Laboratory-based efficacy evaluation of Bacillus thuringiensis var. israelensis and temephos larvicides against larvae of Anopheles stephensi in ethiopia

Teshome, Abebe; Erko, Berhanu; Golassa, Lemu; Yohannes, Gedeon; Irish, Seth R.; Zohdy, Sarah; Dugassa, Sisay

doi:10.1186/s12936-023-04475-9

Cited by 13 publications

(3 citation statements)

References 15 publications

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“…stephensi distribution and year of detection, from the MoH, PMI, our field work (10 sites), and other published work ( Fig. 1 ) [ 4 – 6 , 15 – 18 ]. The proportion of An.…”

Section: Methodsmentioning

confidence: 65%

Resurgence of Clinical Malaria in Ethiopia in the Era of Anopheles stephensi Invasion

Zhou,

Taffese,

Zhong

et al. 2024

Preprint

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Background. The invasion of Anopheles stephensi into Africa poses a potential threat to malaria control and elimination on the continent. However, it is not clear if the recent malaria resurgence in Ethiopia has linked to the expansion of An. stephensi. We aimed to summarize the major achievements and lesson learnt in malaria control in Ethiopia from 2001 to 2022, to assess the new challenges and prospects for the control of An. stephensi. Methods and findings. We obtained the clinical malaria case reports, antimalarial drug treatment records, insecticide-treated and long-lasting insecticidal net (ITN/LLIN) distribution and utilization records, and indoor residual spraying (IRS) coverage data from the Ethiopian Ministry of Health (MoH) for the period 2001–2022. We analyzed clinical malaria hotspots using spatially optimized hotspot analysis. We investigated malaria outbreaks in 2022 and examined the potential role of An. stephensi in the outbreaks. Clinical malaria cases in Ethiopia decreased by 80%, from 5.2 million cases (11% confirmed) in 2004 to 1.0 million cases (92% confirmed) in 2018; however, cases increased steadily to 2.6 million confirmed cases (98% confirmed) in 2022. Plasmodium vivax cases and proportion have increased significantly in the past 5 years. Clinical malaria hotspots are concentrated along the western Ethiopian border areas and have grown significantly from 2017 to 2022. Major malaria outbreaks in 2022/23 were detected in multiple sites across Ethiopia, and An. stephensi was the predominant vector in some of these sites, however, it was absence from many of the outbreak sites. Conclusions. The malaria burden has been significantly reduced in Ethiopia in the past two decades, but in recent years it has increased substantially, and the cause of such increase is a subject of further investigation. Major gaps exist in An. stephensi research, including vector ecology, surveillance, and control tools, especially for adult mosquito control.

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“…stephensi distribution and year of detection, from the MoH, PMI, our field work (10 sites), and other published work ( Fig. 1 ) [ 4 – 6 , 15 – 18 ]. The proportion of An.…”

Section: Methodsmentioning

confidence: 65%

Resurgence of Clinical Malaria in Ethiopia in the Era of Anopheles stephensi Invasion

Zhou,

Taffese,

Zhong

et al. 2024

Preprint

View full text Add to dashboard Cite

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“…stephensi resistance studies thus far, collectively con rm the species is resistant to many of the insecticides used to control adult mosquitoes across vast geographic areas. As such, existing malaria adult vector control methods may not be effective and alternative control methods, such as larval source management [1,25] will be needed to manage this invasive species.…”

Section: Discussionmentioning

confidence: 99%

Resistance of Anopheles stephensi to selected insecticides used for indoor residual spray and long-lasting insecticidal impregnated nets in Ethiopia

Teshome¹,

Erko

Golassa

et al. 2023

Preprint

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Background: Malaria, transmitted by the bite of infective female Anopheles mosquitoes, remains a global public health problem. The presence of invasive Anopheles stephensi, capable of transmitting Plasmodium vivax and P. falciparum, was first reported in Ethiopia in 2016. The ecology of this mosquito species differs from that of An. arabiensis, the primary Ethiopian malaria vector [1]. This study aimed to evaluate the efficacy of selected insecticides, which are used in indoor residual spraying (IRS) and selected long-lasting insecticidal treated nets (LLINs) for malaria vector control, against adults An. stephensi. Methods: Anopheles stephensi were collected as larvae and pupae from Awash Subah Kilo Town and Haro Adi village, Ethiopia. Adult female An. stephensi, reared from larvae and pupae collected from the field, aged 3-5 days were exposed to impregnated papers of IRS insecticides (propoxur 0.1%, bendiocarb 0.1%, pirimiphos-methyl 0.25%), and insecticides used in LLINs (alphacyper-methrin 0.05%, deltamethrin 0.05% and permethrin 0.75%), using diagnostic doses and WHO test tubes in a bio-secure insectary at Aklilu Lemma Institute of Pathobiology, Addis Ababa University (AAU-ALIPB). For each test and control tube, batches of 25 female An. stephensi mosquitoes were used to test each insecticide used in IRS. Additionally, cone tests were conducted to expose An. stephensi to four brands of LLINs, MAGNet™ (alpha-cypermethrin), PermaNet® 2.0 (deltamethrin), DuraNet© (alpha-cypermethrin) and SafeNet® (alpha-cypermethrin). A batch of ten sugar fed female mosquitoes aged 2-5 days were exposed to samples taken from five positions/sides of a net. The data from all replicates were pooled and descriptive statistics were used to describe features of the data. Results: All An. stephensi mosquitoes collected from Awash Subah Kilo Town and Haro Adi village (around Metehara) were resistant to all tested insecticides used in both IRS and LLINs. Of the tested LLINs, only MAGNet™ (alpha-cypermethrin active ingredient) caused 100% knockdown and mortality to An. stephensi at 60 minutes and 24 hours post exposure, while all other net brands resulted below the WHO cut- off points. All these nets, except SafeNet®, were collected during LLIN distribution for community members through the National Malaria Program, in December 2020. Conclusions: Anopheles stephensi is resistant to all tested insecticides used in IRS and in the tested LLIN brands, except MAGNet, did not cause in mortality as expected. This suggests that control of this invasive vector using existing adult malaria vector control methods may not be appropriate and that alternative strategies may be necessary.

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“…Following publication of the original article [ 1 ], the authors flagged the following errors: in the subsection ‘Efficacy of Bacillus thuringiensis var. israelensis and temephos against An.…”

mentioning

confidence: 99%

Correction: Laboratory-based efficacy evaluation of Bacillus thuringiensis var. israelensis and temephos larvicides against larvae of Anopheles stephensi in Ethiopia

Teshome,

Erko,

Golassa

et al. 2023

Malar J

Self Cite

View full text Add to dashboard Cite

Laboratory-based efficacy evaluation of Bacillus thuringiensis var. israelensis and temephos larvicides against larvae of Anopheles stephensi in ethiopia

Cited by 13 publications

References 15 publications

Resurgence of Clinical Malaria in Ethiopia in the Era of Anopheles stephensi Invasion

Resurgence of Clinical Malaria in Ethiopia in the Era of Anopheles stephensi Invasion

Resistance of Anopheles stephensi to selected insecticides used for indoor residual spray and long-lasting insecticidal impregnated nets in Ethiopia

Correction: Laboratory-based efficacy evaluation of Bacillus thuringiensis var. israelensis and temephos larvicides against larvae of Anopheles stephensi in Ethiopia

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