Imported giardiasis: impact of international travel, immigration, and adoption.

From the Swedish national database, regarding notified Giardia cases, we could for the period 1997-2003 identify 3,697 cases of travel-associated giardiasis, 4,151 cases in newly arrived immigrants and refugees, and 455 cases in internationally adopted children. These were compared with data sets on the number of international travelers, immigrants/refugees, and adopted children. The overall risk of being notified with giardiasis in returning travelers was 5.3 of 100,000, with the highest incidences in travelers from the Indian Subcontinent (628 of 100,000), East Africa (358 of 100,000), and West Africa (169 of 100,000). A large proportion of the travel-related cases were seen in persons with family roots in the country of infection-a risk group deserving special attention. The overall risk in immigrants and refugees was 1,180/100,000 with the highest risk in persons from Afghanistan (3,800 of 100,000) and Iraq (2,990 of 100,000). The incidence was highest among internationally adopted children (8,110 of 100,000), with geographical risks not entirely correlating to those in travelers and immigrants.