Mosquitoes’ capacity to transmit malaria may be affected by antibiotics in the blood of patients they bite, according to new research led by Imperial College London, in collaboration with The Cyprus Institute.
Malaria is a disease that infects almost half a billion people and kills over half a million every year, mostly children aged 1-5 in sub-Saharan Africa. Mosquitoes become infected with the malaria parasite when they bite an infected person. They pass on the disease within a couple of weeks when they bite another person.
The team led by Professor George Christophides of Imperial College London and adjunct Professor of the Cyprus Institute previously found that bacteria in the mosquitoes’ guts affect their capacity to transmit malaria. As antibiotics target bacteria, they explored in this new study whether biting a malaria patient who is taking antibiotics might affect the bacteria in the mosquitoes and, through this, their capacity to transmit the parasite.
Indeed, biting and ingesting blood from children infected with malaria, which contained a combination of antibiotics known not to directly affect the malaria parasites, made the mosquitoes more prone to infection by the parasites. It also caused them to live longer, which increased their chances of surviving long enough to pass on the parasite to another person.
Although the new study found that one combination of antibiotics could exacerbate malaria transmission, the researchers stress that they are not suggesting people should avoid using antibiotics. Rather, they suggest that more investigations are needed as different antibiotics might have a different impact on the mosquitoes’ ability to spread malaria. It is possible, they say, that other antibiotics make it harder for mosquitoes to transmit malaria. “Such antibiotics could be used in our fight against malaria”, a member of the team says.
Many different antibiotics are in use in countries where malaria is endemic, for a variety of reasons. Some are used to treat tuberculosis, HIV/AIDS or diarrhoea, while others are used in mass-drug administration programmes to combat neglected tropical diseases such as trachoma, yaws and filariasis. Such programmes have significantly reduced childhood mortality.
“Ultimately, we hope that understanding the effects of the different antibiotics would mean we can combat the spread of malaria more effectively”, Professor George Christophides says.”
“For example, when an antibiotic that makes mosquitoes more able to transmit malaria must be prescribed to a malaria patient, this could be combined with the use of a bed net in order to reduce mosquito bites or concurrent prescription of a drug that can both treat malaria and block its transmission. This is particularly important for young children, who are both highly vulnerable to malaria infection and very efficient at transmitting the disease” he adds.
