New methods for the detection of viruses: call for review of drinking water quality guidelines

Abstract

Drinking water supplies which meet international recommendations for source, treatment and disinfection were analysed. Viruses recovered from 100 L-1,000 L volumes by in-line glass wool filters were inoculated in parallel into four cell culture systems. Cell culture inoculation was used to isolate cytopathogenic viruses, amplify the nucleic acid of non-cytopathogenic viruses and confirm viability of viruses. Over a period of two years, viruses were detected in 23% of 413 drinking water samples and 73% of 224 raw water samples. Cytopathogenic viruses were detected in 6% raw water samples but not in any treated drinking water supplies. Enteroviruses were detected in 17% drinking water samples, adenoviruses in 4% and hepatitis A virus in 3%. In addition to these viruses, astro- and rotaviruses were detected in raw water. All drinking water supplies had heterotrophic plate counts of < 100/mL, total and faecal coliform counts of 0/100 mL and negative results in qualitative presence-absence tests for somatic and F-RNA coliphages (500 mL samples). These results call for a revision of water quality guidelines based on indicator organisms and vague reference to the absence of viruses.

Presencia de virus entéricos en muestras de agua para el consumo humano en Colombia: desafíos de los sistemas de abastecimiento

“…Dicha metodología incluye la vigilancia de las fuentes de agua con base en indicadores microbiológicos y fisicoquímicos, la inspección de las prácticas sanitarias de los sistemas de abastecimiento y el mapa de riesgo del agua para consumo humano con énfasis en las cuencas, y el tratamiento previo y posterior. Sin embargo, este sistema no incluye la vigilancia de los virus en el agua para consumo humano en la red de distribución, debido a la complejidad de las pruebas de laboratorio necesarias y sus costos (36). Sin embargo, el análisis de los virus puede incluirse en los mapas de riesgo de la calidad del agua para consumo humano, con el fin de evaluar su impacto en la salud de la población.…”

Detection of Noroviruses in Tap Water in Japan by Means of a New Method for Concentrating Enteric Viruses in Large Volumes of Freshwater

“…The World Health Organization, U.S. Environmental Protection Agency, European Communities, and other organizations have referred to enteric viruses in their drinking water quality guidelines, but few of them specify which viruses should be monitored and what levels of viruses are acceptable (13). It is important to quantify the viral-contamination levels in tap water in order to evaluate the risk of viral gastroenteritis and to prevent it.…”

“…There has been one report of detection of NVs in tap water (23), but this was due to a failure in water treatment (i.e., inadequate chlorination). Other enteric viruses, such as poliovirus, coxsackievirus, echovirus, adenovirus, and hepatitis A virus, have been isolated from treated tap water (2,13,24,38), but most of those reports included the procedure of cell culturing, and the detection of noncultivable viruses has been limited. The detection of NVs depends mainly on reverse transcription-PCR because no host cell is available for the cultivation of NVs (43).…”

Concentration of Enteroviruses, Adenoviruses, and Noroviruses from Drinking Water by Use of Glass Wool Filters

“…The fibers are inexpensive and require no water conditioning outside of pH adjustment in some circumstances (30,48). Glass wool has been used in virus monitoring studies involving wastewater (10), drinking water (14,41,46), groundwater (6,30,31,43), river water (18,41), and reservoirs (6,43). However, only a handful of studies have attempted to quantify how effective glass wool is for concentrating viruses (7,44,45), and these examined only enteroviruses and rotavirus.…”