Fever in travelers returning from malaria-endemic areas: don't look for malaria only

Returning travelers with fever pose challenges for clinicians because of the multitude of diagnostic alternatives. Case data in a Finnish tertiary hospital were analyzed in order to define the causes of fever in returned travelers and to evaluate the current diagnostic approach.

A retrospective study of patient records comprised 462 febrile adults who, after traveling in malaria-endemic areas, were admitted to the Helsinki University Central Hospital (HUCH) emergency room from 2005 to 2009. These patients were identified through requests for malaria smear.

The most common groups of diagnoses were acute diarrheal disease (126 patients/27%), systemic febrile illness (95/21%), and respiratory illness (69/15%). The most common specific main diagnosis was Campylobacter infection (40/9%). Malaria was diagnosed in 4% (20/462). Blood culture was positive for bacteria in 5% of those tested (21/428). Eight patients were diagnosed with influenza. HIV-antibodies were tested in 174 patients (38%) and proved positive in 3% of them (5/174, 1% of all patients). The cause of fever was noninfectious in 12 (3%), remaining unknown in 116 (25%). Potentially life-threatening illnesses were diagnosed in 118 patients (26%), the strongest risk factors were baseline C-reactive protein (CRP) ≥100 (OR 3.6; 95% CI 2.0-6.4) and platelet count ≤140 (OR 3.8; 95% CI 2.0-7.3). Nine patients (2%) were treated in high dependency or intensive care units; one died of septicemia. Forty-five patients (10%) had more than one diagnosis.

The high proportion of patients with more than one diagnosis proves the importance of careful diagnostics. Every fourth returning traveler with fever had a potentially life-threatening illness. Septicemia was as common as malaria. The proportion of HIV cases exceeded the prevalence in population for which Centers for Disease Control and Prevention, USA (CDC) recommends routine HIV testing. Both blood cultures and HIV tests should be considered in febrile travelers.