Malaria: Anopheles stephensi, the mosquito from Asia that threatens Africa

In Asia, Anopheles stephensi is the main vector of malaria in urban areas.

James Gathany / CDC via AP

Text by: RFI Follow

4 min

Already established in the city of Djibouti a few years ago, a mosquito native to Asia and well adapted to the urban environment has been spotted in Ethiopia and Sudan.

Its geographical area could extend further into Africa, exposing 126 million people living in urban areas to the risk of malaria, according to a study published on September 14 in the scientific journal PNAS. 

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Anopheles stephensi

.

Such is the name of this species of mosquito widespread in Asia and which, more recently, also took up residence in the Horn of Africa.

Until 2011, it was rife in some countries in Southeast Asia, the Indian subcontinent and the Middle East.

It has since been reported in Djibouti in 2012, Ethiopia (2016) and Sudan (2019).

The expansion of this insect vector of malaria raises concern.

While Djibouti had not been confronted with an epidemic of malaria since 1999, here it is that from 2012, the capital had to deal with increasingly important outbreaks of cases.

An alert for the rest of the continent, because as indicated by a study published in the journal Proceedings of the National Academy of Sciences (PNAS), this mosquito has the " 

 ", unlike other vectors main causes of malaria, which prefer rural and peri-urban areas, such as the species

, dominant in Africa. 

Eggs in water tanks

In Asia,

is the main vector of malaria in urban areas.

" 

 ", specifies Carlo Costantini, entomologist researcher at the Institute for Research for Development (IRD).

“ 

 ”.

For

for example, it is the puddles of rain that act as breeding places.

Those of the cities are too dirty or polluted for this species, even if it seems little by little to adapt to it.

The

mosquito

is also distinguished by its behavior towards its hosts.

It stings at dusk, most often outdoors, unlike

, which stings in the middle of the night, usually indoors.

If

colonized African cities, " 

 ", points out Carlo Costantini. 

126 million inhabitants threatened

There is great fear to see this city mosquito gain ground in Africa.

The authors of the study published in PNAS mapped the places where it could be established, via a model taking into account different parameters (temperature, precipitation etc.) Result: out of 68 African cities with more than one million inhabitants , 44 cities would be highly adapted to the insect - like Mombasa in Kenya or Lagos in Nigeria.

126 million people who are today spared the risk of contracting malaria could be exposed.

For the World Health Organization, the spread of this mosquito is " 

 ", while the burden of the disease is already very heavy: 400,000 people die from it each year. on the continent. 

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