The production of cholera toxin by the attached bacteria results in the watery diarrhea associated with this illness. Antacid consumption markedly lowers the infective dose. Cholera can be confirmed only by the isolation of the causative organism from the diarrheic stools of infected individuals. This is clearly the main mechanism for the spread of cholera in poor communities in South America. The excellent sanitation facilities in the U.S. are responsible for the near eradication of epidemic cholera.
Sporadic cases occur when shellfish harvested from fecally polluted coastal waters are consumed raw.
Cholera may also be transmitted by shellfish harvested from nonpolluted waters since V. cholerae O1 is part of the autochthonous microbiota of these waters. Most of these cases were detected only after epidemiological investigation. Probably more sporadic cases have occurred, but have gone undiagnosed or unreported. The illness is generally self-limiting. Antibiotics such as tetracycline have been demonstrated to shorten the course of the illness.