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.

How do you turn vast amounts of genetic data into actionable insight – efficiently and accurately? Professor Bryan Greenhouse of UCSF discusses a series of “hackathons” at the Johns Hopkins Malaria Research Institute (JHMRI) that bring together scientists from around the world to tackle one of the biggest challenges in malaria research: analyzing parasite genetics. By developing open-source tools, workflows, and training resources, these collaborations are making cutting-edge analysis more accessible to labs and public health programs everywhere.

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.

A new study in Kenya shows that mass drug administration of ivermectin safely reduced malaria cases by 26%, offering a promising supplement to insecticide-based prevention.

Transcript

Bed nets and insecticides are commonly used to prevent malaria transmission. But insecticide resistance is making those tools less effective.

There’s a growing interest in ivermectin, an antiparasitic drug normally used to treat neglected tropical diseases such as river blindness or scabies, that is also capable of killing the Anopheles mosquitoes that transmit malaria.

In a new study in the New England Journal of Medicine, researchers from ISGlobal, an institute in Barcelona, investigated whether ivermectin given to at-risk populations en masse – in a policy of ‘mass drug administration’ – might supplement the use of insecticides to reduce malaria transmission.

In Kwale, a coastal county in Kenya where malaria is present year-round, nearly twenty-nine thousand people took part.

Half were given ivermectin at 400μg per kilogram of bodyweight. The other half were given 400mg of albendazole, not an antimalarial drug, but an anti-worming drug comparable to ivermectin.

Each group took the drug once a month for three months. The study looked at both the efficacy and safety of the two interventions.

Both drugs proved safe, but ivermectin had a greater impact, leading to a 26% reduction in malaria cases – higher than the 20% efficacy benchmark set by the World Health Organization.

Source

Source: Ivermectin to Control Malaria — A Cluster-Randomized Trial [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.

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.

Although severe malaria presents in different clinical forms – such as cerebral malaria or severe malarial anemia – a new study reveals that all severe cases have one thing in common: a shared inflammatory signature

Transcript

Whilst most cases of malaria are mild, some take a dangerous turn. In severe cases, the malaria parasite can overwhelm the body, disrupting the blood-brain barrier and leading to cerebral malaria, or destroying so many red blood cells that it triggers life-threatening anemia. Now, a new study has taken a closer look at this progression – from uncomplicated malaria to severe disease.

Researchers looked at three factors: Transcriptomics, the genes being expressed; proteomics, the proteins being produced; and metabolomics, the metabolites and small molecules present. Using a matched-pairs design, they compared blood samples of children with severe malaria versus children with uncomplicated disease.

The finding? Although different types of severe malaria can be distinguished by other factors, they all share a ‘common signalling pattern.’

Two proteins stood out: MMP8 and MMP9 – and those proteins are both involved, in different ways, in the breakdown of the extracellular matrix – the scaffolding between cells. The finding gives researchers new clues into how malaria becomes deadly, and may open the door to better-targeted treatments – or even a vaccine against severe malaria - in the future.

Source

A shared inflammatory signature across severe malaria syndromes manifested by transcriptomic, proteomic and metabolomic analyses [Nature Communications]

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.

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.

How next-generation bed nets could stop malaria by killing the parasites inside mosquitoes, not just the mosquitoes themselves.

Transcript

Bed nets have long been a cornerstone of vector control. Coated with insecticide, they serve a dual purpose: preventing bites and killing mosquitoes. But what if those nets could do more – not only kill the mosquitoes, but for those they don’t kill because of increasing insecticide resistance, at least kill the parasites hidden inside them?

Researchers assembled a library of antiparasitic compounds active against the form of the parasite in the mosquito midgut. They identified 81 promising compounds, some of which were already in clinical development. Of those, 22 were found to be effective against these early stages of parasite development in the mosquito and, therefore, capable of preventing onward transmission.

One class of compound stood out: ELQs, or endochin-like quinolones. These could be absorbed through the mosquito’s legs in tests, therefore viable for use in a mosquito net. The researchers suggest that ELQs could offer a promising new strategy for malaria control, working alongside traditional methods to reduce malaria cases and deaths.

Source

In vivo screen of Plasmodium targets for mosquito-based malaria control (Nature)

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.