부산대학교 도서관

Intestinal worms, or soil-transmitted helminths (STHs), affect hundreds of millions of people in all tropical and subtropical regions of the world. The most prevalent STH is Ascaris lumbricoides. Through large-scale deworming programs, World Health Organization aims to reduce morbidity, caused by moderate-to-heavy intensity infections, below 2%. In order to monitor these control programs, stool samples are examined microscopically for the presence of worm eggs. This procedure requires well-trained personnel and is known to show variability between different operators interpreting the slides. We have investigated whether ABA-1, one of the excretory-secretory products of A. lumbricoides can be used as a coproantigen marker for infection with this parasite. Polyclonal antibodies were generated and a coproantigen ELISA was developed. Using this ELISA, it was found that ABA-1 in stool detected Ascaris infection with a sensitivity of 91.5% and a specificity of 95.3%. Our results also demonstrate that there is a correlation between ABA-1 levels in stool and A. lumbricoides DNA detected in stool. Using a threshold of 18.2 ng/g stool the ABA-1 ELISA correctly assigned 68.4% of infected individuals to the moderate-to-heavy intensity infection group, with a specificity of 97.1%. Furthermore, the levels of ABA-1 in stool were shown to rapidly and strongly decrease upon administration of a standard anthelminthic treatment (single oral dose of 400 mg albendazole). In an Ascaris suum infection model in pigs, it was found that ABA-1 remained undetectable until day 28 and was detected at day 42 or 56, concurrent with the appearance of worm eggs in the stool. This report demonstrates that ABA-1 can be considered an Ascaris -specific coproantigen marker that can be used to monitor infection intensity. It also opens the path for development of point-of-care immunoassay-based tests to determine A. lumbricoides infection in stool at the sample collection site. Author summary: Intestinal worms are one of the most common infections in tropical and subtropical parts of the world. The roundworm Ascaris lumbricoides is the most prevalent and efforts are ongoing to use preventive chemotherapy to reduce both prevalence and intensity of this infection. To monitor these programs, stool-based microscopy is currently used. We have investigated the possibility of using ABA-1, an abundantly secreted protein from the worm, as a biomarker in stool of infected individuals. We have developed an ELISA and using this assay determined that ABA-1 as stool biomarker had a sensitivity of 91.5% and a specificity of 95.3% to detect infection with A. lumbricoides. We also showed that ABA-1 in stool rapidly and strongly decreased upon administration of a standard anthelminthic treatment. The main asset of this novel stool biomarker is its potential to be used in of point-of-care immunoassay-based tests to determine A. lumbricoides infection in stool at the sample collection site. [ABSTRACT FROM AUTHOR]