Diagnosis of intestinal amebiasis using salivary IgA antibody detection.

Attempts were made to use soluble antigen extract of strain HK-9 of Entamoeba histolytica to detect salivary IgA antibodies in intestinal amebiasis patients by using ELISA. Total salivary samples of 109 individuals were divided into four groups. Group I comprised 32 patients whose stools were positive only for E. histolytica cysts and/or trophozoites. Group II comprised 12 individuals whose stools were positive for E. histolytica and other intestinal parasites. Group III comprised 36 individuals whose stools were negative for E. histolytica but contained other intestinal parasites such as E. coli, E. nana, Blastocystis hominis, Trichomonas hominis, Giardia lamblia, Opisthorchis viverrini, and hookworm. Group IV comprised 29 healthy individuals whose stools were free from any intestinal parasitic infections. Based on the mean optical density, OD + 2SD of the results from 29 parasitologically negative healthy individuals, the cut-off OD value for salivary IgA antibodies was 1.265. Therefore, the assays were positive in 14 out of 32 (43.75%) of group I and 2 out of 12 (16.6%) of group II. The assays were positive in 16 out of 36 (44.44%) for group III whereas 2 out of 29 (6.90%) for group IV were positive. The overall sensitivity and specificity of the assays were 36% and 72%, respectively. The false positive rate was 28% and the false negative rate was 64%. The predictive values of positive and negative results were 47% and 63%, respectively. The diagnostic accuracy of ELISA for the presence of salivary IgA antibodies was 58%.

Intestinal parasitoses among the workers and their families at three electricity generating dams in Thailand.

During September 17, 1980 - May 29, 1981 a total of 986 single stool specimens were collected from workers and their families at three electricity generating dams under the administration of the Electricity Generating Authority of Thailand (EGAT). Parasitological surveys were carried out at the dam sites, namely the Khoa Laem Project, the Srinakarin Dam and the Ubolratana Dam. The overall prevalence at all three sites are moderately high (62.50%, 45.33% and 54.05% respectively). The Khoa Laem project had the highest prevalence of E. histolytica infection (16.16%) which may be the result of poorer sanitary standards for workers of the project under construction. The occurrence of opisthorchiasis at the first two sites situated in central Thailand (12.19% and 7.01%) is the result of influx of migrant northeastern workers. The prevalence of other parasites are not remarkable. However, because of the proximity of the people living close to the large bodies of fresh water, urgent measures should be taken to eradicate the parasitic infections among them in order to prevent the spread through the water.