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



A 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.



Imported 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.
Department for Early Warning and Surveillance, Center for Epidemiology and Surveillance of Infectious Diseases, National Institute for Public Health and the Environment, Bilthoven, The Netherlands.
Brechje
B
de Gier
Department of Infectious Diseases, Public Health Service (GGD) of Amsterdam, Nieuwe Achtergracht 100, PO Box 2200, 1000 CE, Amsterdam, The Netherlands. fsuryapranata@ggd.amsterdam.nl.|National Coordination Centre for Travellers' Health Advice (LCR), Nieuwe Achtergracht 100, PO Box 1008, 1000 BA, Amsterdam, The Netherlands. fsuryapranata@ggd.amsterdam.nl.
Franciska S T
FS
Suryapranata
Department of Environment, Public Health Service (GGD) Hart voor Brabant, Ringbaan West 227, 5037 PC, Tilburg, The Netherlands.|Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.
Mieke
M
Croughs
Institute for Tropical Diseases, Harbour Hospital Rotterdam, Haringvliet 72, 3011 TG, Rotterdam, The Netherlands.
Perry J J
PJ
van Genderen
Nijmegen Institute for International Health, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Monique
M
Keuter
Department of Infectious Diseases, Leiden University Medical Centre, C5P46, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands.
Leo G
LG
Visser
Department of Internal Medicine, Division of Infectious Diseases, Tropical Medicine and AIDS, Academic Medical Centre, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
Michele
M
van Vugt
Department of Infectious Diseases, Public Health Service (GGD) of Amsterdam, Nieuwe Achtergracht 100, PO Box 2200, 1000 CE, Amsterdam, The Netherlands.|National Coordination Centre for Travellers' Health Advice (LCR), Nieuwe Achtergracht 100, PO Box 1008, 1000 BA, Amsterdam, The Netherlands.|Department of Internal Medicine, Division of Infectious Diseases, Tropical Medicine and AIDS, Academic Medical Centre, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
Gerard J B
GJ
Sonder
D000076263:Communicable Diseases, Imported / Q000453:epidemiology* / Q000469:parasitology; D006801:Humans; D015994:Incidence; D016778:Malaria, Falciparum / Q000453:epidemiology* / Q000469:parasitology; D016780:Malaria, Vivax / Q000453:epidemiology* / Q000469:parasitology; D009426:Netherlands / Q000453:epidemiology; D012036:Refugees / Q000706:statistics & numerical data; D012307:Risk Factors; D014195:Travel
Epidemiology; Surveillance; Travel