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cercarial dermatitis Dermatitis caused by contact/skin perforation by the cercariae (larval stage) of certain species of schistosomes (parasites) whose normal hosts are birds and nonhuman mammals. This allergic response does not lead to parasitic infestation in humans and produces no long-term disease.
class Waterborne-disease outbreaks are classified according to the strength of the epidemiologic and water-quality data implicating water as the source of the outbreak (see Table 1).
chloramines Disinfection by-products form when free chlorine combines with nitrogen-containing compounds (e.g., urine or perspiration). They can cause eye, skin, lung, and throat irritations and have low disinfection capability. They accumulate in water and the air over pools.
coliforms All aerobic and facultative anaerobic, gram-negative, nonspore-forming, rod-shaped bacteria that ferment lactose with gas formation within 48 hours at 95F (35C).
combined chlorine level See chloramines. The level of chlorine that has combined with organic compounds in the water and is no longer an effective disinfectant.
contact time The length of time water is exposed to a disinfectant; usually measured in minutes (e.g., chlorine contact time).
Cryptosporidium hominis The taxonomy of Cryptosporidium has evolved as a result of advancements in molecular methodology
and genotyping. The former C. parvum now refers to a species that is zoonotic and infects ruminants and humans. C. hominis refers to the species of Cryptosporidium that is infective only in humans and monkeys. Both species were referred to previously as C. parvum.
disinfection by-products Chemicals formed in water through reactions between organic matter and disinfectants. Includes chloramine, an irritant of the eyes, nose, and throat.
fecal coliforms Coliforms that grow and produce gas at 112.1F (44.5C) within 24 hours.
filtration The process of removing suspended particles from water by passing it through one or more permeable membranes or media of limited diameter (e.g., sand, anthracite, or diatomaceous earth).
folliculitis Inflammation of hair follicles. Spa-associated folliculitis is usually associated with infection by
Pseudomonas aeruginosa.
free, residual chlorine level The concentration of chlorine in water that is not combined with other constituents, thus serving as an effective disinfectant.
freshwater Surface water (e.g., water from lakes, rivers, or ponds) that has not been treated in any way to
enhance its safety for recreational use.
interactive fountain A fountain intended for (or accessible to) recreational use. In contrast, noninteractive (ornamental)
fountains intended for public display rather than recreational use are often located in front of buildings and monuments, and their water is not easily accessible for public use.
marine water Untreated recreational water at an ocean setting.
norovirus A group of related, single-stranded RNA, nonenveloped viruses (genus Norovirus, family
Caliciviridae) that cause acute gastroenteritis in humans. Norovirus was recently approved as
the official genus name for the group of viruses provisionally described as Norwalk-like viruses
oocyst The infectious stage of Cryptosporidium species and certain other coccidian parasites with a
protective wall that facilitates survival in water and other environments and renders the parasite
extremely resistant to chlorine.
recreational water venue A body of water used for the purpose of recreation (e.g., swimming, soaking, and athletics)
including any structure that encloses this water. Can include lakes, rivers, the ocean, and manmade
venues (e.g., swimming pools, spas, and waterparks).
spa Any structure, basin, chamber, or tank (located either indoors or outdoors) containing a body
of water intended to be used for recreational or therapeutic use that usually contains a waterjet
or aeration system. It is operated at high temperatures and is usually not drained, cleaned, or
refilled after each use. Sometimes referred to as a hot tub or whirlpool.
treated water Water that has undergone a disinfection process (e.g., chlorination, filtration) for the purpose
of making it safe for recreation. This usually refers to any recreational water in an enclosed,
manufactured structure but might include swimming or wading pools, fountains, or spas filled
with untreated or treated tap water that receives no further treatment.
water-quality indicator A microbial, chemical, or physical parameter that indicates the potential risk for infectious diseases associated with using the water for drinking, bathing, or recreational purposes. The best indicator is one whose density or concentration correlates best with health hazards associated with a type of hazard or pollution.
class Waterborne-disease outbreaks are classified according to the strength of the epidemiologic and
water-quality data implicating water as the source of the outbreak (see Table 1).
class Waterborne-disease outbreaks are classified according to the strength of the epidemiologic and
water-quality data implicating water as the source of the outbreak (see Table 1).

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