Geographical distribution of Anopheles stephensi in eastern Ethiopia

Balkew, Meshesha; Mumba, Peter; Dengela, Dereje; Yohannes, Gedeon; Getachew, Dejene; Yared, Solomon; Chibsa, Sheleme; Murphy, Matthew; George, Kristen; López, Karen; Janies, Daniel; Choi, Sae Hee; Spear, Joseph; Irish, Seth R.; Carter, Tamar E.

doi:10.1186/s13071-020-3904-y

Cited by 99 publications

(141 citation statements)

References 16 publications

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“…stephensi are also found in African populations), allowing it to avoid capture using typical African mosquito survey methods. Indeed, Balkew et al (17) comment that they captured few An. stephensi in their Centers for Disease Control and Prevention (CDC) light traps, and this is a method of survey often applied in Ethiopia.…”

Section: Significancementioning

confidence: 99%

A new malaria vector in Africa: Predicting the expansion range of Anopheles stephensi and identifying the urban populations at risk

Sinka

Pironon

Massey

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

234

197

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In 2012, an unusual outbreak of urban malaria was reported from Djibouti City in the Horn of Africa and increasingly severe outbreaks have been reported annually ever since. Subsequent investigations discovered the presence of an Asian mosquito species; Anopheles stephensi, a species known to thrive in urban environments. Since that first report, An. stephensi has been identified in Ethiopia and Sudan, and this worrying development has prompted the World Health Organization (WHO) to publish a vector alert calling for active mosquito surveillance in the region. Using an up-to-date database of published locational records for An. stephensi across its full range (Asia, Arabian Peninsula, Horn of Africa) and a set of spatial models that identify the environmental conditions that characterize a species’ preferred habitat, we provide evidence-based maps predicting the possible locations across Africa where An. stephensi could establish if allowed to spread unchecked. Unsurprisingly, due to this species’ close association with man-made habitats, our maps predict a high probability of presence within many urban cities across Africa where our estimates suggest that over 126 million people reside. Our results strongly support the WHO’s call for surveillance and targeted vector control and provide a basis for the prioritization of surveillance.

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Section: Significancementioning

confidence: 99%

A new malaria vector in Africa: Predicting the expansion range of Anopheles stephensi and identifying the urban populations at risk

Sinka

Pironon

Massey

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

234

197

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“…The current presence and the possible spread of An. stephensi to African countries poses a potential health risk since it is a malaria vector well adapted to urban centers and it could cause malaria outbreaks of unprecedented sizes (Balkew et al, 2019;Takken and Lindsay, 2019). Our model indicates that the breadth of temperature range for An.…”

Section: Discussionmentioning

confidence: 90%

“…stephensi is a native mosquito of Asia (Sinka et al, 2010), recent research has reported that An. stephensi mosquitoes are already present in Africa, for example in Djibouti (Faulde et al, 2014), Ethiopia (Balkew et al, 2019;Carter et al, 2018), Sudan, and probably in neighboring countries (Takken and Lindsay, 2019;World Health Organization, 2019). The current presence and the possible spread of An.…”

Section: Discussionmentioning

confidence: 99%

Temperature impacts the transmission of malaria parasites byAnopheles gambiaeandAnopheles stephensimosquitoes

Villena

Ryan

Murdock

et al. 2020

Preprint

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Transmission of malaria and other vector-borne diseases (VBDs) is greatly influenced by environmental factors, especially temperature, due to the ectothermic nature of insect and arthropod vectors. However, the response of transmission to temperature and other drivers is complex, as thermal traits of ectotherms are typically non-linear, and they interact to determine transmission constraints. In this study, we assess and compare the effect of temperature on the transmission of two malaria parasites, Plasmodium falciparum and Plasmodium vivax, by two malaria vector species, Anopheles gambiae and Anopheles stephensi. We model the non-linear responses of temperature dependent mosquito and parasite traits (mosquito development rate, bite rate, fecundity, egg to adult survival, vector competence, mortality rate, and parasite development rate) and incorporate these traits into a suitability metric based on a model for the basic reproductive number across temperatures. Our model predicts that the optimum temperature for transmission suitability is similar for the four mosquito-parasite combinations assessed in this study. The main differences are found at the thermal limits. More specifically, we found significant differences in the upper thermal limit between parasites spread by the same mosquito (An. stephensi) and between mosquitoes carrying P. falciparum. In contrast, at the lower thermal limit the significant differences were primarily between the mosquito species that both carried the same pathogen (e.g., An. stephensi and An. gambiae both with P. falciparum). Using prevalence data from Africa and Asia, we show that the transmission suitability metric S(T) calculated from our mechanistic model is an important predictor of malaria prevalence. We mapped risk to illustrate the areas in Africa and Asia that are suitable for malaria transmission year-round based temperature. The wider thermal range of transmission by An. stephensi for both malaria parasites allows for a greater geographic potential for malaria spread. This study could be useful in planing preventive strategies for areas where malaria outbreaks might occur.

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“…More recently, it spread into the Horn of Africa where it was reported in Djibouti city in 2013 [13] and Ethiopia in 2016 [14]. The recent emergence in the Republic of Sudan [15] and more widespread sites in Ethiopia [19] in 2019 suggests the species has the potential to become a widespread African malaria vector. Our data demonstrate that An.…”

Section: Discussionmentioning

confidence: 99%

“…Entomological surveys conducted in 2018 detected the occurrence of An. stephensi in Awash Sebat Kilo town [19].…”

Section: Methodsmentioning

confidence: 99%

Anopheles stephensias an emerging malaria vector in the Horn of Africa with high susceptibility to EthiopianPlasmodium vivaxandPlasmodium falciparumisolates

Ashine

Teka

Esayas

et al. 2020

Preprint

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Anopheles stephensi, an efficient Asian malaria vector, recently spread into the Horn of Africa and may increase malaria receptivity in African urban areas. We assessed occurrence, genetic complexity, blood meal source and infection status of An. stephensi in Awash Sebat Kilo town, Ethiopia. We used membrane feeding assays to assess competence of local An. stephensi to P. vivax and P. falciparum isolates from clinical patients. 75.3% of the examined waterbodies were infested with An. stephensi developmental stages that were genetically closely related to isolates from Djibouti and Pakistan. Both P. vivax and P. falciparum were detected in wild-caught adult An. stephensi. Local An. stephensi was more receptive to P. vivax compared to a colony of An. arabiensis. We conclude that An. stephensi is an established vector in this part of Ethiopia, highly permissive for local P. vivax and P. falciparum isolates and presents an important new challenge for malaria control.Summary of the articleAn. stephensi, a metropolitan malaria vector that recently expanded to the Horn of African, was highly susceptible to local P. falciparum and P. vivax isolates from Ethiopia and may increase malariogenic potential of rapidly expanding urban settings in Africa.

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Geographical distribution of Anopheles stephensi in eastern Ethiopia

Cited by 99 publications

References 16 publications

A new malaria vector in Africa: Predicting the expansion range of Anopheles stephensi and identifying the urban populations at risk

A new malaria vector in Africa: Predicting the expansion range of Anopheles stephensi and identifying the urban populations at risk

Temperature impacts the transmission of malaria parasites byAnopheles gambiaeandAnopheles stephensimosquitoes

Anopheles stephensias an emerging malaria vector in the Horn of Africa with high susceptibility to EthiopianPlasmodium vivaxandPlasmodium falciparumisolates

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