Johns Hopkins Malaria Minute

Professor Jane Carlton is director of the Johns Hopkins Malaria Research Institute. Dr. Chris Smith of the Naked Scientists interviews Jane about her research, her career and the future of malaria.

A new study in rural western Uganda finds that treating baby-carrying cloths, or lesu, with an insecticide with modest repellent effect significantly reduces malaria infections in young children. Transcript In many parts of sub-Saharan Africa, mothers carry their young children on their backs in colorful cotton wraps called lesu. Could treating these cloths with insecticide reduce malaria transmission? A study published in the New England Journal of Medicine explored this question in rural western Uganda, where malaria is transmitted year-round. Researchers enrolled 400 mothers with children aged six to 18 months. Using a blinded randomized placebo-controlled trial design, half received lesu treated with permethrin, a commonly-used insecticide. The other half received untreated cloths. All participants also received insecticide-treated bed nets. Every two weeks for 24 weeks, the mothers and children visited local health centers to check for fever and undergo malaria testing. The results were striking: children carried in permethrin-treated lesu represented 66% fewer malaria cases – 0.73 cases per 100 people compared with 2.13 in the control group. The findings suggest that insecticide-treated lesu – much like treated bed nets – could offer an effective new tool particuarly against outdoor biting for a highly vulnerable population - children under 5 years of age - in sub-Saharan Africa. Source Permethrin-Treated Baby Wraps for the Prevention of Malaria [NEJM] About The Podcast The Johns Hopkins Malaria Minute podcast is produced by the Johns Hopkins Malaria Research Institute to highlight impactful malaria research and to share it with the global community.

Feeding mosquitoes L-DOPA can either strengthen their defences against malaria or shorten their lifespan — showing that in vector control, the dose makes the difference Transcript As with all medicine, the dose determines whether something helps or harms. Researchers recently looked at a substance commonly found in mosquito habitats that might form part of their diet. It's called L-3-4-dihydroxyphenylalanine, or L-DOPA. Mosquitoes use it as a source of melanin. At low doses – up to a concentration of 2% – L-DOPA was toxic to mosquitoes and reduced the number of malaria parasites they carry in a dose-dependent manner. At higher doses, toxicity was stronger and the mosquitoes' rates of survival decreased, demonstrating what's known as a biphasic dose response. These findings offer two potential strategies for L-DOPA in malaria control. Low doses fed to mosquitoes in water could improve their defences against the parasite, thereby reducing onward transmission to humans. Higher doses could be used to kill mosquitoes or reduce their life span, particularly if used in a sugar bait. These strategies align with the need for cost-effective, sustainable and eco-friendly vector control methods. For L-DOPA, it all comes down to the dose. Source Dietary L-3,4-dihydroxyphenylalanine (L-DOPA) augments cuticular melanization in Anopheles mosquitos reducing their lifespan and malaria burden About The Podcast The Johns Hopkins Malaria Minute podcast is produced by the Johns Hopkins Malaria Research Institute to highlight impactful malaria research and to share it with the global community.

In Kwale, Kenya, where bed nets alone can't stop malaria, researchers are testing ivermectin – a drug long used to treat parasitic infections – as a new way to kill mosquitoes. Trials show a 26% drop in malaria cases and added benefits against other mosquito-borne diseases, suggesting ivermectin could be a scalable, community-driven tool in the fight against insecticide resistance. With Carlos Chaccour (researcher at the Navarra Center for International Development) and Joseph Mwangangi (scientist at KEMRI) About The Podcast The Johns Hopkins Malaria Minute is produced by the Johns Hopkins Malaria Research Institute to highlight impactful malaria research and to share it with the global community.

Focusing on patients in Mali, researchers examine why some children develop life-threatening complications like cerebral malaria or severe malarial anemia. With Mark Travassos (University of Maryland School of Medicine), Mahamadou Ali Thera (University of Science Techniques and Technologies of Bamako), and Rafal Sobota (Northwestern University). About The Podcast The Johns Hopkins Malaria Minute is produced by the Johns Hopkins Malaria Research Institute to highlight impactful malaria research and to share it with the global community.

Dr. Alexandra Probst discusses a breakthrough in malaria prevention: bed nets coated with anti-parasitic drugs that stop transmission by curing infected mosquitoes. With Alexandra Probst, former graduate student at Harvard University. About The Podcast The Johns Hopkins Malaria Minute is produced by the Johns Hopkins Malaria Research Institute to highlight impactful malaria research and to share it with the global community.

The extent to which malaria vaccines reduce cases and deaths is a key consideration. But there's another factor, too. with Dr. Lemu Golassa, Head of Medical Parasitology at Addis Ababa University. About The Podcast The Johns Hopkins Malaria Minute is produced by the Johns Hopkins Malaria Research Institute to highlight impactful malaria research and to share it with the global community.

The podcast explores the importance of advocacy for malaria research and control. It follows over 120 advocates gathering in Washington, DC, as part of the 'United to Beat Malaria' campaign, urging Congress to continue supporting global malaria efforts. Key topics include: The US President's Malaria Initiative (PMI), founded in 2005, which provides bed nets, test kits, and treatments to combat malaria The role of global partnerships, including the Global Fund, in distributing resources efficiently. How Uganda's malaria response is supported by international funding for the dissemination of key public health interventions. The importance of sustained funding for malaria research, with US agencies like NIH, CDC, and PMI contributing to vaccine development and disease surveillance. Featuring: Margaret Reilly McDonnell (United to Beat Malaria), Dr David Walton (formerly PMI), Dr Jimmy Opigo (Uganda National Malaria Control Program), Jamie Bay Nishi (ASTMH) and Ed Royce (former House Foreign Affairs Committee (HFAC) Chairman).

Can AI identify mosquito species? VectorCAM, a pocket-sized device, uses machine learning to differentiate species with 95% accuracy, enhancing malaria surveillance efforts Transcript Not all mosquitoes are created equal. Of the more than three thousand species, only a limited number of the Anopheles genus can transmit malaria. Even within that subset, subtle physiological differences affect how malaria spreads. Some mosquitoes prefer to bite indoors, while others outdoors. Some need large bodies of water to breed, while others only need a small puddle. Distinguishing these species is critical for effective malaria control—whether using bed nets, indoor spraying, or outdoor larval management. But identifying them by eye takes expert, entomological knowledge. Could AI help? The VectorCAM team at Johns Hopkins is working on just that. Their pocket-sized device uses a small light and magnifying lens, allowing a phone camera to capture close-up images of mosquitoes placed on slides. With up to 95% accuracy, it can identify mosquito species based on morphology in seconds. The hope is that VectorCAM will help health teams better understand mosquito populations, paving the way for more targeted and relevant malaria control efforts. Source Towards transforming malaria vector surveillance using VectorBrain: a novel convolutional neural network for mosquito species, sex, and abdomen status identifications (Scientific Reports) About The Podcast The Johns Hopkins Malaria Minute podcast is produced by the Johns Hopkins Malaria Research Institute to highlight impactful malaria research and to share it with the global community.

One of the main ways of controlling malaria is to reduce mosquito populations through insecticides. But the mosquitoes are developing resistance, making most insecticides less effective. What if the answer lies beneath our feet? Transcript One of the main ways of controlling malaria is to reduce mosquito populations through insecticides. But the mosquitoes are developing resistance, making most insecticides less effective. We need new vector control interventions – what if the answer lies beneath our feet? Researchers from the Dimopoulos Group at the Johns Hopkins Malaria Research Institute have turned to an unexpected source of inspiration—soil. They've produced a natural biopesticide, derived from a type of bacteria found in soil called Chromobacterium. When you deliver this biopesticide through a sugar bait – which lures the mosquitoes to feed on it – it kills the mosquitoes, regardless of their resistance to insecticides. Additionally, at non-lethal doses, Chromobacterium can enhance the effectiveness of other insecticides, acting as a synergist, as well as making mosquitoes incapable of finding a human to feed on. These findings were first demonstrated in the lab, but have now been confirmed in enclosed field trials in Burkina Faso. It's hoped that this naturally-occurring insecticide could support vector control efforts to curb disease transmission. Source Chromobacterium biopesticide overcomes insecticide resistance in malaria vector mosquitoes (Science) About The Podcast The Johns Hopkins Malaria Minute podcast is produced by the Johns Hopkins Malaria Research Institute to highlight impactful malaria research and to share it with the global community.

Malaria prevention depends on the adoption of multiple behaviors – like sleeping under a bednet and wearing clothes that cover the skin. Researchers find that conversations with people in one's own social circle are the strongest factors that influence behavior uptake. Transcript Malaria prevention depends on the adoption of multiple behaviors – like sleeping under a bednet and wearing clothes that cover the skin – to reduce exposure to infectious mosquitoes. Theories of 'social influence' are often used to explain the uptake of single behaviors, in which an individual's relationship to others explains their adoption of certain behaviors. Yet, to better understand the uptake of different malaria prevention behaviors in a broader context, researchers looked beyond just social ties to consider the influence of behavior carry-over: where an individual who already adopts one prevention behavior is more likely to adopt another. Researchers applied this multi-level social network analysis to structured interviews from 10 villages in Northeast India, all conducted at a single point in time. They found that network exposure – talking to someone in your network who adopts a certain behavior – was the most important and consistent factor in explaining behavior uptake. This was more influential than individual behavior carry-over (which had no effect), existing village behavior patterns, or ties with health workers (which had minimal effect). This reinforces the importance of social discussion as the most significant factor in determining behavior uptake. Source A multilevel social network approach to studying multiple disease-prevention behaviors (Nature Scientific Reports) About The Podcast The Johns Hopkins Malaria Minute podcast is produced by the Johns Hopkins Malaria Research Institute to highlight impactful malaria research and to share it with the global community.

Scientists discover new antibodies - a promising target for clinical exploration. Transcript The currently licenced malaria vaccines and monoclonal antibodies all target a well-known region of the same malaria protein. That protein – the circumsporozoite protein, commonly known as CSP – covers the surface of the parasite as it enters the human skin through a mosquito bite. By targeting CSP, the vaccines aim to stop each malaria parasite in its tracks. But what about other proteins on the sporozoite - the parasite form injected into the blood by the mosquito - or other regions of the CSP protein? In a recent study, scientists screened plasma from malaria-infected individuals for immune responses against sporozoites. Many had developed antibodies against these well-known regions of CSP, but some had developed antibodies targeting a different region of the sporozoite surface. Out of ten new antibodies isolated from these individuals, several were functional – inhibiting the development of later parasite stages that occur in the liver and preventing sporozoite infection in a mouse model of malaria. However, they were targeting a different region of CSP that was only uncovered after processing by the sporozoite. This new region – called pGlu-CSP – is, the authors say, a site of vulnerability and a promising target for future clinical exploration. Source Protective antibodies target cryptic epitope unmasked by cleavage of malaria sporozoite protein (Science) About The Podcast The Johns Hopkins Malaria Minute podcast is produced by the Johns Hopkins Malaria Research Institute to highlight impactful malaria research and to share it with the global community.

Researchers search for ways to predict antimalarial drug resistance and identify more effective drug combinations. Transcript The front-line treatment for malaria is typically a combination of drugs called artemisinin-based combination therapy. Resistance to treatment has already been reported in mild cases of malaria, but now, for the first time, it's also being reported in severe cases of malaria. Severe malaria cases are more likely to end in a fatal outcome, so drug resistance in these scenarios poses a risk to human life. To try and stay one step ahead of resistance, researchers tested compounds and combed through publications to identify 118 compounds active against over 700 parasite clones to see how the parasites evolve under pressure, and to identify mutations in the parasite genome likely to be associated with drug resistance. They confirmed that Plasmodium falciparum – the deadliest and most prevalent species of the malaria parasite – evolves relatively easily, with mutations that affect the drug's mechanism of action and which move through the population. The hope is that this dataset of drug resistance markers could provide an 'early warning system' – to predict drug resistance in the field and to identify a more effective drug combination. Source Artemisinin Partial Resistance in Ugandan Children With Complicated Malaria (JAMA) Systematic in vitro evolution in Plasmodium falciparum reveals key determinants of drug resistance (Science) About The Podcast The Johns Hopkins Malaria Minute podcast is produced by the Johns Hopkins Malaria Research Institute to highlight impactful malaria research and to share it with the global community.