Aetiology of fever in returning travellers and migrants: a systematic review and meta-analysis

Abstract

Background Numerous publications focus on fever in returning travelers, but there is no known systematic review considering all diseases, or all tropical diseases causing fever. Such a review is necessary in order to develop appropriate practice guidelines. Objectives Primary objectives of this review were i) to determine the etiology of fever in travelers/migrants returning from (sub) tropical countries as well as the proportion of patients with specific diagnoses, and ii) to assess the predictors for specific tropical diseases. Method Embase, MEDLINE and Cochrane Library were searched with terms combining fever AND travel/migrants. All studies focusing on causes of fever in returning travelers and/or clinical and laboratory predictors of tropical diseases were included. Meta-analyses were performed on frequencies of etiological diagnoses. Results 10064 studies were identified; 541 underwent full-text review; 30 met criteria for data extraction. Tropical infections accounted for 33% of fever diagnoses, with malaria causing 22%, dengue 5% and enteric fever 2%. Non-tropical infections accounted for 36% of febrile cases, with acute gastroenteritis causing 14% and respiratory tract infections 13%. Positive likelihood ratios demonstrated that splenomegaly, thrombocytopenia and hyperbilirubinemia were respectively 5–14, 3–11 and 5–7 times more likely in malaria than non-malaria patients. High variability of results between studies reflects heterogeneity in study design, regions visited, participants’ characteristics, setting, laboratory investigations performed, and diseases included. Conclusion Malaria accounted for one fifth of febrile cases, highlighting the importance of rapid malaria testing in febrile returning travelers, followed by other rapid tests for common tropical diseases. High variability between studies highlights the need to harmonize study designs and to promote multi-center studies investigating predictors of diseases, including of lower incidence, which may help to develop evidence-based guidelines. The use of clinical decision support algorithms by health workers which incorporate clinical predictors, could help standardize studies as well as improve quality of recommendations.

A High Index of Malaria Suspicion is Necessary for Febrile Episodes in Travellers and Migrants Coming from Endemic Areas

“…According to what is typically described 19,23,24,36 , differential clinical characteristics of a patient with malaria in our study were fever, lower levels of platelets/leukocytes, and higher total bilirubin levels. Thus, fever should always be a warning sign in patients returning from a malaria-endemic area.…”

“…Imported malaria is more commonly diagnosed in VFRs (migrants and travellers) and visitors, as compared to travellers 23,24 . However, more severe cases are detected among travellers, followed by VFRs.…”

“…Furthermore, laboratory results such as thrombocytopenia and higher levels of bilirubin are highly suggestive of Plasmodium spp. infection and, if absent, they have been proposed as biomarkers with negative predictive value 23,24,37 .…”

Household and Hospitalization Costs of Pediatric Dengue Illness in Colombo, Sri Lanka

“…1 Dengue has also become a leading cause of febrile illness in international travelers. [2][3][4][5][6] Dengue infections may progress to dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS), which are associated with higher hospitalization and case-fatality rates, particularly among children. [7][8][9] An estimated 40,500 (range: 17,600-49,800) people die because of dengue-related complications worldwide annually.…”

Fever in the returning traveller

“… 2 Fever in these travellers is caused by tropical infections in 36% of cases (malaria being the most common at 22% of febrile presentations) and non-tropical in 36% (gastrointestinal infections, respiratory tract infections). 3 This article aims to provide a framework to evaluate these patients. It is important to consider when the patient ( who ) has been doing what , where .…”