Vacationers, Business Travelers Account for Most Malaria Cases Imported Into the UK

By Will Boggs MD

January 13, 2019

NEW YORK (Reuters Health) - Vacationers and business travelers combined account for most of the malaria cases imported into the UK, and most of these travelers have not taken the recommended prophylaxis against infection, researchers report.

"The import of malaria plateaued after its early fall, suggesting that any effect of healthcare messages on the need for prophylaxis had been blunted," Dr. Andrew M. L. Lever from Cambridge University Hospitals NHS Foundation Trust told Reuters Health by email. "More widespread dispersal of information on how to avoid this disease is needed."

Malaria is the most common imported tropical disease in the UK, and earlier reports have attributed much of this to people returning to the country of origin of their family and not using malaria chemoprophylaxis.

To update the epidemiology of imported malaria, Dr. Lever and colleagues analyzed the data of patients with confirmed malaria seen in Addenbrooke's Hospital from 2002 to 2016 and compared this with UK national data.

A total of 225 Addenbrooke's patients had confirmed malaria between 2002 and 2016, and there was little evidence of any change in the annual number of cases from 2004 onwards. Nationally, malaria cases declined 31.2% between 1996 and 2003 but changed little thereafter, the researchers report in Clinical Infectious Diseases, online December 7.

The largest single group of cases (27.8%) were from individuals visiting family in their country of origin, but overall, most cases came from UK residents visiting malarious countries for holiday (22.5%) or for work reasons (20.1%).

Among the 193 patients with available data, 60% took no prophylaxis at all, and of the 40% who took prophylaxis nearly a third (32.5%) did not know what they had taken. None of the patients who took prophylaxis completed their chemoprophylaxis regimen.

All but three of the patients treated at Addenbrooke's Hospital recovered.

Treatment outcomes at the national level were similar: 99.6% of patients recovered and 0.4% of patients succumbed to infection.

"Emphasis on prevention is critical," Dr. Lever said. "It is safe, simple, and the major prophylactic drugs have very little in the way of adverse effects - and they work."

"There has been a shift in some health systems away from travel advice and healthcare being part of the general healthcare available to patients (as used to be the case in the NHS), and instead travel health has become a commercial industry," he added. "Health systems are failing their patients if access to health advice for potentially lethal diseases becomes reliant on the traveler having to pay for advice and treatment and is not part and parcel of healthcare provision in all systems."

Dr. Lever noted that the evidence is sparse, but that he would not be surprised if findings were similar elsewhere in Europe and in North America.

According to a 2016 report (covering 2014) from the European Centre for Disease Prevention and Control, 99.9% of malaria cases in Europe were travel related and, as in the UK, the worldwide decrease in malaria incidence had not resulted in a decrease of travel-related cases (

In the U.S., where about 1,700 cases of malaria are diagnosed each year, the vast majority of cases are also in travelers and immigrants returning from countries where malaria transmission occurs ( The same appears to be true in Canada, which saw between 447 and 516 cases annually from 2010 to 2014.

The U.S. Centers for Disease Control and Prevention provides useful information about malaria and its prophylaxis by country ( and tips for travelers on choosing a drug to prevent malaria (


Clin Infect Dis 2018.