Having trouble finding data on viral contamination, but I did find this old article, about coliforms in Colorado (where I am):
Patti J. Psaris1 and David W. Hendricks2
(1) Black and Veatch, Denver, Colorado, U.S.A.
(2) Engineering Research Center, Colorado State University, 80523 Fort Collins, Colorado, U.S.A.
Received: 22 May 1981 Revised: 19 October 1981
Abstract This paper describes the areal distribution of fecal coliform densities within the stream system of the South Platte River basin in Colorado. Low densities, e.g., 0 to 99 fecal coliforms per 100 ml, were found in mountain streams, while higher densities, e.g., 10000 to 100000 and above were found in plains streams. About 49 % of the plains stations and 3 % of the mountain stations were not in compliance with the Colorado secondary contact recreation standard of 2000 fecal coliforms per 100 ml.
I can find lots of information about horrid enterovirus counts in water downstream of bovine sources, and they have been found in groundwater in some areas, but still no data either way on the typical mountain stream.
Still looking.
Here's one, 2004:
Detection of human enteric viruses in stream water with RT-PCR and cell culture.
Denis-Mize K, Fout GS, Dahling DR, Francy DS.
US Geological Survey, Columbus, OH 43229, USA.
A multiplex RT-PCR method was used to measure virus occurrence at five stream water sites that span a range of hydroclimatic, water-quality, and land-use characteristics. The performance of the molecular method was evaluated in comparison with traditional cell culture and Escherichia coli membrane filtration assays. The study incorporated multiple quality controls and included a control for virus recovery during the sampling procedure as well as controls to detect potentially false-negative and false-positive data. Poliovirus recovery ranged from 16 to 65% and was variable, even in samples collected within the same stream. All five sites were positive for viruses by both molecular and cell culture-based virus assays. Enteroviruses, reoviruses, rotaviruses, and hepatitis A viruses were detected, but the use of the quality controls proved critical for interpretation of the molecular data. All sites showed evidence of faecal contamination, and culturable viruses were detected in four samples that would have met the US Environmental Protection Agency's recommended E. coli guideline for safe recreational water.
But it admits that these were all fecally contaminated streams.
Here's an exerpt from a paper written by a guy who works for Katadyn, so believe what you will:
Viruses carried in water, that infect humans, have only one source
human faeces from infected carriers. Waterborne viruses that cause disease include: rotavirus, caliciviruses-which now include the norovirus group with Norwalk virus, adenovirus, astrovirus, Hepatitis A & E, and enteroviruses (which include those that cause Polio and Viral-Meningitis). More than half of the infections with these viruses only cause mild or asymptomatic illness—but they can cause a wide range of serious and even life-threatening illnesses—-especially in children.
The two most common water-borne viruses in North America—-rotovirus and noroviruses are responsible for numerous outbreaks in restaurants each year of what is commonly called “food-poisoning”. Outbreaks of both have occurred from well or river water contaminated with raw sewage. The Center for Disease Control (CDC) has noted outbreaks of norovirus in the Grand Canyon of the Colorado River. The Grand Canyon outbreaks have been traced to a sewage treatment facility at the base of Glen Canyon Dam
just above the Grand Canyon.
Norovirus and the calcivirus group: Symptoms of norovirus are usually over within 48 hours, and include headache, fever, vomiting and diarrhea. Noroviruses are relatively resistant to environmental challenge from cold or heat. Moreover, noroviruses can survive in up to 10 ppm chlorine: well in excess of levels routinely present in public water systems (they are however destroyed by Chlorine Dioxide at 1ppm in 30 minutes.)
Rotavirus: The incubation period for rotavirus disease is approximately 2 days. The disease is characterized by vomiting and watery diarrhea for 3 – 8 days, and fever and abdominal pain occur frequently. Rotavirus is the most common cause of severe diarrhea among children, resulting in the hospitalization of approximately 55,000 children each year in the United States and the death of over 600,000 children annually worldwide.
Hepatitis A: Although hepatitis A, does cause occasional outbreaks in food in the U.S., it has not been recognized as a culprit in backcountry water disease here. However in South America, Africa, and Asia; it and other viruses can be life-threatening in contaminated water. Hepatitis A affects liver function and be a very serious disease, or a long-lasting low-grade infection. Immunization shots are strongly recommended for international travelers.
Hepatitis E has not been a problem in the U.S. water supply. It is estimated to cause 2% mortality in the general population and up to 30% mortality in pregnant women. Major waterborne epidemics have occurred in India (1955 and 1975-1976), USSR (1955-1956), Nepal (1973), Burma (1976-1977), Algeria (1980-1981), Ivory Coast (1983-1984), in refugee camps in Eastern Sudan and Somalia (1985-6), and in Borneo (1987). The first outbreaks reported in the American continents occurred in Mexico in late 1986.
Enteroviruses: The enterovirus family contains at least 62 different viruses that infect humans. The most dangerous cause Polio (now eradicated in the Americas); while others cause aseptic (viral) meningitis—symptoms include fever, severe headache, stiff neck, and nausea and vomiting. Most of the enteroviruses cause cold-like or flu-like symptoms. The CDC states: “Enteroviruses may be found in water sources such as private wells. Wells become contaminated when faeces from infected humans enter the water through various means, including sewage.”
Enteric adenovirus, astroviruses: These commonly infect young children with viral gastroenteritis. They may be transmitted by infected food or water. Viral gastroenteritis is usually a mild illness characterized by nausea, vomiting, diarrhea, malaise, abdominal pain, headache, and fever. The infectious dose is not known but is presumed to be low. Symptoms last 2 to 9 days.
Enteric adenovirus is the most common virus in this group and causes 5-20% of the gastroenteritis in young children. Adenoviruses most commonly cause respiratory illness; however, depending on the infecting serotype, they may also cause various other illnesses, such as gastroenteritis, conjunctivitis, cystitis, and rash illness. A recent study notes that adenovirus is not destroyed by UV light disinfection.
Full link here:
http://ezinearticles.com/?Whats-in-the-Water-Now?&id=710636
P.S.
I simply can't believe that I have to edit out the word "faeces" (but American spelling). Come on!
