Biomedical subjects

A G Ross

Publications and source records attributed to A G Ross.

40 records · Page 3Linked to original sources

PubMedDate not supplied

Human susceptibility to Schistosoma japonicum in China correlates with antibody isotypes to native antigens.

Antibody isotypic responses (IgE, IgA, IgG1, IgG2, IgG3 and IgG4) to Schistosoma japonicum antigens--adult worm (AWA), soluble egg (SEA) and the recombinant proteins TEG (22.6-kDa tegumental antigen, Sj22) and PMY (paramyosin, Sj97)--were measured (in 1998) in a cohort of 179 Chinese subjects 2 years post-treatment. Subjects in the highest intensity re-infection group (> 100 eggs per gram faeces) had significantly higher levels of IgG1 and IgG4 against AWA. Analysis of IgG4/IgE ratios for AWA and SEA linked IgG4 excess to re-infection and IgE excess to non-re-infection. Two years after chemotherapeutic cure, 29 subjects, who were re-infected or never infected but highly water-exposed, were classified as epidemiologically susceptible (n = 15) or epidemiologically insusceptible to infection (n = 14). IgG4 levels against native antigens (AWA and SEA) were higher in susceptible and IgE levels were higher in insusceptible but antibody responses to the recombinant proteins (PMY and TEG) showed no clear pattern or difference between susceptibility groups. These and earlier findings provide evidence that immunity develops against schistosomiasis japonica in China and that susceptibility/resistance correlates with antibody isotypes against native schistosome antigens.

Adolescent↗

PubMedDate not supplied

Serological diagnosis of Schistosoma japonicum infections in China.

This paper reports the results of the dot enzyme-linked immunosorbent assay (dot-ELISA) for the serological diagnosis of 50 acute and 50 chronic Schistosoma japonicum-infected patients employing keyhole limpet haemocyanin (KLH) and soluble egg antigen (SEA) as the specific antigens. The sensitivity of both antigens for the detection of both forms of this infection was 100% and 90%, respectively, using a test serum dilution of 1:100. When the serum dilution was adjusted to 1:500, the sensitivity of the KLH dot-ELISA was 82% and 15%, respectively. Thus, the different manifestations of this disease can be easily distinguished. None of the 44 uninfected control sera gave a positive result with the KLH dot-ELISA, though 6 (14%) did so with the SEA dot-ELISA. Cross reactivity rates of 13% and 23% were observed for clonorchiasis (n = 30) and paragonimiasis (n = 22). Therefore, the overall diagnostic effectiveness of both the KLH dot-ELISA and SEA dot-ELISA for the detection of S. japonicum infection in endemic regions in China was 97% and 92%, respectively.

Acute Disease↗

PubMedDate not supplied

Diagnosis of schistosomiasis japonica in Chinese schoolchildren by administration of a questionnaire.

This paper describes a rapid, simple, cost-effective questionnaire for screening school-aged children at risk for Asian schistosomiasis in China. Five hundred and thirty-two children, aged 8-14 years, were selected from 3 schools in an area moderately endemic for Schistosoma japonicum in Hunan province. The questionnaire, comprising 15 multiple-choice questions, was administered by teachers in order to collect both ethnographic and epidemiological data relevant to current S. japonicum infections. This was followed by Kato-Katz thick smear stool examinations, miracidium hatching tests, and soluble egg antigen-enzyme linked immunosorbent assays in order to validate the efficacy of the questionnaire approach. The results from a combination of all 3 procedures indicated that the overall schistosomiasis prevalence in the 3 schools was 29.9% (138/472). Six risk factors (episodes of diarrhoea, frequency of water contact, school grade attained, weakness, past history of S. japonicum infection(s), and whether a subject had been previously treated for schistosomiasis) in the questionnaire were determined by logistic regression to be highly statistically significant predictors of individual current infection. The sensitivity (93.7%), specificity (91.9%) and low cost (c. US$ 0.6/true positive case) associated with the 6 variables model make the questionnaire approach a very useful diagnostic tool for screening marshland and lake communities at high risk for schistosomiasis in China before selective treatment with praziquantel or diagnostic follow-up. An even simpler 3 variables 'yes/no' model was derived from the questionnaire and found to be nearly as good at predicting individual infection (sensitivity 86.2% and specificity exceeding 97.6%) and extremely simple to use. If validated in other ecological settings in China the questionnaire, modified or as presented here, could be adopted by the national schistosomiasis control programme.

Adolescent↗

PubMedDate not supplied

[Quality and health care reform in Latin America and the Caribbean].

Improving the quality of basic health services, together with the search for equity, efficiency, sustainability, and social participation, has been one of the guiding principles of health sector reform initiatives ever since the I Summit of the Americas was held in 1994. This article addresses some basic concepts, examines the status of quality control within health systems and services in Latin America and the Caribbean, and analyzes the most important trends observed in the Region in the establishment of quality assurance programs. Finally, ways of improving and monitoring quality continuously and sustainable are recommended.

Caribbean Region↗