Increase in imported malaria in the Netherlands in asylum seekers and VFR travellers

Abstract

BackgroundMalaria is a notifiable disease in the Netherlands, a non-endemic country. Imported malaria infections occur regularly among travellers, migrants and visitors. Surveillance data were analysed from 2008 to 2015. Trends in amounts of notifications among risk groups were analysed using Poisson regression. For asylum seekers, yearly incidence was calculated per region of origin, using national asylum request statistics as denominator data. For tourists, denominator data were used from travel statistics to estimate incidence per travel region up to 2012.ResultsA modest increase in overall imported malaria notifications occurred in 2008–2015 (from 222 in 2008 to 344 in 2015). Notably, in 2014 and 2015 sharp increases were seen in malaria among travellers visiting friends and relatives (VFR), and in asylum seekers. Of all Plasmodium falciparum infections, most (1254/1337; 93.8%) were imported from Africa; 1037/1337 (77.6%) were imported from Central and West Africa. Malaria in VFR was mostly caused by P. falciparum infection after visiting Ghana (22%) or Nigeria (19%). Malaria in asylum seekers was mostly caused by Plasmodium vivax infection from the Horn of Africa. The large number of notifications in asylum seekers resulted from both an increase in number of asylum seekers and a striking increase of malaria incidence in this group. Incidence of malaria in asylum seekers from the Horn of Africa ranged between 0.02 and 0.3% in 2008–2013, but rose to 1.6% in 2014 and 1.3% in 2015. In 2008–2012, incidence in tourists visiting Central and West Africa dropped markedly.ConclusionsImported malaria is on the rise again in the Netherlands, most notably since 2013. This is mostly due to immigration of asylum seekers from the Horn of Africa. The predominance of P. vivax infection among asylum seekers warrants vigilance in health workers when a migrant presents with fever, as relapses of this type of malaria can occur long after arrival in the Netherlands.Electronic supplementary materialThe online version of this article (doi:10.1186/s12936-017-1711-5) contains supplementary material, which is available to authorized users.

High prevalence of malaria in a non-endemic setting: comparison of diagnostic tools and patient outcome during a four-year survey (2013–2017)

“…Malaria is no longer endemic in Italy since 1970 when the WHO officially declared Italy malaria-free where nowadays is the most commonly imported disease [ 6 , 20 , 24 , 25 ]. The risk of imported malaria depends on malaria endemicity at the destination, the number and the behavior (adherence to personnel protective measures) of the travellers to risk areas, adequate use of chemoprophylaxis, and efforts for vector control around the accommodation [ 26 ].…”

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“…In Amsterdam the decline in number of cases observed up until 2002 were attributed to a decrease in nonimmune patients [18]. However, this was followed by an increase in the Netherlands most notably since 2013 and mostly due to immigration of asylum seekers from the horn of Africa and among VFRs [19]. An increasing trend in malaria cases between 1973 and 2013 was also seen in the US, a country with a similar epidemiology to the UK where malaria affected mostly VFRs and travellers to Africa, specifically Nigeria [20].…”

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“…A sharp increase in malaria notifications occurred in 2014, coinciding with a large influx of newly arriving refugees in Germany. Roggelin et al [ 6 ] reported an increase of vivax malaria in 2014–2015 in refugees from Eritrea admitted to the University Medical Centre in Hamburg [ 6 , 7 ], as also described in Sweden in 2014 [ 8 , Sonden et al, personal communication], and the Netherlands in 2017 [ 9 ].…”