Recreational Waterborne Illnesses: Recognition, Treatment, and Prevention.

Illness after recreational water activities can be caused by a variety of agents, including bacteria, viruses, parasites, algae, and even chlorine gas. These illnesses are more common in summer. Waterborne illnesses are underreported because most recreational activity occurs in unsupervised venues or on private property, and participants tend to disperse before illness occurs. Symptoms of waterborne illness are primarily gastrointestinal, but upper respiratory and skin manifestations also occur. Gastrointestinal symptoms are usually self-limited, and supportive treatment may be all that is necessary. However, some infections can cause significant morbidity and mortality. Cryptosporidium and Giardia intestinalis are the most common cause of gastrointestinal illness and have partial chlorine resistance. Respiratory infections are typically mild and self-limited. However, if legionnaires' disease develops and is unrecognized, mortality may be as high as 10%. Cellulitis caused by Vibrio vulnificus can result in serious illness, amputation, and death. Early and appropriate antibiotic treatment is important. Chronically ill and immunocompromised persons are at high risk of infection and should be counseled accordingly.

Small Intestinal Infections.

Small intestinal infections are extremely common worldwide. They may be bacterial, viral, or parasitic in etiology. Most are foodborne or waterborne, with specific etiologies differing by region and with diverse pathophysiologies. Very young, very old, and immune-deficient individuals are the most vulnerable to morbidity or mortality from small intestinal infections. There have been significant advances in diagnostic sophistication with the development and early application of molecular diagnostic assays, though these tests have not become mainstream. The lack of rapid diagnoses combined with the self-limited nature of small intestinal infections has hampered the development of specific and effective treatments other than oral rehydration. Antibiotics are not indicated in the absence of an etiologic diagnosis, and not at all in the case of some infections.