fever in the returned traveller
in review
5 min read
Updated 2026-09-29
fever in the returned traveller
Malaria until proven otherwise in anyone febrile within 3 months (up to a year) of travel to an endemic area — thick and thin smears (or rapid antigen test) immediately, repeated q12–24h ×3 if negative. Severe falciparum malaria → IV artesunate via the Canadian Malaria Network. Then narrow the differential with geography, incubation period, and exposures: dengue (short incubation, thrombocytopaenia), enteric fever (stepwise fever, ceftriaxone/azithromycin), leptospirosis (freshwater, jaundice + AKI), rickettsiae (eschar, doxycycline). Isolate and call IPAC/public health immediately for suspected viral haemorrhagic fever.
do not miss
- P. falciparum malaria — can deteriorate within hours in non-immune travellers
- viral haemorrhagic fever (Ebola, Marburg, Lassa, CCHF) within 21 days of exposure in an outbreak area → isolate before any lab work, notify IPAC and public health
- meningococcaemia, rickettsial disease, and enteric fever — all treatable, all lethal if missed
local antibiogram
Enteric fever from South Asia is often fluoroquinolone-resistant, and XDR S. Typhi from Pakistan is ceftriaxone-resistant — travel history drives empiric choice.
history that narrows the differential
| clue | think |
|---|---|
| sub-Saharan Africa | P. falciparum (most imported cases), rickettsiae (African tick bite fever), schistosomiasis (Katayama) |
| South/Southeast Asia | dengue, enteric fever, P. vivax, chikungunya, scrub typhus, leptospirosis |
| Latin America/Caribbean | dengue, chikungunya, Zika, P. vivax, leptospirosis |
| incubation <10 days | dengue, chikungunya, Zika, rickettsiae, influenza, leptospirosis |
| incubation 10–21 days | malaria, enteric fever, leptospirosis, acute HIV, VHF |
| incubation >21 days | malaria (esp. vivax/ovale), TB, hepatitis, amoebic liver abscess, schistosomiasis |
| freshwater exposure | leptospirosis, schistosomiasis |
| eschar | rickettsiae (spotted fever, scrub typhus) → doxycycline |
| VFR travellers (visiting friends and relatives) | highest malaria and enteric fever risk; least likely to take prophylaxis |
initial workup
- malaria: thick and thin smears ± rapid antigen test now; repeat q12–24h until 3 negative sets
- CBC (thrombocytopaenia: malaria, dengue), creatinine, LFTs, glucose, lactate, blood cultures ×2 (enteric fever), urinalysis
- dengue NS1 antigen/PCR (first week) ± IgM; HIV test; CXR; stool studies if diarrhoea
- save acute serum for paired serology
malaria
severe malaria (CATMAT)
Any of: parasitaemia ≥5% (non-immune; ≥10% semi-immune), impaired consciousness or seizures, prostration, respiratory distress/ARDS, shock, Hb ≤70 g/L, glucose <2.2 mmol/L, acidosis, creatinine >265 µmol/L, jaundice, abnormal bleeding.
- IV artesunate 2.4 mg/kg at 0, 12, 24, 48 h — available 24/7 through the Canadian Malaria Network (CMN); IV quinine if artesunate unavailable
- ICU; monitor glucose; daily smears
- after ≥24 h IV and able to take PO → complete a full oral course (e.g. atovaquone-proguanil × 3 days)
- post-artesunate delayed haemolysis → check Hb weekly for 4 weeks
uncomplicated P. falciparum
- admit or observe the first dose for all non-immune patients
- atovaquone-proguanil 4 tablets daily × 3 days, or artemether-lumefantrine × 3 days (ACT)
- alternative: quinine + doxycycline (or clindamycin in pregnancy) × 7 days
- daily smears until negative
P. vivax, P. ovale, P. malariae
- chloroquine (outside Papua/Indonesia — chloroquine-resistant vivax there → atovaquone-proguanil)
- radical cure of vivax/ovale hypnozoites: primaquine 30 mg base daily × 14 days — G6PD first; contraindicated in pregnancy and breastfeeding an infant of unknown G6PD status
- P. knowlesi (Malaysian Borneo): can be severe — manage like falciparum
other causes
| disease | clues | management |
|---|---|---|
| dengue | incubation 4–10 days; fever, retro-orbital headache, myalgia (“breakbone”), rash, leucopaenia, thrombocytopaenia; warning signs at defervescence (day 3–7): abdominal pain, vomiting, bleeding, rising Hct | supportive; acetaminophen only (no NSAIDs); fluids per warning signs |
| chikungunya | severe symmetric polyarthralgia, may persist months | supportive |
| Zika | mild rash, conjunctivitis; congenital microcephaly, Guillain–Barré | supportive; pregnancy counselling |
| enteric fever (S. Typhi/Paratyphi) | incubation 7–21 days; stepwise fever, headache, abdominal pain, constipation or diarrhoea, relative bradycardia, rose spots, splenomegaly; blood cultures | ceftriaxone 2 g IV daily (uncomplicated: azithromycin 1 g PO daily × 7 days); XDR from Pakistan → carbapenem or azithromycin |
| leptospirosis | freshwater/flood exposure; conjunctival suffusion, myalgia (calves); Weil’s disease: jaundice + AKI + haemorrhage | doxycycline (mild) or ceftriaxone/penicillin IV (severe) |
| rickettsiae | eschar, rash, headache | doxycycline 100 mg BID — start empirically |
| viral haemorrhagic fever | outbreak-area exposure ≤21 days, contact with cases/bodies, bushmeat, rodents; fever → haemorrhage, shock | isolation (contact + droplet + airborne-level PPE), public health; supportive; test for malaria in parallel under containment |
| acute schistosomiasis (Katayama) | freshwater exposure in Africa, fever, urticaria, eosinophilia | praziquantel (repeat after 6–8 weeks) ± steroids |
| amoebic liver abscess | fever, RUQ pain weeks–months after travel; single abscess | metronidazole → luminal agent (paromomycin); drainage rarely needed |
eosinophilia and screening
- eosinophilia in a returned traveller or migrant → helminths (Strongyloides, schistosomiasis, filariae, hookworm)
- Strongyloides: autoinfection → persists for decades; hyperinfection/dissemination with steroids, HTLV-1, transplant → Gram-negative bacteraemia/meningitis. Screen serology (or treat empirically) before immunosuppression in anyone from endemic regions → ivermectin 200 µg/kg × 1–2 days
- neurocysticercosis (Taenia solium): seizures + ring-enhancing/calcified lesions → albendazole ± praziquantel with corticosteroids (antiepileptics; ophthalmology exam first)
traps
- a single negative smear excluding malaria
- assuming prophylaxis excludes malaria
- NSAIDs or IM injections in suspected dengue
- ciprofloxacin for enteric fever acquired in South Asia
- steroids (e.g. for a rash or COPD) in a migrant with unscreened Strongyloides
- primaquine without G6PD testing
- sending VHF samples to the routine lab before IPAC/public health are involved