WATERBORNE ADENOVIRUS - A RISK ASSESSMENT

Adenoviruses have been detected in raw sewage throughout the world and are associated with a number of human illnesses but their occurrence and pathogenicity have not been well studied. A risk assessment approa ch was used to determine their significance as a waterborne pathogen. There are 47 types of adenoviruses and the diseases resulting from inf ections include conjunctivitis, pharyngitis, pneumonia, acute and chro nic appendicitis, exanthematous disease, bronchiolitis, acute respirat ory disease, and gastroenteritis (types 40 and 41). Adenovirus is cons idered to be only second to rotavirus in terms of its significance as a pathogen of childhood gastroenteritis. Adenovirus infections are usu ally acute and self-limiting with a greater severity of illness occurr ing in the immunocompromised (e.g. AIDS patients and transplant recipi ents). They are reported to be more resistant to inactivation by UV th an enteroviruses and are sometimes detected at higher levels in pollut ed waters. There are documented outbreaks of conjunctivitis due to ade novirus types 3 & 4 associated with swimming in contaminated recreatio nal waters. Based on the data obtained from human dose-response studie s, the exponential model [P-i = 1 -exp(-rN); r = 0.4172] was chosen fo r this risk assessment. Annual risks of infection in drinking water fo r adenovirus at average levels of 1/1,000L to 1/100L ranged from 8.3/1 0,000 to 8.3/1,000, respectively. Using monitoring data from a recreat ional water, risks were calculated to be as high as 1/1,000 for a sing le exposure. (C) 1997 IAWQ. Published by Elsevier Science Ltd.