scholarly journals Insecticide susceptibility status of human biting mosquitoes in Muheza, Tanzania

2017 ◽  
Vol 19 (3) ◽  
Author(s):  
Basiliana Emidi ◽  
William N. Kisinza ◽  
Robert D. Kaaya ◽  
Robert Malima ◽  
Franklin W. Mosha

Background: There has been a rapid emergence in insecticide resistance among mosquito population to commonly used public health insecticides. This situation presents a challenge to chemicals that are currently used to control mosquitoes in sub-Saharan African. Furthermore, there is limited information on insecticide susceptibility status of human-biting mosquitoes in some areas of Tanzania. This study aimed to determine insecticide susceptibility status of human biting mosquitoes in a rural area of north-eastern Tanzania.Methods: The study was conducted in two villages in Muheza district, Tanzania. Insecticide susceptibility bioassays were performed according to the World Health Organization standard operating procedures on two to five-day old human biting mosquitoes. The mosquitoes of each species were exposed to four classes of insecticides commonly used for malaria vector control. Mosquito mortality rates (%) were determined after 24 hours post insecticide exposure.Results: Mosquito species tested were Anopheles gambiae s.l., An. funestus, Aedes aegypti, and Culex quinquefasciatus species. Real-time PCR have showed that the main sibling species of An. gambiae complex and An. funestus group were An. gambiae s. s. (58.2%) and An. funestus s. s. (91.1%), respectively. All mosquitoes, except Ae. aegypti formosus were susceptible to pirimiphos-methyl (0.25%). An. gambiae s. l. was found to be resistant to permethrin (0.75%) but showed possibility of resistance to DDT (4%) and bendiocarb (0.1%). Our findings have shown that, An. funestus was fully susceptible to all insecticide tested.Conclusion: The present study has revealed different levels of insecticide susceptibility status to four classes of commonly used insecticides in the most common mosquito vectors of human diseases in north-eastern Tanzania. The findings of the present study call for integrated vector control interventions. 

2017 ◽  
Vol 15 (1) ◽  
Author(s):  
Rizka Ilmawati ◽  
Sri Mardoyo ◽  
Suroso Bambang Eko Warno

ABSTRACTMalaria is a contagious disease that still becomes wide health problem in the world, including Indonesia.In 2014, API of Pacitan was the highest in East Java with 75 patients suffered from malaria. One of the endemicvillage in Pacitan is Ngreco village. Malaria vector control effort undertaken in the village is the use of insecticidetreatedbed nets, as recommended by the World Health Organization (WHO). The use of insecticide-treated netseffectively prevent transmission of malaria when supported with good care to insecticide-treated nets.This study aims to determine the effectiveness of insecticide-treated nets used by Ngreco Villagecommunity as malaria vector control to the decline in malaria cases. This is a quasi-experimental research. Thedata were collected through interview and sampling. The research sample was 29 homes for interviews and 4insecticide-treated nets used by the community for Bio-assay Test.The results of this study shows a decrease in new case of malaria in 2007-2010 from 23 new cases into2 new cases in 2011 to 2015. The results of efficacy test conducted on four samples of net used by thecommunity showed that net with 30 months of use (effectiveness <80%) are no longer effective to be used as avector control of malaria, while net with 12 months of use (effectiveness> 80%) is still effective to be used asmalaria vector control.The society should pay more attention on how to laundry the net that it is durable as malaria vectorcontrol. The health center needs to conduct controlling of mosquito nets routinely to find out whether the netsare still effective that replacement or dyeing of the of net can be performed.Keywords: Insecticidal mosquito net, effectiveness, malaria


2020 ◽  
Vol 41 (1) ◽  
pp. 114-118
Author(s):  
N.I. Udoidung ◽  
K.N. Opara ◽  
P.D. Okodi ◽  
N.D. Ekpo ◽  
I. Atting

Rapid emergence in insecticide resistance among malaria vector populations to commonly used public health insecticides poses a challenge to current malaria vector control strategies and interventions in sub- Saharan Africa. This study was conducted to determine the susceptibility status of female An.gambiae s.l to Propoxur (0.01%) and bendiocarb (0.1%) (carbamate) and pirimiphosmethyl (0.25%) (organophosphate) insecticides in Uyo Metropolis, Akwa Ibom State, Nigeria. The larvae of An. gambiae s.l were collected from natural water bodies and other potential breeding sites from different sites in Uyo Metropolis. Insecticide susceptibility bioassays were performed according to the World Health Organization standard operating procedures on 2-3 days old, sugar-fed but none blood fed female Anopheles mosquitoes. Post exposure mortality after 24 hours and knockdown values for KDT50 and KDT95 were calculated. Knock-down at 1 hour insecticide exposure ranged from 94 % to 100 %. Mortality after 24 hours post exposure was 100% for all insecticides except Propoxur which was 98 %. There was high variability in KDT50 and KDT95 values (in minutes) with propoxur (4.337 and 15.620), Bendiocarb (9.523 and 20.996) and pirimiphosmethyl (39.908 and 61.722) respectively. Adopting the WHO criteria, the mosquitoes were not resistant to any of the insecticides tested. The results therefore showed that vector control campaigns employing the use of any of these insecticides in the study area would not be compromised. However, there is need for continued monitoring to ensure early detection of resistance. Keywords: Anopheles gambiae; insecticide susceptibility; Uyo; Akwa Ibom State; Nigeria.


2014 ◽  
Vol 56 (6) ◽  
pp. 493-497 ◽  
Author(s):  
Gabriel de Deus Vieira ◽  
Sergio de Almeida Basano ◽  
Tony Hiroshi Katsuragawa ◽  
Luís Marcelo Aranha Camargo

Mosquito nets treated with long-lasting insecticide (LLINs), when used in compliance with guidelines of the World Health Organization, may be effective for malaria vector control. In 2012, approximately 150,000 LLINs were installed in nine municipalities in the state of Rondônia. However, no studies have assessed their impact on the reduction of malaria incidence. This study analyzed secondary data of malaria incidence, in order to assess the impact of LLINs on the annual parasite incidence (API). The results showed no statistically significant differences in API one year after LLIN installation when compared to municipalities without LLINs. The adoption of measures for malaria vector control should be associated with epidemiological studies and evaluations of their use and efficiency, with the aim of offering convincing advantages that justify their implementation and limit malaria infection in the Amazon Region.


2022 ◽  
Vol 15 (1) ◽  
Author(s):  
Sundus Shafat Ahmad ◽  
Manju Rahi ◽  
Poonam Saroha ◽  
Amit Sharma

AbstractMalaria constitutes one of the largest public health burdens faced by humanity. Malaria control has to be an efficient balance between diagnosis, treatment and vector control strategies. The World Health Organization currently recommends indoor residual spraying and impregnated bed nets as two malaria vector control methods that have shown robust and persistent results against endophilic and anthropophilic mosquito species. The Indian government launched the National Framework for Malaria Elimination in 2016 with the aim to achieve the elimination of malaria in a phased and strategic manner and to sustain a nation-wide malaria-free status by 2030. India is currently in a crucial phase of malaria elimination and novel vector control strategies maybe helpful in dealing with various challenges, such as vector behavioural adaptations and increasing insecticide resistance among the Anopheles populations of India. Ivermectin can be one such new tool as it is the first endectocide to be approved in both animals and humans. Trials of ivermectin have been conducted in endemic areas of Africa with promising results. In this review, we assess available data on ivermectin as an endectocide and propose that this endectocide should be explored as a vector control tool for malaria in India. Graphical Abstract


2021 ◽  
Vol 3 (3) ◽  
Author(s):  
Hassan Vatandoost

Mosquitoes belong to order of Diptera. The main important vectors are genus Aedes, Culex and Anopheles. They transmit different agents such bacteria, viruses, and parasites. According to the latest information around 7 hundred million people around the world are suffering from mosquitoborne illness resulting over one million deaths. The main important disease transmitted by Anopheles is malaria. Other genus of mosquitoes including Aedes and Culex species transmit different arboviral disease to human. According to guideline of World Health Organization, the mina control of disease is vectors control. The main important vector control is using different insecticides. Using chemical insecticides for controlling mosquitoes is limited because they develop resistance against these insecticides. So, efforts have been made to control the mosquito vectors by eco-friendly techniques. In this research all, the relevant information regarding the topic of research is research through the internet and used in this paper. An intensive search of scientific literature was done in “PubMed”, “Web of Knowledge”, “Scopus”, “Google Scholar”, “SID”, etc Results shows that one of important environmental friendly vector control is biological control, using different predators and other microorganisms for vector and pest control. Dragonflies do eat mosquitos and serve as mosquito predators. They feed on mosquitos and reduce their number in outdoor areas. The dragonflies are scary biters, but they are dangerous to mosquitos. Worldwide results showed that dragonflies are able to control Aedes, Culex and Anopheles mosquito species. The artificial rearing of these predators and releasing for biological control is an appropriate measure for vector control worldwide.


1993 ◽  
Vol 27 (6) ◽  
pp. 391-397 ◽  
Author(s):  
Domingo Montada Dorta ◽  
V. Vasuki ◽  
A. Rajavel

Three organophosphorus compounds- malathion, folithion and temephos- and two synthetic pyrethroids- alphamethrin and deltamethrin- were used for monitoring the susceptibility status of larvae and adults of six vector mosquitoe species: Culex quinquefasciatus (Filariasis) and Aedes albopictus (Dengue) (both laboratory and field strains); laboratory strains of Aedes aegypti (Dengue), Anopheles slephensi and Anopheles culicifacies (Malaria), and Culex tritaeniorhynchus (Japanese encephalitis) in India. From the LC50 values obtained for these insecticides, it was found that all mosquito species including the field strains of Cx. quinquefasciatus and Ae. albopictus were highly susceptible Except for Cx. quinquefasciatus (field strain) against malathion, 100% mortality was observed at the discriminating dosages recommended by World Health Organization. The residual effect of alphamethrin, deltamethrin, malathion and folithion at 25 mg (ai)/m² on different surfaces against six species of vector mosquitoes showed that alphamethrin was the most effective on all four treated surfaces (mud, plywood, cement and thatch). Nevertheless, residual efficacy lasted longer on thatch than on the other surfaces. Therefore, synthetic pyrethroids such as alphamethrin can be effectively employed in integrated vector control operations.


2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Henry Ddumba Mawejje ◽  
Maxwell Kilama ◽  
Simon P. Kigozi ◽  
Alex K. Musiime ◽  
Moses Kamya ◽  
...  

Abstract Background Long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) are the malaria control interventions primarily responsible for reductions in transmission intensity across sub-Saharan Africa. These interventions, however, may have differential impact on Anopheles species composition and density. This study examined the changing pattern of Anopheles species in three areas of Uganda with markedly different transmission intensities and different levels of vector control. Methods From October 2011 to June 2016 mosquitoes were collected monthly using CDC light traps from 100 randomly selected households in three areas: Walukuba (low transmission), Kihihi (moderate transmission) and Nagongera (high transmission). LLINs were distributed in November 2013 in Walukuba and Nagongera and in June 2014 in Kihihi. IRS was implemented only in Nagongera, with three rounds of bendiocarb delivered between December 2014 and June 2015. Mosquito species were identified morphologically and by PCR (Polymerase Chain Reaction). Results In Walukuba, LLIN distribution was associated with a decline in Anopheles funestus vector density (0.07 vs 0.02 mosquitoes per house per night, density ratio [DR] 0.34, 95% CI: 0.18–0.65, p = 0.001), but not Anopheles gambiae sensu stricto (s.s.) nor Anopheles arabiensis. In Kihihi, over 98% of mosquitoes were An. gambiae s.s. and LLIN distribution was associated with a decline in An. gambiae s.s. vector density (4.00 vs 2.46, DR 0.68, 95% CI: 0.49–0.94, p = 0.02). In Nagongera, the combination of LLINs and multiple rounds of IRS was associated with almost complete elimination of An. gambiae s.s. (28.0 vs 0.17, DR 0.004, 95% CI: 0.002–0.009, p < 0.001), and An. funestus sensu lato (s.l.) (3.90 vs 0.006, DR 0.001, 95% CI: 0.0005–0.004, p < 0.001), with a less pronounced decline in An. arabiensis (9.18 vs 2.00, DR 0.15 95% CI: 0.07–0.33, p < 0.001). Conclusions LLIN distribution was associated with reductions in An. funestus s.l. in the lowest transmission site and An. gambiae s.s. in the moderate transmission site. In the highest transmission site, a combination of LLINs and multiple rounds of IRS was associated with the near collapse of An. gambiae s.s. and An. funestus s.l. Following IRS, An. arabiensis, a behaviourally resilient vector, became the predominant species, which may have implications for malaria vector control activities. Development of interventions targeted at outdoor biting remains a priority.


2021 ◽  
Vol 3 (6) ◽  
Author(s):  
Théophile Vitoussia ◽  
Alain Brillard ◽  
Justin Bertsch ◽  
Olivier Allgaier ◽  
Gontrand Leyssens ◽  
...  

AbstractIn Sub-Saharan countries, cooking is usually done at a domestic scale using rudimentary stoves with wood or charcoal as combustibles. To improve the cooking behavior and reduce the deforestation, an improved pellet cookstove was conceptualized with guiding ideas in mind such as simplicity, robustness and ability to burn pellets built with local wood residues under a natural draught. Combustion and water ebullition tests were performed with two configurations of the upper part of the cookstove: thick steel plate or ring, and with standardized EN+ pellets as combustible. The main pollutant gases (CO, CO2 and NOx), together with O2, were continuously measured at different positions of the cookstove during a water ebullition test with the ring configuration. The levels measured above the pot were lower than the thresholds currently proposed by the World Health Organization. Simple and phenomenological thermal models were proposed to simulate the plate, or ring, and water temperatures during the combustion or water ebullition tests and to determine the intrinsic convection coefficients. The maximal relative differences between the experimental and simulated temperatures were computed between 7 and 21%. The stove power was evaluated at 4336 ± 23 W. The cookstove yield for the water ebullition test with the ring configuration was computed equal to 12.3 ± 0.1%, slightly lower than that of cookstoves previously analyzed in the literature.


2020 ◽  
Author(s):  
Stefan David Baral ◽  
Katherine Blair Rucinski ◽  
Jean Olivier Twahirwa Rwema ◽  
Amrita Rao ◽  
Neia Prata Menezes ◽  
...  

BACKGROUND SARS-CoV-2 and influenza are lipid-enveloped viruses with differential morbidity and mortality but shared modes of transmission. OBJECTIVE With a descriptive epidemiological framing, we assessed whether recent historical patterns of regional influenza burden are reflected in the observed heterogeneity in COVID-19 cases across regions of the world. METHODS Weekly surveillance data reported by the World Health Organization from January 2017 to December 2019 for influenza and from January 1, 2020 through October 31, 2020, for COVID-19 were used to assess seasonal and temporal trends for influenza and COVID-19 cases across the seven World Bank regions. RESULTS In regions with more pronounced influenza seasonality, COVID-19 epidemics have largely followed trends similar to those seen for influenza from 2017 to 2019. COVID-19 epidemics in countries across Europe, Central Asia, and North America have been marked by a first peak during the spring, followed by significant reductions in COVID-19 cases in the summer months and a second wave in the fall. In Latin America and the Caribbean, COVID-19 epidemics in several countries peaked in the summer, corresponding to months with the highest influenza activity in the region. Countries from regions with less pronounced influenza activity, including South Asia and sub-Saharan Africa, showed more heterogeneity in COVID-19 epidemics seen to date. However, similarities in COVID-19 and influenza trends were evident within select countries irrespective of region. CONCLUSIONS Ecological consistency in COVID-19 trends seen to date with influenza trends suggests the potential for shared individual, structural, and environmental determinants of transmission. Using a descriptive epidemiological framework to assess shared regional trends for rapidly emerging respiratory pathogens with better studied respiratory infections may provide further insights into the differential impacts of nonpharmacologic interventions and intersections with environmental conditions. Ultimately, forecasting trends and informing interventions for novel respiratory pathogens like COVID-19 should leverage epidemiologic patterns in the relative burden of past respiratory pathogens as prior information.


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