Antibiotics are already used for short-term prevention of malaria by travellers

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[NAIROBI] Malaria sufferers might be able to protect themselves against life-threatening bouts of the disease by taking a single course of antibiotics, research in mice has shown.

Preventive treatment with 'needle-free'  antibiotic vaccines could be used to control the infection in areas with high levels of transmission, a study published last month (14 July) in Science Translational Medicine suggests.

There are still no available vaccines against malaria. And although some antibiotics with anti-malarial properties, such as doxycycline, that kill the parasites directly are already in use as one-off, short-term prophylaxis, their  prolonged use is not an option for millions of people in the developing world where malaria is endemic.

Now, azithromycin and clindamycin, two common antibiotics, have been shown to  provide additional and long-term protection against malaria, even after they are no longer taken.

"The combination of the prophylactic effect with the subsequent immune-mediated protection may be enough to protect population groups at risk, such as infants and young children, from severe forms of malaria," Steffen Borrmann, a lead author of the study and parasitologist at the Kenya Medical Research Institute, told SciDev.Net.

The team treated mice with the antibiotics before infecting them with malaria. After taking the drugs, the mice developed vaccine-like immunity lasting at least 40 days, and almost all were protected from complications that are often lethal.

It is still not clear how long the immunity would last in humans, but Borrmann told SciDev.Net that "life-long would be the ultimate goal but we would be happy to achieve 1–2 year protection, [to last] during the most critical years in early childhood in high transmission areas".

The antibiotics work by causing small cavities in malaria parasites during their passage into the liver of the infected host. This stops the parasites from entering the blood stream,  giving time for the immune system to launch a sustained defence against the parasites.

This mode of action is similar to experimental vaccines that use weakened, whole parasites to elicit an immune response, said Borrmann.   

The tested antibiotics are available as safe, generic drugs, and there are no patent issues preventing their use in clinical trials or in clinical practice.

But they would likely not work in areas with low transmission levels, since the degree of immunity to subsequent infections depends on the quantity of malaria parasites already infecting the patient, Borrmann said.

Willis Akhwale, head of Kenya's Disease Prevention and Control department at the Ministry of Public Health and Sanitation, welcomed the findings, adding that the fight against malaria requires new tools to fully eliminate the disease.

"As we move from control to elimination, countries in Sub-Saharan Africa need new tools towards the eradication of malaria since insecticide treated nets and artemesinin combination therapies may not sustain the fight," he said.

Link to full article in Science Translational Medicine