A surveillance study published in Morbidity and Mortality Weekly Report suggests that a lack of disease-prevention knowledge among owners of animals such as backyard poultry contributes to intestinal-disease outbreaks in the United States.
"An estimated 450,000 enteric illnesses, 5,000 hospitalizations, and 76 deaths associated with animal contact occur each year in the United States," the Centers for Disease Control and Prevention (CDC)–led research team wrote. "Humans might encounter animal feces or bodily fluids through contact with the animal itself, the animal's environment, or the animal's food or water."
Enteric infections affect the lower digestive tract—the stomach and intestines—and typically cause diarrhea, nausea, and vomiting. Many of them go unreported.
Most poultry outbreaks began at private homes
From 2009 to 2021, 557 US animal-related enteric disease outbreaks were reported, accounting for 14,377 illnesses, 2,656 hospitalizations, and 22 deaths. While multistate outbreaks made up 29% of all outbreaks, they accounted for 80% of illnesses, 88% of hospitalizations, and 82% of deaths.
Salmonella was the most common cause of single-source outbreaks (52%), making up 85% of associated illnesses, 91% of hospitalizations, and 77% of deaths. The second, third, and fourth leading pathogens were Cryptosporidium, Escherichia coli, and Campylobacter.
Strengthening the capacity of local, state, and territorial health departments to investigate and report animal contact outbreaks is critical to improving surveillance of animal contact outbreaks.
The main exposure settings among single-location outbreaks were private homes (40%) and farms or dairies (21%). Ruminants (eg, cattle) were the most common source of single-animal outbreaks (37%), followed by poultry (33%) and turtles (12%).
But poultry were tied to the most outbreak-associated single-species illnesses (66%), hospitalizations (70%), and deaths (83%). Most poultry-related outbreaks (84%) and illnesses (98%) involved private homes. The most common pathogen-animal pair was Salmonella and poultry, followed by Cryptosporidium and ruminants and Salmonella and turtles.
The authors recommend educating ruminant farmers and owners of backyard flocks and turtles about proper animal-handling hygiene and disease prevention. The disproportionate impact of multistate outbreaks underscores the importance of collaborative national responses and may indicate limited investigative resources at the state or local levels.
"Strengthening the capacity of local, state, and territorial health departments to investigate and report animal contact outbreaks is critical to improving surveillance of animal contact outbreaks," they wrote.
