New Drug Turns Human Blood Into Mosquito-Killing Weapon

Nitisinone, a drug for rare diseases, kills mosquitoes when present in human blood and may become a new tool to fight malaria, offering longer-lasting, environmentally safer effects than ivermectin.

Controlling mosquito populations is a key strategy in the fight against malaria.

Currently, several approaches are used to reduce mosquito numbers and limit malaria transmission. One method involves the use of the antiparasitic drug ivermectin. When mosquitoes feed on blood containing ivermectin, their lifespan is shortened, which can reduce the spread of the malaria parasite.

However, ivermectin presents challenges. It is toxic to the environment, and its widespread use in both humans and animals to treat parasitic infections raises the risk of drug resistance.

Now, a study published in Science Translational Medicine has identified a promising alternative. Researchers discovered that when people take the medication nitisinone, their blood becomes lethal to mosquitoes, offering a potential new tool for mosquito control and malaria prevention.

How Nitisinone Works

"One way to stop the spread of diseases transmitted by insects is to make the blood of animals and humans toxic to these blood-feeding insects," said Lee R. Haines, associate research professor of biological sciences at the University of Notre Dame, honorary fellow at the Liverpool School of Tropical Medicine and co-lead author of the study. "Our findings suggest that using nitisinone could be a promising new complementary tool for controlling insect-borne diseases like malaria."

Typically, nitisinone is a medication for individuals with rare inherited diseases — such as alkaptonuria and tyrosinemia type 1 — whose bodies struggle to metabolize the amino acid tyrosine. The medication works by blocking the enzyme 4-hydroxyphenylpyruvate dioxygenase (HPPD), preventing the build-up of harmful disease byproducts in the human body. When mosquitoes drink blood that contains nitisinone, the drug also blocks this crucial HPPD enzyme in their bodies. This prevents the mosquitoes from properly digesting the blood, causing them to quickly die.

The researchers analyzed the nitisinone dosing concentrations needed for killing mosquitoes, and how those results would stack up against ivermectin, the gold standard ectoparasitic drug (medication that specifically targets ectoparasites such as mosquitoes).

"We thought that if we wanted to go down this route, nitisinone had to perform better than ivermectin," said Álvaro Acosta Serrano, professor of biological sciences at Notre Dame and co-corresponding author of the study. "Indeed, nitisinone performance was fantastic; it has a much longer half-life in human blood than ivermectin, which means its mosquitocidal activity remains circulating in the human body for much longer. This is critical when applied in the field for safety and economical reasons."

Testing Nitisinone in Humans

The research team tested the mosquitocidal effect of nitisinone on female Anopheles gambiae mosquitoes, the primary mosquito species responsible for spreading malaria in many African countries. If these mosquitoes become infected with malaria parasites, they spread the disease when they feast on a human.

To evaluate how the drug affected the mosquitoes when fed fresh human blood containing nitisinone, researchers collaborated with the Robert Gregory National Alkaptonuria Centre at the Royal Liverpool University Hospital. The center was performing nitisinone trials with people diagnosed with alkaptonuria, who then donated their blood for the study. Those taking nitisinone were found to have blood that was deadly to mosquitoes, which Haines describes as having a "hidden superpower."

The research team collected data on how the drug was metabolized in peoples' blood, allowing the team to fine-tune their modeling and provide pharmacological validation of nitisinone as a potential mosquito population control strategy.

Nitisinone was shown to last longer than ivermectin in the human bloodstream, and was able to kill not only mosquitoes of all ages — including the older ones that are most likely to transmit malaria — but also the hardy mosquitoes resistant to traditional insecticides.

"In the future, it could be advantageous to alternate both nitisinone and ivermectin for mosquito control," Haines said. "For example, nitisinone could be employed in areas where ivermectin resistance persists or where ivermectin is already heavily used for livestock and humans."

Next Steps and Broader Impacts

Next, the research team aims to explore a semi-field trial to determine what nitisinone dosages are best linked to mosquitocidal efficacy in the field.

"Nitisinone is a versatile compound that can also be used as an insecticide. What's particularly interesting is that it specifically targets blood-sucking insects, making it an environmentally friendly option," Acosta Serrano said.

As an unintended benefit, extending the use of nitisinone as a vector control tool could consequently increase drug production and decrease the price of the medication for patients suffering from rare genetic diseases in the tyrosine metabolism pathway.

Reference: "Anopheles mosquito survival and pharmacokinetic modeling show the mosquitocidal activity of nitisinone" by Lee R. Haines, Anna Trett, Clair Rose, Natalia García, Marcos Sterkel, Dagmara McGuinness, Clément Regnault, Michael P. Barrett, Didier Leroy, Jeremy N. Burrows, Giancarlo Biagini, Lakshminarayan R. Ranganath, Ghaith Aljayyoussi and Álvaro Acosta-Serrano, 26 March 2025, Science Translational Medicine.
DOI: 10.1126/scitranslmed.adr4827

The study was funded by the UK Medical Research Council, Biotechnology and Biological Sciences Research Council, Wellcome Trust Institutional Strategic Support Fund, the Medical Research Council Doctoral Training Partnership and the University of Glasgow Wellcome Centre for Integrative Parasitology.