Combining indoor residual spraying and insecticide-treated nets for malaria control in Africa: a review of possible outcomes and an outline of suggestions for the future

SummaryAvailable data in Uganda indicate a resurgence of malaria morbidity and mortality countrywide. This study assessed the burden of malaria, treatment and prevention practices in order initiate a policy debate on the scaling-up of current interventions. A triangulation of methods using a cross-sectional survey and key informant interviews was used to assess self-reported malaria at a household level in Mukono District, Uganda. A total of 5583 households were surveyed, and a high proportion (2897, 51·9%) reported a person with malaria two weeks prior to the survey. Only 546 households (9·8%) owned and used insecticide-treated nets (ITNs) for malaria prevention. Similarly, only a few households (86, 1·5%) used indoor residual spraying. Self-treatment with home-stocked drugs was high, yet there was low awareness of the effectiveness of expired drugs on malaria treatment. Self-reported malaria was associated with socioeconomic, behavioural and environmental factors, but more especially with household ownership of ITNs. These results will contribute to the current debate on identifying new approaches for scaling-up prevention interventions and effective case management, as well as selection of priority interventions for malaria control in Uganda.

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Evidence of pyrethroid resistance in Anopheles amharicus and Anopheles arabiensis from Arjo-Didessa irrigation scheme, Ethiopia

PLoS ONE ◽

10.1371/journal.pone.0261713 ◽

2022 ◽

Vol 17 (1) ◽

pp. e0261713

Author(s):

Assalif Demissew ◽

Abebe Animut ◽

Solomon Kibret ◽

Arega Tsegaye ◽

Dawit Hawaria ◽

...

Keyword(s):

Malaria Control ◽

Pyrethroid Resistance ◽

Management Strategies ◽

Resistance Management ◽

Indoor Residual Spraying ◽

Resistance Mechanisms ◽

Malaria Vectors ◽

Insecticide Treated Nets ◽

Irrigation Area ◽

Specific Pcr

Background Indoor residual spraying and insecticide-treated nets are among the key malaria control intervention tools. However, their efficacy is declining due to the development and spread of insecticide resistant vectors. In Ethiopia, several studies reported resistance of An. arabiensis to multiple insecticide classes. However, such data is scarce in irrigated areas of the country where insecticides, pesticides and herbicides are intensively used. Susceptibility of An. gambiae s.l. to existing and new insecticides and resistance mechanisms were assessed in Arjo-Didessa sugarcane plantation area, southwestern Ethiopia. Methods Adult An. gambiae s.l. reared from larval/pupal collections of Arjo-Didessa sugarcane irrigation area and its surrounding were tested for their susceptibility to selected insecticides. Randomly selected An. gambiae s.l. (dead and survived) samples were identified to species using species-specific polymerase chain reaction (PCR) and were further analyzed for the presence of knockdown resistance (kdr) alleles using allele-specific PCR. Results Among the 214 An. gambiae s.l. samples analyzed by PCR, 89% (n = 190) were An. amharicus and 9% (n = 20) were An. arabiensis. Mortality rates of the An. gambiae s.l. exposed to deltamethrin and alphacypermethrin were 85% and 86.8%, respectively. On the other hand, mortalities against pirmiphos-methyl, bendiocarb, propoxur and clothianidin were 100%, 99%, 100% and 100%, respectively. Of those sub-samples (An. amharicus and An. arabiensis) examined for presence of kdr gene, none of them were found to carry the L1014F (West African) allelic mutation. Conclusion Anopheles amharicus and An. arabiensis from Arjo-Didessa sugarcane irrigation area were resistant to pyrethroids which might be synergized by extensive use of agricultural chemicals. Occurrence of pyrethroid resistant malaria vectors could challenge the ongoing malaria control and elimination program in the area unless resistance management strategies are implemented. Given the resistance of An. amharicus to pyrethroids, its behavior and vectorial capacity should be further investigated.

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Assessment of the effect of insecticide-treated nets and indoor residual spraying for malaria control in three rural kebeles of Adami Tulu District, South Central Ethiopia

Malaria Journal ◽

10.1186/1475-2875-11-127 ◽

2012 ◽

Vol 11 (1) ◽

pp. 127 ◽

Cited By ~ 21

Author(s):

Damtew Bekele ◽

Yeshambel Belyhun ◽

Beyene Petros ◽

Wakgari Deressa

Keyword(s):

Malaria Control ◽

Indoor Residual Spraying ◽

Insecticide Treated Nets ◽

Central Ethiopia ◽

South Central

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Upaya Pengendalian Malaria Dalam Rangka Pre-Eliminasi di Kabupaten Garut: Sebuah studi kualitatif

Buletin Penelitian Sistem Kesehatan ◽

10.22435/hsr.v22i4.1761 ◽

2020 ◽

Vol 22 (4) ◽

pp. 255-264

Author(s):

Endang Puji Astuti ◽

Mara Ipa ◽

Aryo Ginanjar ◽

Tri Wahono

Keyword(s):

Malaria Control ◽

Central Government ◽

Indoor Residual Spraying ◽

Control Program ◽

Malaria Vector Control ◽

Insecticide Treated Nets ◽

Malaria Control Program ◽

Program Policy ◽

Depth Interviews ◽

Insecticide Spray

Indonesia is one of the malaria-endemic countries commits to eliminate malaria in 2030. The implementation of malaria control program policy is a determinant to achieve the goal. This research was qualitative that described the implementation of malaria control program policy in Garut Regency, West Java Province. The data collected through in-depth interviews and documents’ review. The implementation of malaria control had referred to guidelines from the Ministry of Health, Republic of Indonesia. This control was also technically adjusted to regional conditions. Case detection of malaria was conducted such as a mass blood survey, rapid diagnostic tests and a microscopic laboratory test both passive and active. The malaria case surveillance has already accomplished. However, the vector was left. The malaria vector control focused on the distribution of insecticide-treated nets and the insecticide spray by the Indoor Residual Spraying (IRS) technique. The analysis indicated that the cross-program cooperation at the central government was well coordinated. However, at the level of the district, this cooperation has to be tightened. Moreover, malaria control budget was still the under district level, so that controlling malaria program did not cover all aspects of the implementation. Abstrak Indonesia sebagai salah satu negara endemis malaria, berkomitmen melakukan eliminasi di tahun 2030. Implementasi kebijakan program pengendalian malaria menjadi determinan keberhasilan eliminasi. Tujuan penelitian ini memberikan gambaran pelaksanaan program pengendalian malaria di Kabupaten Garut, Provinsi Jawa Barat. Pengumpulan data dilakukan dengan wawancara mendalam pada pengelola Program Penanggulangan Malaria serta telaah dokumen dan data dianalisis secara kualitatif. Hasil penelitian menunjukkan bahwa kebijakan pelaksanaan program pengendalian malaria di Kabupaten Garut, Provinsi Jawa Barat sudah merujuk pada pedoman Kementerian Kesehatan RI, secara teknisnya disesuaikan dengan kondisi wilayah. Penemuan penderita dilakukan secara pasif maupun aktif melalui Mass Blood Survey (MBS), dengan pemeriksaan menggunakan Rapid Diagnostic Test (RDT) dan laboratorium secara mikroskopis, Surveilans yang dilakukan oleh Puskesmas hanya terfokus pada surveilans kasus dan belum dilakukan surveilans vektor malaria. Pengendalian vektor malaria yang dilakukan berupa pembagian kelambu dan penyemprotan insektisida dengan metode Indoor Residual Spraying (IRS). Kerjasama lintas program berjalan dengan baik, namun kerjasama lintas sektor terutama pada tingkat kabupaten masih perlu dilakukan dan ditingkatkan. Pembiayaan program pengendalian malaria hanya dari pemerintah daerah dan belum dapat mengakomodir kegiatan pengendalian secara keseluruhan.

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Effectiveness and cost-effectiveness of reactive, targeted indoor residual spraying for malaria control in low-transmission settings: a cluster-randomised, non-inferiority trial in South Africa

The Lancet ◽

10.1016/s0140-6736(21)00251-8 ◽

2021 ◽

Vol 397 (10276) ◽

pp. 816-827 ◽

Cited By ~ 1

Author(s):

David Bath ◽

Jackie Cook ◽

John Govere ◽

Phillemon Mathebula ◽

Natashia Morris ◽

...

Keyword(s):

South Africa ◽

Cost Effectiveness ◽

Malaria Control ◽

Indoor Residual Spraying ◽

Low Transmission ◽

Cluster Randomised

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Impact of seasonality and malaria control interventions on Anopheles density and species composition from three areas of Uganda with differing malaria endemicity

Malaria Journal ◽

10.1186/s12936-021-03675-5 ◽

2021 ◽

Vol 20 (1) ◽

Author(s):

Henry Ddumba Mawejje ◽

Maxwell Kilama ◽

Simon P. Kigozi ◽

Alex K. Musiime ◽

Moses Kamya ◽

...

Keyword(s):

Species Composition ◽

Vector Control ◽

Malaria Control ◽

Mosquito Species ◽

Density Ratio ◽

Indoor Residual Spraying ◽

Sub Saharan Africa ◽

Malaria Vector Control ◽

Vector Density ◽

Llin Distribution

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.

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Addressing key gaps in implementation of mosquito larviciding to accelerate malaria vector control in southern Tanzania: results of a stakeholder engagement process in local district councils

Malaria Journal ◽

10.1186/s12936-021-03661-x ◽

2021 ◽

Vol 20 (1) ◽

Author(s):

Salum A. Mapua ◽

Marceline F. Finda ◽

Ismail H. Nambunga ◽

Betwel J. Msugupakulya ◽

Kusirye Ukio ◽

...

Keyword(s):

Malaria Control ◽

Public Engagement ◽

Indoor Residual Spraying ◽

Malaria Vectors ◽

Malaria Vector Control ◽

Production Plant ◽

Community Members ◽

Key Informants ◽

Larval Source Management ◽

Source Management

Abstract Background Larval source management was historically one of the most effective malaria control methods but is now widely deprioritized in Africa, where insecticide-treated nets (ITNs) and indoor residual spraying (IRS) are preferred. However, in Tanzania, following initial successes in urban Dar-es-Salaam starting early-2000s, the government now encourages larviciding in both rural and urban councils nationwide to complement other efforts; and a biolarvicide production-plant has been established outside the commercial capital. This study investigated key obstacles and opportunities relevant to effective rollout of larviciding for malaria control, with a focus on the meso-endemic region of Morogoro, southern Tanzania. Methods Key-informants were interviewed to assess awareness and perceptions regarding larviciding among designated health officials (malaria focal persons, vector surveillance officers and ward health officers) in nine administrative councils (n = 27). Interviewer-administered questionnaires were used to assess awareness and perceptions of community members in selected areas regarding larviciding (n = 490). Thematic content analysis was done and descriptive statistics used to summarize the findings. Results A majority of malaria control officials had participated in larviciding at least once over the previous three years. A majority of community members had neutral perceptions towards positive aspects of larviciding, but overall support for larviciding was high, although several challenges were expressed, notably: (i) insufficient knowledge for identifying relevant aquatic habitats of malaria vectors and applying larvicides, (ii) inadequate monitoring of programme effectiveness, (iii) limited financing, and (iv) lack of personal protective equipment. Although the key-informants reported sensitizing local communities, most community members were still unaware of larviciding and its potential. Conclusions The larviciding programme was widely supported by both communities and malaria control officials, but there were gaps in technical knowledge, implementation and public engagement. To improve overall impact, it is important to: (i) intensify training efforts, particularly for identifying habitats of important vectors, (ii) adopt standard technical principles for applying larvicides or larval source management, (iii) improve financing for local implementation and (iv) improve public engagement to boost community awareness and participation. These lessons could also be valuable for other malaria endemic areas wishing to deploy larviciding for malaria control or elimination.

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Effectiveness of a national mass distribution campaign of long-lasting insecticide-treated nets and indoor residual spraying on clinical malaria in Malawi, 2018–2020

BMJ Global Health ◽

10.1136/bmjgh-2021-005447 ◽

2021 ◽

Vol 6 (5) ◽

pp. e005447

Author(s):

Hillary M Topazian ◽

Austin Gumbo ◽

Katerina Brandt ◽

Michael Kayange ◽

Jennifer S Smith ◽

...

Keyword(s):

Mass Distribution ◽

Indoor Residual Spraying ◽

Malaria Risk ◽

Bed Nets ◽

Insecticide Treated Nets ◽

District Health ◽

High Transmission ◽

Limited Effectiveness ◽

Mass Distribution Campaign ◽

Distribution Campaign

IntroductionMalawi’s malaria burden is primarily assessed via cross-sectional national household surveys. However, malaria is spatially and temporally heterogenous and no analyses have been performed at a subdistrict level throughout the course of a year. The WHO recommends mass distribution of long-lasting insecticide-treated bed nets (LLINs) every 3 years, but a national longitudinal evaluation has never been conducted in Malawi to determine LLIN effectiveness lifespans.MethodsUsing District Health Information Software 2 (DHIS2) health facility data, available from January 2018 to June 2020, we assessed malaria risk before and after a mass distribution campaign, stratifying by age group and comparing risk differences (RDs) by LLIN type or annual application of indoor residual spraying (IRS).Results711 health facilities contributed 20 962 facility reports over 30 months. After national distribution of 10.7 million LLINs and IRS in limited settings, malaria risk decreased from 25.6 to 16.7 cases per 100 people from 2018 to 2019 high transmission seasons, and rebounded to 23.2 in 2020, resulting in significant RDs of −8.9 in 2019 and −2.4 in 2020 as compared with 2018. Piperonyl butoxide (PBO)-treated LLINs were more effective than pyrethroid-treated LLINs, with adjusted RDs of −2.3 (95% CI −2.7 to −1.9) and −1.5 (95% CI −2.0 to −1.0) comparing 2019 and 2020 high transmission seasons to 2018. Use of IRS sustained protection with adjusted RDs of −1.4 (95% CI −2.0 to −0.9) and −2.8% (95% CI −3.5 to −2.2) relative to pyrethroid-treated LLINs. Overall, 12 of 28 districts (42.9%) experienced increases in malaria risk in from 2018 to 2020.ConclusionLLINs in Malawi have a limited effectiveness lifespan and IRS and PBO-treated LLINs perform better than pyrethroid-treated LLINs, perhaps due to net repurposing and insecticide-resistance. DHIS2 provides a compelling framework in which to examine localised malaria trends and evaluate ongoing interventions.

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