Parasitic disease

Malaria incidents are on the rise. There were 249 million cases of this parasitic disease in 2022, five million more than in 2021. Africa suffers more than any other region from malaria, with 94% of cases and 95% of deaths worldwide. This year two revolutionary malaria vaccines are being rolled out across the continent. Nadine Dreyer asks Jaishree Raman if 2024 will be the year the continent takes a significant leap towards beating the disease.

The RTS,S malaria vaccine

• The long-awaited vaccine was described as a breakthrough for science, child health and malaria control.
• It is being aimed at children under the age of 5, who make up about 80% of all malaria deaths in Africa.
• Among children aged 5 and 17 months who received 4 doses of RTS,S, the vaccine prevented about 30% of them from developing severe malaria.
• Since 2019 more than 2 million children in Ghana, Kenya and Malawi have been vaccinated with the RTS,S malaria vaccine.

R21/Matrix M

• The R21 vaccine is a significant improvement on the RTS,S vaccine, with 75% efficacy over a year.
• The R21/Matrix M vaccine is very cost-effective, projected to retail at $2-$4 a dose, comparable in price to other childhood vaccines used in Africa.
• These very encouraging findings prompted several malaria-endemic African countries, including Ghana and Nigeria, to approve use of the R21/Matrix M vaccine well before the World Health Organization.
• The WHO finally approved and prequalified R21/Matrix M for use in the last quarter of 2023.

No silver bullet

• While the fight against malaria has been significantly bolstered by the availability of these vaccines, they are not the silver bullets that are going to get us to an Africa free of malaria.
• This will be the year that many vulnerable young African children will have access to not one, but two malaria vaccines.

Jaishree Raman receives funding from the Global Fund, the Gates Foundation, the South Africa Research Trust, the South African Medical Research Council, the National Research Foundation, and the National Institute for Communicable Diseases. She is affiliated with the Wits Research Institute for Malaria, University of Witwatersrand, and the Institute for Sustainable Malaria Control, the University of Pretoria.

• Sanofi, DNDi and the HAT-r-ACC consortium announce the European Medicines Agency’s (EMA) Committee for Medicinal Products for Human Use (CHMP) has adopted a positive scientific opinion of Fexinidazole Winthrop as first oral treatment of acute form of sleeping sickness (rhodesiense).
• rhodesiense sleeping sickness, an acute and lethal form of this parasitic disease found in Eastern and Southern Africa.
• Sleeping sickness, or human African trypanosomiasis (HAT), is usually fatal without treatment.
• Both forms of sleeping sickness are transmitted by the bite of infected tsetse flies, which are found in 36 African countries.

• Many of these unique, iconic creatures are under threat.
• Invasive pathogens – parasites, viruses, bacteria, fungi – often attract less attention, but they too can pose a significant threat to native animals.

What is sarcoptic mange, and where did it come from?

• These mites are happy to infest many mammals, including humans (in which case the disease is called scabies).
• Research suggests the spread of the mites around the world is associated with European colonialism, although where they originally evolved is uncertain.

How does sarcoptic mange spread among solitary wombats?

• In some animals, the mange-causing mites move directly from one animal to another when the animals come into direct contact.
• However, wombats are relatively solitary.
• Research shows mites can survive in the cool, humid soil of the burrow for between five and 16 days.

The ratio of wombats to burrows may be the key

• At higher densities, individual animals come into contact more often so the pathogen is more likely to spread.
• In our research, we found individual wombats continued to be infected and diseased even when population density declined.
• Our research suggests the number of burrows per wombat likely influences how often they can encounter mites in the environment.

How big a problem is sarcoptic mange?

• Our study is the third formally documented decline in a bare-nosed wombat population from a sarcoptic mange outbreak.
• Does this mean bare-nosed wombat populations are threatened everywhere by this invasive pathogen – or even worse, at risk of going extinct?
• Another finding of our study was a potential indicator of the risk of population decline from sarcoptic mange.

What can be done?

• Across southeast Australia a significant number of wildlife carers, rehabilitators, and rescue organisations make important contributions to the welfare of bare-nosed wombats.
• Indeed, the last decade has seen significant advances through collaboration, research and engagement that are benefiting wombats.
• The Australian Pesticide and Veterinary Management Authority makes important decisions about granting permits for management of mange in wombats.

• They are, in turn, left more vulnerable to an array of infections, with hookworm, a soil-transmitted parasitic disease particularly prevalent.
• Marcella De Martin, the wife of Billy Lerner, is determined to help stop this health crisis.
• Along with her business partner, Alexson Roy and the Billy4Kids foundation, Marcella De Martin has supplied 200 pairs of canvas runners to the Liberty Children's Home in Ladyville Belize.
• As the newly appointed ambassador of Billy4Kids, Marcella De Martin is determined to stop the repetitive cycle of poverty faced by the children of Belize.