Net gains on malaria prevention threatened by climate change

Joseph Okanga/Reuters

Cradling her week-old son at a neonatal clinic in Nairobi’s sprawling Eastlands estate, where a steady throb from the stereos of battered public minibuses echoes through the streets, new mother Mary Onyango is a picture of concentration.

She watches the nurse carefully explain how to use a mosquito net properly, and listens intently when the importance of covering sleeping children is explained.

Over the past decade and a half, the level of infant mortality in Kenya has dropped at one of the fastest rates recorded anywhere in the world. The fall has attracted the attention of development scholars and researchers, andinspired gushing headlines in publications such as the Economist, which called the decline in child mortality rates in Africa “the best story in development”.

In Kenya, child mortality fell by about 8% annually from 2005 on, with infant mortality declining from 52 deaths for every 1,000 live births in 2008/9 to 39 in 1,000 in 2014. The under-five mortality rate fell from 74 deaths for every 1,000 live births in 2008/9 to 52 deaths for every 1,000 live births in 2014.

A World Bank study attributes the continued decline in infant mortality partly to an aggressive mosquito net distribution programme, which resulted in an increase in the use of treated bednets from 8% of all households in 2003 to 60% in 2008.

Dr Francis Kimani, head of the malaria unit at the Kenya Medical Research Institute, says that while progress has been made the scale of the burden means the disease remains a long-term problem.

“We can celebrate the fact that we have reversed the upward trend in malaria incidences but in terms of absolute numbers the burden is still high. The key challenge is in sustaining the downward trend and improving control measures such as expanding net use, taking care of pregnant mothers and doing away with anaemia in children which can help steer us eventually towards a future without malaria.”

About three-quarters of Kenyans live in areas where they are exposed to malaria risk. The disease accounts for 30–50% of all outpatient attendance and a fifth of all admissions to health facilities.

The economic toll of the disease is considerable, with researchers estimating 170 million working days are lost because of malaria each year. The UN’s millennium development goals set a 2015 deadline for reducing the global malaria burden by 75%, and reversing the global spread of the disease.

But in Kenya and elsewhere in Africa, as well as good news, there is a worrying new challenge: climate change. Rising temperatures have opened the door to the spread of mosquitoes to areas in which they were barely a threat two decades ago.

Mosquitoes are notoriously adaptable creatures, constantly developing resistance to insecticides, while the malaria parasite evolves to resist drugs.

Dr Andrew Githeko, one of the leading malaria researchers in Kenya, says the spread of mosquitoes to the traditionally cooler highlands, where previously there were low levels of malaria, was a major problem.

“We started noticing this phenomenon in the late 80s and early 90s, with hikes of unusually warm and wet weather in many parts of the country consistent with global warming. The phenomenon peaked with the El Nino rains seen in the early 1990s, and then we witnessed sudden epidemics of highland malaria, which is a particularly severe form considering that the people in those areas will not have developed natural immunity.”

Githeko says Africa needs to take steps to deal with this fresh challenge and continue to roll back malaria.

Such measures include improving house construction methods by, for example, using screens to stop mosquitoes and building a good distance from marshlands. These techniques have been successfully deployed in countries ranging from Italy to the US.

Enhanced research to tackle resistance to insecticides and treatment is also key, he says, although he points out trends are broadly positive.

“We can’t be disheartened. When I started research work in 1986, I was astonished to find eight in 10 children had malaria and were consequently anaemic. We used to lose a lot of mothers. The real effort started in 2000 with the distribution of bednets, and things are completely different now. You can just see the children are so much happier and buoyant in the schools now than used to be the case in the past.”

Another challenge for Kenya is the lack of general knowledge about how to tackle malaria and over-dependence on donors for health sector funding.

Spreading information to young mothers like Onyango remains key to reducing transmission levels, because they are at the frontline in tackling the deadly parasite.

“We can spend too much time distributing nets but we need to ensure they are actually used at rates of 80% and above,” says Dr Waqo Ejersa, head of the malaria control unit at Kenya’s ministry of health. “Investing in behavioural change communication, including interpersonal communication is really important because prevention is essential.”



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