In March 2012, the World Health Organisation (WHO) issued a policy recommendation for a new intervention against Plasmodium falciparum malaria - seasonal malaria chemoprevention (SMC), previously referred to as intermittent preventive treatment in children (IPTc), in children under five years old. SMC is defined as the intermittent administration of full treatment courses of an anti-malarial treatment combination during the malaria season to prevent illness and death from the disease.
The objective is to maintain therapeutic anti-malarial drug concentrations in the blood throughout the period of greatest risk. This will reduce the incidence of both simple and severe malaria disease and the associated anaemia and result in healthier, stronger children able to develop and grow without the interruption of disease episodes. SMC has been shown to be effective, cost effective and feasible for the prevention of malaria among children in areas where the malaria transmission season is no longer than four months.
A review of trials that evaluated the impact of SMC in preventing malaria in pre-school children living in endemic areas with seasonal transmission showed that SMC prevented approximately three quarters of all clinical malaria episodes and a similar proportion of severe malaria episodes, and that these benefits remained even where insecticide treated net usage is high. Other studies have also showed the beneficial additive effect of SMC given during the transmission season alongside other malaria control interventions such as the distribution and promotion of use of LLINs. Although the effectiveness and safety of SMC using amodiaquine and sulphadoxine/pyrimethamine has been proved in clinical trials, there is no established delivery system.
Malaria transmission in Nigeria
Nigeria is made up of six geopolitical zones and 37 states including the Federal Capital Territory. Nigeria has a tropical climate with wet and dry seasons. The dry season occurs from October to March and the wet season between April and September. There is a period of cooler weather accompanied by the dry, dusty Harmattan wind, felt mostly in the north in December and January. The temperature in Nigeria varies between 25°C and 40°C, and rainfall ranges from 2,650 millimetres in the southeast to less than 600 millimetres in some parts of the north, mainly on the fringes of the Sahara Desert. The ecology of Nigeria varies from the mangrove swamps and tropical rain forest belts in the coastal areas through to open woodland and savannah on the low plateau, which extends through much of the central part of the country to the semi-arid plains and Sahel grassland in the north and the highlands to the east.
The geographic location of Nigeria makes the climate suitable for malaria transmission throughout the country. It is estimated that up to 97 percent of the country’s more than 150 million people risk getting the disease. The remaining three percent of the population who live in the mountains in southern Jos (the Plateau State), at an altitude ranging from 1,200 to 1,400 metres, are at relatively low risk for malaria.
The seasonality, intensity and duration of the malaria transmission season vary according to the five ecological strata that extend from the south to the north. These include: mangrove swamps, rain forest, guinea-savannah, Sudan-savannah and Sahel-savannah. The duration of malaria transmission is longer in the south and reduces as one moves north (see map), being perennial in duration in most of the south, but lasting three months or less in the northeast region bordering Chad.
The dominant vector species in Nigeria are the Anopheles gambiae species and the A. funestus group. The most prevalent species of malaria parasites in Nigeria is Plasmodium falciparum (over 95 percent). It is responsible for the most severe forms of the disease. The other types found in the country, Plasmodium ovale and Plasmodium malariae, play a minor role. Plasmodium malariae tends to only occur in children with mixed infections.
Seasonal Malaria Chemoprevention in Nigeria
The areas of northern Nigeria where malaria transmission lasts less than four months present an opportunity for those at risk to benefit from the implementation of SMC. Whereas the feasibility and effectiveness of SMC has been demonstrated elsewhere, the approaches to implementation, which require high coverage levels, have to be contextualised to fit the local setting. Thus there is a need to explore possible approaches in the Nigerian context that will provide effective delivery systems for the eventual scaling up of the intervention to cover areas in northern Nigeria with highly seasonal malaria transmission.
What Malaria Consortium is doing
Malaria Consortium has already started working with the Ministry of Health to roll out SMC in Katsina through its management of SuNMaP (the DFID-funded Support for the National Malaria Programme) and with support from the Bill & Melinda Gates Foundation. SuNMaP will also support the roll out of SMC across Jigawa state and Malaria Consortium has plans to extend the activity to additional states in due course.
Project brief - Seaonal malaria chemoprevention in Katsina, Nigeria, Malaria Consortium
Technical brief - Seasonal malaria chemoprevention
Technical brief - Chimioprévention du paludisme saisonnier