Description

• Typhoid fever is an acute systemic illness in humans caused by Salmonella typhi (2).
  • Classic example of enteric fever caused by Salmonella bacterium
• Enteric fevers due to Salmonella paratyphi and other Salmonella spp. can present in a manner similar to classic typhoid fever.
• Typhoid is endemic in developing nations with poor sanitation. Most cases in North America and other developed nations are acquired after travel to disease-endemic areas.
• Travelers are at greater risk of typhoid.
• Mode of transmission is fecal–oral through ingestion of contaminated food (poultry or milk) or water.
• Incubation period varies from 7 to 21 days.
• System(s) affected: gastrointestinal; pulmonary; skin/exocrine
• Synonym(s): typhoid; typhus abdominalis; enteric fever; nervous fever; slow fever

Geriatric Considerations
Disease is more serious in the elderly.

Pediatric Considerations
Disease is more serious in infants and children.

Epidemiology

Although typhoid outbreaks have been described in the United States, most cases are reported in international travelers returning from endemic transmission areas.

• Predominant age: all ages
• Predominant sex: male = female

Incidence
In the United States, 300 to 500 new cases per year. Worldwide, typhoid fever infects over 21 million people/year with ~ 200,000 deaths.

Etiology and Pathophysiology

• Historically, typhoid fever (untreated) occurs in several week-long stages.
• The initial infection is transmitted via the fecal–oral route, with resultant bacteremia and sepsis. Involvement of the bowel wall (Peyer patch) rarely may be associated with bleeding from the bowel or bowel perforation.
• The first stage involves fluctuations in temperature with relative bradycardia (Faget sign). Other symptoms include headache, cough, malaise, epistaxis, and abdominal pain.
• The second stage involves higher fever (with persistent relative bradycardia). Mental status changes are possible (agitation—“nervous fever”). Rose spots appear on the chest and abdomen. In some patients, abdominal pain is common as is constipation or diarrhea (with characteristic malodorous “pea soup” appearance).
• The third week is when most complications occur due to intestinal hemorrhage or encephalitis.
• The final week is defervescence and recovery.
• A chronic carrier state may occur with S. typhi shedding in the stools. Potential person-to-person transmission may occur. In a chronic carrier state, S. typhi resides in the biliary tract and gallbladder. Chronic suppressive antimicrobials may clear the carrier state; in rare cases, cholecystectomy is performed to clear S. typhi carrier state.

Risk Factors

• Consider in patients presenting with fever after tropical travel or exposure to a chronic carrier.
• Small inocula of S. typhi (~100,000 organisms) cause disease in >50% of healthy individuals.

General Prevention

• Food and water precautions help prevent all enteric infections, including typhoid fever.
• Avoid tap water, salad/raw vegetables, unpeeled fruits, and dairy products in tropical travel.
• Avoid undercooked poultry or poultry products left unrefrigerated for prolonged periods.
• Wash hands before and after food preparation.
• For high-risk travel to an endemic area, consider typhoid vaccination (3).
  • Parenteral ViCPS or capsular polysaccharide typhoid vaccine (Typhim Vi) or
  • Ty21a or live oral typhoid vaccine (Vivotif Berna), particularly if prolonged risk (>4 weeks)
• Consider vaccination for workers exposed to S. typhi or those with close contact with a carrier of S. typhi.
• Occupational health and safety precautions. Consider screening of domestic and commercial food handlers.