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New malaria risk in Africa

Just as anti-malaria efforts have begun to control the deadly disease in Africa, a new threat from a different type of mosquito has emerged. Here’s what you need to know.

20 September 2022 | By Glynis Horning

According to the latest World Malaria Report, more than 627 000 people died of malaria worldwide in 2020 – mostly children under age 5 in sub-Saharan Africa. 

South Africa has been making great strides since 2010 to eliminate the killer illness, and they were stepped up after the Elimination 8 Malaria Programme to which we belong, along with our neighbours Mozambique, Botswana, Namibia, Angola, Swaziland, Zimbabwe and Zambia).

Cases fell again with the Covid pandemic, but in January this year Dr Jaishree Raman, principal medical scientist at the National Institute for Communicable Diseases (NICD), reported that malaria cases and deaths were on the rise since the relaxation of travel restrictions and increased border movement.

The major transmitter of malaria in South Africa has been the Anopheles funestus mosquito, and more recently the Anopheles arabiensis and Anopheles merus varieties, reports the journal Nature. These mosquitoes occur mostly in rural areas, and they have been effectively controlled by programmes that encourage use of mosquito nets around beds, and by indoor spraying of long-lasting residual insecticides.

This month, however, the NICD warned that another type of mosquito is spreading through Africa: Anopheles stephensi, known as the Asian malaria mosquito because it’s widespread in Southeast Asia and parts of the Arabian Peninsula. It arrived in Djibouti in the Horn of Africa around 2012, and by 2017 had reached Ethiopia, Somalia and Sudan. 

This month Raman and NICD colleague Shuné Oliver report that Anopheles stephensi has not yet been detected in Southern Africa – “nevertheless, the South African national malaria control programme, with the support of the NICD, is increasing surveillance activities in areas where this species may occur”. 

New challenges

The difficulty with controlling the new mosquito, they say, is that it rapidly adapts to changes in the environment, and is found in both rural and urban areas. And it’s difficult to find, particularly in the urban areas where it thrives. It likes being near humans, and lays its eggs on any water source, from puddles to water containers, abandoned tyres and rubbish, and the eggs can survive being dry for long spells. What’s more, this mosquito feeds on its human hosts both indoors and outdoors, reducing the efficacy of control methods such as insecticide-treated nets and indoor residual spraying. 

“The invasion of this urban mosquito into Africa threatens the malaria elimination aspirations of the continent, particularly as 42.5% of Africa’s population now live in urban areas,” Raman and Oliver conclude.

How can you stay safe?

The Asian mosquito requires investing in new control methods that target outdoor-biting mosquitoes, the two say. Governments must also invest in educating communities on appropriate methods for storing water and eliminating potential breeding sources. 

What can you do to help keep yourself, your family and your community safe from this mosquito should it reach here – and from other kinds of Anopheles mosquitoes? 

The key is not to leave water standing, and to take care to remove objects that could collect rainwater (old tyres, tins, pots etc). Spread the word on this to family, friends and community groups.

“If you will be travelling to a malaria risk area in the coming summer months, avoid bites and take malaria prophylaxis (preventative medication),” says Dr Albie de Frey of Travel Doctor. 

Most importantly, know the signs of malaria, and get help early if you suspect you may have it, he says. Symptoms may occur weeks, months and even years after you have been bitten. They include cold shivers, high fever, sweating, headache, nausea, vomiting, diarrhoea, muscle pain, weakness, and finally, jaundice, bleeding, convulsions and coma (‘cerebral malaria’).

It’s easy to mistake these for flu and of late, Covid-19, with fatal results, so if you have been to a malaria risk area at any stage, tell your health practitioner, and insist on being tested, says Dr De Frey. “A single negative malaria test never excludes it – repeat the test within hours if the person is no better or gets worse.”

If you are diagnosed with malaria, it needs to be treated as a medical emergency, he says, and early treatment is essential. “Pregnant women and young children are extremely vulnerable.” 

“Medications must be prescribed by a doctor after consultation as they can’t be acquired without a prescription,” says Clicks pharmacist Waheed Abdurahman.  

IMAGE CREDIT: 123rf.com