VAIL, COLO. – Two-thirds of all cases of typhoid fever seen in the United States result from travel to India or neighboring Pakistan or Bangladesh.
Add in Mexico, the Philippines, and Guatemala, and travel to just those six countries accounts for 80% of all U.S. cases of typhoid fever, according to a Centers for Disease Control and Prevention study.
Jay S. Keystone
Some 41% of cases in the United States during 1999-2006 occurred in patients aged 17 years or younger.
"This is a very important disease in children," Dr. Jay S. Keystone noted in highlighting the CDC report at a conference on pediatric infectious diseases sponsored by Children’s Hospital, Colorado, Aurora.
The infection has substantial morbidity, as 73% of patients were hospitalized, half for longer than a week. The mortality rate, however, was only 0.2%.
Dr. Keystone stressed that prolonged fever is the key distinguishing feature of typhoid. The fever lasts weeks longer than those of dengue or chikungunya, which persist for about 1 week. So once malaria has been ruled out, weeks of fever have accrued, and the clinical picture isn’t consistent with mononucleosis, cytomegalovirus, or other viral illnesses, it’s time to think about typhoid fever.
Other than prolonged fever, the classic symptoms include headache, cough, diarrhea, and abdominal pain.
Only 5% of patients in the CDC study had been vaccinated against typhoid fever prior to their foreign travel. However, it’s important to recognize that the vaccine is only about 70% effective, so immunization against typhoid – unlike the other standard travel vaccines, which are 95% or more effective – does not rule out the disease, noted Dr. Keystone, professor of medicine at the University of Toronto and a past president of the International Society of Travel Medicine.
A relatively long period of effective antibiotic therapy (average, 3-5 days) is required before patients with typhoid become afebrile. Azithromycin or ceftriaxone are good choices for empiric therapy during the 3-day wait for results of blood, stool, and urine cultures, the physician said.
Azithromycin gets the edge because only 5-7 days of therapy are required, in contrast to 14 days for ceftriaxone, he added.
In the CDC series, 13% of Salmonella ser Typhi isolates were multidrug-resistant to ampicillin, chloramphenicol, and trimethoprim-sulfamethoxazole. Some 38% were resistant to nalidixic acid, which is a marker for reduced susceptibility to fluoroquinolones. The proportion of nalidixic acid-resistant isolates tripled from 1999 to 2006 (JAMA 2009;302:859-65).
Dr. Keystone declared having no relevant financial interests.