Epidemiologic Notes and Reports Gastrointestinal Illness among Scuba Divers -- New York City
In July 1982, an outbreak of gastrointestinal illness occurred among New York City's Police and Fire Departments' scuba divers following dives in sewage-contaminated waters. Although the causes of illness in many divers were not identified, gastrointestinal parasites were found in 12 divers.
The Fire Department developed a scuba diving program in early 1982 to train 40 firefighters in two rescue companies to respond to pier fires and water-related emergencies. In July 1982, one company trained primarily along the Hudson River at 47th Street and the other mainly at the Brooklyn Navy Yard. The Police Department diving team, which has been in operation since the mid-1960s with five divers, expanded to 16 divers in January 1982. Besides responding to water-related emergencies, police divers explore river beds for evidence and help recover lost or stolen property.
The divers generally use standard scuba masks and wet suits. Despite this protective gear, they report ingesting small quantities of polluted water while swimming at the surface or while using mouthpieces that have dangled in the water before use.
A questionnaire survey of 55 of the Police and Fire Departments' divers was administered in July 1982. Divers ranged in age from 21 to 52 years (mean 35.5 years). All were male. Approximately 95% were white and the others black or Hispanic. The survey revealed 21 cases of recent or current gastrointestinal illness, defined as 2 or more days of any of the following: (1) diarrhea (watery stool), (2) crampy abdominal pain, or (3) change in stool consistency. Three cases developed in the spring of 1982, and the remaining 18 cases in July 1982.
Twenty symptomatic divers had stools cultured for bacterial pathogens, and all 55 divers had purged stools examined for parasites. No specimens were obtained for viral studies. One bacterial culture was positive for Campylobacter. The purged stool examinations revealed 12 cases of gastrointestinal parasites--five of Entamoeba histolytica and seven of Giardia lamblia.
To determine if diving in polluted water was an important risk factor for gastrointestinal illness and parasitic infection, investigators questioned and examined a comparison group of 116 nondiving firefighters. Study participants submitted purged stool specimens. The incidence of gastrointestinal illness in July 1982 among the nondivers was estimated by reviewing sick-leave records.
During July, the divers had developed gastrointestinal illness more than four times as frequently as the nondiving firefighters. When symptomatic firefighters were questioned about possible common sources of exposure, such as weddings, picnics, camping trips, or other group activities, none except scuba diving was identified. Neither travel nor sexual orientation, two additional risk factors for parasites, differed among divers with parasites, uninfected divers, and nondiving firefighters.
Twenty-three nondiving firefighters had purged stools examined for parasites; none had G. lamblia or E. histolytica.
At the Fire Department training sites along the Hudson and East Rivers, the New York City Department of Health tested the water for total coliforms, pathogenic bacteria (Salmonella, Shigella, Campylobacter, and Yersinia) and parasites. Relatively few pathogens were found in these highly polluted waters. However, examination of river water utilizing a high-volume water filter revealed numerous parasites including G. lamblia and E. histolytica-like cysts. Reported by A Goodman, MD, S Schultz, MD, E Bell, E Gumbs, MD, S Friedman, MD, New York City Dept of Health, C Robinson, MD, New York City Police Dept, C Jones, MD, New York City Fire Dept; C Hibler, PhD, Dept of Pathology, Colorado State University.
Editorial Note: In recent years, gastrointestinal illness has been reported to be associated with swimming in polluted water (1). The causes of these infections have been somewhat obscure. In some cases, symptoms were probably caused by viruses; in others, bacterial agents, such as Shigella, have been isolated. The majority of cases, however, have remained undiagnosed.
More than 188,000,000 gallons of raw sewage are discharged daily into the Hudson and East Rivers of New York City. Swimming is limited by the Department of Health to beaches monitored regularly for fecal contamination; thus, swimming in New York City's coastal waters has never been considered an important risk factor for illness.
The results of this investigation provide strong evidence that scuba diving in sewage-contaminated water is associated with gastrointestinal illness. The data suggest that parasites are an important cause of illness and that the major health hazard arises from ingesting sewage-contaminted water. Police and Fire Department scuba divers now practice in waters designated acceptable by the Department of Health.
Advanced diving equipment, such as high-pressure masks, wireless radio devices, and dry suits, should be used to minimize exposure; a recent study of various types of diving suits found that a dry suit in combination with a full-face mask, afforded the best protection against microbial contamination (2). The National Oceanic and Atmospheric Administration is continuing this study.
Routine health surveillance of divers also may minimize the consequences of diving in contaminated waters. Divers should be questioned as to the nature of any illness requiring absence from work. Informed police and fire health officials could then appropriately advise the divers' personal physicians as to the possibility of water-related infection. Worker education may serve the same purpose.
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