Salmonella causes an estimated 1.35 million infections in the United States every year, making it one of the most common foodborne illnesses in the country. Of those infections, about 26,500 lead to hospitalization and 420 result in death. Globally, salmonella is a major contributor to the 600 million annual cases of foodborne disease tracked by the World Health Organization.
How Many People Get Salmonella Each Year
The 1.35 million annual U.S. figure from the CDC is itself an estimate, because most cases are never formally diagnosed. Someone gets diarrhea for a few days, rides it out at home, and never visits a doctor or submits a stool sample. The confirmed, lab-reported number is far smaller. The true burden is calculated by adjusting upward for all those unreported cases.
To put that number in perspective, roughly 1 in every 245 Americans gets a salmonella infection in any given year. Over a lifetime, the odds of getting it at least once are high. Children under 5 are hit hardest. Bloodstream infections from salmonella occur at a rate of about 7.5 per 100,000 in infants under 1, dropping to around 2.3 per 100,000 in children aged 1 to 4, and falling further as kids get older. Adults over 65 and people with weakened immune systems also face higher risk of severe illness.
Where Salmonella Comes From
Only about 5% of salmonella illnesses can be traced back to a known outbreak, which means the vast majority of cases are “sporadic,” with no clear link to a contaminated batch of food that made the news. That makes pinpointing exact sources tricky, but newer genetic sequencing techniques have given researchers a much sharper picture.
A CDC analysis using whole-genome sequencing predicted that over 33% of human salmonella infections originated from chicken, followed by 27% from vegetables. Pork was the dominant source for certain strains. This challenges the common assumption that eggs and poultry are the only foods to worry about. Produce, including items like tomatoes, leafy greens, and sprouts, accounts for a substantial share of infections.
Food isn’t the only route. Reptiles and amphibians naturally carry salmonella in their gut, and contact with pet lizards, turtles, and snakes is a recognized transmission path. In Ontario, Canada, about 6% of sporadic salmonella cases involved people who had handled a reptile or amphibian in the week before getting sick. The U.S. has seen multiple multistate outbreaks tied to pet turtles, bearded dragons, and even dwarf clawed frogs. Backyard poultry flocks are another well-documented source.
When Infections Peak
Salmonella follows a clear seasonal pattern, rising in summer and dropping in winter. Infections peak roughly two weeks after the hottest days of the year, typically in late July or early August in temperate climates. Warmer temperatures help bacteria multiply faster on food that’s been left out, and summer habits like outdoor grilling and picnics create more opportunities for undercooked or improperly stored food to cause trouble. About 20% of the variation in salmonella rates can be explained by ambient temperature alone.
What the Illness Feels Like
Symptoms usually start 6 hours to 6 days after you’re exposed, with most people noticing something within the first 1 to 3 days. The hallmarks are diarrhea, stomach cramps, and fever. Nausea and vomiting are common too. For the majority of people, this clears up within 4 to 7 days without any treatment beyond staying hydrated.
That said, salmonella is not always a minor inconvenience. The roughly 26,500 annual hospitalizations in the U.S. reflect cases where dehydration became severe, the infection spread to the bloodstream, or the person’s immune system couldn’t contain it. Infants, older adults, and people on immunosuppressive medications are most vulnerable to these complications.
Long-Term Effects After Recovery
Most people recover fully, but a small percentage develop reactive arthritis, a painful joint inflammation that appears weeks after the initial infection. The pooled incidence is about 12 cases per 1,000 salmonella infections, or roughly 1.2%. Individual studies have found rates anywhere from less than 1% to as high as 29%, depending on the population studied and how closely researchers followed up. Adults tend to be affected more than children, with a median incidence of about 11% in adult study populations compared to 5% in children.
Reactive arthritis typically affects the knees, ankles, or feet and can resolve within six months. However, an estimated 63% of people who develop it go on to have a chronic form, with joint symptoms lingering or recurring well beyond that initial window. This is one of the less well-known consequences of what most people think of as a straightforward stomach bug.
Who Is Most at Risk
Age is the single biggest risk factor for both getting salmonella and having a severe case. Children under 5, especially infants, have the highest infection rates. Their immune systems are still developing, and behaviors like putting objects in their mouths increase exposure. Thirty percent of all foodborne deaths worldwide occur in children under 5.
Older adults face a different set of risks. While they may not get infected as frequently as young children, their infections are more likely to become invasive, spreading beyond the gut into the bloodstream. People taking medications that suppress stomach acid also face increased risk, since stomach acid is one of the body’s first defenses against ingested bacteria. The same applies to anyone with a compromised immune system, whether from HIV, chemotherapy, organ transplant medications, or other causes.