Objectives:
Cryptosporidium belongs to enteric parasites responsible for prolonged symptoms in the gastrointestinal tract, both in immunocompetent and immunocompromised individuals. One of the risk factors of infection is contact with an infected person or animals (cattle). The case is described of a young man admitted to the Department of Tropical and Parasitic Diseases of the Medical University in Poznań, Poland, because of watery diarrhea with high fever and in whom symptomatic treatment did not produce any improvement.

Material and Methods:
A 21-year -old male was examined and his epidemiologic history obtained. Primary blood test, anti- Toxocara IgG (ELISA) and anti-Toxoplasma gondii IgG and IgM (ELISA) were performed. PCR detected 16 enteropathogens in a stool sample. Microscopic parasitic stool examination was also performed based on Ziehl-Neelsen method, which allowed the assessment of the presence of cryptosporidium life stages.

Results:
Epidemiology data provided information that the patient was a veterinary student who therefore had many contacts with domestic animals. Multiplex PCR detected a genetic material of Cryptosporidium. The result was confirmed with repeated positive direct stool examinations which gave the evidence of Cryptosporidium spp. oocysts and vacuolar forms of Blastocystis spp.

Conclusions:
1) Cryptosporidium is responsible for watery diarrhea in healthy individuals. 2) Contact with animals (cattle) is a potential risk factor for infection. 3) Protozoan co-infection should be treated to shorten the symptomatic period and to avoid post-infection complications. 4) Different diagnostic methods increase the possibility to establish appropriate diagnosis