Migrants as a Major Risk Group for Imported Malaria in
European Countries
Patricia Schlagenhauf, Robert Steffen, and Louis Loutan
cation with surveillance groups provided additional
information.
It has been estimated that at the end of the twentieth century, some 150 million people were living outside the country of their birth. International travel and
migration are changing the epidemiology of imported
malaria in Europe. A growing proportion of imported
cases is seen in immigrants and refugees arriving and in
settled migrants returning to their country of origin to
visit friends and relatives (VFR). Physicians in industrialized countries need to be aware of the malaria risk in
these communities from both a prevention and treatment
perspective.1 The goal of this research was to quantify the
current situation in Europe.
Proportion of Nonnationals
Depending on the country of origin of the report,
the proportion of cases varied from 33% in the United
Kingdom to 86% in a region of France, reflecting the profile of immigration in various areas at different time
points. On pooling the reports, 43% of malaria cases registered in important European centers occur in nonnationals, frequently settled immigrants VFR. In Italy,
where 44% of cases were related to foreigners, VFRs
accounted for 72% of the cases reported in this group.2
Methods and Results
Increasing Proportion of Nonnationals
All reports describe an increasing proportion of
malaria cases occurring in nonnationals. In the report
describing imported malaria cases in northern Italy,4 the
proportion of immigrants increased from 34% in 1991
to 59.9% in 1995 (p = .002). In the Netherlands, for the
period 1979 to 1988, only 15% of cases were in persons
originating in a malaria-endemic area, whereas for the
period 1991 to 1994, 40% of cases were in persons from
malaria-endemic areas, and 8% of cases were in children
born to settled immigrants resident in the Netherlands.5
Systematic searches of MEDLINE and available
national malaria statistics were scanned to identify studies and reports showing the proportions of malaria cases
occurring in nonnationals in European countries. Nonnationals were defined as being foreign born residents,
which embraces various categories of migrants, including immigrants, refugees, asylum seekers, foreign workers, illegal migrants, or aliens. Only reports describing
more than 250 malaria cases were included in the analysis. The period of the search was January 1991 to September 2001.
A total of five MEDLINE reports2–6 were found that
satisfied the inclusion criteria, and personal communi-
Comment
Data from the aforementioned studies show that residents of foreign origin represent a growing proportion
of imported cases, reflecting to some extent the increasing number of migrants in western Europe. In Britain,
an older study has shown that migrants VFRs have a
malaria incidence rate almost three times higher that that
of tourists to Africa,7 suggesting a higher risk of exposure and/or insufficient protection measures. Although
no prospective studies exist that confirm the hypothesis, migrants VFRs may be more exposed as they visit their
families in rural areas with higher transmission rates and
simple nonair-conditioned living conditions. Many return
home during summer holidays, a period corresponding
to the rainy season in West Africa or to the monsoon season in India when malaria transmission is at its peak. Many
migrants VFRs mistakenly believe that they retain lifetime immunity and although immunity does wane when
constant reexposure stops, some immunologic memory
remains that partly explains the lower case fatality in
Patricia Schlagenhauf, PhD, Robert Steffen, MD: University
of Zürich Travel Clinic and World Health Organization
Collaborating Center for Travelers’ Health, Institute for Social
and Preventive Medicine, University of Zürich, Zürich,
Switzerland; Louis Loutan, MD, MPH: Travel and Migration
Medicine Unit, Department of Community Medicine,
University Hospital of Geneva, Geneva, Switzerland.
The authors had no financial or other conflicts of interest to
disclose.
Correspondence: Patricia Schlagenhauf, PhD, University of
Zürich Travel Clinic and World Health Organization
Collaborating Center for Travelers’ Health, Institute for Social
and Preventive Medicine, University of Zürich,
Sumatrastrasse 30, 8006 Zürich, Switzerland.
J Travel Med 2003; 10:106–107.
106
Schlagenhauf et al., Migrants as a Major Risk Group for Imported Malaria in European Countries
107
Table Major Reports on Imported Malaria Cases in Europe (1991 to 2001)
Paper/report*
Total no. of
cases
Nonnationals
Proportion of
nonnationals
Romi
2001
Italy
TropNetEurop†
2001
Europe
Minodier
1999
France
Matteelli
1999
N.Italy
CNRMI‡
1999
France
Wetsteyn
1997
Netherlands
Bradley
1994
UK
Total
5,898
2,595
2,679
884
315
271
694
416
3,069
1,596
286
137
3,551
1,172
16,492
7,071
44 %
33%
86%
60%
52%
48%§
33%
43%
*Selection criteria for papers and reports: reports on imported malaria cases in Europe with n > 250 with specified proportion of nonnationals.
†
Personal communication Tomas Jelinek. TropNetEurop Sentinel Surveillance Report on Plasmodium falciparum September 2001. Notification centers
in 15 European countries (accounts for approximately 10% of European cases).
‡
Personal communication Fabrice Legros. Centre National de Référence pour les Maladies d’Importation (CNRMI) report calculates that an
estimated 5,940 cases are imported. The number here refers to the notified number of cases.
§
40% originally from malaria endemic areas; 8% were children born to immigrants resident in The Netherlands.
migrants. This is not the case in children born of settled
immigrants who are particularly at risk of acquiring
malaria when visiting relatives.3,5
The evidence here points to a growing proportion
of cases of imported malaria seen in foreign-born residents and migrants VFRs in Europe. It is necessary to
specifically target malaria prevention for such groups
on a European scale. New communication channels
need to be explored, and we suggest simple immediate
measures highlighting malaria risk, such as (1) stickers for
airline tickets in the migrants’ languages designed in a culturally sensitive way and (2) in-flight messages both to
and from malaria destinations detailing malaria prevention measures on the in-flight and providing advice on
coping with suspected malaria on the return flight,
respectively.
Acknowledgment
PS did the search, collated, and analyzed the data and
drafted the paper. LL and RS contributed to the concept
and background information and to revising the paper.
References
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