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MCQs in Tropical Medicine

Rob Skelly DTM+H FRCP

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Answer 45

Enteric fever

True a. Bone marrow culture increases diagnostic yield in those previously given antibiotics.
True b. is zoonotic

False c. is associated with poor sanitation
False d. the incubation period is usually 4-6 weeks
False e. rose spots occur in typhoid but not paratyphoid fever

Blood culture is positive in 80% of cases in the first week. When antibiotics have already been given, bone marrow biopsy and culture may be positive when blood culture is negative. In untreated cases urine and stool cultures become positive in the third and forth weeks.

Chronic carriage is more likely with increasing age especially for women. Gallstones increase the risk of chronic faecal carriage and urinary schistosomiasis increases the risk of chronic urinary carriage.

Leucocytosis would be against a diagnosis of typhoid.

The incubation period for typhoid is 7-21 days.

Rose spots appear on the abdomen and chest in the second week. They are pale red macules 2-4mm in diameter. They may occur in both typhoid and paratyphoid fevers.

Copyright: Rob Skelly 2006