Public Health - Environmental Health Science
Field development and validation of a salivary hepatitis E assay in Bangladesh
Hepatitis E virus (HEV) is the leading global cause of acute viral hepatitis; particularly in South Asia where seasonal floods contaminate drinking water supplies leading to frequent hepatitis E (HE) epidemics. Whereas case-fatality rates in the general population can vary from 0.1-3.0%, elevated mortality (10-40%) in pregnant women infected with HEV genotype 1 has been demonstrated consistently in South Asia. Current methods to confirm infection rely on enzyme immunoassays (EIA) for detection of IgM or IgG antibodies to HEV (anti-HEV) in serum or PCR of HEV RNA in serum or stool. Collection of blood and stool is invasive and suffers practical constraints in children under 5 and pregnant women in resource-limited settings which may impede the ability to make frequent follow-up measurements in epidemiologic studies. This research will serve three purposes. First, to optimize and validate an HEV salivary EIA by evaluating the sensitivity, specificity, and reliability of HEV EIAs in de-identified paired saliva and finger-stick blood samples from patients at Dhaka Shishu Hospital, Dhaka, Bangladesh an area where HEV is endemic. Second, to evaluate the acceptance, usability, and reliability of a saliva self-sampling protocol via a brief survey after patients self-sample saliva. And third, to advance efforts to integrate the optimized HEV salivary EIA into ongoing and future epidemiologic studies which would refine understanding of the time windows of seroconversion and progression of infectious vs subclinical HE symptoms. Future studies building on this pilot research will improve the scientific evidence base about the time windows of HEV exposure and infection in populations with unique susceptibility.
Douglas Granger, SON; Barbara Detrick, SOM, Pathology