Development of an ELISA for serosurveillance of human hookworm

Hookworm infection, caused by Necator americanus, Ancylostoma duodenale, and Ancylostoma ceylanicum is a leading cause of malnutrition and stunted growth in poor communities across sub-Saharan Africa, Asia, and parts of South America. Recent studies have revealed the re-emergence of this parasite in the USA. The burden of hookworm infection is generally associated with chronic illness rather than mortality in the host. Anemia, stunted development, and intellectual and cognitive deficiencies are among the most serious outcomes of persistent hookworm infections in children and women of reproductive age. In addition, chronic low-intensity hookworm infection reduces vaccine efficacy and exacerbates other globally relevant infectious diseases such as tuberculosis, malaria, and HIV, which are co-endemic with hookworm. Current strategies to control hookworm rely primarily on the Mass Drug Administration of anthelminthic drugs. However, recent evidence calls into question the long-term effectiveness of this approach to control and eliminate hookworm in endemic populations, raising concern about the emergence of drug resistance. The current method to screen for STH infections is microscopic demonstration and quantification of eggs in the stool. For screening, WHO considers the Kato-Katz thick smear as a benchmark for diagnosing hookworm infection. This method, however, has poor sensitivity. Processing multiple smears per sample or examining multiple samples over consecutive days can increase the sensitivity of the Kato-Katz thick smear. While screening multiple samples improves sensitivity, it presents considerable logistical and financial challenges and is not practical in all settings. To address this, WHO recently published a Target Product Profile for soil-transmitted helminths to develop low-cost screening tools that meet demands, currently not met by the Kato-Katz thick smear. To address this need, in Phase I we propose the development of an ELISA to screen for human IgG against hookworm infection. In collaboration with Yale University, we will perform a combination of in-silico and in-vitro studies, to help characterize biomarkers of interest (Aim 1), which will be used in the development of an ELISA (Aim 2). We will then evaluate assay performance (Aim 2) using well-characterized cohorts of serum samples. Our goal is to achieve sensitivity and specificity as outlined in the TPP, with further improvement in Phase II. The proposed commercial ELISA kit will allow for the replacement of the existing, relatively insensitive microscopic tools, to integrate as part of monitoring and evaluation programs for hookworm infection around the world. This will directly impact future global policy and strategy for the control of hookworm infection.