Introduction:
Giardiasis is one of the widespread diarrheal diseases of humans caused by the protozoan parasite Giardia intestinalis. Annually in Poland, about 2000 symptomatic cases of giardiasis are registered. The clinical symptoms of giardiasis include acute or chronic diarrhea, malabsorption, abdominal pain and weight loss.

Aim:
An epidemiological analysis of the morbidity of giardiasis registered in the Warmia and Mazury province between 2009 and 2013.

Material and methods:
The symptomatic cases of giardiasis noted in the annual reports of selected infectious diseases (document MZ-57) by the Department of Epidemiology of the Voivodeship Sanitary-Epidemiological Station in Olsztyn were examined. The analyses were conducted with regards to seasonality, the number of cases and their distribution according the patient’s age, gender and place of residence.

Results and discussion:
In the Warmia and Mazury province between 2009 and 2013 a total of 694 cases (113–177 per year) of giardiasis were registered with the incidence nearly twice as high as the entire country (Poland 5.2 per 100 000 inhabitants; Warmia and Mazury province 9.6). Children up to 9 years of age represented 61.5% (n = 427) of all noted cases. No gender-specific differences were observed. Far more infected peoplewere in urban areas (n = 499; 72%) than in rural areas (n = 195; 28%) (P < 0.001). The peak incidences of giardiasis occurred during the winter period.

Conclusions:
This paper provides data for public health education concerning the scope and magnitude of giardiasis in theWarmia and Mazury province and can be used to establish research priorities and to plan future prevention efforts.