Targeting malaria vectors through their blood meals for malaria transmission control

2016 ◽  
Author(s):  
Brian D. Foy
2012 ◽  
Vol 8 (5) ◽  
pp. 874-877 ◽  
Author(s):  
Samson S. Kiware ◽  
Nakul Chitnis ◽  
Gregor J. Devine ◽  
Sarah J. Moore ◽  
Silas Majambere ◽  
...  

Mosquitoes, which evade contact with long-lasting insecticidal nets and indoor residual sprays, by feeding outdoors or upon animals, are primary malaria vectors in many tropical countries. They can also dominate residual transmission where high coverage of these front-line vector control measures is achieved. Complementary strategies, which extend insecticide coverage beyond houses and humans, are required to eliminate malaria transmission in most settings. The overwhelming diversity of the world's malaria transmission systems and optimal strategies for controlling them can be simply conceptualized and mapped across two-dimensional scenario space defined by the proportion of blood meals that vectors obtain from humans and the proportion of human exposure to them which occurs indoors.


2014 ◽  
Vol 13 (S1) ◽  
Author(s):  
Alexandra Hiscox ◽  
Tobias Homan ◽  
Corné Vreugdenhil ◽  
Bruno Otieno ◽  
Anthony Kibet ◽  
...  

2019 ◽  
Vol 4 (6) ◽  
pp. e001776 ◽  
Author(s):  
Hannah R Meredith ◽  
Luis Furuya-Kanamori ◽  
Laith Yakob

BackgroundLong-lasting insecticidal nets and indoor residual sprays have significantly reduced the burden of malaria. However, several hurdles remain before elimination can be achieved: mosquito vectors have developed resistance to public health insecticides, including pyrethroids, and have altered their biting behaviour to avoid these indoor control tools. Systemic insecticides, drugs applied directly to blood hosts to kill mosquitoes that take a blood meal, offer a promising vector control option. To date, most studies focus on repurposing ivermectin, a drug used extensively to treat river blindness. There is concern that overdependence on a single drug will inevitably repeat past experiences with the rapid spread of pyrethroid resistance in malaria vectors. Diversifying the arsenal of systemic insecticides used for mass drug administration would improve this strategy’s sustainability.MethodsHere, a review was conducted to identify systemic insecticide candidates and consolidate their pharmacokinetic/pharmacodynamic properties. The impact of alternative integrated vector control options and different dosing regimens on malaria transmission reduction are illustrated through mathematical model simulation.ResultsThe review identified drugs from four classes commonly used in livestock and companion animals: avermectins, milbemycins, isoxazolines and spinosyns. Simulations predicted that isoxazolines and spinosyns are promising candidates for mass drug administration, as they were predicted to need less frequent application than avermectins and milbemycins to maintain mosquitocidal blood concentrations.ConclusionsThese findings will provide a guide for investigating and applying different systemic insecticides to achieve more effective and sustainable control of malaria transmission.


2015 ◽  
Vol 112 (49) ◽  
pp. 15178-15183 ◽  
Author(s):  
Alvaro Molina-Cruz ◽  
Gaspar E. Canepa ◽  
Nitin Kamath ◽  
Noelle V. Pavlovic ◽  
Jianbing Mu ◽  
...  

Plasmodium falciparum malaria originated in Africa and became global as humans migrated to other continents. During this journey, parasites encountered new mosquito species, some of them evolutionarily distant from African vectors. We have previously shown that the Pfs47 protein allows the parasite to evade the mosquito immune system of Anopheles gambiae mosquitoes. Here, we investigated the role of Pfs47-mediated immune evasion in the adaptation of P. falciparum to evolutionarily distant mosquito species. We found that P. falciparum isolates from Africa, Asia, or the Americas have low compatibility to malaria vectors from a different continent, an effect that is mediated by the mosquito immune system. We identified 42 different haplotypes of Pfs47 that have a strong geographic population structure and much lower haplotype diversity outside Africa. Replacement of the Pfs47 haplotypes in a P. falciparum isolate is sufficient to make it compatible to a different mosquito species. Those parasites that express a Pfs47 haplotype compatible with a given vector evade antiplasmodial immunity and survive. We propose that Pfs47-mediated immune evasion has been critical for the globalization of P. falciparum malaria as parasites adapted to new vector species. Our findings predict that this ongoing selective force by the mosquito immune system could influence the dispersal of Plasmodium genetic traits and point to Pfs47 as a potential target to block malaria transmission. A new model, the “lock-and-key theory” of P. falciparum globalization, is proposed, and its implications are discussed.


2020 ◽  
Vol 47 (4) ◽  
Author(s):  
Riyani Setiyaningsih

Abstract The target of malaria elimination in Indonesia is expected to be achieved in 2030. One of the activities to support malaria elimination is vector surveillance. Several districts in Indonesia have certificates of malaria, including Jembrana, Bali Province, Bulukumba, South Sulawesi Province, and Bengkalis, Riau Province. Analysis of the presence of malaria vectors and Plasmodium needs to be done for the potential occurances of malaria transmission in eliminated malaria areas. Bioecology study of malaria vectors were conducted to determine receptivity status and others risk factors and the potential for malaria transmission based on ecosystems in Jembrana, Bulukumba and Bengkalis districts. As part of national research of disease vector and reservoir (Rikhus Vektora), mosquitoes and larval field-collection methods, molecular plasmodium detection and blood meal analyses were carried out according Rikhus vektora guidelines. The result showed that Anopheles kochi and An. tesselatus were positive confirmed with Plasmodium falciparum by using PCR in Jembrana, Bali province, which were found in non-forest ecosystems near settlements and beaches near settlements. In addition, Anopheles barbirostris, Anopheles vagus, and Anopheles peditaeniatus were also positive confirmed with P. falciparum by using similar methods in Bulukumba, South Sulawesi province. An. barbirostris was found in forest ecosystems near settlement, Anopheles vagus was found in remote forest ecosystems of settlements and beaches near settlements, and Anopheles peditaenistus was found in non-forest ecosystems near settlements. While Anopheles sinensis was confirmed positive with P. falciparum in Bengkalis, Riau province. Jembrana, Bulukumba and Bengkalis districts are recognized as receptive areas and have potential for re-transmission of malaria. Vector surveillance and the implementation of approriate vector control and migration surveillance are needed to ascertain wheter the positive Anopheles with positives Plasmodium falciparum getting the parasites from imported cases or there has been a local transmission (indigenous) in these areas. This information is needed to prevent malaria re-transmission in the eliminated areas. Keywords : elimination, malaria, vector Abstrak Target eliminasi malaria di Indonesia harapannya dapat dicapai tahun 2030. Salah satu kegiatan yang dilakukan untuk menunjang elimnasi malaria adalah surveilans vektor. Beberapa Kabupaten di Indonesia telah memperoleh serfikat eliminasi malaria diantaranya Kabupaten Jembrana Propinsi Bali, Bulukumba Propinsi Sulawesi Selatan, dan Bengkalis Propinsi Riau. Analisis keberadaan vektor dan patogen malaria perlu dilakukan untuk melihat potensi terjadinya penularan malaria kembali di daerah yang telah mendapatkan sertifikat eliminasi malaria. Studi bioekologi vektor malaria dilakukan untuk mengetahui status reseptivitas dan faktor risiko lainnya, serta potensi penularan malaria berbasis ekosistem di daerah tersebut. Sebagai bagian dari dari Riset khusus (rikhus) vektora, koleksi lapangan nyamuk dan jentik, prosedur deteksi melekuler plasmodium dan analisis pakan darah dilakukan dengan menggunakan pedoman Rikhus vektora. Hasil studi menunjukkan bahwa Anopheles kochi dan Anopheles tesselatus, yang masing-masing ditemukan di eksoistem non hutan dekat pemukiman dan pantai dekat pemukiman ditemukan positif mengandung Plasmodium falciparum di Kabupaten Jembrana, Bali. Sedangkan di Kabupaten Bulukumba, Sulawesi Selatan, Anopheles barbirostris, Anopheles vagus, dan Anopheles peditaeniatus merupakan spesies Anopheles yang terkonfirmasi positif mengandung P. falciparum. An. barbirostris ditemukan di ekosistem hutan dekat pemukiman, Anopheles vagus ditemukan di ekosistem hutan jauh pemukiman dan pantai dekat pemukiman, dan Anopheles peditaenistus ditemukan di ekosistem non hutan dekat pemukiman. Sedangkan Anopheles sinensis merupakan satu-satunya spesies Anopheles yang ditemukan positif mengandung P. falciparum di Kabupaten Bengkalis, Riau. Dari hasil studi menunjukkan, Kabupaten Jembrana, Bulukumba, dan Bengkalis merupakan daerah reseptif dan berpotensi terjadinya penularan kembali malaria. Surveilans vektor dan implementasi pengendalian vektor yang tepat serta surveilans migrasi secara ketat diperlukan untuk memastikan apakah Anopheles yang positif tersebut mendapatkan parasit P. falciparum dari kasus import ataukah memang sudah terjadi transmisi secara lokal (indigenous) di wilayah tersebut. Hal ini perlu dilakukan agar tidak terjadi penularan kembali malaria di daerah yang sudah tereliminasi tersebut. Kata kunci: eliminasi, malaria, vektor


2020 ◽  
Author(s):  
Souleymane Doucoure ◽  
Omar Thiaw ◽  
Amélé N. Wotodjo ◽  
Charles Bouganali ◽  
Nafissatou Diagne ◽  
...  

Abstract Background: In Dielmo, Senegal, the widespread use of long lasting insecticidal nets has decreased both the incidence of malaria and the density of the anopheles population. However, persistent low-level malaria transmission may hamper efforts to eliminate the disease. Therefore, continuous monitoring of the vector population is needed in order to improve knowledge of anopheles biting behaviour and to readjust control interventions.Methods: In 2015, anopheles were collected every month for a whole year and each specimen was identified using morphological and molecular techniques. The biting pattern of each species was analysed according to night (7pm–7am) and day (7am–11am) periods, the place of biting and the season. The ELISA CSP technique was used to evaluate the entomological inoculation rate (EIR).Results: An. arabiensis and An. funestus s.s. were found to be the main vectors biting human in Dielmo. Overall, the biting rate was low, at 3.84bites per night (bpn) and 1.27 bites per day (bpd), respectively. The EIR was 2.51 and 5.03 infected bites per year during the night and day, respectively. During the night, the An. arabiensis and An. funestus biting rate was 1.81 bpn and 1.71 bpn, respectively (p=0.80). During daylight hours, their aggressiveness decreased to 0.51 bpd and 0.73 bpd for An. arabiensis and An. funestus, respectively (p=0.30). During the night, depending on the seasons, only An. funestus displayed a significant outdoor biting behaviour both in the rainy and dry seasons, while during the day, no specific trend of indoor or outdoor biting was observed, regardless of the season for both vectors.Conclusion: This study highlighted low level anopheles nocturnal and diurnal biting and the associated risk of malaria transmission. It showed also the influence of the season on the indoor and outdoor biting pattern, indicating that the human population could be exposed all year round to a low level of anopheles bites. Control programs should increase awareness of the use of bed-nets throughout the year, particularly shortly after dawn when people are still indoors.


2021 ◽  
Author(s):  
Jean Baptiste Yaro ◽  
Alfred Tiono ◽  
Antoine Sanou ◽  
Hyacinthe K Toe ◽  
John Bradley ◽  
...  

Abstract Background: In rural Burkina Faso, the malaria vector An. gambiae s.l. is primarily thought to feed indoors at night. Identification of factors which influence mosquito house entry could lead to development of novel malaria vector control interventions. A study was therefore carried out to identify risk factors associated with house entry of An. gambiae s.l. in south-west Burkina Faso, an area of high insecticide resistance. Methods: Mosquitoes were sampled monthly during the malaria transmission season using CDC light traps in 252 houses from 10 villages, each house sleeping at least one child aged five to 15 years old. Putative risk factors for house entry of An. gambiae s.l. were measured, including socio-economic status, caregiver’s education and occupation, number of people sleeping in the same room as the child, use of anti-mosquito measures, house construction and fittings, proximity of mosquito aquatic habitats and presence of animals near the house. Mosquito counts were compared using a generalised linear mixed-effect model with negative binomial and log link function, adjusting for repeated collections. Results: 20,929 mosquitoes were caught, of which 16,270 (77.7%) were An. gambiae s.l. Of the 6,691 An. gambiae s.l. identified to species, 4,101 (61.3%) were An. gambiae and 2,590 (38.7%) An. coluzzii. Having an electricity supply (incidence rate ratio, IRR = 0.4, 95% CI = 0.3–0.7, p = 0.001) and a metal-roofed house (IRR, = 0.6, 95% CI = 0.4–1.0, p = 0.034) were associated with fewer malaria vectors inside the home. Conclusion: This study demonstrated that there were fewer An. gambiae s.l. in homes with electricity and a metal roof compared to those that did not. Brightly-lit, well-built houses with metal roofs may reduce entry of malaria mosquitoes compared to dimly-lit, poorly-built thatched roofed houses.


2020 ◽  
Author(s):  
Sawdetuo Aristide HIEN ◽  
Dieudonné Diloma Soma ◽  
Simon Pengwende Sawadogo ◽  
Serge Bèwadéyir Poda ◽  
Moussa Namountougou ◽  
...  

Abstract Background The fight against vector is essential in malaria prevention strategies in several endemic countries in Africa. In Burkina Faso, malaria transmission is seasonal in most parts of country, so a single round of spraying should provide effective protection against malaria, provided the insecticide remains effective over the entire malaria transmission season. The outcomes of indoor residual spraying towards curtailing malaria transmission are firstly to decrease the life span of vector mosquitoes and also to reduce the malaria vectors density. Methods CDC light trap and early morning collections by pyrethrum spray catches were performed monthly to determine the change in malaria vector indices in sprayed (Diebougou) and unsprayed sites (Dano). The female’s malaria vectors collected by both methods were used to determine their blood feeding, biting and sporozoites rate and malaria transmission risk estimated by entomological inoculation rate. Results Anopheles gambiae complex composed to Anopheles gambiae, Anopheles coluzzii and Anopheles arabiensis were present throughout the transmission season, but An. gambiae was the predominant species collected (P =0.0005), comprising 88% of the total collected and the most infected species. Malaria vectors densities were significantly lower in sprayed villages (n=4,303) compared with unsprayed villages (n=12,569) during post-spraying period (P = 0.0012). In addition, mean human biting rate of An. gambiae sl and An . funestus ss were significantly lower in sprayed areas compared to unsprayed areas (P<0.05). Overall, malaria vector transmission risk was significant lower in villages which received IRS (P=0.0001) whatever the malaria vectors species ( An. gambiae sl and An. funestus ss). Conclusions The results showed that in the sprayed area (Diebougou), vector densities, human biting rates and malaria transmission risks were very lower than unsprayed areas (Dano). The findings also showed a change in vector behavior especially within An. funestus which became more zoophagic following IRS. The indoor residual spraying could be recommanded as control tool in areas where malaria transmission occured a given period of year.


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