Mosquito that transmits malaria has been detected for the first time in Ethiopia. The study led by a Baylor University researcher says that the discovery points towards more people being put at risk for malaria in new regions.
The mosquito, Anopheles stephensi, is normally found in the Middle East, Indian Subcontinent and China. Earlier research had shown that more than 68 per cent of Ethiopia’s population is at risk for malaria with an average of 2.5 million cases reported annually, according to the World Malaria Report of 2017.
Speaking about it, lead researcher Tamar Carter, Ph.D said, “From a public health standpoint, or that mosquito populations are increasing where they were once were scarce.” She further added, “If these mosquitoes carry malaria, we may see an emergence of malaria in new regions.”
The study, ‘First detection of Anopheles stephensi Liston, 1901 (Diptera: culicidae) in Ethiopia using molecular and morphological approaches’ — published in Acta Tropica, an international journal on infectious diseases added that more studies are needed to determine how effective Anopheles stephensi is in delivering a single-celled parasite that can trigger different forms of malaria.
Speaking about it, Carter said, “We also need to investigate how the Anopheles stephensi got to Ethiopia and other parts of the Horn of Africa. The question I am particularly interested in is if Anopheles stephensi is a relatively recent introduction or something that has been flying under the radar in Ethiopia for a long time.”
She further added that clarifying it will help guide better mosquito control efforts in Ethiopia. Carter said, “We plan to use genomic techniques to study the history of Anopheles stephensi in Ethiopia. More research is needed on the feeding and breeding behaviour of the Ethiopian Anopheles stephensi, and how well it responds to insecticides, to determine best ways to control the mosquito population.”
The study says if Anopheles stephensi’s propensity for feeding indoors is observed in Ethiopia, different malaria control strategies may need to be implemented, such as insecticide-treated bed nets and indoor residual insecticide spraying.
The study saw researchers from Jigjiga University in Ethiopia, led by co-first-author Solomon Yared of Jihjiga collect mosquito larvae and pupae from water reservoirs in Kabri Dehar, an eastern Ethiopian city with a population of 1.3 million throughout November and December.
These larvae were reared to adulthood and subsequent review of the morphological data confirmed findings from the genetic analysis.
The highest levels of malaria transmission are observed in the north, west and eastern lowland of Ethiopia, according to the research article. Malaria transmission exhibits a seasonal and unstable pattern there, varying with altitude and rainfall.
To date, 44 species and subspecies of anopheline mosquitoes have been documented in Ethiopia, with the predominant malaria type being Anopheles arabiensis. According to Carter, to gain better insight into the geographic range of Anopheles stephensi, the next step is to conduct mosquito surveys in multiple locations throughout Ethiopia.
Researchers believe the effort should centre on the eastern portion, where they said information on malaria vectors in general is scarce. They said both rural and urban surveys are needed, particularly to investigate the role that livestock presence plays in Anopheles stephensi abundance.