EPIDEMIOLOGIC FEATURES OF INTESTINAL PARASITIC INFECTIONS IN ITALIAN MENTAL INSTITUTIONS

To determine the prevalence of intestinal parasitic infections in the residents of four Italian psychiatric institutions, we examined the st ool specimens collected in triplicate from 238 residents, enrolled bet ween May 1995 and May 1996. Besides, physician and staff nurses provid ed data about each resident by standardized questionnaires. Parasites were detected in the fecal samples from 128 patients (53.8%). However, in the stool specimens from 106 residents only non-pathogenic protozo a were found (82.8%). Trichuris trichiura ova, Giardia lamblia cysts a nd trophozoites, Cryptosporidium parvum oocysts, and Balantidium coil cysts were found in the fecal samples from 22 residents (9.2%). B. hom inis was the most prevalent parasite. It was detected in the fecal spe cimens from 97 residents (40.8%). The so-called nonpathogenic amebae w ere detected in the fecal specimens from 65 residents, though, at the same time, there was no evidence of Entamoeba histolytica infection. T welve residents (5.0%) showed intestinal colonization by nonpathogenic flagellates. All the subjects with T. trichiura infection were housed in the facility of Ancona. Parasites were found in fecal samples from all the 11 residents with behavioural aberrations, but only three of those suffering from intestinal pathogen infection associated to diarr hea. Statistical analyses revealed that the presence of pathogenic par asites in fecal specimens was significantly associated with diarrhea, nausea, vomiting, abdominal pain, fever, behavioural aberrations and n onpathogenic protozoa (p < 0.01), but did not demonstrate any other si gnificant associations between these parasites and the other variables , such as pruritus, mucus or blood in the stools and presence of fecal leukocytes. On the other hand, the presence of nonpathogenic protozoa was significantly related to aberrations such as pica, geophagia, phy tophagy, coprophagy, coprophilia and pathogenic parasites (p < 0.01). Data analyses revealed that both pathogenic and nonpathogenic parasite s were significantly more common in institutionalized patients than in controls. The rare presence of clinical signs and symptoms in coloniz ed patients represents an important public health problem, since the p resence of asymptomatic carriers among residents with low hygienic con ditions, raises concern of transmission of parasitic infections to pro fessional staff and other residents. Since the eradication of parasiti c colonization in residential facilities is hard to reach, an effectiv e prevention is the only measure to deal with this public health probl em.