Phys · infectious
Tropical and Travel-Related Infections
Also known as fever in returning traveller · imported malaria · falciparum malaria · severe malaria · dengue fever · dengue haemorrhagic fever · enteric fever · typhoid fever · scrub typhus · Katayama fever · acute schistosomiasis · Weil disease · leptospirosis · melioidosis · strongyloides hyperinfection · eosinophilia in returning traveller
Consultant-physician-depth guide to the febrile returning traveller — the incubation-period framework that narrows the differential, the rule-out-malaria-first principle, falciparum malaria (thick and thin films, RDT, IV artesunate for severe disease and artemether-lumefantrine for uncomplicated disease), dengue (breakbone fever, plasma leakage, warning signs, fluid-centred supportive care), enteric (typhoid) fever with the step-ladder pattern and ceftriaxone, rickettsial disease (eschar, doxycycline), schistosomiasis (Katayama fever, eosinophilia, praziquantel), leptospirosis (Weil disease), melioidosis in northern Australia (ceftazidime then prolonged oral eradication), the intestinal parasites giardia, amoeba and strongyloides (hyperinfection risk), the eosinophilia workup, and pre-travel advice — structured for FRACP DWE and DCE preparation.
Checked against its sources on 13 Sept 2026
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- Any febrile traveller returning from a malaria-endemic area has falciparum malaria until proven otherwise — a single negative film never excludes malaria; repeat every 12 to 24 hours for at least three sets
- Severe falciparum malaria is a medical emergency — give IV artesunate 2.4 mg/kg immediately if any WHO severity criterion is present (impaired consciousness, prostration, respiratory distress, jaundice, hyperparasitaemia, acidosis, renal failure, hypoglycaemia)
- Dengue warning signs (abdominal pain, persistent vomiting, clinical fluid accumulation, mucosal bleeding, lethargy, hepatomegaly, rising haematocrit with falling platelets) herald the critical plasma-leakage phase around defervescence
- Narrow pulse pressure (20 mmHg or below) in dengue indicates impending shock — give cautious isotonic crystalloid
- Typhoid with severe abdominal pain and rigidity means perforation of a Peyer patch ulcer — surgical emergency in the third week
- An eschar with fever and headache in a traveller from Asia or northern Australia is scrub typhus or another rickettsial disease — start doxycycline empirically; do not wait for serology
- Any patient from a tropical area starting corticosteroids or other immunosuppression must be screened and treated for strongyloides first — hyperinfection is fatal in over half of cases
- Fever with conjunctival suffusion and jaundice after freshwater or animal exposure is leptospirosis (Weil disease) — start ceftriaxone
- Suspected viral haemorrhagic fever (fever within 21 days of returning from an endemic area) — isolate immediately in a negative-pressure room, notify public health, and use full PPE before any investigation
Tropical and Travel-Related Infections
[1]The one-minute consultant answer
A fever in a returning traveller is malaria until proven otherwise — and the single most dangerous mistake in tropical medicine is sending a febrile traveller home after one negative blood film. The GeoSentinel Surveillance Network found that among ill returned travellers presenting with fever, malaria was the most common specific diagnosis (21 per cent), that 26 per cent were hospitalised, and that malaria accounted for a third of the deaths [1]. The framework that drives every decision is therefore: take a precise travel and exposure history, send the minimum investigation set immediately, and rule out falciparum malaria first — because untreated severe falciparum malaria is nearly 100 per cent fatal within 24 to 48 hours.
Two questions change everything. First, where did they go, and when did they return? The incubation period narrows the differential. Fever within one week of return points to arboviruses (dengue, chikungunya), plague or anthrax. Fever one to four weeks after return brings in malaria, typhoid, dengue, rickettsial disease, leptospirosis and schistosomiasis. Fever weeks to months later raises tuberculosis, visceral leishmaniasis, amoebic liver abscess and chronic schistosomiasis. Second, what did they do? Freshwater exposure points to schistosomiasis and leptospirosis; rural Asia or northern Australia in the wet season points to scrub typhus and melioidosis; visiting friends and relatives (VFR travellers, who often take no prophylaxis) is the highest-risk group for falciparum malaria and typhoid. [1]
The treatment decisions that examiners test are few and must be automatic: severe falciparum malaria gets IV artesunate 2.4 mg/kg at 0, 12 and 24 hours then daily — the SEAQUAMAT trial showed a 34.7 per cent mortality reduction versus quinine in adults [2], and AQUAMAT confirmed a 22.5 per cent reduction in African children [3]. Uncomplicated falciparum malaria gets an oral artemisinin-based combination therapy (ACT) — artemether-lumefantrine, six doses over three days with fatty food. Dengue has no specific antiviral — management is careful fluid-centred supportive care, avoiding NSAIDs and aspirin because of bleeding risk. Typhoid gets ceftriaxone (fluoroquinolones are unreliable because of resistance). Rickettsial disease gets doxycycline — empirically, before serology returns. Schistosomiasis gets praziquantel, leptospirosis gets ceftriaxone or doxycycline, melioidosis gets ceftazidime then a three-month oral eradication phase, and strongyloides gets ivermectin — but only after you have screened for it, because giving corticosteroids to a carrier triggers fatal hyperinfection.
References9ShowHide
- [1]Wilson ME, Weld LH, Boggild A, et al. Fever in returned travelers: results from the GeoSentinel Surveillance Network Clin Infect Dis, 2007.PMID 17516399
- [2]Dondorp A, Nosten F, Stepniewska K, Day N, White N Artesunate versus quinine for treatment of severe falciparum malaria: a randomised trial Lancet, 2005.PMID 16125588
- [3]Dondorp AM, Fanello CI, Hendriksen IC, et al. Artesunate versus quinine in the treatment of severe falciparum malaria in African children (AQUAMAT): an open-label, randomised trial Lancet, 2010.PMID 21062666
- [4]Jauréguiberry S, Ndour PA, Roussel C, et al. Postartesunate delayed hemolysis is a predictable event related to the lifesaving effect of artemisinins Blood, 2014.PMID 24859359
- [5]Simmons CP, Farrar JJ, Nguyen VV, Wills B. Dengue N Engl J Med, 2012.PMID 22494122
- [6]GBD 2017 Typhoid and Paratyphoid Collaborators The global burden of typhoid and paratyphoid fevers: a systematic analysis for the Global Burden of Disease Study 2017 Lancet Infect Dis, 2019.PMID 30792131
- [7]Varghese GM, Dayanand D, Gunasekaran K, et al. Intravenous Doxycycline, Azithromycin, or Both for Severe Scrub Typhus N Engl J Med, 2023.PMID 36856615
- [8]Currie BJ Melioidosis: evolving concepts in epidemiology, pathogenesis, and treatment Semin Respir Crit Care Med, 2015.PMID 25643275
- [9]Buonfrate D, Fittipaldo A, Vlieghe E, Bottieau E Clinical and laboratory features of Strongyloides stercoralis infection at diagnosis and after treatment: a systematic review and meta-analysis Clin Microbiol Infect, 2021.PMID 34325063