Dr. Henrietta Mensah-Brown holds a PhD in molecular biology of infectious diseases from the University of Ghana.
Her research areas are malaria biology and immunology, focusing on the pathogenesis of Plasmodium falciparum malaria in children. One aspect of her work is aimed at gaining a better understanding of the mechanisms used by Plasmodium falciparum for invasion of red blood cells. Another aspect is focused on investigating immune responses to proteins used in red cell invasion and the targets of invasion inhibitory antibodies.Â
Every two minutes, a child under five dies of malaria, according to World Health Organization, Many of these deaths are preventable and treatable. In 2019, there were 229 million malaria cases globally that led to 409,000 deaths. Of these deaths, 67 per cent (274,000) were children under 5 years of age. This translates into a daily toll of nearly 750 children under age 5.
In sub Saharan Africa, an estimated 627,000 people died of malaria in 2020, with most being young children.
- One aspect of your research focuses on investigating immune responses to proteins used in red cell invasion and the targets of invasion inhibitory antibodies. Can this be considered as a pathway or a complementary solution used in the development of vaccines? May you explain this in simple terms
The red blood cell stage of the parasite life cycle is a crucial stage, and red cell invasion is a crucial step during the stage. The parasite must invade the red blood cell in order to avoid the host immune system. The process of invasion involves several proteins which makes it difficult to target a single protein to prevent invasion. However, because erythrocytic invasion is such a crucial step, targeting invasion proteins as part of a multi-component vaccine that targets multiple other stages of the life cycle may be a good strategy to help eliminate malaria.
- One of the aspects of your research on Malaria in children is gaining a better understanding of the mechanisms used by Plasmodium falciparum for invasion of red blood cells. Could you explain how the parasite (Plasmodium falciparum) invades the red blood cells in simple terms? How long this takes and at what point does severe malaria infection occurs?
Red cell invasion by malaria parasites is a crucial step in the life cycle of the parasite where the parasites must invade the red blood cell in order to survive and maintain infection. All parasites invade red blood cells, regardless of whether the infection is mild or severe.
The parasite life cycle in the human host begins with a mosquito bite, which causes parasites to be released into the bloodstream where they travel to the liver. In the liver, the parasites begin a process of cell division which leads to the formation of tiny parasite forms called merozoites which are released into the bloodstream. Merozoites must invade the red blood cell in order to proliferate. The process of invasion is complex. The parasite produces proteins that it uses as ligands to attach to proteins on the surface of the red blood cell to facilitate its entry into the red blood cells. The process of red cell invasion is fast, occurring within seconds of attachment to a red blood cell.
- Why are children more at risk for severe infection from malaria? And which stage of development is affected the most with regards to children under age 5?
Severe malaria is multi-syndromic and often manifests as cerebral malaria, severe malaria anaemia and respiratory distress. The distribution of severe malaria syndromes varies by age across transmission intensities, influenced mainly by changes in community-level immunity patterns.
Immunity to malaria is acquired over time, after multiple infections. Children are more at risk because they lack immunity to help fight malaria infection effectively, and therefore the more severe forms of disease are found in children. The question of what makes one child more susceptible to severe disease than another child in the same community is a question that scientists are still working hard to understand.
- What are some of the risks factors associated with severe malaria infection in children?
Generally, the risk of malaria infection is increased by factors such as the lack of insecticide treated mosquito nets, living near stagnant water bodies and staying outdoors for extended periods at night. Several publications in Africa have shown that the risk of severe malaria in children is also increased by multiple socio-economic factors including the educational level of the parents, the type of housing and the occupation of the parents.
- What is the prevalence of severe malaria in children in Ghana in terms of percentage?
The WHO estimates that there were approximately 5 million cases of malaria in Ghana in 2020, which resulted in an estimated 12000 deaths. Overall, malaria accounts for approximately 8% of under-5-mortality in Ghana.
- What are some of the strategies that can help to prevent and control occurrence of severe malaria infection in children?
The use of insecticide treated nets for children under the age of 5 is encouraged to help reduce the burden of malaria in children. Inside residual spraying to help control the vector as well as community engagement and education so that they can understand how and where mosquitoes breed to cause disease. These vector control strategies have worked in the past and can help reduce the incidence of malaria overall.Awareness on How to Combat Severe Malaria in Children