TABLE 2.
Randomized clinical trials to determine the health risks related to bathing in polluted water
| Marine water* | Fresh water† | |
|---|---|---|
| Number of participants | 1216 | 2067 |
| Bathers | 548 | 1033 |
| Nonbathers | 668 | 1034 |
| Age, years | ≥18 | ≥4 |
| Number of beaches | 4 | 5 |
| Location of beaches | Great Britain | Germany |
| Indicators tested | Fecal streptococci | Escherichia coli |
| Total coliforms | Enterococci | |
| Fecal coliforms | Clostridium perfringens | |
| Pseudomonas aeruginosa | Somatic coliphages | |
| Total staphylococci | Aeromonas species | |
| P aeruginosa | ||
| Medical follow-up | Interview and medical examination two days before exposure | Interview and medical examination two days before exposure |
| Interview one week after exposure | Interview the day of exposure | |
| Interview and medical examination one week after exposure | ||
| Mailed questionnaire three weeks after exposure | Mailed questionnaire three weeks after exposure | |
| Bathing | At least 10 min with at least three complete | Exactly 10 min with at least three complete immersions of the head |
| immersions of the head | ||
| Main outcomes | Bathing associated with gastroenteritis, acute respiratory febrile illness, and ear and eye ailments | Bathing associated with gastroenteritis and skin problems. There was a statistical tendency toward an association between bathing and ear ailments |
| Relationship between fecal streptococci and gastroenteritis (>32 fecal streptococci/100 mL), and between fecal streptococci and acute febrile respiratory illness (>60 fecal streptococci/100 mL). Relationship between fecal coliforms and ear ailments (>100 fecal coliforms/100 mL) | Relationship between gastroenteritis and four indicators of fecal contamination (E coli, enterococci, C perfringens and somatic coliphages) | |
| Guideline values suggested: 100 E coli/100 mL, 25 enterococci/100 mL, 10 somatic coliphages/100 mL or 10 C perfringens/100 mL |