Depending on the specific species, salmonellosis results in typhoid fever or gastroenteritis.

• Typhoid (enteric) fever: Typhoid fever is a systemic disease characterized by fever and abdominal pain and caused by dissemination of S. typhi or S. paratyphi, for which humans are the only hosts.
  • - Disease results from ingestion of food or water contaminated by chronic carriers and is rare in developed nations. Worldwide, there are ~27 million cases, with 200,000-600,000 deaths annually.
  • - After an incubation period of 5-21 days, prolonged fever (>75% of cases), headache (80%), chills (35-45%), anorexia (55%), and abdominal pain (30-40%) are common. Other signs and symptoms may include sweating, cough, malaise, arthralgias, nausea, vomiting, and diarrhea—or, less often, constipation.
  • - Physical findings include rose spots (a faint, salmon-colored, blanching, maculopapular rash), hepatosplenomegaly, epistaxis, and relative bradycardia.
  • - Intestinal perforation and/or GI hemorrhage can occur in the third and fourth weeks of illness; neurologic manifestations (e.g., meningitis, Guillain-Barré syndrome) occur in 2-40% of pts.
  • - Long-term Salmonella carriage (i.e., for >1 year) in urine or stool develops in 1-5% of pts.
• Nontyphoidal salmonellosis (NTS): Most commonly caused by S. typhimurium or S. enteritidis, NTS typically presents within 6-48 h of exposure as gastroenteritis (nausea, vomiting, nonbloody diarrhea, abdominal cramping, and fever) that lasts 3-7 days.
  • - In the United States, NTS causes ~12 million illnesses annually.
  • - Disease is acquired from multiple animal reservoirs. The main mode of transmission is via contaminated food products, such as eggs (S. enteritidis), poultry, undercooked meat, dairy products, manufactured or processed foods, and fresh produce. Infection is also acquired during exposure to pets, especially reptiles.
  • - Stool cultures remain positive for 4-5 weeks and—in rare cases of chronic carriage—for >1 year.
  • - Bacteremia, usually due to S. choleraesuis and S. dublin, develops in 8% of pts; of these pts, 5-10% develop localized infections (e.g., hepatosplenic abscesses, meningitis, pneumonia, osteomyelitis).
  • - Reactive arthritis can follow Salmonella gastroenteritis, particularly in persons with the HLA-B27 histocompatibility antigen.