Yes, Salmonella is one of the most common zoonotic infections in the world, meaning it spreads from animals to humans. The CDC estimates Salmonella causes about 1.35 million infections in the United States every year, making it the leading cause of hospitalizations and deaths linked to foodborne illness. While contaminated food is the most familiar route, direct contact with animals is a significant and often underappreciated pathway.
What Makes Salmonella Zoonotic
A zoonotic disease is any infection that passes from animals to people. Salmonella fits this definition perfectly: the bacteria live naturally in the intestines of a wide range of animals, often without making those animals visibly sick. Cattle, chickens, rodents, reptiles, and amphibians are all common carriers. Dogs and cats rarely develop salmonellosis themselves, but they can carry and shed the bacteria. Horses can pick up Salmonella from contaminated environments, feed, or water, and some become silent carriers that intermittently pass the bacteria in their stool while appearing completely healthy.
People get infected through two main zoonotic routes. The first is eating contaminated animal products like undercooked poultry, eggs, or unpasteurized milk. The second is direct or indirect contact with a live animal or its environment. Touching a reptile, cleaning a chicken coop, or even handling pet food can transfer the bacteria to your hands and then to your mouth. CDC surveillance classifies Salmonella transmission across five major pathways: foodborne, waterborne, person-to-person, animal contact, and environmental. The animal contact pathway accounts for a meaningful share of cases, and the environmental pathway includes an additional subset of infections presumed to be animal-associated.
Which Animals Carry the Highest Risk
Reptiles stand out as particularly high-risk carriers. A large systematic review found that about 30% of all reptiles carry Salmonella, but the rates vary dramatically by species. Snakes have the highest prevalence at 63%, followed by lizards at 34%, and turtles and crocodiles at roughly 11% each. Captive reptiles are far more likely to harbor the bacteria than wild ones: 38% of captive reptiles test positive compared to about 15% of wild reptiles. Bearded dragons and iguanas have been the most frequently identified reptile sources of human salmonellosis cases from 1997 to 2017, with most of those cases involving children under five.
Backyard poultry is another major source. Chickens, ducks, and other birds can carry Salmonella on their feathers, feet, and in their droppings even when they look perfectly healthy. The CDC has linked multiple outbreaks directly to backyard flocks in recent years. The risk comes not just from eating their eggs but from handling the birds themselves or anything in their living area.
Livestock, particularly cattle and pigs, are important reservoirs as well. Multidrug-resistant strains of Salmonella Typhimurium, one of the most common disease-causing types, were first identified spreading from cattle to other livestock in the United Kingdom in the early 1980s before disseminating globally through the 1990s. Genomic surveillance in the U.S. has confirmed that major livestock sources of this strain can now be traced using whole-genome sequencing, and researchers have correctly attributed seven of eight major zoonotic outbreaks between 1998 and 2013 to their animal origins using this technology.
How the Infection Takes Hold
Once Salmonella bacteria enter your body, typically through your mouth, they travel to your small intestine. There, they attach to the lining of your gut using tiny hair-like structures on their surface. After anchoring themselves, the bacteria actively invade the cells of your intestinal wall. Unlike many bacteria that wait passively to be absorbed, Salmonella essentially forces its way into cells using specialized molecular machinery that injects proteins into your gut lining, triggering the cells to pull the bacteria inside. This invasion triggers the immune response that causes the hallmark symptoms of the infection.
Symptoms and How Long They Last
Symptoms typically appear between 6 hours and 6 days after exposure. The most common signs include diarrhea, abdominal cramps, fever, nausea, vomiting, chills, and headache. Some people notice blood in their stool. Most cases resolve within a few days to a week without specific treatment, though diarrhea can persist for up to 10 days. Even after the active infection clears, it can take several months for your bowel habits to fully return to normal.
Children under five, adults over 65, and people with weakened immune systems face the greatest risk of severe illness. In these groups, the infection is more likely to spread beyond the gut into the bloodstream, which can become life-threatening without medical attention.
Reducing Your Risk From Animals
If you keep backyard poultry, wash your hands with soap and water immediately after touching the birds, their eggs, or anything in their coop. Keep hand sanitizer near the coop for moments when soap isn’t available. Don’t kiss or snuggle your birds, and avoid eating or drinking in the area where they roam. All poultry supplies, including feed containers and coop shoes, should stay outside the house and be cleaned outdoors. Children under five should not handle chicks, ducklings, or other live poultry at all.
Reptile owners face similar precautions. Given that nearly two-thirds of pet snakes carry Salmonella, thorough handwashing after any contact is essential. Many reptile owners are unaware that Salmonella can be acquired from their pets, and this knowledge gap leads to poor hygiene practices that increase transmission risk. The CDC recommends that households with children under five, elderly individuals, or immunocompromised people avoid keeping snakes as pets entirely.
Safe Cooking Temperatures for Animal Products
Cooking animal products to the right internal temperature kills Salmonella reliably. All poultry, including breasts, whole birds, ground poultry, and stuffing, needs to reach 165°F (74°C). Eggs and egg dishes require 160°F (71°C). Use a food thermometer rather than judging by color or texture, since Salmonella can survive in meat that looks fully cooked. These temperatures apply whether you’re preparing store-bought products or eggs from your own backyard flock.