Assessment of immediate and delayed hypersensitivity skin tests with Schistosoma mansoni adult worm antigen in a rural Egyptian population
Higashi, G.I.; El-Asfahani, A.M.; El-Bolkainy, M.N.; Chu, E.W.; Raafat, M.
Tropical and Geographical Medicine 32(3): 245-250
1980
ISSN/ISBN: 0041-3232 PMID: 7210159 Document Number: 156420
Of 418 farmers from Dakahlia Governorate, Egypt, examined for immediate and delayed hypersensitivity responses to schistosome adult worm skin test antigen, 98% (411) showed a reaginic hypersensitivity to 20 mu g protein antigen. All were 20 years old or older and were part of a study to detect schistosomal urinary bladder cancer. Of 108 adult urban dwellers without antecedent or current history of schistosomiasis, 35% (38) showed a reaginic hypersensitivity to 20 mu g protein antigen. 43% (180) of the farmers and 4.6% (5) of the controls showed positive delayed responses. Urine from 339 of the farmers was examined using the Nuclepore filtration technique and cytotology smears, 17 (5%) and 20 (6%), respectively, being positive for Schistosoma haematobium eggs. Of a subsample of 97 examined by microscopic examination of terminal urine sediment, 21 were positive for S. haematobium. 44 of the 97 also had S. mansoni eggs in stool samples. Both species were found in 12 individuals. Positive immediate skin tests performed in 91 of the subsample of 97 were similar for egg positive (63 of 64) and egg negative (27 of 27) farmers but for the delayed skin reactions 7 of the egg negative and 35 egg positive individuals were positive.