East African countries have been urged to increase surveillance of malaria drugs after a key drug failed to treat patients in the United Kingdom.

The drug combination known as artemether-lumefantrine (AL) is commonly used as a first line treatment for patients who have malaria.

Although the World Health Organisation recommends five different Artemisinin-based combination therapies (ACTs) for the treatment of uncomplicated malaria, Kenya’s Ministry of Health recommends only Coartem (artemether-lumefantrine) to be dispensed in public health facilities.

The drug combination was unable to cure four patients, who had all visited Africa, in early signs the parasite is evolving resistance.

Although a team at the London School of Hygiene and Tropical Medicine said it was too early to panic, it still called for an urgent appraisal of drug-resistance levels in Africa.

Two of the patients are said to have travelled to Uganda, one to Angola and one to Liberia, suggesting that the drug-resistant malaria could be emerging across the continent.

“There has been anecdotal evidence in Africa of treatment failure on a scale that is clinically challenging,” said Dr Colin Sutherland, who led the study among the patients in the UK.

“We need to go in and look carefully at drug efficacy,” he added.

Malaria is a major killer of under-fives, with one child dying from the disease every two minutes.

The malaria parasites are spread by bites from female anopheles mosquitoes.

Last year alone, the global tally of malaria reached 212 million cases and 429,000 deaths.

Most patients are treated with artemether-lumefantrine. But clinical reports detailed in the journal Antimicrobial Agents and Chemotherapy, showed the therapy failed in the four patients between October 2015 and February 2016.

The patients initially responded to therapy and were sent home, but were readmitted a month later when the infection rebounded.

Researchers said the treatment failure was due to strains of the disease showing reduced susceptibility and a “potential first sign of drug resistance” to AL.

“Frontline doctors should be alert to the possibility of artemisinin-based drugs failing, and assist with the collection of detailed information about specific travel destinations,” said Dr Sutherland.

The new findings come at a time when researchers are fighting to stop the drug resistance being experienced in parts of Southeast Asia from spreading to Africa.

This is because many patients who suspect that they have malaria often go for over-the-counter drugs without getting tested for the disease, exposing themselves to different combinations of the drug, which may end up being a threat.

In other cases, some patients who get the drugs default without completing their dosage.

This, says Dr Bernhards Ogutu, a chief research officer at the Kenya Medical Research Institute (Kemri), is one of the factors that could potentially lead to drug resistance.