ABSTRACT

Carriage detection in food workers is very important in protecting public health from Giardia and Cryptosporidium infections which are two of the major causes of food borne outbreaks. However, false negative results can be reported with routine methods such as native-lugol and acid-fast staining in the carriers. In this study, we aimed to determine the appropriate method for carrier screening by comparison of the different analyses used in the diagnosis of Giardia and Cryptosporidium in food workers.

Stool specimens of 500 food worker who applied to our laboratory for carrier screening were investigate by routine microscopic examination with native-lugol and Kinyoun acid-fast stain method and searched for Giardia and Cryptosporidium antigens with Direct Fluorescent Antibody (DFA) and immunochromatographic assay.

As a result of the study, Giardia spp. was detected with native-lugol staining method, immunochromatographic assay and DFA assay as 13 (2.6%), 8 (1.6%), 24 (4.8%) respectively of specimens whereas Cryptosporidium spp. was not determined. When DFA assay was considered the reference method, sensitivity and specificity of the native lugol method and immunochromatographic assay were found to be 54.1%, 100% and 33.3%, 100% respectively.

In our study, we were found low sensitivity of immunochromatographic method and it is inappropriate as a test for detecting carriers in food workers. We concluded that, to be able to detect other parasites, the native-lugol method must be performed for screening carriers, and patients who were found Giardia and Cryptosporidium negative by this assay should be confirmed with more sensitive immunodiagnostic method. (Turkiye Parazitol Derg 2013; 37: 4-8)

Keywords: Food worker, Giardia, Cryptosporidium