Innovative Technique Diagnoses Intestinal Parasitic Infections

A recently developed method for directly diagnosing intestinal parasites has been evaluated in the field and compared with standard methodology.

Soil-transmitted helminthes and intestinal protozoa infection are widespread in developing countries, yet an accurate diagnosis is rarely performed as the highly trained laboratory scientists required are seldom available in poor resource settings.

Microbiologists at the San Raffaele Hospital (Milan, Italy) in collaboration with others, analyzed stool samples from 180 pupils from two primary schools in India and Tanzania. Three diagnostic methods were used: direct fecal smear, formol-ether concentration method (FECM) and mini-FLOTAC. The latter is a simplified device and one of the main advantages of this method is that it can be more easily transferred and carried out in laboratories with limited facilities as there is no centrifugation required. The mini-FLOTAC comprises two physical components, the base and the reading disc. There are two 1-mL flotation chambers, which are designed for optimal examination of fecal sample suspensions in each flotation chamber and which permits a maximum magnification of ×400.

Overall, 72% of the pupils were positive for any intestinal parasitic infection, 24% carried dual infections, and 11% had three infections or more. The most frequently encountered intestinal parasites were Entamoeba coli, Entamoeba histolytica/dispar, Giardia intestinalis, hookworm, and Schistosoma mansoni in Tanzania. Significant differences were found in the detection of parasitic infections among the three methods. The mini-FLOTAC was the most sensitive method for helminthic infections at 90%, for the FECM provided 60% detection, and only 30% for the direct fecal smear. However, the FECM was the most sensitive for intestinal protozoa infections at 88% with 70% for direct fecal smear, and 68% for the mini-FLOTAC.

The authors concluded that the mini-FLOTAC for the diagnosis of intestinal helminthes and protozoa is a valid, sensitive, and potentially low-cost alternative technique that could be used in resource-limited settings, particularly for helminthic diagnosis. The mini-FLOTAC and fill-FLOTAC were invented and patented by Prof. Giuseppe Cringoli (University of Naples Federico II, Italy).

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San Raffaele Hospital
University of Naples Federico II