Ecological Sciences Thematic Group, Ifakara Health Institute, Bagamoyo, Pwani, 0000, Tanzania
- Vector Biology, Swiss Tropical and Public Health Institute, Basel, Basel, CH-4002, Switzerland
- Science, University of Basel, Basel, Basel, CH-4002, Switzerland
- Faculty of Health Science, School of Public Health, University of the Witwatersrand, Johannesburg, Johannesburg, 0000, South Africa
| | - Marta Ferreira Maia
- Wellcome Trust Research Program, Kenya Medical Research Institute(Kemri ), Kilifi, Mombasa, 0000, Kenya
- Medicine, Centre for Global Health and Tropical Medicine, University of Oxford, Oxford, OX3 7FZ, UK
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18
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Stromsky VE, Hajkazemian M, Vaisbourd E, Mozūraitis R, Noushin Emami S. Plasmodium metabolite HMBPP stimulates feeding of main mosquito vectors on blood and artificial toxic sources. Commun Biol 2021; 4:1161. [PMID: 34620990 PMCID: PMC8497504 DOI: 10.1038/s42003-021-02689-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 09/16/2021] [Indexed: 02/08/2023] Open
Abstract
Recent data show that parasites manipulate the physiology of mosquitoes and human hosts to increase the probability of transmission. Here, we investigate phagostimulant activity of Plasmodium-metabolite, (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate (HMBPP), in the primary vectors of multiple human diseases, Anopheles coluzzii, An. arabiensis, An. gambiae s.s., Aedes aegypti, and Culex pipiens/Culex torrentium complex species. The addition of 10 µM HMBPP to blood meals significantly increased feeding in all the species investigated. Moreover, HMBPP also exhibited a phagostimulant property in plant-based-artificial-feeding-solution made of beetroot juice adjusted to neutral pH similar to that of blood. The addition of AlbuMAXTM as a lipid/protein source significantly improved the feeding rate of An. gambiae s.l. females providing optimised plant-based-artificial-feeding-solution for delivery toxins to control vector populations. Among natural and synthetic toxins tested, only fipronil sulfone did not reduce feeding. Overall, the toxic-plant-based-artificial-feeding-solution showed potential as an effector in environmentally friendly vector-control strategies.
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Affiliation(s)
- Viktoria E Stromsky
- Department of Molecular Biosciences, Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Melika Hajkazemian
- Department of Molecular Biosciences, Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Elizabeth Vaisbourd
- Department of Molecular Biosciences, Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Raimondas Mozūraitis
- Laboratory of Chemical and Behavioural Ecology, Institute of Ecology, Nature Research Centre, Vilnius, Lithuania
- Department of Zoology, Stockholm University, Stockholm, Sweden
| | - S Noushin Emami
- Department of Molecular Biosciences, Wenner-Gren Institute, Stockholm University, Stockholm, Sweden.
- Molecular Attraction AB, Elektravägen 10, 126 30 Hägersten, Stockholm, Sweden.
- Natural Resources Institute, FES, University of Greenwich, London, UK.
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19
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A Broad-Based Mosquito Yeast Interfering RNA Pesticide Targeting Rbfox1 Represses Notch Signaling and Kills Both Larvae and Adult Mosquitoes. Pathogens 2021; 10:pathogens10101251. [PMID: 34684200 PMCID: PMC8541554 DOI: 10.3390/pathogens10101251] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 09/21/2021] [Accepted: 09/23/2021] [Indexed: 12/03/2022] Open
Abstract
Prevention of mosquito-borne infectious diseases will require new classes of environmentally safe insecticides and novel mosquito control technologies. Saccharomyces cerevisiae was engineered to express short hairpin RNA (shRNA) corresponding to mosquito Rbfox1 genes. The yeast induced target gene silencing, resulting in larval death that was observed in both laboratory and outdoor semi-field trials conducted on Aedes aegypti. High levels of mortality were also observed during simulated field trials in which adult females consumed yeast delivered through a sugar bait. Mortality correlated with defects in the mosquito brain, in which a role for Rbfox1 as a positive regulator of Notch signaling was identified. The larvicidal and adulticidal activities of the yeast were subsequently confirmed in trials conducted on Aedes albopictus, Anopheles gambiae, and Culex quinquefasciatus, yet the yeast had no impact on survival of select non-target arthropods. These studies indicate that yeast RNAi pesticides targeting Rbfox1 could be further developed as broad-based mosquito larvicides and adulticides for deployment in integrated biorational mosquito control programs. These findings also suggest that the species-specificity of attractive targeted sugar baits, a new paradigm for vector control, could potentially be enhanced through RNAi technology, and specifically through the use of yeast-based interfering RNA pesticides.
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20
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Singh L, Singh K. Ivermectin: A Promising Therapeutic for Fighting Malaria. Current Status and Perspective. J Med Chem 2021; 64:9711-9731. [PMID: 34242031 DOI: 10.1021/acs.jmedchem.1c00498] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Finding new chemotherapeutic interventions to treat malaria through repurposing of time-tested drugs and rigorous design of new drugs using tools of rational drug design remains one of the most sought strategies at the disposal of medicinal chemists. Ivermectin, a semisynthetic derivative of avermectin B1, is among the efficacious drugs used in mass drug administration drives employed against onchocerciasis, lymphatic filariasis, and several other parasitic diseases in humans. In this review, we present the prowess of ivermectin, a potent endectocide, in the control of malaria through vector control to reduce parasite transmission combined with efficacious chemoprevention to reduce malaria-related fatalities.
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Affiliation(s)
- Lovepreet Singh
- Department of Chemistry, UGC Centre for Advanced Studies-II, Guru Nanak Dev University, Amritsar-143 005, India
| | - Kamaljit Singh
- Department of Chemistry, UGC Centre for Advanced Studies-II, Guru Nanak Dev University, Amritsar-143 005, India
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21
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Kumar G, Ojha VP, Pasi S. Applicability of attractive toxic sugar baits as a mosquito vector control tool in the context of India: a review. PEST MANAGEMENT SCIENCE 2021; 77:2626-2634. [PMID: 33314493 DOI: 10.1002/ps.6226] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 11/27/2020] [Accepted: 12/13/2020] [Indexed: 06/12/2023]
Abstract
Vector-borne diseases (VBD) constitute 17% of all infectious diseases that pose a major public health concern around the world. In India, VBD like malaria and dengue continue to account for a significant disease burden. Management of these diseases is dependent in part upon effective vector control and hence several vector control strategies are in use for controlling mosquito populations. However, vectors evolve over time and become capable of averting many of the used control measures, leading to a constant need to find for novel and improved interventions. Attractive toxic sugar bait (ATSB) is a novel vector control strategy that is highly effective at regulating vector density in a particular area. ATSBs exploit the sugar feeding behaviour of mosquitoes. They are developed by combining small amounts of toxins with sugar. A chemical attractant is also included to lure the mosquito into the toxic sugary trap. Although effective, ATSB testing has been limited in scope around the world and ATSBs are completely unexplored in India. In this review, we provide an in-depth account of the development of ATSBs. We highlight the potential of ATSBs in controlling major Indian vectors of malaria and dengue, and we discuss possible challenges that could affect the efficacy of ATSBs in India. © 2020 Society of Chemical Industry.
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Affiliation(s)
- Gaurav Kumar
- ICMR-National Institute of Malaria Research, New Delhi, India
| | | | - Shweta Pasi
- ICMR-National Institute of Malaria Research, New Delhi, India
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22
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Ekoka E, Maharaj S, Nardini L, Dahan-Moss Y, Koekemoer LL. 20-Hydroxyecdysone (20E) signaling as a promising target for the chemical control of malaria vectors. Parasit Vectors 2021; 14:86. [PMID: 33514413 PMCID: PMC7844807 DOI: 10.1186/s13071-020-04558-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 12/19/2020] [Indexed: 01/07/2023] Open
Abstract
With the rapid development and spread of resistance to insecticides among anopheline malaria vectors, the efficacy of current World Health Organization (WHO)-approved insecticides targeting these vectors is under threat. This has led to the development of novel interventions, including improved and enhanced insecticide formulations with new targets or synergists or with added sterilants and/or antimalarials, among others. To date, several studies in mosquitoes have revealed that the 20-hydroxyecdysone (20E) signaling pathway regulates both vector abundance and competence, two parameters that influence malaria transmission. Therefore, insecticides which target 20E signaling (e.g. methoxyfenozide and halofenozide) may be an asset for malaria vector control. While such insecticides are already commercially available for lepidopteran and coleopteran pests, they still need to be approved by the WHO for malaria vector control programs. Until recently, chemicals targeting 20E signaling were considered to be insect growth regulators, and their effect was mostly studied against immature mosquito stages. However, in the last few years, promising results have been obtained by applying methoxyfenozide or halofenozide (two compounds that boost 20E signaling) to Anopheles populations at different phases of their life-cycle. In addition, preliminary studies suggest that methoxyfenozide resistance is unstable, causing the insects substantial fitness costs, thereby potentially circumventing one of the biggest challenges faced by current vector control efforts. In this review, we first describe the 20E signaling pathway in mosquitoes and then summarize the mechanisms whereby 20E signaling regulates the physiological processes associated with vector competence and vector abundance. Finally, we discuss the potential of using chemicals targeting 20E signaling to control malaria vectors.![]()
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Affiliation(s)
- Elodie Ekoka
- WITS Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa. .,Centre for Emerging, Zoonotic & Parasitic Diseases, National Institute for Communicable Diseases, Johannesburg, South Africa.
| | - Surina Maharaj
- WITS Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Centre for Emerging, Zoonotic & Parasitic Diseases, National Institute for Communicable Diseases, Johannesburg, South Africa
| | - Luisa Nardini
- WITS Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Centre for Emerging, Zoonotic & Parasitic Diseases, National Institute for Communicable Diseases, Johannesburg, South Africa
| | - Yael Dahan-Moss
- WITS Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Centre for Emerging, Zoonotic & Parasitic Diseases, National Institute for Communicable Diseases, Johannesburg, South Africa
| | - Lizette L Koekemoer
- WITS Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Centre for Emerging, Zoonotic & Parasitic Diseases, National Institute for Communicable Diseases, Johannesburg, South Africa
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23
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Khaligh FG, Jafari A, Silivanova E, Levchenko M, Rahimi B, Gholizadeh S. Endectocides as a complementary intervention in the malaria control program: a systematic review. Syst Rev 2021; 10:30. [PMID: 33455581 PMCID: PMC7812718 DOI: 10.1186/s13643-021-01578-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 01/02/2021] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Malaria is the most common vector-borne disease transmitted to humans by Anopheles mosquitoes. Endectocides and especially ivermectin will be available as a vector control tool soon. The current review could be valuable for trial design and clinical studies to control malaria transmission. METHODS PubMed/MEDLINE, Scopus, Web of Science, and Science Direct were searched for original English published papers on ("Malaria chemical control" OR "Malaria elimination" OR "Anopheles vector control" OR "Malaria zooprophylaxis") AND ("Systemic insecticides" OR "Endectocides" OR "Ivermectin"). The last search was from 19 June 2019 to 31 December 2019. It was updated on 17 November 2020. Two reviewers (SG and FGK) independently reviewed abstracts and full-text articles. Data were extracted by one person and checked by another. As meta-analyses were not possible, a qualitative summary of results was performed. RESULTS Thirty-six published papers have used systemic insecticides/endectocides for mosquito control. Most of the studies (56.75%) were done on Anopheles gambiae complex species on doses from 150 μg/kg to 400 μg/kg in several studies. Target hosts for employing systemic insecticides/drugs were animals (44.2%, including rabbit, cattle, pig, and livestock) and humans (32.35%). CONCLUSIONS Laboratory and field studies have highlighted the potential of endectocides in malaria control. Ivermectin and other endectocides could soon serve as novel malaria transmission control tools by reducing the longevity of Anopheles mosquitoes that feed on treated hosts, potentially decreasing Plasmodium parasite transmission when used as mass drug administration (MDA).
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Affiliation(s)
- Fereshteh Ghahvechi Khaligh
- Social Determinants of Health Research Center, Clinical Research Institute, Urmia University of Medical Sciences, Urmia, Iran.,Medical Entomology Department, School of Public Health, Urmia University of Medical Sciences, Urmia, Iran
| | - Abbas Jafari
- Department of Clinical Toxicology, School of Medicine, Urmia University of Medical Sciences, Urmia, Iran.,Cellular and Molecular Research Center, Research Institute on Cellular and Molecular Medicine, Urmia University of Medical Sciences, Urmia, Iran
| | - Elena Silivanova
- All-Russian Scientific Research Institute of Veterinary Entomology and Arachnology, Branch of Federal State Institution Federal Research Centre Tyumen Scientific Centre, Siberian Branch of the Russian Academy of Sciences (ASRIVEA - Branch of Tyumen Scientific Centre SB RAS), Institutskaya st. 2, Tyumen, Russian Federation, 625041
| | - Mikhail Levchenko
- All-Russian Scientific Research Institute of Veterinary Entomology and Arachnology, Branch of Federal State Institution Federal Research Centre Tyumen Scientific Centre, Siberian Branch of the Russian Academy of Sciences (ASRIVEA - Branch of Tyumen Scientific Centre SB RAS), Institutskaya st. 2, Tyumen, Russian Federation, 625041
| | - Bahlol Rahimi
- Department of Health Information Technology, School of Applied Medical Sciences, Urmia University of Medical Sciences, Urmia, Iran
| | - Saber Gholizadeh
- Social Determinants of Health Research Center, Clinical Research Institute, Urmia University of Medical Sciences, Urmia, Iran. .,Medical Entomology Department, School of Public Health, Urmia University of Medical Sciences, Urmia, Iran.
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24
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Vector control for malaria elimination in Botswana: progress, gaps and opportunities. Malar J 2020; 19:301. [PMID: 32843037 PMCID: PMC7449088 DOI: 10.1186/s12936-020-03375-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 08/13/2020] [Indexed: 12/29/2022] Open
Abstract
Botswana has in the recent past 10 years made tremendous progress in the control of malaria and this informed re-orientation from malaria control to malaria elimination by the year 2020. This progress is attributed to improved case management, and scale-up of key vector control interventions; indoor residual spraying (IRS) and long-lasting insecticidal nets (LLINs). However, insecticide resistance, outdoor biting and resting, and predisposing human behaviour, such as staying outdoors or sleeping outdoors without the use of protective measures, pose a challenge to the realization of the full impact of LLINs and IRS. This, together with the paucity of entomological data, inadequate resources and weak community participation for vector control programme implementation delayed attainment of Botswana’s goal of malaria elimination. Also, the Botswana National Malaria Programme (NMP) experiences the lack of intersectoral collaborations and operational research for evidence-based decision making. This case study focuses on the vector control aspect of malaria elimination by identifying challenges and explores opportunities that could be taken advantage of to benefit the NMP to optimize and augment the current vector control interventions to achieve malaria elimination by the year 2030 as per the Global Technical Strategy for Malaria 2016–2030 targets. The authors emphasize the need for timely and quality entomological surveillance, operational research and integrated vector management.
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25
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Sougoufara S, Ottih EC, Tripet F. The need for new vector control approaches targeting outdoor biting Anopheline malaria vector communities. Parasit Vectors 2020; 13:295. [PMID: 32522290 PMCID: PMC7285743 DOI: 10.1186/s13071-020-04170-7] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 06/04/2020] [Indexed: 12/13/2022] Open
Abstract
Since the implementation of Roll Back Malaria, the widespread use of insecticide-treated nets (ITNs) and indoor residual spraying (IRS) is thought to have played a major part in the decrease in mortality and morbidity achieved in malaria-endemic regions. In the past decade, resistance to major classes of insecticides recommended for public health has spread across many malaria vector populations. Increasingly, malaria vectors are also showing changes in vector behaviour in response to current indoor chemical vector control interventions. Changes in the time of biting and proportion of indoor biting of major vectors, as well as changes in the species composition of mosquito communities threaten the progress made to control malaria transmission. Outdoor biting mosquito populations contribute to malaria transmission in many parts of sub-Saharan Africa and pose new challenges as they cannot be reliably monitored or controlled using conventional tools. Here, we review existing and novel approaches that may be used to target outdoor communities of malaria vectors. We conclude that scalable tools designed specifically for the control and monitoring of outdoor biting and resting malaria vectors with increasingly complex and dynamic responses to intensifying malaria control interventions are urgently needed. These are crucial for integrated vector management programmes designed to challenge current and future vector populations.
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Affiliation(s)
- Seynabou Sougoufara
- Centre of Applied Entomology and Parasitology, School of Life Sciences, Keele University, Staffordshire, UK
| | - Emmanuel Chinweuba Ottih
- Centre of Applied Entomology and Parasitology, School of Life Sciences, Keele University, Staffordshire, UK
| | - Frederic Tripet
- Centre of Applied Entomology and Parasitology, School of Life Sciences, Keele University, Staffordshire, UK
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26
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Meza FC, Roberts JM, Sobhy IS, Okumu FO, Tripet F, Bruce TJA. Behavioural and Electrophysiological Responses of Female Anopheles gambiae Mosquitoes to Volatiles from a Mango Bait. J Chem Ecol 2020; 46:387-396. [PMID: 32274623 PMCID: PMC7205772 DOI: 10.1007/s10886-020-01172-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 01/09/2020] [Accepted: 03/16/2020] [Indexed: 01/03/2023]
Abstract
Attractive Toxic Sugar Baits (ATSB) are used in a “lure-and-kill” approach for management of the malaria vector Anopheles gambiae, but the active chemicals were previously unknown. Here we collected volatiles from a mango, Mangifera indica, juice bait which is used in ATSBs in Tanzania and tested mosquito responses. In a Y-tube olfactometer, female mosquitoes were attracted to the mango volatiles collected 24–48 h, 48–72 h and 72–96 h after preparing the bait but volatiles collected at 96–120 h were no longer attractive. Volatile analysis revealed emission of 23 compounds in different chemical classes including alcohols, aldehydes, alkanes, benzenoids, monoterpenes, sesquiterpenes and oxygenated terpenes. Coupled GC-electroantennogram (GC-EAG) recordings from the antennae of An. gambiae showed robust responses to 4 compounds: humulene, (E)-caryophyllene, terpinolene and myrcene. In olfactometer bioassays, mosquitoes were attracted to humulene and terpinolene. (E)-caryophyllene was marginally attractive while myrcene elicited an avoidance response with female mosquitoes. A blend of humulene, (E)-caryophyllene and terpinolene was highly attractive to females (P < 0.001) when tested against a solvent blank. Furthermore, there was no preference when this synthetic blend was offered as a choice against the natural sample. Our study has identified the key compounds from mango juice baits that attract An. gambiae and this information may help to improve the ATSBs currently used against malaria vectors.
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Affiliation(s)
- Felician C Meza
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Huxley Building, Keele, Staffordshire, ST5 5BG, UK
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Of Mlabani Passage, P.O. Box 53, Ifakara, Tanzania
| | - Joe M Roberts
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Huxley Building, Keele, Staffordshire, ST5 5BG, UK
- Centre for Integrated Pest Management, Department of Crop and Environment Sciences, Harper Adams University, Newport, Shropshire, TF10 8NB, UK
| | - Islam S Sobhy
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Huxley Building, Keele, Staffordshire, ST5 5BG, UK
- Department of Plant Protection, Faculty of Agriculture, Suez Canal university, 41522, Ismailia, Egypt
| | - Fredros O Okumu
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Of Mlabani Passage, P.O. Box 53, Ifakara, Tanzania
| | - Frederic Tripet
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Huxley Building, Keele, Staffordshire, ST5 5BG, UK
| | - Toby J A Bruce
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Huxley Building, Keele, Staffordshire, ST5 5BG, UK.
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Wooding M, Naudé Y, Rohwer E, Bouwer M. Controlling mosquitoes with semiochemicals: a review. Parasit Vectors 2020; 13:80. [PMID: 32066499 PMCID: PMC7027039 DOI: 10.1186/s13071-020-3960-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Accepted: 02/11/2020] [Indexed: 12/20/2022] Open
Abstract
The use of semiochemicals in odour-based traps for surveillance and control of vector mosquitoes is deemed a new and viable component for integrated vector management programmes. Over 114 semiochemicals have been identified, yet implementation of these for management of infectious diseases such as malaria, dengue, chikungunya and Rift Valley fever is still a major challenge. The difficulties arise due to variation in how different mosquito species respond to not only single chemical compounds but also complex chemical blends. Additionally, mosquitoes respond to different volatile blends when they are looking for a mating partner, oviposition sites or a meal. Analytically the challenge lies not only in correctly identifying these semiochemical signals and cues but also in developing formulations that effectively mimic blend ratios that different mosquito species respond to. Only then can the formulations be used to enhance the selectivity and efficacy of odour-based traps. Understanding how mosquitoes use semiochemical cues and signals to survive may be key to unravelling these complex interactions. An overview of the current studies of these chemical messages and the chemical ecology involved in complex behavioural patterns is given. This includes an updated list of the semiochemicals which can be used for integrated vector control management programmes. A thorough understanding of these semiochemical cues is of importance for the development of new vector control methods that can be integrated into established control strategies.
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Affiliation(s)
- Madelien Wooding
- Department of Chemistry, University of Pretoria, Hatfield, Pretoria, South Africa
| | - Yvette Naudé
- Department of Chemistry, University of Pretoria, Hatfield, Pretoria, South Africa
| | - Egmont Rohwer
- Department of Chemistry, University of Pretoria, Hatfield, Pretoria, South Africa
| | - Marc Bouwer
- Forestry and Agricultural Biotechnology Institute, University of Pretoria, Hatfield, Pretoria, South Africa
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Sippy R, Rivera GE, Sanchez V, Heras F, Morejón B, Beltrán E, Hikida RS, López-Latorre MA, Aguirre A, Stewart-Ibarra AM, Larsen DA, Neira M. Ingested insecticide to control Aedes aegypti: developing a novel dried attractive toxic sugar bait device for intra-domiciliary control. Parasit Vectors 2020; 13:78. [PMID: 32066486 PMCID: PMC7027216 DOI: 10.1186/s13071-020-3930-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 02/03/2020] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND Illnesses transmitted by Aedes aegypti (Linnaeus, 1762) such as dengue, chikungunya and Zika comprise a considerable global burden; mosquito control is the primary public health tool to reduce disease transmission. Current interventions are inadequate and insecticide resistance threatens the effectiveness of these options. Dried attractive bait stations (DABS) are a novel mechanism to deliver insecticide to Ae. aegypti. The DABS are a high-contrast 28 inch2 surface coated with dried sugar-boric acid solution. Aedes aegypti are attracted to DABS by visual cues only, and the dried sugar solution elicits an ingestion response from Ae. aegypti landing on the surface. The study presents the development of the DABS and tests of their impact on Ae. aegypti mortality in the laboratory and a series of semi-field trials. METHODS We conducted multiple series of laboratory and semi-field trials to assess the survivability of Ae. aegypti mosquitoes exposed to the DABS. In the laboratory experiments, we assessed the lethality, the killing mechanism, and the shelf life of the device through controlled experiments. In the semi-field trials, we released laboratory-reared female Ae. aegypti into experimental houses typical of peri-urban tropical communities in South America in three trial series with six replicates each. Laboratory experiments were conducted in Quito, Ecuador, and semi-field experiments were conducted in Machala, Ecuador, an area with abundant wild populations of Ae. aegypti and endemic arboviral transmission. RESULTS In the laboratory, complete lethality was observed after 48 hours regardless of physiological status of the mosquito. The killing mechanism was determined to be through ingestion, as the boric acid disrupted the gut of the mosquito. In experimental houses, total mosquito mortality was greater in the treatment house for all series of experiments (P < 0.0001). CONCLUSIONS The DABS devices were effective at killing female Ae. aegypti under a variety of laboratory and semi-field conditions. DABS are a promising intervention for interdomiciliary control of Ae. aegypti and arboviral disease prevention.
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Affiliation(s)
- Rachel Sippy
- Institute for Global Health & Translational Science, SUNY-Upstate Medical University, Syracuse, NY, USA.,Department of Geography, University of Florida, Gainesville, FL, USA
| | - Galo E Rivera
- Center for Research on Health in Latin America, Pontificia Universidad Católica del Ecuador, Quito, Ecuador.,Vector Biology Group, Max Plank Institute for Infection Biology, Berlin, Germany
| | - Valeria Sanchez
- Institute for Global Health & Translational Science, SUNY-Upstate Medical University, Syracuse, NY, USA.,Unidad Académica de Ciencias Químicas y de la Salud, Universidad Técnica de Machala, Machala, Ecuador
| | - Froilán Heras
- Institute for Global Health & Translational Science, SUNY-Upstate Medical University, Syracuse, NY, USA.,Unidad Académica de Ciencias Químicas y de la Salud, Universidad Técnica de Machala, Machala, Ecuador
| | - Bianca Morejón
- Center for Research on Health in Latin America, Pontificia Universidad Católica del Ecuador, Quito, Ecuador.,Biology Division, College of Arts and Sciences, Kansas State University, Manhattan, KS, USA
| | - Efraín Beltrán
- Unidad Académica de Ciencias Químicas y de la Salud, Universidad Técnica de Machala, Machala, Ecuador
| | | | - María A López-Latorre
- Center for Research on Health in Latin America, Pontificia Universidad Católica del Ecuador, Quito, Ecuador.,Medical School, College of Health Sciences, Universidad de las Américas, Quito, Ecuador
| | - Alex Aguirre
- Center for Research on Health in Latin America, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
| | - Anna M Stewart-Ibarra
- Institute for Global Health & Translational Science, SUNY-Upstate Medical University, Syracuse, NY, USA. .,Department of Medicine, SUNY-Upstate Medical University, Syracuse, NY, USA. .,Department of Public Health and Preventative Medicine, SUNY-Upstate Medical University, Syracuse, NY, USA. .,InterAmerican Institute for Global Change Research (IAI), Montevideo, Uruguay.
| | - David A Larsen
- Department of Public Health, Syracuse University, Syracuse, NY, USA.
| | - Marco Neira
- Center for Research on Health in Latin America, Pontificia Universidad Católica del Ecuador, Quito, Ecuador.
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29
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Billingsley P, Binka F, Chaccour C, Foy B, Gold S, Gonzalez-Silva M, Jacobson J, Jagoe G, Jones C, Kachur P, Kobylinski K, Last A, Lavery JV, Mabey D, Mboera D, Mbogo C, Mendez-Lopez A, Rabinovich NR, Rees S, Richards F, Rist C, Rockwood J, Ruiz-Castillo P, Sattabongkot J, Saute F, Slater H, Steer A, Xia K, Zullinger R. A Roadmap for the Development of Ivermectin as a Complementary Malaria Vector Control Tool. Am J Trop Med Hyg 2020; 102:3-24. [PMID: 31971144 PMCID: PMC7008306 DOI: 10.4269/ajtmh.19-0620] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 10/22/2019] [Indexed: 12/14/2022] Open
Abstract
In the context of stalling progress against malaria, resistance of mosquitoes to insecticides, and residual transmission, mass drug administration (MDA) of ivermectin, an endectocide used for neglected tropical diseases (NTDs), has emerged as a promising complementary vector control method. Ivermectin reduces the life span of Anopheles mosquitoes that feed on treated humans and/or livestock, potentially decreasing malaria parasite transmission when administered at the community level. Following the publication by WHO of the preferred product characteristics for endectocides as vector control tools, this roadmap provides a comprehensive view of processes needed to make ivermectin available as a vector control tool by 2024 with a completely novel mechanism of action. The roadmap covers various aspects, which include 1) the definition of optimal dosage/regimens for ivermectin MDA in both humans and livestock, 2) the risk of resistance to the drug and environmental impact, 3) ethical issues, 4) political and community engagement, 5) translation of evidence into policy, and 6) operational aspects of large-scale deployment of the drug, all in the context of a drug given as a prevention tool acting at the community level. The roadmap reflects the insights of a multidisciplinary group of global health experts who worked together to elucidate the path to inclusion of ivermectin in the toolbox against malaria, to address residual transmission, counteract insecticide resistance, and contribute to the end of this deadly disease.
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Affiliation(s)
| | - Fred Binka
- University of Health and Allied Sciences
| | | | | | | | | | | | | | | | | | | | - Anna Last
- London School of Hygiene and Tropical Medicine
| | | | - David Mabey
- London School of Hygiene and Tropical Medicine
| | | | | | | | | | | | | | - Cassidy Rist
- Virginia-Maryland College of Veterinary Medicine at Virginia Tech
| | | | | | | | | | | | | | - Kang Xia
- School of Plant and Environmental Sciences, Virginia Tech
| | - Rose Zullinger
- US President’s Malaria Initiative/US Centers for Disease Control and Prevention
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30
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Hamerly T, Tweedell RE, Hritzo B, Nyasembe VO, Tekwani BL, Nanayakkara NPD, Walker LA, Dinglasan RR. NPC1161B, an 8-Aminoquinoline Analog, Is Metabolized in the Mosquito and Inhibits Plasmodium falciparum Oocyst Maturation. Front Pharmacol 2019; 10:1265. [PMID: 31708786 PMCID: PMC6823860 DOI: 10.3389/fphar.2019.01265] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 09/30/2019] [Indexed: 11/26/2022] Open
Abstract
Malaria is a major global health threat, with nearly half the world’s population at risk of infection. Given the recently described delayed clearance of parasites by artemisinin-combined therapies, new antimalarials are needed to facilitate the global effort toward elimination and eradication. NPC1161 is an 8-aminoquinoline that is derived from primaquine with an improved therapeutic profile compared to the parent compound. The (R)-(−) enantiomer (NPC1161B) has a lower effective dose that results in decreased toxic side effects such as hemolysis compared to the (S)-(+)-enantiomer, making it a promising compound for consideration for clinical development. We explored the effect of NPC1161B on Plasmodium falciparum oocyst and sporozoite development to evaluate its potential transmission-blocking activity viz. its ability to cure mosquitoes of an ongoing infection. When mosquitoes were fed NPC1161B 4 days after P. falciparum infection, we observed that total oocyst numbers were not affected by NPC1161B treatment. However, the sporozoite production capacity of the oocysts was impaired, and salivary gland sporozoite infections were completely blocked, rendering the mosquitoes non-infectious. Importantly, NPC1161B did not require prior liver metabolism for its efficacy as is required in mammalian systems, suggesting that an alternative metabolite is produced in the mosquito that is active against the parasite. We performed liquid chromatography–mass spectrometry (LC-MS)/MS analysis of methanol extracts from the midguts of mosquitoes fed on an NPC1161B (434.15 m/z)-treated blood meal and identified a compound with a mass of 520.2 m/z, likely a conjugate of NPC1161B or an oxidized metabolite. These findings establish NPC1161B, and potentially its metabolites, as transmission-blocking candidates for the treatment of P. falciparum.
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Affiliation(s)
- Timothy Hamerly
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States.,Department of Infectious Diseases & Immunology, Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States
| | - Rebecca E Tweedell
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States.,Department of Infectious Diseases & Immunology, Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States
| | - Bernadette Hritzo
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States
| | - Vincent O Nyasembe
- Department of Infectious Diseases & Immunology, Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States
| | - Babu L Tekwani
- Division of Drug Discovery, Department of Infectious Diseases, Southern Research, Birmingham, AL, United States
| | - N P Dhammika Nanayakkara
- National Center for Natural Products Research, University of Mississippi School of Pharmacy, Oxford, MS, United States
| | - Larry A Walker
- Division of Drug Discovery, Department of Infectious Diseases, Southern Research, Birmingham, AL, United States
| | - Rhoel R Dinglasan
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States.,Department of Infectious Diseases & Immunology, Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States
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31
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Siewe Fodjo JN, Kugler M, Hotterbeekx A, Hendy A, Van Geertruyden JP, Colebunders R. Would ivermectin for malaria control be beneficial in onchocerciasis-endemic regions? Infect Dis Poverty 2019; 8:77. [PMID: 31439040 PMCID: PMC6706915 DOI: 10.1186/s40249-019-0588-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 08/09/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND There is accumulating evidence supporting the use of ivermectin as a malaria control tool. Recent findings from the repeat ivermectin mass drug administrations for control of malaria trial demonstrated a reduced incidence of malaria in villages which received repeated ivermectin mass drug administration (MDA; six doses) compared to those who had only one round of ivermectin. Several other studies investigating the benefits of ivermectin for malaria purposes are ongoing/planned. MAIN TEXT While ivermectin MDA offers promising perspectives in the fight against malaria, we highlight the added benefits and anticipated challenges of conducting future studies in onchocerciasis-endemic regions, which are confronted with a substantial disease burden including onchocerciasis-associated epilepsy. Increasing the frequency of ivermectin MDA in such places may reduce the burden of both malaria and onchocerciasis, and allow for more entomological investigations on both the Anopheles mosquitoes and the blackflies. Upfront, acceptability and feasibility studies are needed to assess the endorsement by the local populations, as well as the programmatic feasibility of implementing ivermectin MDA several times a year. CONCLUSIONS Onchocerciasis-endemic sites would doubly benefit from ivermectin MDA interventions, as these will alleviate onchocerciasis-associated morbidity and mortality, while potentially curbing malaria transmission. Involving onchocerciasis programs and other relevant stakeholders in the malaria/ivermectin research agenda would foster the implementation of pluri-annual MDA in target communities.
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Affiliation(s)
- Joseph Nelson Siewe Fodjo
- Global Health Institute, University of Antwerp, Kinsbergen centrum, Doornstraat 331, 2610, Antwerp, Belgium
| | - Marina Kugler
- Global Health Institute, University of Antwerp, Kinsbergen centrum, Doornstraat 331, 2610, Antwerp, Belgium
| | - An Hotterbeekx
- Global Health Institute, University of Antwerp, Kinsbergen centrum, Doornstraat 331, 2610, Antwerp, Belgium
| | - Adam Hendy
- Department of Pathology, University of Texas Medical Branch, Galveston, USA
| | | | - Robert Colebunders
- Global Health Institute, University of Antwerp, Kinsbergen centrum, Doornstraat 331, 2610, Antwerp, Belgium.
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32
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Zappia SPW, Chubaty AM, Roitberg BD. State-dependent domicile leaving rates in Anopheles gambiae. Malar J 2018; 17:25. [PMID: 29329539 PMCID: PMC5767056 DOI: 10.1186/s12936-017-2166-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 12/29/2017] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Transmission of Plasmodium greatly depends on the foraging behaviour of its mosquito vector (Anopheles spp.). The accessibility of blood hosts and availability of plant sugar (i.e., nectar) sources, together with mosquito energy state, have been shown to modulate blood feeding (and thus biting rates) of anopheline mosquitoes. In this study, the influence of mosquito starvation status and availability of nectar on the decision of female Anopheles gambiae mosquitoes to leave a bed net-protected blood host was examined. METHODS Two small-scale mesocosm experiments were conducted using female mosquitoes starved for 0, 24 or 48 h, that were released inside a specially constructed hut with mesh-sealed exits and containing a bed net-protected human volunteer. Floral cues were positioned on one side of the hut or the other. Several biologically plausible exponential decay models were developed that characterized the emigration rates of mosquitoes from the huts. These varied from simple random loss to leaving rates dependent upon energy state and time. These model fits were evaluated by examining their fitted parameter estimates and comparing Akaike information criterion. RESULTS Starved mosquitoes left domiciles at a higher rate than recently fed individuals however, there was no difference between 1- and 2-day-starved mosquitoes. There was also no effect of floral cue placement. The best fitting emigration model was one based on both mosquito energy state and time whereas the worst fitting model was one based on the assumption of constant leaving rates, independent of time and energy state. CONCLUSIONS The results confirm that mosquito-leaving behaviour is energy-state dependent, and provide some of the first evidence of state-dependent domicile emigration in An. gambiae, which may play a role in malarial transmission dynamics. Employment of simple, first-principle, mechanistic models can be very useful to our understanding of why and how mosquitoes leave domiciles.
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Affiliation(s)
- Simon P. W. Zappia
- Evolutionary and Behavioural Ecology Research Group, Department of Biological Sciences, Simon Fraser University, Burnaby, BC Canada
| | - Alex M. Chubaty
- Evolutionary and Behavioural Ecology Research Group, Department of Biological Sciences, Simon Fraser University, Burnaby, BC Canada
- Natural Resources Canada, Canadian Forest Service, Victoria, BC Canada
- Faculté de foresterie, de géographie et de géomatique, Département des sciences du bois et de la forêt, Université Laval, Québec, Canada
| | - Bernard D. Roitberg
- Evolutionary and Behavioural Ecology Research Group, Department of Biological Sciences, Simon Fraser University, Burnaby, BC Canada
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33
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Maia MF, Tenywa FC, Nelson H, Kambagha A, Ashura A, Bakari I, Mruah D, Simba A, Bedford A. Attractive toxic sugar baits for controlling mosquitoes: a qualitative study in Bagamoyo, Tanzania. Malar J 2018; 17:22. [PMID: 29321011 PMCID: PMC5763615 DOI: 10.1186/s12936-018-2171-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 01/04/2018] [Indexed: 11/15/2022] Open
Abstract
Background Malaria elimination is unlikely to be achieved without the implementation of new vector control interventions capable of complementing insecticide-treated nets and indoor residual spraying. Attractive-toxic sugar baits (ATSBs) are considered a new vector control paradigm. They are technologically appropriate as they are simple and affordable to produce. ATSBs kill both female and male mosquitoes attracted to sugar feed on a sugary solution containing a mosquitocidal agent and may be used indoors or outdoors. This study explored the views and perceptions on ATSBs of community members from three Coastal Tanzanian communities. Methods Three communities were chosen to represent coastal urban, peri-urban and rural areas. Sensitization meetings were held with a total of sixty community members where ATSBs were presented and explained their mode of action. At the end of the meeting, one ATSB was given to each participant for a period of 2 weeks, after which they were invited to participate in focus group discussions (FGDs) to provide feedback on their experience. Results Over 50% of the participants preferred to use the bait indoors although they had been instructed to place it outdoors. Participants who used the ATSBs indoors reported fewer mosquitoes inside their homes, but were disappointed not to find the dead mosquitoes in the baits, although they had been informed that this was unlikely to happen. Most participants disliked the appearance of the bait and some thought it to be reminiscent of witchcraft. Neighbours that did not participate in the FGDs or sensitizations were sceptical of the baits. Conclusions This study delivers insight on how communities in Coastal Tanzania are likely to perceive ATSBs and provides important information for future trials investigating the efficacy of ATSBs against malaria. This new vector control tool will require sensitization at community level regarding its mode of action in order to increase the acceptance and confidence in ATSBs for mosquito control given that most people are not familiar with the new paradigm. A few recommendations for product development and delivery are discussed.
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Affiliation(s)
- Marta Ferreira Maia
- KEMRI-Wellcome Trust Research Programme, P.O. Box 230, Kilifi, 80108, Kenya. .,Swiss Tropical and Public Health Institute, Socinstr. 57, 4002, Basel, Switzerland. .,University of Basel, St. Petersplatz 1, 4002, Basel, Switzerland.
| | | | - Hannah Nelson
- CIVICUS-World Alliance for Citizen Participation, 25 Owl Street, 6th Floor, Johannesburg, South Africa
| | - Athumani Kambagha
- Ifakara Health Institute, P.O. Box 74, Bagamoyo, Pwani, United Republic of Tanzania
| | - Abigail Ashura
- International Development Consultants, Ground Floor 369 Kilwa House, Toure Drive, Oyster Bay-Kinondoni, P.O. Box 23197, Dar es Salaam, United Republic of Tanzania
| | - Ibrahim Bakari
- International Development Consultants, Ground Floor 369 Kilwa House, Toure Drive, Oyster Bay-Kinondoni, P.O. Box 23197, Dar es Salaam, United Republic of Tanzania
| | - Deogratis Mruah
- International Development Consultants, Ground Floor 369 Kilwa House, Toure Drive, Oyster Bay-Kinondoni, P.O. Box 23197, Dar es Salaam, United Republic of Tanzania
| | - Aziza Simba
- International Development Consultants, Ground Floor 369 Kilwa House, Toure Drive, Oyster Bay-Kinondoni, P.O. Box 23197, Dar es Salaam, United Republic of Tanzania
| | - Ally Bedford
- International Development Consultants, Ground Floor 369 Kilwa House, Toure Drive, Oyster Bay-Kinondoni, P.O. Box 23197, Dar es Salaam, United Republic of Tanzania
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