Travelers Returning to Italy with Fever

Abstract & Commentary

Synopsis: Seven percent of more than 2,000 hospital admissions to the Division of Infectious Tropical Diseases at the Luigi Sacco Hospital, University of Milan, were due to fever in travelers and migrants returning from the tropics. Malaria was the most frequent diagnosis.

Source: Spinello A, et al. Prospective Observational Study of Fever in Hospitalized Returning Travelers and Migrants from Tropical Areas, 1997-2000. J Travel Med. 2004;11:135-142.

All patients presenting with fever and a history of travel and /or residence in a tropical country during the 6 months prior to admission were enrolled in a study to identify the prevalence of febrile travelers, the causes of fever in his group, and the usefulness of laboratory testing performed to evaluate them. Ninety-one men and 56 women were enrolled (147 total); 107 individuals resided in Italy (n =101) or other European nations (n = 6), and 40 were migrants. Of those presenting with illness, 67.3% occurred in persons in the 20-39 year age group. Travelers had returned from Africa (61%), Asia (22%), Central and South America (13%), and the Middle East (2%).

Fever was present in 7% of all those admitted (147/2074). Data that were available on 142 patients revealed that antimalarial prophylaxis was taken by 32 patients: 29/106 Italian or European subjects and only 3/38 migrants. Thirteen patients either discontinued malaria chemoprophylaxis before the scheduled time or they had been prescribed an inappropriate regimen for their destination. Most persons were admitted for their illness within 2 weeks after their return. The Table below shows the microbiological diagnoses obtained for 115 patients.

Malaria was the most common diagnosis. Of the 70 patients with malaria, only 14 had received antimalarial prophylaxis. Of note, 5 patients who had been taking mefloquine developed malaria, 4 due to Plasmodium vivax and 1 due to Plasmodium falciparum acquired in Tanzania. Fifty-one of 52 patients with P. falciparum infection, had contracted it in Africa. Malaria was also the most common diagnosis in persons who presented with fever more than 30 days after return form the tropics. The most useful diagnostic tests performed were direct microscopic examination and PCR of peripheral blood for malaria parasites for the evaluation of fever. They were positive in about 65% of the cases in which they were requested.

Positive microbial cultures ranged from 4% of stool to 21% of urine specimens; blood cultures were positive in all diagnosed cases of typhoid fever and in 1 case of sepsis due to Escherichia coli. Hepatitis A and dengue were the most frequent viral diagnoses, accounting for 12% of diagnoses in all febrile travelers. Nearly 5 % of patients received a diagnosis of schistosomiasis. Serology for typhoid fever, brucellosis, and rickettsiosis were not helpful in the majority of cases.

Comment by Maria D. Mileno, MD

Few of the prospective studies which were cited in this paper had addressed the relatively common problem of fever in returning travelers. In this observational study, 80% of patients were hospitalized within 2 weeks of return home and 50% within 5 days. Of the 7% who had fever and required hospitalization, it is not surprising that malaria was the most common diagnosis. Other reviews of outpatients who return with illness suggest that more common diagnoses are responsible for their illnesses, yet the message remains—malaria must be excluded first in all persons with fever who return from malarious areas.

Several interesting points were raised. Kenya remains the most popular destination for Italian travelers, resulting in high risk of exposure to P. falciparum, and yet there was a very low rate of compliance with malaria chemoprophylaxis. Migrants, in particular, hardly participated in a chemoprophylaxis regimen. All persons who presented 1 month after their return to Italy had malaria, with late onset illness observed in 4 of 5 persons with P.vivax, despite mefloquine prophylaxis, as might be expected.

Caring for febrile returned travelers can be quite challenging. Thoughtful testing directed to identification of P. falciparum and other likely causes of fever can uncover the majority of diagnoses in this group. More reports examining trends in specific groups of returned travelers should be undertaken.

Maria D. Mileno, MD, Director, Travel Medicine, The Miriam Hospital, Associate Professor of Medicine, Brown University, Providence, RI, and Associate Editor of Travel Medicine Advisor.