Urban Mosquito Epidemic Fuels Malaria Surge in East Africa: Causes and Solutions

A new mosquito species, Anopheles stephensi, is spreading in East Africa. This mosquito thrives in cities and resists many insecticides. Experts warn this could lead to a serious increase in malaria cases, reversing progress made against the disease.

In 2022, Africa reported about 95% of the world’s 249 million malaria cases and 608,000 deaths. Children under five made up 80% of these deaths.

Anopheles stephensi first appeared in Djibouti in 2012. Although Djibouti had almost eliminated malaria, the disease returned, with over 70,000 cases in 2020. The mosquito spread to Ethiopia, where malaria cases surged from 4.1 million cases and 527 deaths late last year to 7.3 million cases and 1,157 deaths by October 2024.

This new mosquito breeds year-round in urban environments, using artificial water sources like tanks and gutters. It bites earlier than other mosquitoes, making bed nets less effective.

Meera Venkatesan, the malaria division chief for USAID, says this invasion could disrupt malaria control efforts in Africa.

There are concerns that stephensi could invade large cities like Mombasa in Kenya and Khartoum in Sudan. One study from 2020 warned it might reach up to 126 million people living in urban areas across Africa.

In a recent turn of events, Egypt declared itself malaria-free, but this status could be at risk with the arrival of Anopheles stephensi.

Although confirmed in Kenya since late 2022, stephensi has not reached cooler high-altitude areas like Nairobi yet. Research on its biology and behavior is lacking, and experts emphasize the need for further studies.

Stephensi’s spread could coincide with rising drug-resistant malaria cases reported in Uganda, Rwanda, Tanzania, and Eritrea. Dorothy Achu from WHO warns of imminent resistance developing.

WHO is working with African nations to address treatment options. However, new malaria variants also challenge existing diagnostic tests.

Increased transmission could further complicate the spread of drug resistance and new mutations in malaria parasites. Coordination among African governments is poor, according to Achu.

Mbogo from the Pan-African Mosquito Control Association emphasizes the need for cross-border cooperation and data-sharing among scientists and countries to effectively combat malaria’s rising threat.