Viruses

Introduction

Water is a vital element that is necessary for life and has many purposes in our daily routine, more than we realize. How many purposes come to your mind? Think about it, water is used for bathing, for washing our hands, provides a habitat for wild aquatic life, cleans our atmosphere through precipitation, and is used to quench our thirst, just to name a few. With all of these purposes in mind, have you ever thought about what is or could be in the water you use besides the molecules H₂0? Other than providing nutrients to all living things, water surprisingly carries additional elements that you may be oblivious to.

Viruses: What are they?

An online dictionary defines the term virus as an ultramicroscopic (20 to 300nm in diameter) infectious agent that replicates only within the cells of living hosts and is composed of an RNA or DNA core, a protein coat, and in complex types, a surrounding envelope. (www.dictionary.com)

Viruses and Our Water: The Facts

Several years of study has shown that the presence of enteric viruses in water is very prevalent. Studies conducted also support that these enteric viruses can easily survive sewage treatment methods and many persist for several months in natural waters. Reported survival times for certain enteric viruses are 2-168 days in tap water, 2-130 days in seawater, and 25-125 days in soil. Because water is recycled, individuals can be exposed to waterborne viruses, for example, through the consumption of contaminated water, through the crops we grow, or as a result of recreational activities involving water.

Sewage water is a common source of water that suffers from viral contamination. More than 100 different enteric viruses are known to be excreted from humans. The average density of enteric viruses in the United States has been estimated to be 7,000 viruses per liter. The amount of viruses present in raw sewage depends on factors such as the level of hygiene in a population, the incidence of disease in a community, and the time of year

A specific type of disease that, like viruses, is commonly transmitted through water is Cryptosporidiosis.

What is Cryptosporidiosis?

Cryptosporidiosis, also referred to as “Crypto” is a disease caused by a tiny microscopic parasite. The parasite is commonly passed on through water and is a frequent cause of water borne diseases in the United States.

The Parasite

The parasite is called Cryptosporidium and there are several different types of this parasite that infect humans and animals. The parasite has an outer shell that allows it to survive out side of the body, and makes it resistant to chlorine disinfections.

The Disease

Cryptosporidiosis generally starts about seven days after you are infected by the parasite. Generally the small intestine is the area of the body that is primarily affected, but in some instances, the digestive tract or respiratory tact can possibly be affected. A very common symptom of the disease is watery diarrhea, but others include; Stomach pain or cramps, dehydration, nausea, vomiting, fever, and weight loss. Symptoms normally last about 1 to 2 weeks and can possibly return briefly for up to 30 days. However, some people do not experience any symptoms. Those with weak immune systems have to be careful because they can develop serious chronic and fatal illnesses.

Safety Tips for Prevention

The Center for Disease Control and Prevention (CDC) offers several helpful tips to prevent viruses and diseases.

Practice good hygiene

This would include washing hands with soap and water for at least 20 seconds, rubbing hands together vigorously and scrubbing all surfaces.

Avoiding water that might be contaminated

Do not swallow water while swimming in swimming pools, hot tubs, interactive fountains, lakes, rivers, springs, ponds, streams or the ocean. Do not drink inadequately treated water or ice made from water during communitywide outbreaks caused by contaminated drinking water.

And always practice extra caution when traveling, especially to places where the safety of drinking water is questionable.

For more information and ways to prevent Cryptosordiosis and other diseases check out The Center for Disease Control and Prevention (CDC) website.

http://www.cdc.gov/crypto/gen_info/prevent.html

http://www.cdc.gov/crypto/

References:

Viruses

Bosch, A. (2007). Human Viruses in Water, Volume 17: Perspectives in Medical Virology (1 ed.). UK: Elsevier Science. This book, discovered through Ohiolink, discusses in deep detail topics involving the role of viruses, types of viruses, and its impact on water.

Melnick, J., Gerba, C., & Wallis, C. (1978). Viruses in Water. Bulletin of the World Health Organization, 56(4), 499-508. This article draws attention to the increasing problem of viral contamination of water and the obstacles and problems faced in the topic of eliminating viral pathogens from water supplies.

Middelboe, M., Jacquet, S., & Weinbauer, M. (2008). Viruses in fresh water ecosystems: an introduction to exploration of viruses in new aquatic habitats. Freshwater Biology, 53(6), 1069-1075. This article explains the issue of fresh water biology and its dealings with viruses in fresh water ecosystems while summarizing the progress in fresh water viral ecology made by diverse research groups.

Orlando, E., & Hessler, W. (2007, December 3). Human pathogens are permeating into deep groundwater, threatening drinking water supplies. Environmental Health News: Front Page. Retrieved October 20, 2010, from http://www.environmentalhealthnews.org/newscience/2007/2007-1203borchardtetal.html This web article addresses the concern of human viruses found in groundwater from a confined bedrock aquifer, and reveals the results that researchers have found through testing water samples found in the groundwater aquifer.

Templeton, M., Andrews, R., & Hofmann, R. (2008). Particle-Associated Viruses in Water: Impacts on Disinfection Processes. Department of Civil Engineering, University of Toronto, Toronto, Ontario, Canada, 38(3), 137-164. This article summarizes the occurrence of particle-associated viruses in the aquatic environment in addition to its subsequent impact on disinfection processes.

Cryptosporidiosis

Furlow, B. (2005). To your good health!. New Scientist, 188(2528), 47-49. Retrieved from Academic Search Premier Database. This article examines the causes and prevention of the waterborne disease, cryptosporidiosis. It looks at Epidemiologist Floyd Frost’s proposal that people are less likely to expierence this disease in places where slight contaminations are present.
Meinhardt, PL., Casemore, DP., & Miller, KB. (1996) Epidemiologic aspects of humancryptosporidiosis and the role of waterborne transmission. Epidemiologic Reviews.Vol.18 (no. 2), 118-136. Retrieved October 29, 2010, from the Google Scholarsearchengine. http://epirev.oxfordjournals.org/content/18/2/118.full.pdf. This article examines what cryptosporidiosis is and what effects the transition through water has on ageographic level and on an environmental level.
Navin, T.R., & Juranek, D.D. (May - Jun., 1984). Cryptosporidiosis: Clinical, Epidemiologic, and Parasitologic Review. Reviews of Infectious Disease.s Vol. 6, No. 3, pp. 313-327. The University of Chicago Press. Retrieved October 29, 2010, from the JSTOR database http://www.jstor.org/stable/4453342. This explains cryptosporidiosis in great detail. It explains the life cycle of the parasite and the clinical aspects of the disease.
Perz, J.F., Ennever,F.K, & Le Blancq, S.M. (1998). Cryptosporidium in Tap Water: Comparison of Predicted Risks with Observed Levels of Disease. Am. J. Epidemiol., 1 February; 147: 289 - 301. This article looks at the potential of transmitting this disease through tap water by using a risk assessment.
Fayer, Ronald , & Xiao, Lihua. (Eds.). (2008). Cryptosporidium and cryptosporidiosis. Boca Raton : CRC Press ; [London] : IWA Pub., 2nd ed. This book explains all aspects of the disease cryptosporidiosis and parasite to great detail. Also explores cause and effects of this disease.

By Hiram College students: Shalimma Fadzl and Shanisha Fadzl