Cyclospora cayetanensis is an emergent parasite traditionally associated with diarrhoea in travellers to endemic countries. Several cases of cyclosporiasis were also reported in non travellers associated with imported food and waterborne outbreaks. Recently, only sporadic cases were described in Europe, probably because it’s underdiagnosed. Cyclospora is a protozoan very difficult to identify. It’s not detected in specimen routinely tested for ova and parasite, if not explicitly requested. Other reasons include morphologic similarities of Cyclospora cayetanensis oocysts with those of Cryptosporidium; necessity of proficiency in parasitology and probably because its notification is not obligatory in all countries.
We report one case of acquired cyclosporiasis in Portugal in an immunocompromised boy, that is, to the best of our knowledge, the first reported in our country. Cyclosporosiasis should be considered in all persons with persistent or remitting-relapsing diarrheal illness, regardless of immunological status and explicitly requesting testing for this parasite.