Malaria Transmission

Previous malaria control studies in Ghana have shown that community-wide approaches can substantially reduce malaria infections. In a mass testing, treatment and tracking (MTTT) study, more than 75% of people in target communities were reached, leading to a 24% reduction in asymptomatic malaria after one year. However, rapid diagnostic tests (RDTs) can miss very low-level infections, meaning some infected individuals are not treated and can continue to spread malaria. A pilot malaria mass drug administration (MDA) study using artemether-lumefantrine (AL) in the Eastern Region of Ghana showed a very large reduction (over 95%) in parasite carriage after repeated rounds of treatment. Despite this success, malaria infections later fluctuated, possibly because some parasites remained in mosquitoes and because mature gametocytes-the parasite stage responsible for transmission-are not fully eliminated by standard malaria medicines. To better interrupt malaria transmission, this study will use MDA with dihydroartemisinin-piperaquine (DHAP) combined with a single low dose of primaquine (PQ), which targets these transmission stages. The intervention will be given to the whole community every two months (six times per year) and compared with the current standard malaria control measures. The study will examine whether this approach reduces malaria parasite carriage, whether malaria returns after treatment stops, and whether repeated MDA affects malaria drug resistance markers in the population. This two-year implementation research will generate practical evidence to guide national malaria policy in Ghana and inform the potential use of MDA in other malaria-endemic African countries.

Malaria is a major problem in western Kenya, particularly around Lake Victoria. Whilst current prevention methods like bed nets and vaccines help to reduce malaria burden, additional tools are needed to better protect communities from malaria. The investigators will test a new technology called LASER Guardian™, which are devices that release chemicals to keep mosquitoes away from homes. The investigators will conduct a large study involving 69 villages in western Kenya over two years. Each village will be randomly chosen to receive one of three approaches: the new LASER devices, indoor residual spraying with insecticide (a method already known to work), or the standard prevention methods currently used. All villages will continue to receive the usual malaria prevention tools provided by the Kenyan government, including bed nets and vaccines. In villages receiving LASER, the investigators will install 2-3 small device inside structures once a year for two years. In villages receiving IRS, the investigators will spray the inside walls of homes with insecticide once a year for two years. The investigators want to find out if the LASER devices can reduce malaria better than current methods alone, and whether they work as well as indoor spraying. To do this, the investigators will carry out surveys of the community every six months over two years (four rounds in total), testing about 4,485 children between ages 1 and 15 from approximately 3,450 households in each survey to see how many have malaria. The investigators will also work with local health clinics to track malaria cases, study mosquitoes to understand how the interventions affect them, talk with community members about their experiences, and calculate the costs of these different approaches. This study will help us understand whether LASER tool can effectively protecting against malaria in Kenya and other African countries where malaria is common.

The goal of this clinical trial is to learn if the genetically-modified malaria parasite NF54/iGP3 will safely infect humans with malaria. The investigators will also determine how the parasite grows in humans, and the effect of anti-malarial drugs. Researchers will use a controlled human malaria infection (CHMI) model to infect participants with malaria to observe the development of the disease, collect malaria-infected blood, and then treat the participants to cure the malaria infection. The collected malaria-infected blood will be used to create a frozen stock of malaria parasites for use in future research.