Imagine that if any mosquito bites you, it must die a few hours later, poisoned by the same blood it sucked.
That is an exciting possibility, that has already been proven in parts of Kenya.
When people take tablets of Ivermectin, a common drug used to treat head lice and elephantiasis, their blood becomes poisonous to mosquitoes for at least 28 days.
About 96 per cent of insects die after the bite and cannot bite another person to transmit malaria.
What is not clear is whether this is an effective way to control malaria in a larger community.
To test this, scientists from the Kemri-Wellcome Trust will administer the drug to about 32,000 people in selected areas of Msambweni and Lungalunga subcounties in Kwale county. The exercise begins on Tuesday, October 3.
The participants were assigned to two arms, with one arm receiving Ivermectin, the trial drug, and the control group receiving albendazole, a medication used to treat certain tapeworm infections.
The two principal investigators in the study, Dr Marta Maia and Dr Joseph Mwangangi, said they will assess the safety of using ivermectin, and the efficacy of this strategy to reduce malaria transmission.
“Our aim is to improve the tools we have for malaria control and what better way than to explore an affordable and accessible drug like ivermectin, which has a well-established safety profile,” Dr Mwangangi said.
The exercise is a project of the Broad One Health Endectocide-based Malaria Intervention in Africa (Bohemia) but implemented by the Kemri-Wellcome Trust.
The project aims to evaluate the effectiveness of Ivermectin as a novel and complementary strategy to reduce malaria transmission by reducing mosquito populations.
The Kenyan trial is the second as part of similar studies funded by Unitaid and led by the Barcelona Institute of Global Health (ISGlobal), Wellcome Trust said in a statement.
The second study is being implemented in Mozambique.
The Kilifi-based Trust said although bed nets remain the principal prevention method, mosquitoes are adapting and becoming resistant to insecticides.
In addition, mosquitos have changed their behaviours to bite at times when people are not under their bed nets and are also feeding on animals. This has resulted in the need for scientists to look for novel tools to complement bed nets in the fight against malaria.
“Administering Ivermectin to as many people as possible at the same time in a community might be a new way to control malaria transmission. With Bohemia, we are trying to generate evidence for this strategy,” Dr Maia, the co-principal investigator, said.
Multiple studies conducted since 2010, including one in Kisumu, show that malaria-carrying mosquitoes die after feeding on individuals who have ingested the drug, Ivermectin.
The Kisumu study, led by the Liverpool School of Tropical Medicine, tested the safety and efficacy (in terms of mosquito-killing capacity) of higher doses of ivermectin.
The researchers treated 141 adults with uncomplicated malaria with the antimalarial treatment plus either three days of ivermectin (600 or 300 microgramme/kg per day) or a placebo.
Results show that the blood of patients treated with both ivermectin doses killed mosquitoes, even 28 days after treatment.
Modelling analysis suggested that adding the 300 microgramme/kg dose of Ivermectin to mass antimalarial drug administration could significantly reduce malaria prevalence by an additional 44 per cent in low transmission settings aiming at malaria elimination, according to the Barcelona Institute of Global Health.
“If the dose or frequency required to reduce malaria transmission is higher, it will be important to establish the safety of the new treatment schemes,” the institute said.
“Based on pharmacokinetic modelling, a regime consisting of a daily dose of 600 mcg/kg for three days has the potential to sustain ivermectin concentrations lethal to Anopheles mosquitoes for at least one week.”
