Environmental hepatitis A detection and awareness on a Native American reservation.

Editor – Inequalities in health between and within populations are a major public concern (1). Hepatitis A incidence among Native Americans is the highest of any subpopulation in the USA, similar to that in developing countries (2). Outbreaks on the Hoopa Valley Reservation, California, reinforce the cyclical trend of community infection. During the last outbreak in 1993-95, over 10% of the community were treated for exposure to hepatitis (D. Marshall, personal communication). Several environmental factors exacerbate the risk of hepatitis A infection, including dumping of human waste near swimming and camping areas, high winter groundwater and old septic tanks, and an itinerant community in the area. To evaluate the environmental risk of infection by hepatitis A virus (HAV) on the reservation, sample sites were selected by assessing the opportunity for virus-infected faeces to enter the water and by examining the levels of water use. Global Information System (GIS) technology data and previous thermotolerant (faecal) coliform testing results were used for this purpose. Five litres of water were collected from each of 24 environmental sites, representing a cross-section of source water (rivers and creeks) and groundwater (wells). Previously described methods were modified to accommodate larger samples and laboratory facilities which were a considerable distance away, over 443 km, from the reservation (3). Briefly, 1-litre water samples were passed over a positively charged filter, transported, and eluted with urea–arginine phosphate buffer. Following RNA extraction using guanidi-nium isothiocyanate, reverse-transcription polymerase chain reaction (RT-PCR) detected the presence of HAV based on amplification of a 247-bp amplicon sequence bridging the VP3/VP1 regions (nucleotides 2413–2389). Positives from agarose gels were purified and sequenced (4). The molecular detection technique reliably detected 30 plaque-forming units (PFU) of HAV per litre of environmental water. Positive and negative controls for RT-PCR and the entire protocol confirmed that the technique was consistently executed. One of the five samples from a creek was consistent with presence of HAV; nucleotide sequencing of the fragment showed a sequence identical to HAV strain HM-175. In addition, a person upstream of the sampling site showed symptoms consistent with HAV, indicating a possible source of water contamination. Ruling out contingencies proved futile, as the symptomatic individual would not consent to an HAV test and not enough RNA remained for expanded RT-PCR. Health education for culturally appropriate hepatitis A prevention was tailored to Native Americans at Trinity Valley Elementary School (ages 5-13) and Hoopa Elementary and High School …