Detection of Adenoviruses and Rotaviruses in Drinking Water Sources Used In Rural Areas of Benin,West Africa

Diseases associated with viruses also found in environmental samples cause major health problems in developing countries. Little is known about the frequency and pattern of viral contamination of drinking water sources in these resource-poor settings. We established a method to analyze 10 liters of water from drinking water sources in a rural area of Benin for the presence of adenoviruses and rotaviruses. Overall, 541 samples from 287 drinking water sources were tested. A total of 12.9% of the sources were positive for adenoviruses and 2.1% of the sources were positive for rotaviruses at least once. Due to the temporary nature of viral contamination in drinking water sources, the probability of virus detection increased with the number of samples taken at one test site over time. No seasonal pattern for viral contaminations was found after samples obtained during the dry and wet seasons were compared. Overall, 3 of 15 surface water samples (20%) and 35 of 247 wells (14.2%) but also 2 of 25 pumps (8%) tested positive for adenoviruses or rotaviruses. The presence of latrines within a radius of 50 m in the vicinity of pumps or wells was identified as being a risk factor for virus detection. In summary, viral contamination was correlated with the presence of latrines in the vicinity of drinking water sources, indicating the importance of appropriate decision support systems in these socioeconomic prospering regions.Although access to safe drinking water is considered a human right, many people suffer from inadequate water supply. Especially in developing countries, improper water quality causes major public health problems affecting mortality rates in highly susceptible people (small children and immunocompromised patients) as well as economic income problems due to disease-related nonproductive time. Only 37.4% of households have access to piped water sources in Benin, West Africa, and in rural areas, even fewer have access (3). Many diseases like diarrhea, gastroenteritis, keratoconjunctivitis, respiratory infections, and hepatitis are associated with viruses, often found in environmental samples like groundwater, surface water, sewage, costal water, shellfish, and tap water (5, 6, 10, 13, 23, 38). Virus concentrations in environmental samples are low both due to the inability to replicate without a host cell and because of continuous degradation and dilution effects. On the other hand and in contrast to most bacterial infections, even small amounts of viruses (as few as 10 PCR-detectable units) are sufficient to establish an infection in the new host (24). Bacterial indicators seem to be inappropriate for analyzing viral contamination, since viruses are more resistant to environmental conditions (2) and spread over a longer distance than bacteria (9). Therefore, viruses are often found without any bacterial indicator for fecal contamination (2, 6). In North America, 15 to 30% of all gastrointestinal diseases were suspected of being related to water (30), whereas worldwide, over 88% of diarrheal diseases are waterborne or water related (18).Routine screening of environmental samples for viral contamination is controversially being discussed at the moment. Furthermore, no standard procedure for the detection of viruses in environmental samples currently exists. In numerous studies, virus concentration from water was achieved by filtration using electropositive filters (1MDS) (12, 15, 25, 26, 33). Further methods using ultrafiltration, glass wool filters (7, 22), or immunomagnetic separation (16, 28) were used to detect small amounts of viruses independently of matrix effects. However, the U.S. Environmental Protection Agency listed adenovirus as one of nine microorganisms on the contamination candidate list for drinking water as a potential indicator virus due to an outstanding resistance to UV disinfection. The 51 presently recognized adenovirus serotypes are responsible for a great variety of human diseases like diarrhea, keratoconjunctivitis, and respiratory infections. However, severe diarrhea, especially in small children and immunocompromised patients, is often caused by rotaviruses. The fatal outcome of infant diarrhea substantially contributes to the high mortality rate of children under the age of 5 years in developing countries (8). In Benin, the probability of dying per 1,000 live births under 5 years of age (under-5 mortality rate) was 152 in 2004, and 17.1% of these deaths were caused by diarrheal diseases (37). To address the frequency and pattern of viral contamination in drinking water sources in rural areas of West Africa, we analyzed water samples during the dry and wet seasons in Benin for contamination with adenoviruses as indicators and rotaviruses as important pathogens in developing countries.