World Malaria Day 2023
“Time to deliver zero malaria: invest, innovate, implement”
Overview: 2023 - fight against malaria across Africa
Professor Sarah Staedke
In September 2022, I joined LSTM as a Professor of Malaria and Global Health based in Kisumu, Kenya with the KEMRI (Kenya Medical Research Institute)-CDC (US Centers for Disease Control)-LSTM collaboration. My research explores new ways to control malaria in Kenya and Uganda.
In the areas where we work, malaria is a major health problem. Malaria is transmitted year-round, and the mosquitoes that transmit malaria are very efficient (and clever). People can be infected with malaria repeatedly, especially young children, and are at constant risk of illness, severe disease, and death due to malaria.
To control malaria, we can try to reduce exposure to infected mosquitoes, treat people with malaria medicines to prevent or clear parasites, and use vaccines to strengthen children’s immunity against malaria. My research is focused on new approaches to control mosquito vectors and reduce transmission.
In western Kenya, we are conducting a large trial of ‘attractive targeted sugar bait’ (ATSB) stations in 70 clusters of villages near Lake Victoria. ATSBs are A4-sized panels containing thickened fruit syrup laced with an insecticide, which are hung on the outside of households. ATSBs are designed to attract and kill mosquitoes, and could be used alongside other methods to prevent malaria, like bednets.
To determine if the ATSBs are effective, we are following children aged 1-15 years to compare the number of malaria episodes that occur in children from the villages where ATSBs are hung, to those from villages without ATSBs. The study started in March 2022 and will continue until March 2024.
Over the past year, we have distributed over 200,000 ATSB stations, and followed 1,969 children in our cohort studies who completed 14,765 clinic visits. At enrollment 47% of cohort children tested positive for malaria parasites and 928 episodes of malaria have been diagnosed during follow-up, indicating the high burden of malaria in this area and need to intensify control. Over the next year, we will continue to monitor the ATSB stations, follow-up children in our cohort study, survey the communities in the study area, study mosquitoes, and talk to community members to better understand their perceptions of ATSBs.
In Uganda, we are conducting a trial of bednets distributed by the Ugandan Ministry of Health in 64 communities across 32 districts. Traditionally, bednets have been treated only with pyrethoids, but mosquitoes have become resistant to this commonly used insecticide. We are comparing new types of nets that incorporate pyrethroid insecticides plus additional chemicals, including the synergist piperonyl butoxide (PBO LLINs) and pyriproxyfen, an insect growth regulator (Royal Guard LLINs). The trial started in 2021 and will complete in 2023.
In a survey of close to 5,000 children aged 2–10 years from over 3,500 houses, we found that improved housing was strongly associated with a lower burden of malaria across a wide range of sites in Uganda. Overall, 15% of children living in improved houses tested positive for malaria, compared to 30% of those living in traditional houses. Housing modifications are being evaluated as an intervention to control malaria in Uganda and elsewhere, and should be considered as an important tool in our fight against malaria.
Research protects Mother and Baby from malaria during first trimester
Research coordinated by LSTM has helped the World Health Organization (WHO) improve its guidelines for treating malaria in pregnancy.
Malaria in pregnancy is a major threat to the mother and the developing fetus resulting in an estimated 10,000 deaths of the mother-to-be each year. The malaria parasite has found a clever way to stick to the placenta impairing the transfer of oxygen and nutrient to the growing fetus, which can cause the baby to be born too small, too early, or a pregnancy loss.
Prompt recognition and treatment with safe and effective drugs are therefore essential. However, it is often not known which drugs are safe to use in pregnancy, especially in the first three months (or first trimester), for fear of harming the fetus. This has resulted in many pregnant women with malaria in the first trimester being treated with old and ineffective drugs because insufficient safety data was available for newer, more effective antimalarials.
One such old drug is Quinine, which has to be taken three times per day for seven days and is associated with many side effects, such as ringing in the ears and dizziness. This can make it difficult for women to finish their treatment, which can have severe consequences for the pregnancy and the baby.
Researchers studied a group of newer medicines called ACTs (Artemisinin-based Combination Therapies) to see if they were safe to use during the first trimester of pregnancy. ACTs were already known to be safe in the 2nd and 3rd trimesters and much more effective than quinine.
They combined information on 35,000 pregnant women from multiple studies using data on treatment received in routine care. The outcomes of 750 women who had been treated with ACTs in the first trimester were compared to the outcomes of pregnancies treated with quinine in the first trimester. They found that women who were treated with an ACT were about 40% less likely to have a miscarriage or stillbirth or a baby born with congenital malformations than those treated with quinine.
The data was collected over 25 years as part of an excellent collaboration between researchers worldwide who shared their data, including those from Thailand and 11 sites in Africa. The results led the WHO to revise their malaria treatment guidelines which will benefit the over 120 million pregnancies occurring each year in malaria-endemic countries in Africa, south-east Asia and Latin America.