|  | Conditions & Treatments | Cold & Flu

Stomach Flu (Gastroenteritis): Causes, Symptoms & Prevention

Acute gastroenteritis ("stomach flu") is inflammation of the stomach and intestines caused by viruses (70%), bacteria (15–20%), or parasites. It is not influenza (a respiratory virus).

Common Pathogens

CategoryExamplesTransmissionIncubation
VirusesNorovirus (most common adult), Rotavirus (children), Adenovirus, Astrovirus, SapovirusFecal-oral, fomites, aerosolized vomit, food/water12–48h
BacteriaSalmonella, Campylobacter, E. coli (ETEC, EHEC), Shigella, C. difficile, VibrioContaminated food (poultry, eggs, produce), water, person-to-person6h–5 days
ParasitesGiardia, Cryptosporidium, CyclosporaContaminated water, food, zoonotic1–14 days

Symptoms

  • Watery diarrhea (non-bloody usually viral; bloody suggests bacterial/parasitic)
  • Nausea, vomiting (often first, prominent in norovirus)
  • Abdominal cramps, low-grade fever, myalgias, headache
  • Dehydration signs: dry mouth, ↓urination, dizziness, tachycardia

Transmission Prevention

  1. Hand hygiene: Soap + water > alcohol gel for norovirus/C. diff (non-enveloped).
  2. Food safety: Cook to safe temps, avoid cross-contamination, wash produce, pasteurized dairy.
  3. Water safety: Treat/boil if uncertain; avoid swallowing recreational water.
  4. Isolation: Stay home 48h after last symptom (norovirus sheds weeks).
  5. Disinfection: Bleach (1000–5000 ppm) for norovirus; EPA-registered for C. diff.
  6. Vaccines: Rotavirus (infants), Cholera (travelers), Typhoid (endemic areas/travel).

Management

  • Oral rehydration (ORS) is cornerstone. WHO-ORS or commercial (Pedialyte).
  • Antiemetics (ondansetron) for vomiting preventing ORS tolerance.
  • Antibiotics only for confirmed bacterial etiology (bloody diarrhea, high fever, travel, immunocompromise).
  • Antimotility agents (loperamide) avoid in bloody/febrile diarrhea.
  • Probiotics (LGG, S. boulardii) may shorten duration modestly.

Seek care for: signs of severe dehydration, bloody stool, fever >39°C, >6 stools/day, symptoms >3 days, immunocompromise, pregnancy, elderly.

Cold & Flu - Related Articles