Cystic Fibrosis Gene and Cholera
Cystic fibrosis is a disease identified by the thick and sticky mucus a person creates. They have a difficult time clearing this mucus from their lungs, so multiple medications and physical modalities are used to treat it. Cystic fibrosis gene carriers could be protected against cholera which could be one explanation for how the gene has lasted throughout history.

Cholera infections cause profuse watery diarrhea and vomiting, which depletes the body of fluids very quickly. In cystic fibrosis, those fluids are thicker than normal which prevents cholera from causing rapid dehydration. The dangerous part of cholera is the loss of fluids very quickly.
In those of European descent, cystic fibrosis is the most frequent, severe, recessive disorder. If two parents are carriers of the cystic fibrosis gene, their child has a 25% chance of having cystic fibrosis and a 50% chance of being a carrier of the gene. The current life expectancy for someone with cystic fibrosis is 50 years old, a massive improvement beyond infancy just a handful of decades ago. It is believed 1 in 35 Americans are carriers of the gene.
Cystic fibrosis affects the pancreas and the lungs most because the secretions in the pancreas can become thick and clog the ducts. People with cystic fibrosis also have a higher risk for respiratory infections because clearing mucus from their lungs is difficult.
The only way to learn if you are a carrier is by genetic testing. Carriers of the gene have been studied and may have very mild symptoms of cystic fibrosis. They might have a higher risk of sinusitis, low blood pressure in females, high risk of gestational diabetes, higher risk of diabetes and arthritis as an older adult, and reduced fertility.
People that carry the cystic fibrosis gene also have some protection against typhoid. The typhoid bacteria cannot bind to the cells as easily and very few bacteria ever make it to the intestines. The cystic fibrosis mutation protects against multiple diarrheal illnesses which used to be far more lethal to babies than cystic fibrosis, but with modern medicine and IV fluids-that is no longer the case.
With modern technology, embryos can be screened for cystic fibrosis and other illnesses prior to implantation with IVF. Pre-implantation gene diagnosis includes extracting a few cells from a developing embryo and testing for a variety of ailments based on the parents’ medical and family histories.
See a primary care provider at Away Clinic for questions about cystic fibrosis and referrals for genetic testing. For travel vaccines like cholera and typhoid, feel free to make an appointment online at any of our locations.