People at high risk of malaria may benefit from taking a cocktail of antibiotics as a preventative step, according to the results of a study in mice.
Scientists from Britain, Germany and Kenya said the drugs could prompt healthy people to develop a natural immunity to malaria parasites, providing protection against future malaria infections.
The researchers said that a natural immunisation technique like this could only be used in specific settings, where malaria seasons are high risk but relatively short, and where those in danger could be sure to take the protective medicines before being infected.
"The best application for this would be in areas where there is highly seasonal malaria transmission like in the savannah areas of Mali and Burkina Faso, where the malaria transmission only occurs for a short period but is extremely intense," said Steffen Borrmann, from the Kenya Medical Research Institute in Kilifi, who worked on the study.
The antibiotics work by causing a cellular defect in malaria parasites during their journey into the liver of the infected host, the researchers said in a report on their findings published in the Science Translational Medicine journal.
This blocks the malaria parasite's fatal conversion from the liver stage to the disease-causing blood stage. The blocked parasite inside the liver prompts the body to develop a strong protective immunity to malaria, a bit like a traditional vaccination, they said.
"But we are not developing this or proposing this as a vaccine as such," Borrmann said in a telephone interview. "It would be one additional tool in the larger set of weapons against malaria which could be used in certain circumstances."
Malaria kills up to a million people a year, most of them children living in Africa, where a child dies of the disease every 45 seconds, according to the World Health Organisation. It is caused by Plasmodium parasites, which are spread by the bites of infected Anopheles mosquitoes.
Mice protected against malaria
Borrmann and his colleagues conducted the study by giving preventative antibiotics to healthy mice and then infecting them with malaria parasites. They found that the mice generated a vaccine-like immunity against re-infection.
The results also showed that even when given low doses of antibiotics, almost all the mice were protected from the fatal brain complications associated with the most dangerous malaria parasite, Plasmodium falciparum.
British drugmaker GlaxoSmithKline is currently carrying out late-stage testing in people of an experimental vaccine against malaria and expects to see results by 2011. The company says that if it proves effective, it will seek regulatory approval for the vaccine, called Mosquirix, by 2012.
Borrmann and colleagues now want to test their findings in clinical trials to see if their approach works in humans.
"If successful, periodic administration of antibiotics in high-risk population groups, such as young children, may prove to be a valuable tool for controlling or eliminating malaria in regions of high transmission," they wrote. (Reuters Health/ Kate Kelland - 15 July 2010)