Typhoid fever

The distinction from non-typhoidal salmonellosis is central. Typhoidal disease is invasive and systemic, has a human-only reservoir, requires a large inoculum, and presents with fever and constipation or late diarrhoea; non-typhoidal salmonellosis comes from poultry, eggs, reptiles, and turtles, requires a smaller inoculum, and causes self-limited gastroenteritis, in which antibiotics are avoided because they prolong faecal shedding, except in infants, the elderly, the immunocompromised, and those with sickle cell disease, in whom Salmonella osteomyelitis is a classic association. In typhoid, antibiotics are always indicated. Diagnosis is by blood culture early and stool culture later, with bone marrow culture the most sensitive; the Widal serological test is unreliable. Complications include ileal perforation, myocarditis, encephalopathy, and chronic gallbladder carriage. Both injectable Vi polysaccharide and oral live attenuated Ty21a vaccines exist, the latter contraindicated in immunocompromise and requiring avoidance of concurrent antibiotics.