Twelve Finnish tourists contracted falciparum malaria from Gambia in the period between 3 and 27 November 2008. Three of the patients needed intensive care due to complications. In all these cases there was a delay of at least four days in seeking treatment. All patients recovered.

Usually, between 20 and 30 cases of imported malaria are diagnosed every year in Finland (population 5.3 million); most of them are contracted in Africa. In 2007, three cases were imported from Gambia. The cluster of twelve patients described here raises the total number in 2008 to 36 cases to date.

All twelve patients were thoroughly interviewed. The age distribution was 27-66 years, seven patients were male and five were female. The travellers came from different parts of Finland, and they stayed in different tourist resorts in Gambia, approximately 20 km from the capital city Banjul. One traveller resided in the countryside for one month. The other patients stayed in Gambia for one to two weeks.

All except one had booked the trip from the same travel agency. Five travellers had booked a last-minute trip (booking less than five days before departure). One had bought the trip ten days before, and five more than three weeks before the departure. Booking information for the last case was not available.

Ten of the patients had received information about the risk of malaria in Gambia and knew that prophylaxis using anti-malarial drugs was recommended. Six travellers got the information from the travel agency, two from the internet, one had previous information and one was a healthcare professional. Two travellers had not been informed about the risk of malaria; one of them had booked the trip by telephone, the other one on the internet.

None of the patients had used adequate malaria chemoprophylaxis. Three patients had used chloroquine, which is not recommended prophylaxis for tropical Africa. One of them got the prescription from a physician and two of them used chloroquine - against professional advice - stored from a previous trip. Nine travellers did not use any chemoprophylaxis. One of them was prescribed adequate prophylaxis but did not take it because of warnings about side-effects he had read on the internet.

Ten of the patients had either received information on protection from mosquito bites from the travel agency or had found it on their own from various sources. There was wide variation, however, on how the instructions were followed.

The only travel agency organising package trips to Gambia takes approximately 5,000 Finns yearly to Gambia in the period from mid-October to mid-April. The number of travellers has not increased in the last few years. The National Public Health Institute informed clinical practitioners and sent out a press release about the situation on 14 November 2008, which has had wide media coverage. The travel agency discontinued selling last-minute trips to Gambia immediately and has decided to sell trips no later than two weeks prior to departure and to put extra effort into informing the travellers.

The number of Finnish travellers to this region of Africa has not increased in the last few years. Interestingly, there have been similar clusters of falciparum malaria in travellers returning from Gambia also in other European countries; in total, more than 39 travellers were reported to TropNetEurop and GeoSentinel [1]. It is not clear, if this increase in malaria cases is related to a higher malaria activity in Gambia or to a decrease in compliance with protective measures or in risk awareness among travellers purchasing last-minute package tours. In fact, a recently published analysis showed that the risk to acquire malaria in Gambia seems to have decreased significantly between 1999 and 2007 [2]. But this trend could have been changed in 2008. According to unconfirmed information, the rainy season has been longer than usual this year.

Irrespective of what the reasons for this increase in travel-related malaria are, this cluster demonstrates once again the need for adequate chemoprophylaxis and information on protection from mosquito bites for all travellers to West-Africa.

1. ProMED-mail. Malaria - Europe, USA, ex Gambia. Archive Number 20081201.3775. 1 December 2008. Available from: http://www.promedmail.org/pls/otn/f?p=2400:1001:::NO::F2400_P1001_BACK_PAGE,F2400_P1001_PUB_MAIL_ID:1000%2C74978
2. Ceesay SJ, Casals-Pascual C, Erskine J, Anya SE, Duah NO, Fulford AJ, et al. Changes in malaria indices between 1999 and 2007 in The Gambia: a retrospective analysis. Lancet. 2008;372(9649):1545-54.