Traveler’s diarrhea is an invasive disease associated with travel. The morbidity rate ranges from 30 to 70% and depends on the destination and seasonality. The epidemiology and clinical features of traveler’s diarrhea were first described in 1963. Among the etiological diversity of pathogens, protozoa come to the fore. A significant part is accounted for by Blastocystis spp., D. fragilis, Giardia spp. Other rare causes can be Cryptosporidium parvum, Entamoeba histolytica, Microsporidia and Cystoisospora. Parasitic infestation is most often diagnosed in returning travelers, due to the longer incubation period and the prescription of antibiotics. The diagnosis of traveler’s diarrhea in humans is established taking into account epidemiological, clinical data and the results of special laboratory studies. The latter play a leading role in the evidentiary verification of the protozoan etiology of travelers’ diarrhea, which directly affects the effectiveness of the therapy of patients and the prevention of the development of chronic forms of protozoa and delayed post-infectious complications. Due to technical availability, traditional microscopic methods remain the most popular in the laboratory diagnosis of protozoan intestinal diseases and are based on the detection of «diagnostic forms» of parasites — trophozoites, cysts, oocysts and/or others depending from the features of the life cycle of a specific species of protozoan parasites. However, microscopic methods of diagnosing intestinal protozoan parasitosis have a number of significant limitations: the means and procedures of microscopic examination of faecal smears (coproscopy) are considered satisfactory for the detection of Giardia spp., only to a certain extent (partially) suitable for the detection/identification of Blastocystis spp. and completely unsuitable for performing research aimed at the detection/identification of D. fragilis.
