Imported malaria and high risk groups: observational study using UK surveillance data 1987-2006
BMJ 2008; 337 doi: https://doi.org/10.1136/bmj.a120 (Published 03 July 2008) Cite this as: BMJ 2008;337:a120All rapid responses
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Editor,
With great interest we read the observational study of Smith and
colleagues. (1) They examined trends in incidence of imported malaria in
the United Kingdom between 1987 and 2006. In the 20-year study period a
significant increase of the incidence of falciparum malaria was reported,
whereas the number of vivax malaria cases decreased steadily over the
years.
The reported increase in falciparum malaria in the UK does not
correspond with our own observations on imported malaria in the
Netherlands during recent years. We examined all consecutive malaria cases
in the Harbour Hospital and Institute for Tropical diseases in Rotterdam,
the Netherlands between January 1, 1999 and January 1, 2008. The number of
falciparum cases clearly decreased after the year 2000 from 40 patients in
2001 to 20 in 2007. Imported malaria with non-falciparum species also
declined in this observational period. Interestingly, the same evolution
of imported malaria has been noted in the Netherlands as a whole, where
official malaria notifications have decreased from 569 cases in 2000 to
210 cases in 2007.(2,3) Moreover, this trend is not restricted to the
Netherlands alone. The WHO data on imported malaria in most European
countries show that reported falciparum malaria cases are declining over
the past years. (4)
Compatible with the UK experience, also in the Netherlands travelers
to Ghana and Nigeria account for about half of all imported falciparum
cases, suggesting considerable overlap in countries of acquisition of
malaria. (3) From table 1 in the paper by Smith and colleagues, it appears
that during the last five years of the study period numbers of falciparum
malaria cases have decreased compared with the 1996-2001 time period.
This is supported by the number of imported falciparum malaria cases in
2007, as reported by the WHO for the UK, (4) that has not been so low
since 1994. Since the authors used a linear regression for analysis of
linear trend over a much longer period of 20 years, this newly evolving
trend of decreasing incidence rates since 2001 may have been lost.
International travel is still on the rise and the incidence of
malaria does not decline dramatically over the world in general. (5)
Decreased incidence rates of imported malaria in the Netherlands and most
European countries may suggest that travelers to malaria endemic regions
are nowadays better prepared against the transmission of Plasmodium
species by mosquito bites, either by adhering more strictly to personal
protective measures like insect repellants and/or a more compliant intake
of newer and more convenient chemoprophylactic drugs like
atovaquone/proguanil.
Jacob M. Bezemer, M.Sc.
Dennis A. Hesselink, M.D., Ph.D.
Perry J.J. van Genderen, M.D., Ph.D.
Reference:
(1) Adrian D Smith, David J Bradley, Valerie Smith, Marie Blaze, Ron
H Behrens, Peter L Chiodini and Christopher J M Whitty Imported malaria
and high risk groups: observational study using UK surveillance data 1987-
2006 BMJ 2008;337; a120
(2) van der Eerden LJM , Bosman A , Visser LG . Afname van
importmalaria, een overzicht van 2002. Infectieziekten Bulletin 2003 Dec
12 ; 14 : 419 – 423 . (Dutch)
(3) Government report on infectious diseases in the Netherlands.
(Dutch)
[http://www.rivm.nl/cib/binaries/StaatvanInfectieziekten2007_tcm92-
53097.pdf] (Accessed 2008 July 17)
(4) WHO data on malaria: [http://data.euro.who.int/cisid] (Accessed
2008 July 10)
(5) World Health Organization and UNICEF: World Malaria Report 2005
Roll Back Malaria 2005
[http://www.rbm.who.int/wmr2005/html/exsummary_en.htm] (Accessed 2008 July
10)
Competing interests:
None declared
Competing interests: No competing interests
Imported malaria in High Risk Groups
Sir,
Smith et al. revealed the disproportionate burden of imported malaria
in ethnic minority groups who have visited friends and relatives in their
country of origin. Their study also showed that where the reason for
travelling was known, those who had been on holiday to a malarious area
accounted for only 15% of imported falciparum malaria cases, but nearly
half (46%) of the deaths occurred in this group.(1) Previous studies have
shown that during face-to-face consultations, travel agents provide health
advice inconsistently and only mention health risks when prompted.(2)
We recently reviewed travel brochures from 27 British tour operators
which featured holidays to malarious African countries. Of the 27, in only
12 did we find any mention of malaria or the advisability of malaria
prophylaxis. Only four brochures mentioned malaria on the same page as a
holiday to a recognised malarious region.
Such literature would be an ideal place to target advice to
travellers, and these results show that this opportunity is being missed.
More generally, these findings suggest that the travel industry is
failing to take the risk of malaria to travellers of whatever variety
sufficiently seriously. We note that there is no specific guidance given
by the Association of British Travel Agents (ABTA) to tour operators
regarding malaria.(3) Also, the airline industry trade association, the
International Air Transport Association (IATA), advises member airlines on
disinfection of aircraft to remove insects, but no recommendations
regarding the offering of health advice to passengers.(4) Accordingly,
people travelling independently to visit relatives in malarious countries
are unlikely to be exposed to any relevant health advice at all prior to
travelling.
We believe that the travel industry has an obligation to improve the
quantity and quality of malaria advice it provides in its brochures and
other promotional publications, with particular emphasis on malaria
prevention where appropriate. For independent travellers, malaria advice
should be provided by the airline, for example on the ticket itself. This
would help target those travelling on business or visiting friends and
family in their country of origin.
1. Imported malaria and high risk groups: observational study using
UK surveillance data 1987-2006. Smith et al. BMJ 2008 Jul 3;337:a135. doi:
10.1136/bmj.a135.
2. Provision of health information by British travel agents.
Grabowski P, Behrens RH. Trop Med Int Health. 1996 Oct;1(5):730-2.
3. ABTA Code of Conduct 2008, section 2F
4. IATA “Health Tips for Travellers”.
http://www.iata.org/Whip/_Files/WgId_0073/HEALTH%20TIPS.pdf
Competing interests:
None declared
Competing interests: No competing interests