Which animal is a reservoir for Escherichia coli O157:H7 associated with outbreaks?

Which animal is a reservoir for Escherichia coli O157:H7 associated with outbreaks?

• A. Pigs
• B. Chickens
• C. Cattle
• D. Sheep

Answer: (C)

E. coli O157:H7 is a Shiga toxin–producing strain that commonly colonizes the intestines of healthy cattle and is shed in their feces without causing illness in the animals. This makes cattle a key reservoir, because humans most often acquire the infection through fecal-oral routes linked to beef processing and consumption, especially ground beef, as well as through contamination of produce and water with cattle feces. While other animals can harbor various pathogens, outbreaks of this particular serotype are most consistently connected to cattle sources, underscoring their central role as the reservoir.

E. coli O157:H7 is a Shiga toxin–producing strain that commonly colonizes the intestines of healthy cattle and is shed in their feces without causing illness in the animals. This makes cattle a key reservoir, because humans most often acquire the infection through fecal-oral routes linked to beef processing and consumption, especially ground beef, as well as through contamination of produce and water with cattle feces. While other animals can harbor various pathogens, outbreaks of this particular serotype are most consistently connected to cattle sources, underscoring their central role as the reservoir.