Drug For Rare Disease Turns Human Blood Into Mosquito Poison

Scientists have proposed an innovative approach to control mosquito populations and combat malaria: adding a drug to human blood that is toxic to insects, so that when mosquitoes feed on this blood, it marks their last meal.

The drug in question is nitisinone, and a proof-of-concept study led by a team from the Liverpool School of Tropical Medicine in the UK showed that the substance can be deadly to mosquitoes even in low doses in human blood.

Effective Results in Mosquitoes Feeding on Treated Blood

When mosquitoes fed on the blood of three people who were already taking nitisinone to treat a genetic disorder, the insects died within 12 hours.

Nitisinone is already approved for treating certain rare, inherited diseases. It works by blocking the production of a specific protein, which leads to a reduction in toxic byproducts in the human body. However, when mosquitoes ingest blood containing nitisinone, they quickly die.

One way to stop the spread of insect-borne diseases is to make the blood of animals and humans toxic to these blood-feeding insects, says microbiologist Lee R. Haines from the Liverpool School of Tropical Medicine.

Our findings suggest that using nitisinone could be a promising new complementary tool for controlling insect-borne diseases like malaria.

Concerns Over Ecological Impact and Resistance

Although this is still very much a proof-of-concept idea, enthusiasm should be tempered by initial results from other antiparasitic drugs that can kill insects vital to ecosystems, and may not necessarily reduce malaria rates.

Previous studies show that nitisinone does not seem to kill other vital insects that play roles in pollination, but researchers have not well-studied its broader ecological impacts.The authors of the study suggest that incorporating mosquito-killing drugs into mass drug administration programs could lead to insecticide resistance becoming a problem in the future.

The researchers tested the effects of nitisinone-laced blood on mosquitoes, as well as using mathematical models to figure out the impact of different doses on simulated human populations. They found that the drug was effective at killing mosquitoes of all ages, including the older insects that are more likely to carry malaria.

The team compared nitisinone to ivermectin, which is already used as a potential tool to kill mosquitoes as they feed, noting that antiparasitic drugs like this are not a new idea.

While ivermectin given to humans or cows can kill mosquitoes at lower concentrations than nitisinone, the new drug acts more quickly, often within a day. It also stays in human blood for a longer time, making it more likely that mosquitoes will come into contact with it.

Nitisinone’s Superior Performance and Long-Lasting Effect

We thought that if we wanted to go down this route, nitisinone had to perform better than ivermectin, says parasitologist Álvaro Acosta Serrano from the Liverpool School of Tropical Medicine. Indeed, nitisinone’s performance was fantastic.

It has a much longer half-life in human blood than ivermectin, which means its mosquito-killing activity remains circulating in the human body for much longer. This is critical when applied in the field for safety and economic reasons.

Unlike ivermectin, nitisinone does not target the nervous system, so it is less neurotoxic. Moreover, studies show that ivermectin kills other insects.

A New Hope in the Fight Against Malaria

Malaria still causes over half a million deaths each year, and efforts to combat it have stalled in the face of growing populations and the disease developing increased resistance to treatments.

This new approach offers some renewed hope for fighting malaria, and with further research, it could support other measures to stop the spread of the disease – without the risk of harm to humans or wildlife.

Acosta Serrano says, We can also use nitisinone as an insecticide because it is a versatile compound.

Read the original article on: Science Alert

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