HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Moriearty, P. L. Articles by Lewert, R. M. Search for Related Content PubMed PubMed Citation Articles by Moriearty, P. L. Articles by Lewert, R. M.

Delayed Hypersensitivity in Ugandan Schistosomiasis

II. Epidemiologic Patterns of Intradermal Responses^*

Pamela L. Moriearty AND Robert M. Lewert

Intradermal tests for immediate hypersensitivity (IHS) and delayed hypersensitivity (DHS) to Schistosoma mansoni adult worm and cercarial antigens and stool examinations were carried out among residents of Uganda with different histories of exposure to S. mansoni. Among residents of a highly endemic village, S. mansoni eggs were found in the stools of 83% of adult males and children and 49% of adult females; DHS responses among infected individuals ranged from 30% in adult females to 64% in adult males. Stool egg counts did not increase significantly with longer residence among professional fishermen of the village, a group in which DHS reactions were common. In a survey of an area of low endemicity 11% of stools were found to contain S. mansoni eggs. DHS responses were less frequent than in the highly endemic area, reaching a peak of 43% among adult males with IHS (1 of 5 adult males with S. mansoni eggs in the stool had DHS). Among former residents of the highly endemic districts of West Nile, Madi, and Acholi currently living in a nonendemic city (Kampala) overt S. mansoni infections were generally less common and less intense than in residents of the highly endemic village, but DHS response patterns were strikingly similar in the 2 groups. DHS responses were retained in some individuals for up to 4 years in the absence of exposure to cercariae. In some immigrants from North America or Europe, apparently light and in some cases recent S. mansoni infections were found; DHS responses in this immigrant group were more frequent than might have been predicted on the basis of results in African residents of an area of low endemicity. DHS responses to schistosome antigen were found among 7% of residents of districts of Uganda not known to be endemic for S. mansoni. Findings in this investigation were consistent with the hypothesis that DHS response frequencies in groups from endemic areas are related to the frequency of past exposure to schistosome infection in the groups. The DHS response may prove to be of use in reconstructing past epidemiological conditions in groups, e.g., after population migrations or treatment programs. It was postulated that the high frequency of DHS responses among recent immigrants may have been influenced by lack of prenatally acquired or genetically determined tolerance to schistosome antigens or to occurrence of Jones-Mote type late reactions. The possible role of DHS in resistance to superinfection in schistosomiasis is considered.

Accepted for publication August 18, 1973.

^* These investigations have been supported in major part by United States Public Health Service—National Institute of Allergy and Infectious Diseases Grant No. AI 00884, and in part by the United States-Japan Cooperative Medical Science Program Grant AI 07724, and by a travel grant from the Rockefeller Foundation: Biomedical Sciences Grant No. GA MNS 6952.

Address reprint requests to: Dr. Robert M. Lewert, Department of Microbiology, University of Chicago, Cummings Life Sciences Center, 920 East 58th Street, Chicago, Illinois 60637.

Trainee, United States Public Health Service Training Grant No. AI 00331.