Cholera - Vibrio cholerae
Cholera attacks the digestive tract by causing severe fluid loss from the body. This is caused when the bacterium secretes a toxin, cholera toxin, which affects the water in the small intestine. This causes severe dehydration and diarrhea, which will eventually kill you if not treated.
Transferred to and from
Cholera bacteria is usually found in water or a food source that have been contaminated by feces from a person infected with cholera. This disease is more vulnerable to places that have poor sanitation and poor water treatment. Brackish water is also known to carry the disease within raw shellfish. This is one of the only ways it can be contracted in the US and there are still very few cases. Third world countries are at less of a risk.
One in ten people who get this disease will contract severe symptoms. They will get profuse watery diarrhea, vomiting, and leg cramps. If not treated when they get these severe symptoms, you can die within hours.
This can be hidden in raw shellfish and contaminated water and food. It causes no change to occur to the food or water, so you cannot tell if it is contaminated or not.
If you are in an area where there is known to be cholera, only drink bottled water and wash your hands on a regular basis. This makes it very unlikely for you to get the disease. Also only eat food that is hot and freshly prepared. If you do contract the disease, you will have to have rehydration treatments and antibiotics.