Dirofilariasis is a parasitic disease of dogs and other carnivores transmitted mainly by the mosquitoes of the genera Culex, Aedes, Anopheles. Full life cycle of the Dirofilaria nematodes in humans is extremely rarely observed, usually lacking species determination at the molecular level. We report fully documented unusual clinical manifestation of subcutaneous dirofilariasis with intensive microfilariemia in peripheral blood revealed by the Knott's concentration technique. The identification of the Dirofilaria repens nematode was based on typical morphological findings for adult gravid female nematode found in the histopathological preparations. The morphology of microfilariae obtained from patient's peripheral blood was also typical for D. repens. The final identification was confirmed by the molecular analysis of microfilariae collected from the blood.

Intestinal coccidian parasites are intracellular protozoa most frequently transmitted during food-borne and water-borne infections. This group of parasites is responsible for acute diarrhoeal illnesses especially among immunocompromised patients. However, they are more frequently detected in immunocompetent individuals including travellers, and they should also be considered as important etiologic factors of travellers' diarrhoea. We examined 221 immunocompetent patients hospitalized due to acute or chronic diarrhoea and other gastrointestinal symptoms after returning from international journeys to hot climates. A basic microscopical examination and acid - fast staining of stool samples was performed. Each patient was also a part of the epidemiological investigation to define potential risk factors of tropical gastrointestinal infections. Intestinal coccidiosis was confirmed in 12 out of 221 successively hospitalized patients (5.4%). The most common coccidian parasite was Cryptosporidium spp., detected in nine Polish travellers (4.1%). Cyclospora spp. was diagnosed in three cases (1.4%), including two mixed infections with Cryptosporidium spp., and Cystoisospora spp. in two other cases (0.9%). The study has revealed that intestinal coccidian parasites are a significant threat to immunocompetent travellers and should be always considered in the differential diagnosis of gastrointestinal disorders. Therefore, it is necessary to perform specialized diagnostic methods for the detection of Cryptosporidium spp., Cystoisospora spp., and Cyclospora spp. oocysts in reference parasitology laboratories. Clinical observations demonstrated simultaneously an insufficient level of knowledge in Polish tourists concerning the main risk factors of intestinal parasitic diseases during international travels, particularly to developing countries with lower economic and sanitary conditions.

Protozoa of the genus Cryptosporidium are common parasites of domestic and wild animals—mammals, birds, reptiles, and fishes. The invasive forms are thick-walled oocysts, which can be present in water supplies, on fruits, vegetables, or in the soil contaminated with feces. In this work, we describe three cases of middle-aged persons with massive Cryptosporidium hominis infection and chronic diarrhea with no immunological abnormalities and no history of previous travels to tropical countries. The lesions discovered during colonoscopy within the large intestine–cryptitis and the histopathological changes were related to massive cryptosporidiosis. All these statements indicate necessity of parasitological stool examination in cases with chronic diarrhea in which no etiological agents are detected, but not only in HIV positive individuals. Parasite’s eradication leads to symptom disappearance as well as improvement of histopathological mucosa alterations.

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.Parasitic infections among patients hospitalized in the Tropical and Parasitic Clinic of