Anopheles stephensi is typically found in India and the Persian Gulf but has made its way to several African countries. This invasive species is believed to be connected to a recent surge in malaria in Djibouti, prompting efforts by the World Health Organization to prevent its further spread in Africa.
Malaria scientist Fitsum Tadesse presented his research at a meeting of the American Society of Tropical Medicine in Seattle, suggesting that these invasive mosquitoes were also responsible for the outbreak in Ethiopia.
In January, health officials in Dire Dawa, a major transportation hub, reported a rapid rise in malaria cases. Tadesse and his team investigated the situation, tracking over 200 malaria cases, examining mosquito breeding sites, and testing invasive mosquitoes for the malaria parasite.
Their findings revealed that the invasive mosquitoes were "strongly linked" to the outbreak. This discovery is concerning because these mosquitoes are different from native species found in Africa, as they can thrive in urban environments and areas with artificial containers where native mosquitoes do not breed.
According to experts, if these invasive mosquitoes establish themselves in Africa, it could pose a significant threat. Traditional mosquito-control measures in Africa, such as bed nets and indoor spraying, may not be effective against these mosquitoes, as they tend to bite people outdoors.
However, due to limited surveillance, scientists are uncertain about the extent of the invasive mosquito population and their contribution to malaria cases in Africa.
Longer rainy seasons and the conflict in northern Ethiopia, which has diverted resources away from malaria control, have contributed to the rise in malaria cases in the country. This situation has raised concerns among experts, as it threatens to reverse the significant progress Ethiopia had made in reducing malaria cases.
In response, experts suggest that African communities may need to consider measures used in India to combat these invasive mosquitoes, such as introducing mosquito larvae-eating fish or regulating containers with standing water. The challenge of slowing progress against malaria further complicates efforts to combat this parasitic disease, which claims the lives of over 600,000 people each year, primarily in Africa.
Anne Wilson, an infectious diseases expert, emphasizes that the impact of new tools like pesticides and vaccines is being closely monitored, but the proliferation of this invasive mosquito species may leave little time to address the problem.