Table 1.
Recreational water illness pathogens and their management
| PATHOGEN | SYMPTOMS AND UNIQUE FEATURES | TREATMENT AND PREVENTION | SPECIAL RISK GROUPS |
|---|---|---|---|
| Bacteria | |||
|
| |||
| • Campylobacter | Diarrhea, fever; 50% of children have blood in stools Incubation 3 d (range 1–7 d) |
Self-limited; rare use of fluoroquinolones or azithromycin | Pregnant women, children, the elderly, immunocompromised patients Users of PPIs Those handling raw meat, especially poultry Users of private wells |
| • Salmonella | Fever more common; nausea, diarrhea, cramps Incubation 8–72 h (longer if water-borne than if food-borne) |
Rehydration Occasional antibiotics, especially in children younger than 1 y or in severe illness |
Corticosteroid users Patients with AIDS or cancer Transplant recipients |
| • Shigella | Highly infective Abdominal pain, frequent but low-volume stools Affects lower GI tract, so dehydration is less common |
Oral rehydration Antibiotic use more common Azithromycin or ceftriaxone in those < 18 y Fluoroquinolone in those 18 y or older Avoid antimotility agents |
Young children Patients with poor nutrition International travelers |
| • Enteropathogenic Escherichia coli | Highly infective, short incubation Enterotoxin-producing strains cause bloody diarrhea and hemolytic uremic syndrome (higher risk in children) |
Monitor creatinine Avoid antibiotics |
Children, the elderly Commonly, those in the same household as the infected patient |
| Protozoan parasites | |||
|
| |||
| • Giardia | Incubation 7–14 d Loose, foul-smelling stools; flatulence; fatigue Induces lactose intolerance |
Oral metronidazole if symptomatic Lactose avoidance Avoid swimming until asymptomatic for 14 d |
Those with immune deficiencies Children < 5 y Wilderness water users |
| • Cryptosporidium | Incubation 5–7 d The organism is chlorine-resistant |
Self-limiting in immunocompetent patients Nitazoxanide for young children (some trials have also used it in adults with HIV) |
Those with immune deficiencies Solid organ transplant recipients after surgery |
| Viruses | |||
|
| |||
| • Rotavirus | More severe and prolonged diarrhea | Rehydration Vaccine 50% effective for prevention |
Children < 5 y Unimmunized patients |
| • Norovirus (Norwalk-like virus) | Short incubation | Rehydration Probiotics (limited evidence) Zinc if malnourished |
Young children, the elderly Those with immune deficiencies |
| • Adenovirus | Respiratory and GI symptoms Fever, pneumonia, and diarrhea in children Keratoconjunctivitis |
Symptomatic treatment | Young children Those with immune deficiencies |
| Harmful algal bloom toxins | |||
|
| |||
| • Microcystin-LR and many others; released by some algal blooms | Exacerbations of asthma; hepatic and neurotoxins; probable carcinogens | Supportive treatment Avoid swimming in water with visible algal blooms |
Toxic to all age groups |
GI—gastrointestinal, PPI—proton pump inhibitors.