Malaria is an infective disease caused by sporozoan parasites that are transmitted through the bite of an infected tiny flying insect vector – mosquito; it is marked … … by paroxysms of chills and fever. As the world marks World Malaria Day this April 25, Editor MORGAN NWANGUMA examines the extent of the war against a life-threatening but preventable disease that continues to ravage most of the tropics, and to a lesser extent the Middle East and even parts of Europe.
World Malaria Day takes place on 25 April each year; it is an internationally recognised day, to highlight the global efforts to control malaria and celebrating the gains that have been made by those in some endemic countries. Malaria is clearly a life-threatening disease caused by parasites that are transmitted to people through the bites of infected female Anopheles mosquitoes. Good news is that it is both preventable and curable.
The Malaria Burden
In 2016, there were an estimated 216 million cases of malaria in 91 countries, an increase of 5 million cases over 2015. Available data from the World Health Organisation (WHO) also has it that malaria deaths reached 445 000 in 2016, a similar number (446 000) to that of 2015. Meanwhile the African Region according to the world body carries an excessively high share of the global malaria burden. In 2016, the region was home to 90% of malaria cases and 91% of malaria deaths.
Total funding for malaria control and elimination reached an estimated US$ 2.7 billion in 2016. Contributions from governments of endemic countries amounted to US$ 800 million, representing 31% of funding. Malaria is caused by Plasmodium parasites which are spread to people through the bites of infected female Anopheles mosquitoes. There are 5 parasite species that cause malaria in humans, and 2 of these species are, P. falciparum and P. vivax which constitute the biggest health risk of them all.
P. falciparum is the most prevalent malaria parasite on the African continent. It is also the cause of most malaria-related deaths all over the world. P. vivax is the dominant malaria parasite in most countries outside of sub-Saharan Africa.
Signs and Symptoms of Malaria
Malaria is an acute febrile illness. In a non-immune individual, symptoms usually appear 10–15 days after the infective mosquito bite. The first symptoms which are fever, headache, and chills – may be mild and difficult to recognise as malaria. If not treated within 24 hours, experts say P. falciparum malaria can progress to severe illness, and sometimes even leading to death.
Children with severe malaria frequently develop one or more of the following symptoms: severe anaemia, respiratory distress in relation to metabolic acidosis, or cerebral malaria. In adults, multi-organ involvement is also frequent. In malaria endemic areas, people may develop partial immunity, allowing asymptomatic infections to occur.
Malaria Prevention Measures
Vector control is the main way to prevent and reduce malaria transmission. If coverage of vector control interventions within a specific area is high enough, then a measure of protection will be conferred across the community. The World Health Organisation (WHO) recommends protection for all people at risk of malaria with effective malaria vector control. Two forms of vector control that have been effective in a wide range of circumstances include insecticide-treated mosquito nets and indoor residual spraying.
Insecticide-treated mosquito nets
Long-lasting insecticidal nets (LLINs) are the preferred form of insecticide-treated mosquito nets (ITNs) for public health programmes. In most settings, the world body recommends LLIN coverage for all people at risk of malaria. The most cost-effective way to achieve this is by providing LLINs free of charge, to ensure equal access for all. In parallel, effective behaviour change communication strategies are required to ensure that all people at risk of malaria sleep under a LLIN every night, and that the net is properly maintained.
Indoor spraying with residual insecticides
Indoor residual spraying (IRS) with insecticides is a powerful way to rapidly reduce malaria transmission. Its potential is realised when at least 80% of houses in targeted areas are sprayed. Indoor spraying is effective for 3–6 months, depending on the insecticide formulation used and the type of surface on which it is sprayed. In some settings, multiple spray rounds are needed to protect the population for the entire malaria season.
Antimalarial medicines can also be used to prevent malaria. For travellers, experts recommend preventive measures through chemoprophylaxis, which suppresses the blood stage of malaria infections, thereby forestalling malaria disease. For pregnant women living in moderate-to-high transmission areas, WHO recommends intermittent preventive treatment with sulfadoxine-pyrimethamine, at each scheduled antenatal visit after the first trimester. Similarly, for infants living in high-transmission areas of Africa, 3 doses of intermittent preventive treatment with sulfadoxine-pyrimethamine are recommended, delivered alongside routine vaccinations.
In 2012, WHO recommended Seasonal Malaria Chemoprevention as an additional malaria prevention strategy for areas of the Sahel sub-region of Africa. The strategy involves the administration of monthly courses of amodiaquine plus sulfadoxine-pyrimethamine to all children less than 5 years of age – during the high transmission season.
Other Methods of Prevention
Community participation and health education strategies promoting awareness of malaria and the importance of control measures have been successfully used to reduce the incidence of malaria in some areas of the developing world. Recognising the disease in the early stages can prevent the disease from becoming fatal. Education can also inform people to cover over areas of stagnant, still water, such as water tanks that are ideal breeding grounds for the parasite and mosquito, thus cutting down the risk of the transmission between people.
This is generally used in urban areas where there are large centres of population in a confined space, and where transmission would be most likely. Intermittent preventive therapy is another intervention that has been used successfully to control malaria in pregnant women, infants, and in preschool children where transmission is seasonal.
The primary objective of treatment is to ensure complete cure, that is, the rapid and full elimination of the Plasmodium parasite from the patient’s blood, in order to prevent progression of uncomplicated malaria to severe disease or death, and to chronic infection that leads to malaria-related anaemia. From a public health perspective, treatment is meant to reduce transmission of the infection to others, by reducing the infectious reservoir and by preventing the emergence and spread of resistance to antimalarial medicines. The Current WHO-recommended first-line treatment for the majority of malaria cases is artemisinin-based combination therapy (ACT). These medicines, in addition to diagnostics, are available to treat, and in some cases prevent the disease.
World Malaria Day – 2018
World Malaria Day is an occasion to highlight the need for continued investment and sustained political commitment for malaria prevention and control. In 2016 the theme for the celebrations was ‘End Malaria for Good’. Due to the great progress made under the Millennium Development Goals, it became important to build on this success so as to ‘end malaria for good’ under the Sustainable Development Goals. And so, the campaign continues to this day on the same note, as it were.
In pushing for prevention therefore, this year’s global theme for World Malaria Day remains ‘End Malaria for Good’. In the lead-up to 25 April, the World Health Organisation is drawing our attention towards prevention, which is a vital approach for winning the war against a disease that continues to kill more than 400 000 people each year. Since the year 2000, malaria prevention programmes have played an important role in reducing cases and deaths, primarily through the scale up of insecticide-treated nets and indoor spraying with insecticides.
Across sub-Saharan Africa, where the disease is heavily concentrated, a greater share of the population is sleeping under insecticide-treated nets. In 2015, an estimated 53% of the population at risk slept under a treated net compared to 30% in 2010. In 20 African countries, preventive treatment for pregnant women increased five-fold between 2010 and 2015.
But this is still not enough for us; there is need to speed up the rate of progress. And so, the Global Technical Strategy for Malaria of WHO has called for a 40% reduction in malaria cases and deaths by 2020, compared to 2015 baseline levels. As it is, only about 40 of the world’s 91 countries with malaria transmission are working assiduously to attain these feats. This is unlike in many low-income countries with a high malaria burden where progress has been slow.
In its bid to hasten progress in reaching these global targets, the world body is calling on malaria-affected countries and their development partners to increase investments in malaria prevention. Similarly, the Organisation calls out for greater funding for the development, evaluation and deployment of new tools.
With all these put together, affected countries will be motivated to action towards eliminating the scourge while also contributing to other Sustainable Development Goals, such as improving maternal and child health. WHO is therefore confident that given the necessary resources, with the cooperation of all partners, we can truly End Malaria for Good.