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BIOMARKERS OF VIRAL EXPOSURE
FOUT, G. BIOMARKERS OF VIRAL EXPOSURE. Presented at Biosolids Exposure Workshop, Cincinnati, OH, March 17, 2006.
The objectives of this task are to:
Viral and protozoan pathogens associated with raw sludge can cause encephalitis, gastroenteritis, hepatitis, myocarditis, and a number of other diseases. Raw sludge that has been treated to reduce these pathogens can be used for land application according to the regulations specified in 40 CFR Part 503. However, little data on the efficacy of typical full-scale treatment processes employed to inactivate pathogens found in biosolids exists due to the high cost of assays. In addition, while laboratory-scale studies are often used to demonstrate the effectiveness of new treatment processes, the methods available do not detect all of the pathogens that would be expected to cause disease following biosolids applications.
EPA has received numerous complaints from individuals and environmental groups stating that people and livestock near biosolids applications have experienced illness. However, outbreaks have not been linked to biosolids applications. Nevertheless, more research is needed to verify that there is no risk associated with this practice. Epidemiological-based studies that could provide needed exposure data are expensive, difficult to conduct and interpret and, more importantly, usually exclude children, who are more susceptible than adults to many of the diseases that are associated with enteric pathogens. As suggested by the National Research Council in 2002, better methods for exposure measurement are needed.
EPA has initiated a new study of infections from drinking water using technology that is directly applicable to biosolids exposure studies. The new study will target salivary antibodies to assess exposure to Cryptosporidium, noroviruses and rotaviruses. Saliva has major advantages over serum as a medium for antibody detection in that the non-invasive collection of saliva can be applied to children and is much more acceptable to all study participants. The study is using a novel, highly sensitive analytical method for antibody analyses. The method uses an array of fluorescent beads, which allows simultaneous detection and quantification of salivary antibody responses to multiple pathogens and immunoglobulin types in a single assay. This system has significantly less cost and variability than standard enzyme-linked immunosorbent assays. The drinking water exposure study will measure immune responses in study participants on a monthly basis before and after a new drinking water treatment plant that meets bin 2, Long Term 2 Enhanced Surface Water Treatment Rule requirements comes on line. This presentation will discuss the methods used in the drinking water study and how they would be applicable to similar studies related to biosolids.