Microscopic detection of intestinal Sarcocystis infection diagnosed in international travelers at the Institute of Tropical Medicine, Antwerp, Belgium, from 2001 to 2020

Although a stay in tropical regions is considered a risk factor for acquiring Sarcocystis infection, to date intestinal sarcocystosis has never been described in returning travelers. We did a retrospective cross-sectional study, retrieving all Sarcocystis spp. microscopy-positive stool results of individuals who attended the travel clinic of the Institute of Tropical Medicine, Antwerp in the period from 2001 to 2020. We reviewed the medical records and report on the epidemiology and clinical features of intestinal sarcocystosis in international travelers. In 57 (0.09%) of 60,006 stool samples, oocysts or sporocysts of Sarcocystis spp. were found, often together with other intestinal infections. Twenty-two (37%) individuals were asymptomatic, 17 (30%) had intestinal ± extraintestinal symptoms, and 18 (32%) had extraintestinal symptoms only. Only one traveler had symptoms suggestive of acute gastrointestinal sarcocystosis without an alternative diagnosis. Intestinal Sarcocystis infection predominated in male travelers. At least 10 travelers most likely acquired intestinal Sarcocystis in Africa, where it was never described before. In a national reference travel clinic in Europe, the presence of intestinal Sarcocystis oocysts is a rare finding, predominant in male travelers. Infection with this parasite infrequently leads to suggestive clinical manifestations such as acute gastrointestinal symptoms. Our data strongly suggest that Sarcocystis can be acquired throughout tropical areas, including Africa.