Molecular surveillance leads to the first detection of Anopheles stephensi in Kenya.

Ochomo, Eric; Milanoi, Sylvia; Abong’o, Bernard; Onyango, Brenda; Muchoki, Margaret; Omoke, Diana; Olanga, Evelyne; Njoroge, Laban; Juma, Elijah; Otieno, James Dan; Matoke-Muhia, Damaris; Kamau, Luna; Rafferty, Cristina Salazar; Gimnig, John E.; Shieshia, Mildred; Wacira, Daniel; Mwangangi, Joseph; Maia, Marta; Chege, Charles; Omar, Ahmeddin; Rono, Martin K.; Abel, Lucy; Obala, Andrew; O’Meara, Wendy Prudhomme; Mbogo, Charles M.; Kariuki, Lenson

doi:10.21203/rs.3.rs-2498485/v2

Cited by 4 publications

(1 citation statement)

References 24 publications

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“…Tanzania faces biological and other threats that may compromise its progress and prospects to eliminate malaria by 2030 [ 26 ]. Of the biological threats, Tanzania has reported a high prevalence of mosquitoes with resistance to multiple insecticides [ 4 , 27 ], and it is at high risk of the invasive An, stephensi vector, which has been reported in Kenya and the Horn of Africa [ 28 ]. In addition, artemisinin partial resistance (ART-R) has been reported in some parts of Kagera region near the border with Rwandan and Uganda, with an average prevalence of Kelch 13 R561H mutation of 7.7% among symptomatic patients and a high prevalence in Karagwe (22.8%) and Kyerwa district (14.4%) [ 29 , 30 ].…”

Section: Introductionmentioning

confidence: 99%

High prevalence and risk of malaria among asymptomatic individuals from villages with high prevalence of artemisinin partial resistance in Kyerwa district of Kagera region, north-western Tanzania

Mandai,

Francis,

Challe

et al. 2024

Malar J

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Background Although Tanzania adopted and has been implementing effective interventions to control and eventually eliminate malaria, the disease is still a leading public health problem, and the country experiences heterogeneous transmission. Recent studies reported the emergence of parasites with artemisinin partial resistance (ART-R) in Kagera region with high prevalence (> 10.0%) in two districts of Karagwe and Kyerwa. This study assessed the prevalence and predictors/risk of malaria infections among asymptomatic individuals living in a hyperendemic area where ART-R has emerged in Kyerwa District of Kagera region, north-western Tanzania. Methods This was a community-based cross-sectional survey which was conducted in July and August 2023 and involved individuals aged ≥ 6 months from five villages in Kyerwa district. Demographic, anthropometric, clinical, parasitological, type of house inhabited and socio-economic status (SES) data were collected using electronic capture tools run on Open Data Kit (ODK) software. Predictors/risks of malaria infections were determined by univariate and multivariate logistic regression, and the results were presented as crude (cORs) and adjusted odds ratios (aORs), with 95% confidence intervals (CIs). Results Overall, 4454 individuals were tested using rapid diagnostic tests (RDTs), and 1979 (44.4%) had positive results. The prevalence of malaria infections ranged from 14.4% to 68.5% and varied significantly among the villages (p < 0.001). The prevalence and odds of infections were significantly higher in males (aOR = 1.28, 95% CI 1.08 –1.51, p = 0.003), school children (aged 5–≤10 years (aOR = 3.88, 95% CI 3.07–4.91, p < 0.001) and 10–≤15 years (aOR = 4.06, 95% CI 3.22–5.13, p < 0.001)) and among individuals who were not using bed nets (aOR = 1.22, 95% CI 1.03–1.46, p = 0.024). The odds of malaria infections were also higher in individuals with lower SES (aOR = 1.42, 95% CI 1.17–1.72, p < 0.001), and living in houses without windows (aOR = 2.08, 95% CI 1.46–2.96, p < 0.001), partially open (aOR = 1.33, 95% CI 1.11–1.58, p = 0.002) or fully open windows (aOR = 1.30, 95%CI 1.05–1.61, p = 0.015). Conclusion The five villages had a high prevalence of malaria infections and heterogeneity at micro-geographic levels. Groups with higher odds of malaria infections included school children, males, and individuals with low SES, living in poorly constructed houses or non-bed net users. These are important baseline data from an area with high prevalence of parasites with ART-R and will be useful in planning interventions for these groups, and in future studies to monitor the trends and potential spread of such parasites, and in designing a response to ART-R.

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Section: Introductionmentioning

confidence: 99%

High prevalence and risk of malaria among asymptomatic individuals from villages with high prevalence of artemisinin partial resistance in Kyerwa district of Kagera region, north-western Tanzania

Mandai,

Francis,

Challe

et al. 2024

Malar J

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Implications of Climate Change and Anopheles stephensi Liston in Africa: Knowledge Gaps and Lessons from History

Pecor,

Potter,

Linton

2023

Curr Trop Med Rep

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Purpose of Review The invasive Asian mosquito vector—Anopheles stephensi Liston, 1901—is poised to greatly complicate malaria eradication efforts across Africa. This species has been reported in an increasing number of African nations and has the potential to introduce malaria into most of Africa’s largest cities. Climate change is a dominant force changing population dynamics across the continent and driving human populations to migrate to urban centers. Recent Findings This work presents all high-quality surveillance data documenting An. stephensi to date, including an overlooked report of the species collected in Egypt in 1966. Finally, we provide detailed images of adult and larval morphology and bionomics descriptions. Summary Based on our current knowledge of Anopheles stephensi, we explore how climate change may impact its distribution and malaria rates in the coming decades. We also identify key knowledge gaps related to this species invasion including the most up-to-date information on the taxonomy, morphological characters, and bionomics of An. stephensi. Tools that are publicly available via VectorMap are also presented along with guidance on strengthening surveillance programs targeting An. stephensi using these tools.

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Evidence for a role of Anopheles stephensi in the spread of drug- and diagnosis-resistant malaria in Africa

Emiru,

Getachew,

Murphy

et al. 2023

Nat Med

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Anopheles stephensi, an Asian malaria vector, continues to expand across Africa. The vector is now firmly established in urban settings in the Horn of Africa. Its presence in areas where malaria resurged suggested a possible role in causing malaria outbreaks. Here, using a prospective case–control design, we investigated the role of An. stephensi in transmission following a malaria outbreak in Dire Dawa, Ethiopia in April–July 2022. Screening contacts of patients with malaria and febrile controls revealed spatial clustering of Plasmodium falciparum infections around patients with malaria in strong association with the presence of An. stephensi in the household vicinity. Plasmodium sporozoites were detected in these mosquitoes. This outbreak involved clonal propagation of parasites with molecular signatures of artemisinin and diagnostic resistance. To our knowledge, this study provides the strongest evidence so far for a role of An. stephensi in driving an urban malaria outbreak in Africa, highlighting the major public health threat posed by this fast-spreading mosquito.

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Molecular surveillance leads to the first detection of Anopheles stephensi in Kenya.

Cited by 4 publications

References 24 publications

High prevalence and risk of malaria among asymptomatic individuals from villages with high prevalence of artemisinin partial resistance in Kyerwa district of Kagera region, north-western Tanzania

High prevalence and risk of malaria among asymptomatic individuals from villages with high prevalence of artemisinin partial resistance in Kyerwa district of Kagera region, north-western Tanzania

Implications of Climate Change and Anopheles stephensi Liston in Africa: Knowledge Gaps and Lessons from History

Evidence for a role of Anopheles stephensi in the spread of drug- and diagnosis-resistant malaria in Africa

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