Cholera is now no longer considered a pressing health threat in Europe and North America due to filtering and chlorination of water supplies, but it still strongly affects populations in developing countries. In the past, vessels flew a yellow quarantine flag if any crew members or passengers had cholera. No one aboard a vessel flying a yellow flag would be allowed ashore for an extended period, typically 30 to 40 days.Historically many different claimed remedies have existed in folklore. Many of the older remedies were based on the miasma theory, that the disease was transmitted by bad air. Some believed that abdominal chilling made one more susceptible, and flannel and cholera belts were included in army kits. In the 1854–1855 outbreak in Naples, homeopathic camphor was used according to Hahnemann. T. J. Ritters Mothers Remedies book lists tomato syrup as a home remedy from northern America. Elecampane was recommended in the United Kingdom, according to William Thomas Fernie. The first effective human vaccine was developed in 1885, and the first effective antibiotic was developed in 1948. Cholera cases are much less frequent in developed countries where governments have helped to establish water sanitation practices and effective medical treatments. In the 19th century the United States, for example, had a severe cholera problem similar to those in some developing countries.
Any individual, even a healthy adult in middle age, can undergo a severe case, and each persons case should be measured by the loss of fluids, preferably in consultation with a professional health care provider.The cystic fibrosis genetic mutation known as delta-F508 in humans has been said to maintain a selective heterozygous advantage: heterozygous carriers of the mutation (who are not affected by cystic fibrosis) are more resistant to V. cholerae infections. In this model, the genetic deficiency in the cystic fibrosis transmembrane conductance regulator channel proteins interferes with bacteria binding to the intestinal epithelium, thus reducing the effects of an infection. Mechanism
When consumed, most bacteria do not survive the acidic conditions of the human stomach. The few surviving bacteria conserve their energy and stored nutrients during the passage through the stomach by shutting down protein production. When the surviving bacteria exit the stomach and reach the small intestine, they must propel themselves through the thick mucus that lines the small intestine to reach the intestinal walls where they can attach and thrive.Once the cholera bacteria reach the intestinal wall, they no longer need the flagella to move. The bacteria stop producing the protein flagellin to conserve energy and nutrients by changing the mix of proteins that they express in response to the changed chemical surroundings. On reaching the intestinal wall, V. cholerae start producing the toxic proteins that give the infected person a watery diarrhea.