Field Comparison of Immunodiagnostic and Parasitological Techniques for the Detection of Schistosomiasis Japonica in the People’s Republic of China

Abstract

A total of 1,811 individuals from two villages located in the areas of China endemic for Schistosoma japonicum were analyzed by the Kato-Katz parasitologic examination, indirect hemagglutination assay (IHA), and enzyme-linked immunosorbent assay (ELISA). Statistical analysis of the results showed the kappa indices ranged from 0.106 to 0.234 between IHA and the stool examination and ranged from 0.037 to 0.134 between ELISA and the fecal examination. The sensitivity value of the IHA was 83.7% in Village A and 92.3% in Village B; the specificity value of the IHA was 55.8% in Village A and 67.3% in Village B. The sensitivity value of the ELISA was 88.4% in Village A and 96.2% in Village B; the specificity value of the ELISA was 38.4% in both Village A and Village B. A search for a good diagnostic test that can be applied in field situations in China should be given high priority.

An Integrated Strategy for Transmission Control of Schistosoma japonicum in a Marshland Area of China: Findings from a Five-Year Longitudinal Survey and Mathematical Modeling

“…Moreover, the dilemma in the detection of S. japonicum infection in humans still remains. 16,17,24 The KK method, a standard method for the detection and quantification of egg burdens in humans, 19 has very poor sensitivity, especially when the intensity of infection is very low. 16,17 In our study, the infection intensity in humans gradually reduced along with the decrease in human infection rate.…”

“…The "observed" prevalence of infection among humans used in the model were adjusted according to the sensitivity (65%) and specificity (100%) of the KK method, respectively 16,24 ; because specificity = 100%, the "adjusted" prevalence = the "observed" prevalence/sensitivity. The unit of snail density (snails/0.11 m 2 ) was converted into snails/m 2 when it was used in the model.…”

“…The coverage of selected human treatment with praziquantel is assumed to be 45% (i.e., 45% of infected humans were treated with praziquantel) and the drug efficacy is assumed to be 85% (e.g., 85% of treated infected humans are cured). 16,23,24 A 20% reduction in human water contact and 30% coverage of sanitation facilities were assumed from the sanitation improvement. A reduction in 35% snail habitats was assumed to manage agricultural practice with 40% reduction in density of snails.…”

“…14 Specifically, these interventions included that 1) all bovines were removed from the study area (e.g., some farm bovines were replaced with tractors, or transferred to non-endemic regions; some bovines were killed) in February, 2006; 2) all residents 5 to 65 years of age in the study area, except those who received direct fecal examination from the 12 natural villages and the school, were examined annually using indirect hemagglutination assay (IHA) [15][16][17] in autumn, and all IHA positives were subjected to fecal examination (e.g., Kato-Katz egg count) to confirm infection. Residents with positive egg counts were treated with a single oral dose of praziquantel (40 mg/kg of body weight) as recommended by the World Health Organization (WHO) 18 ; 3) improved sanitation facilities(e.g., sanitary lavatories and piped water were installed; 4) a health education program was Abstract.…”

Diagnosing schistosomiasis: where are we?

“…IHA was applied in Chinese population studies as an alternative test to detect human infection with S. japonicum. Although this technique shows good levels of sensitivity (71%-97%) 27 , its specificity is low or varies considerably 28 , making it unsuitable for individual diagnosis and treatment. Its application at the population level is also limited and can only be recommended as an auxiliary method for pre-control use, due to drawbacks, some of them also common in other immunological techniques: a) sensitivity, depending on which standard is applied; b) intrinsic test characteristics, such as antigen and erythrocyte type; c) prevalence of infection in the investigated community; d) possible persistence of positive reactions after treatment; and e) cross-reactions with other helmiths 29 .…”