Risk factors for mortality from imported falciparum malaria in the United Kingdom over 20 years: an observational study
BMJ 2012; 344 doi: https://doi.org/10.1136/bmj.e2116 (Published 27 March 2012) Cite this as: BMJ 2012;344:e2116All rapid responses
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Checkley and colleagues report an important study of the factors associated with malaria mortality in the UK using statutory notification data. [1] The principal finding that mortality increases with increasing age and is higher in malaria-naïve holidaymakers is striking.
The peak of mortality in December is also interesting. Analogies are drawn with cardiovascular mortality (which peaks over the festive period). Since malaria infection requires travel to an endemic region “winter sun” holidays are also proposed. There was a higher risk of mortality associated with travel to the Gambia, a popular package holiday destination. In addition, the authors suggest that misdiagnosis of influenza-like illness may be a factor: we have recently confirmed that clinical features alone poorly distinguish malaria from influenza in controlled experimental infections. [2]
Importantly the majority (94.3%) of individuals identified by Checkley and colleagues had not received effective chemoprophylaxis, although several cautions surround the completeness of the chemoprophylaxis data. [1]
Nevertheless, this study identifies a high-risk group for which an effective intervention currently exists (chemoprophylaxis), and intervention strategies to target these individuals are urgently needed. Most package holiday companies require holidaymakers to hold travel insurance, or at least declare they will obtain it. A similar requirement with regards to malaria advice/chemoprophylaxis for travellers to malaria-endemic regions should be considered.
References:
1. Checkley, A. M.; Smith, A.; Smith, V.; Blaze, M.; Bradley, D.; Chiodini, P. L.; Whitty, C. J., Risk factors for mortality from imported falciparum malaria in the United Kingdom over 20 years: an observational study. BMJ 2012, 344, e2116.
2. Lillie, P. J.; Duncan, C. J. A.; Sheehy, S. H.; Meyer, J.; O'Hara, G. A.; Gilbert, S. C.; Hill, A. V. S., Distinguishing malaria and influenza: early clinical features in controlled human experimental infection studies. Travel Medicine and Infectious Disease 2012, (in press).
Competing interests: No competing interests
Re: Risk factors for mortality from imported falciparum malaria in the United Kingdom over 20 years: an observational study
It is a very interesting and informative article on application of Principles of epidemiology on identifying the risk factors responsible for mortality due to imported Plasmodium falciparum in UK and identifying the messages and target groups for advice to travellers/ tourists.
This article observed that deaths were more common in theelderly population. But in the elderly, many alterations of both innate and clonotypic immunity have been observed1. Alterations to the immune system in the elderly are generally viewed as a deterioration of immunity, leading to the use of the term immunosenescence1.
In the present study the mortality and case fatality among children was nil. This, according to authors, is because of lack of access to health care in the endemic countries visited, which, however, is not the case in the UK.
In our opinion, the children from the endemic countries (which are developing or underdeveloped countries) may have been malnourished and hence immunologically weak, which explains the higher endemicity found among children in these countries as compared to developed countries like the UK.
References:
1. Vasto S, Caruso C.Immunity & Ageing: a new journal looking at ageing from an immunological point of view.Immun Ageing. 2004 Oct 29;1(1):1.
Competing interests: No competing interests