Share thisProviding consistent and repeatable water quality will instill confidence that the water remained the same and within specification for the duration of your study.
The composition of water will influence research results. Regarding the potential effects of a variable water quality on the repeatability of a research project, I would offer the following comments and reference provided by Dr. Tim Martin, Director, Animal Care Program, St. Joseph’s Hospital and Medical Center, Phoenix.
I feel it is imperative that our industry establish quality standards for drinking water. The only requirement at this time is for the “potable, uncontaminated drinking water” [from the Guide for the Care and Use of Laboratory Animals]. The problem with this statement is the variability in the mineral and chemical content from state to state, city to city, and institution to institution. This difference can directly affect the outcome or repeatability of research projects. An example of this can be found in an article from the Proceedings of the National Academy of Science (2003 Sep 16; 100(19):11065-9) entitled “Trace amounts of copper in water induce amyloid plaques and learning deficits in a rabbit model of Alzheimer's disease.” The level of copper present in drinking water affected the quality of the Alzheimer’s model. Some of the original work on this model was conducted at an AAALAC accredited facility where the rabbits received their water from an automated watering system. The source of the water was the municipal supply. The drinking water was routinely tested for impurities and bacterial contamination and the results were always within the established EPA standards. The animals developed plaques as expected. When the project was moved to another institution 25 miles away, the rabbits did not respond the same. They had developed fewer plaques. The only difference was the source of water. At the second institution, all the animals were given distilled bottled water.
Both institutions adhere to the current standards for animal husbandry; however just one minimal difference in husbandry practice greatly affected the outcome of a research project.
What Impure Water Can Do
To understand just how potent impure water can be, think about cryptosporidium. This is a resilient waterborne parasite that travels in a protozoan cyst. The cyst travels via warm-blooded animal feces into water sources and enters the animal host predominantly via ingestion. Once inside the host, the organism ensures survival by reproducing asexually and sexually before building itself two different types of floating mobile home: a thick-walled oocyst that gets excreted and a thin-walled oocyst that infects the body.
The parasite causes intestinal infection, revealing itself only when the host comes down with full blown diarrhea and stomach cramps between one and twelve days later.
The infection spreads like wildfire among animal populations—and in breeding facilities, tens of thousands may become infected. In municipalities, contaminated water sources are so interlinked, cryptosporidiosis is nearly impossible to contain. In one of many recent outbreaks, 400,000 people in Milwaukee became ill with cryptosporidium and 100 people died.
The real issues with cryptosporidiosis are treatment and removal. The organism resists traditional water purification chemicals such as chlorine, and older water treatment facilities aren’t set up to deal with stronger disinfectants. The process of reverse osmosis will remove cryptosporidium from water.
What You Can Do
Water conditions designed to meet human consumption standards may not necessarily be adequate for research models. Certain contaminants could impact the research being conducted, adversely affect animal health, and ultimately require more vet time and employee time. A facility could even be faced with the cost of replacing study animals. Where possible, stay informed.