Introduction: Malaria is one of the most common causes of preventable deaths in the developing countries, especially among children. A previous study of imported malaria in Iceland during 1980-1997 identified 15 confirmed cases. The objective of this retrospective study was to update epidemiological data on malaria in Iceland, 1998-2014.

Materials and methods: The inclusion criteria were a positive thick or thin blood smear for malaria parasites at the Dept. of Microbiology at Landspitali University Hospital, which serves as a referral laboratory for malaria diagnosis in the country. Medical records of confirmed cases, nationwide sales data for antimalarial agents and international travel of Icelanders were reviewed.

Results:
Thirty-one cases of malaria were confirmed in Iceland during 1998-2014, 1.8 cases/year on average, a rate of 0.6 cases/100.000 inhabitants/year. The rate was 0.3/100.000 inhabitants/year in the previous study 1980-1997 (p=0.056). Plasmodium falciparum was identified in 71% of cases, P. vivax in 16%, P. ovale and P. malariae in 7% each. Only 2 patients (7%) had used chemoprophylaxis prior to diagnosis. Two patients needed intensive care, but no fatalities were documented. One patient had a relapse. The most common agent used for treatment was atovaquone with proguanil, however annual sales figures plateaued during 2010-2014 despite a significant increase in foreign travel by Icelanders during the same period.

Conclusion: The detection rate for malaria in Iceland showed a tendency for increase between study periods while a slight decrease was noted in the neighbouring countries at the same time. The importance of antimalarial chemoprophylaxis and other preventive measures among Icelandic travellers to endemic areas needs to be emphasized.

Figure 1
Identification of confirmed malaria cases, Iceland 1998-2014.

Figure 2
The number of confirmed malaria infections, Iceland 1998-2014. No significant change was noted during the study period.

Figure 3
Annual sales figures for antimalarial agents in Iceland in comparison with international travel of Icelanders through the international Airport Leifsstöð in Keflavík. The left y-axis shows sales by defined daily doses (DDD). The right y-axis shows the annual number of international travel by Icelanders   through Keflavik Airport Leifsstöð (grey line). Atovaquone – proguanil (orange line) and Mefloquine (blue line) were chosen as both agents only have malaria prevention and therapy as their indication. Mefloquine was withdrawn from the Icelandic market by the distributor in August 2013.

Table 1 - Description of cases

Table 2 - Blood test results

Table 3 - Treatment, length of hospital stay and patient outcome

Kristján Godsk Rögnvaldsson¹, Sigurður Guðmundsson^1,2, Magnús Gottfreðsson^1,2

¹Faculty of Medicine, School of Health Sciences, University of Iceland, ²Landspitali University Hospital, Reykjavik, Iceland.