Salmonella Typhi

Salmonella Typhi is a facultative anaerobic bacteria that causes typhoid fever in humans. The bacteria can be found in food or drink that has been in contact with a contaminated drinking supply system; it can survive for weeks in water or dried sewage. Salmonella bacteria prefer wet environments shielded from the sun. They survive between the pH’s of 4 to 8+, and can grow between 8 and 45 C and can survive under low oxygen tension such as in manure slurry pits. After about 30 day of contact with soil, salmonella dissipates. Waste water from Mexico City brought to the Mezquital Valley for the purpose of irrigation, can carry with it this bacteria, and contaminate crops. Crops that are eaten raw and not washed thoroughly, are most often the means by which this bacteria enters the human digestive tract. It is likely the pathogen enters the vegetable through a wound or opening in the tissue. The bacteria invades the small intestine and if it continues to persist, can enter the bloodstream affecting the lymph nodes, liver and spleen, with symptoms including, nausea, loss of appetite, rash, fever and in some cases death. The CDC considers Mexico at high risk of Typhoid fever and recommends travellers receive the vaccine.