Fever in the Returning Traveller
Summary
Fifty million people travel to the developing world every year, many of whom develop a travel-related illness often involving fever caused by infection. In this article Dr Charis Marwick and Dr Dilip Nathwani provide an overview of the main regional causes of fever to aid diagnosis and treatment.
Key Points
- Fifty million people travel to the developing world each year, and 20–70% report a travel-related illness.
- Many febrile illnesses in these travellers are due to infections encountered all over the world.
- Fever without focal symptoms is most common and most often due to malaria or dengue.
- Fever with diarrhoea is next most common and is usually due to giardiasis, amoebiasis, shigellan or campylobacter infection.
- A full medical history and physical examination are essential for correct diagnosis.
- Thick and thin blood films are the gold standard for diagnosing malaria, and stool examination is essential where diarrhoea is present.
- Malaria due to P. falciparum should be treated in hospital.
- Prevention can never be perfect, but is better than cure.
Declaration of interests: No conflict of interests declared
Introduction
With global travel increasing annually, there is an inevitable increase in imported infection. Of the 50 million travellers to the developing world each year, up to 5% will seek medical advice during their trip or on return, while 20–70% will report some illness associated with their travel.1 Those visiting family or friends and adventure tourists are at greatest risk.1 A systematic approach to the assessment of the febrile traveller with knowledge of the most common, region-specific pathogens will aid diagnosis and treatment.
Causes of fever
A large proportion of febrile returning travellers will have cosmopolitan infections such as pneumonia, viral respiratory tract infection and urinary tract infection. However, specific tropical infections must be considered with malaria and dengue being the most common.
In 2003, there were 996 cases of malaria in European travellers reported to TropNetEurop2 (the European Network on Imported Infectious Disease surveillance system). Of these, 831 were P. falciparum infections (818 mono and 13 mixed infections), 133 were P. vivax and 32 were P. ovale.2 Recently published data on 17,353 travellers from developed to developing countries have demonstrated important differences in morbidity depending on the country of destination3 (data from the multinational Geosentinel surveillance database.
The most common clinical presentation was a systemic febrile illness without localising symptoms or signs. Malaria was the most common diagnosis overall in these patients. However, in travellers from destinations other than sub-Saharan Africa and Central America, dengue was more prevalent. After malaria and dengue, infectious mononucleosis was the most common cause of fever, followed by rickettsial disease and then typhoid.
Acute diarrhoea was the second most common presentation. The most common identified causes were giardiasis, amoebiasis, campylobacter and shigella.
Destination-specific variations in the proportionate morbidity associated with different etiologic agents, in patients presenting with a systemic febrile illness or acute diarrhoea, are shown in Table 1.3 This may aid clinicians in narrowing down the likely aetiology of an illness. Similarly, a prospective study of 91 febrile travellers presenting to the Hospital of Tropical Medicine, London, demonstrated malaria, non-specific viral illness, dengue and dysentery as the most common diagnoses.4
Awareness of recent outbreaks of infection worldwide and the current regional susceptibility of malaria is necessary in assessing the ill traveller. Up-to-date information for non-healthcare professionals is available from the Scottish Centre for Infection & Environmental Health (SCIEH) and the World Health Organisation (WHO). Healthcare professionals involved in the advice and treatment of travellers should register with the SCIEH clinicia