Elderly are almost 10 times more likely to die of malaria than younger tourists
Tourists who have visited a malaria-infected country and are over the age of 65 are almost 10 times more likely to die from the disease than those who are aged 18-35, reveals a study published on bmj.com today. The death rate among tourists is particularly high when returning from a ‘winter sun’ holiday in the Gambia, West Africa.
Authors from the London School of Hygiene and Tropical Medicine and the University of Oxford carried out an observational study based on 20 years of UK data involving over 25,000 patients. They looked at the comparison between fatal and non-fatal cases of malaria and found that tourists are over 9 times more likely to die from the disease than those who are of African heritage travelling to meet friends or family. Most cases of travellers’ malaria in the UK do affect people of African heritage, but their risks of dying from the disease are relatively low. This may be due to early exposure to malaria, or to greater awareness of the symptoms and a tendency to seek medical help earlier.
The risk of dying from malaria increased steadily with age, with 25/548 (4.6%) of cases being fatal in people aged over 65. There were no deaths in children under 5 years. Overall, case fatality was 3.0% (81 deaths in 2740 cases) in tourists compared with 0.32% (26/8077) in travellers visiting friends and relatives. Those born in African countries with endemic malaria had a case fatality of 0.4% (36/8937) compared with 2.4%. Case fatality was particularly high in people visiting the Gambia (3.9%, (28/726)) compared with any other west African country (0.4% (58/13,448). Looking only at tourists increased this difference, with a case fatality of 6.0% (20/333) for cases from the Gambia compared with 1.4% (8/565) for tourists visiting the rest of west Africa.
There are reported to be 250 million cases of malaria in the world each year with over 800,000 associated deaths. Travel to infected countries such as Africa is increasing and the UK has one of the highest rates of imported malaria in the world, half of which comes from migrants travelling from infected countries.
For tourists, low drug prophylaxis rates and low awareness of the dangers of malaria may well be factors for death from malaria. There is also a higher death rate in December with over a quarter of deaths occurring then, which may be due to travellers mistaking symptoms for common winter viruses, or getting less rapid diagnosis over the holiday period. The more commonly malaria is seen in an NHS region, the lower the death rate suggesting familiarity with treating the disease may lead to better outcomes. Delay in seeking care may well be a major factor; treated early the outcome for malaria should be good.
Why are malaria mortality rates different in recent studies?
An article in The Lancet on 3 February 2012 estimated that 1.24 million people died of malaria in 2010 while for the same year, WHO estimated 655 000 people died.
WHO is grateful for efforts of all partners to improve estimates on malaria and other diseases in public health.
It is well appreciated in the public health community that estimates are very much influenced by the study sites, data, assumptions and methodology used in their studies. In this study, the variation in estimates of deaths over the age of 5 is because different methodologies were used.
WHO stands by their previous estimates that were based on the methodology developed by the UN agency in collaboration with other partners. WHO welcomes the Institute for Health Metrics and Evaluation’s estimates that actually show more similarities than differences. Both approaches show that an unacceptably high number of people still die from malaria. The trends in disease are steadily downward by both methods, thanks to investments in scaling up life-saving tools.
To improve disease estimates in the future, it is imperative that resource-constrained countries be supported to develop robust health information systems. This includes accurate diagnosis of causes of deaths; and that all experts working on disease estimates work together more collaboratively to produce accurate and timely data. This information is critical for the decision-making that ensures public health interventions reach the right communities and have the greatest potential of helping more people live longer, healthier lives.
The authors conclude that those of African heritage who are visiting friends and family are far more likely to get malaria due to low prophylaxis uptake, but tourists travelling from Europe, especially on winter sun holidays in Africa are far more likely to die from the disease once acquired, a risk that further increases in older tourists. They stress the importance of interventions from doctors who should give pre-travel advice encouraging prompt presentation when returning travellers have a fever and the need for taking anti-malaria drugs. They say doctors must make holidaymakers aware that malaria is common, fatal and needs early diagnosis, but they should also be targeting those of African heritage.
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Stephanie Burns
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BMJ-British Medical Journal