In areas of Africa where malaria is only a problem during a short rainy season, monthly courses of antimalarial drugs can provide very effective prevention of malaria in children. This approach, called intermittent preventive treatment in children (IPTc) but now known as Seasonal Malaria Chemoprevention (SMC), may also be useful in large areas of Africa where malaria is transmitted for longer each year. It is uncertain if IPTc would be effective, acceptable to communities or sustainable when delivered over a longer period, but this is an important public health question of key interest to policy makers, because in areas with a longer transmission season, the burden of malaria is typically higher than in highly seasonal areas.

Another form of prevention that would be operationally easier for African countries to put into practice would be to treat malaria patients with long-lasting antimalarials, which protect children against further malaria episodes for several weeks. Because malaria disproportionately affects certain high risk children more than others, causing repeated attacks of fever and leading to severe anaemia, long-acting drugs may be a simple and effective way to target limited resources at the individuals who most need protection. This may be particularly beneficial where malaria is a seasonal problem, because repeated malaria attacks will not only be borne by a few unfortunate children, but will also occur close together in time.

The investigators propose a clinical trial to evaluate these two forms of chemoprevention in Kumasi, Ghana, an area with an extended malaria transmission season. Children under 5 years of age currently have access to diagnosis and treatment of malaria via by community based health workers. Children enrolled in the study will receive either the standard community-based diagnosis and treatment, treatment with a longer-acting artemisinin combination therapy (ACT), or standard care plus five monthly courses of seasonal malaria chemoprevention (SMC) during the peak in transmission.

Inclusion Criteria:

• Children aged between 3-59 months
• Care giver or parent willing to participate and have given informed consent
• Children living in the study area

Exclusion Criteria:

• Children who are unable to take and retain medication
• Children who have a severe or chronic illness
• Children who have a history of serious adverse reaction to the study drugs