Bacillary dysentery (invasive bacterial diarrhoea)

What it is

Dysentery is the clinical diagnosis when fever, crampy abdominal pain and bloody diarrhea come together, and it points to a bacterial cause rather than to the viral gastroenteritis or food poisoning that accounts for most acute diarrhea in developed countries.

Causes and risk

Potential causative agents are Campylobacter, hemorrhagic E. coli (O157:H7), entamoeba histolytica, salmonella, shigella and yersinia. Incubation and duration separate them, and blood in the stool is possible with most of the bacterial ones.

• Shigella: incubation 1-6 days, duration 2-3 days, with fever, abdominal pain and diarrhea, possible blood.
• Salmonella: incubation 6-48 hours, duration 1-7 days, with nausea, vomiting, fever and abdominal pain, possible blood.
• Campylobacter: incubation 1-10 days, duration 5-14 days, with fever, headache, abdominal pain, nausea and vomiting, possible blood.
• Enterohemorrhagic E. coli: incubation 1-9 days, duration 1 week, with fever, nausea, abdominal pain and diarrhea, possible blood.

Travel is the other half of the risk. Traveler's diarrhea is caused predominantly by bacterial pathogens, up to 80%-90%, and is associated with hygiene practices. Handwashing has been shown to reduce the risk of traveler's diarrhea by 30%, and alcohol-based hand sanitizer is also effective. Avoiding street vendor foods, tap water, ice and raw foods is traditional advice but has not been shown to reduce the risk, and there is not sufficient evidence to recommend a probiotic.