THE ROLE OF BLASTOCYSTIS-HOMINIS AS A POSSIBLE INTESTINAL PATHOGEN INTRAVELERS

The role of Blastocystis hominis as a pathogen for man has been contro versially discussed, while travel history has been implicated as a ris k factor of infection. Few controlled studies of the association betwe en B. hominis and symptomatic diseases have been performed. Therefore, a case-control study among 795 German tourists returning from tropica l countries was conducted, The prevalence of the organism among patien ts with and without symptoms was assessed. Blastocystis hominis was de tected in 69 of 469 (14.7%) patients with diarrhoea and in 21 of 326 ( 5.7%) controls. However, other organisms causing diarrhoea were detect ed in 18 of the 69 (26.1%) symptomatic patients with B. hominis, Thus, 51 of 469 (10.8%) symptomatic patients had B. hominis in the absence of other pathogens in their stool, significantly more than in the asym ptomatic group (5.2%; P = 0.005). Irrespective of the development of s ymptoms, the organism was most frequently acquired during journeys to the Indian subcontinent The results of this study suggest that B. homi nis is associated with development of diarrhoea in travellers to tropi cal destinations and that frequently concurrent infections with other organisms occur.