| Transmission | |
 |
The most common species causing disease in humans are dairy cattle, beef cattle, and poultry. |
|
|
However, S. typhimurium DT104 has also been isolated in sheep, pigs, goats, rabbits, dogs, seabirds, rodents, porpoises, cats, horses, and feed. The bacteria can be carried in any of these species for weeks or months, and also continues shedding long after the animal has visibly recovered. Many animals will never show signs, but will just serve as reservoirs and passive carriers of the disease. |
| S. typhimurium DT104, as with all Salmonella species, is primarily transmitted through the fecal-oral route. Humans normally acquire the disease from eating contaminated animal products or raw vegetables that have been contaminated. Other modes of zoonotic transmission include direct contact with livestock, wildlife, or pets, especially cats and turtles. Animal-animal transmission happens at the farm through contaminated food and water sources, pastureland, or contact with newly acquired animals. On the way to the slaughterhouse, stress and overcrowded conditions associated with transport increase the number of bacteria shed. Environmental conditions at the slaughterhouse can easily cause indirect transmission through contaminated equipment or people. | |
| Since one infected animal can infect an entire slaughterhouse, and therefore, expose many people to harmful animal products, safety precautions must be taken at three different levels which must cooperate with each other - the farm, the slaughterhouse, and the preparation of food by the consumer/handler. The USDA contains further information on this subject. | |
