Parasitic infections among patients hospitalized in the Tropical and Parasitic Clinic of Poznan University of Medical Sciences, Poland between 2015 and 2018. Is there a relationship between protozoa infection and gastrointestinal symptoms?

Introduction
Diarrhoea is a common reason for hospitalization among travellers returning from the tropics. The aetiology is predominantly bacterial, but it can also be caused by parasites such as Giardia intestinalis, Cryptosporidium spp., and Blastocystis spp.

Aim
We analysed patients from the Poznan Tropical and Parasitic Clinic to evaluate the presence of parasitic infections and to find correlations between infections, journeys, and gastrointestinal symptoms.

Material and methods
In our study we examined 2561 stool samples obtained from patients hospitalized in the Tropical and Parasitic Department of Poznan Medical University, Poland. Microscopic examinations of samples were performed based on a direct thin smear in 0.9% NaCl, which allowed the assessment of the presence of protozoa life stages.

Results
In 106 (4.14%) of the 2561 examined samples we detected parasites, mainly from people coming back from tropical areas (61.32%). Mostly we detected Blastocystis sp. and Giardia intestinalis. Fifty percent of patients suffered from gastrointestinal symptoms, so careful microscopic stool examination should be performed in every case in which intestinal pathology occurs, and certainly in travelling individuals.

Conclusions
Traveling is a real risk factor for protozoa infection. The most common parasites detected in the stool are Blastocystis sp. and Giardia intestinalis. Parasitic coinfection should be taken into consideration as a pathologic agent in patients suffering from abdominal signs and persistent diarrhoea. Prolonged protozoa infection and its role in microbiota alterations requires further investigation.