Fever in a returned traveller

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History

  • Pretravel
    • Vaccinations
    • Prophylaxis, e.g. malaria
    • Vector protection, including bed nets and mosquito spray
  • Travel
    • Make explicit timeline of locations visited, for how long
    • Assess activities and exposures in each location
    • Food (especially street food) and water sources
    • Recreational water
    • Animals
    • Insect bites
    • Sex and other body fluid exposures
  • Combine timeline of exposures with incubation periods to rule out diseases
    • Dengue: 3-5 days
    • Malaria: 7-21 days
    • Hepatitis A: 6 days to 6 weeks
    • Hepatitis B: 1-6 months
    • Typhoid: 7-21 days
    • Non-typhoidal Salmonella: 3-7 days

Differential Diagnosis

Most common conditions

  1. Malaria (20-30%)
  2. Acute diarrhea or gastroenteritis (10-20%)
  3. Respiratory infections (10-15%)
  4. Dengue (5%)
  5. Enteric fever (2-7%)
  6. Skin and soft tissue infections (2-11%)
  7. Rickettsioses, including African tick bite fever and Mediterranean spotted fever (3%)
  8. Urinary tract infections and sexually-transmitted infections (2-3%)
  9. Viral hepatitis (3%)
  10. Mononucleosis or viral syndrome (4-25%)

Most common by location of travel

Life-threatening infections

Disease Incubation Distribution Exposures Diagnosis
Viruses
Avian influenza 2-8 days East and Southeast Asia poultry PCR
MERS-CoV 2-14 days Arabian peninsula infected humans or camels PCR
Ebola, Lassa fever, or Marburg hemorrhagic fever up to 22 days Africa infected humans and animals PCR
Crimean-Congo hemorrhagic fever 1-9 days (tick) or 3-13 days (contact) southern Europe, Middle East, Africa, northwestern China Ixodes ticks or infected humans or animals PCR
Yellow fever 3-8 days South America and Africa Aedes mosquitoes PCR or IgM
Japanese encephalitis 5-15 days Asia and western Pacific Culex mosquitoes IgM
Rift Valley fever 2-6 days Africa and the Arabian peninsula mosquitoes, or blood from infected animals PCR or IgM
Rabies 20 to 60 days (usually 4 weeks) worldwide animal bite saliva PCR; serum/CSF RFFIT; skin biopsy PCR or RFFIT
Bacteria
Anthrax 1 day (cutaneous) to 1-7 days (pulmonary) Africa and Asia infected animals or animal products bacterial culture or PCR
Enteric fever 6-30 days South and Southeast Asia fecal-oral transmission bacterial culture
Epidemic typhus 7-14 days Central Africa, Asia, North and South America Human body lice, flying squirrel parasites, possibly ticks IgM/IgG and PCR
Leptospirosis 2-29 days worldwide but particularly South and Southeast Asia and South America urine of infected animals IgM/IgG and PCR
Louseborne relapsing fever 4-14 days Ethiopia, Eritrea, and Sudan Human body lice blood film examination, IgM/IgG, or PCR
Melioidosis 1-21 days (but up to years) South and Southeast Asia, northern Australia, and case reports from Africa and South America contaminated soil or surface water bacterial culture
Endemic typhus 7-14 days worldwide but particularly Southeast Asia rodent fleas IgM/IgG or PCR
Oroya fever or Carrion disease 10 days to 7 months South America, particularly Peru Sandflies bacterial culture
Scrub typhus 6-20 days Asia and northern Australia chiggers IgM/IgG or PCR
Rickettsial spotted fever 2-14 days worldwide mostly ticks IgM/IgG or PCR
Plague 2-6 days (bubonic) or 1-3 days (pneumonic) remote Africa, Asia, and South America rodent fleas bacterial culture
Protozoa
East African sleeping sickness 7-21 days eastern and southern Africa tsetse flies blood film examination, lymph aspirate exam, or chancre biopsy
Falciparum malaria 7-30 days, or longer African, Asia, South America Anopheles mosquitoes thick-and-thin blood film examination or rapid antigen test
Knowlesi malaria 10-14 days Southeast Asia, particularly Borneo Anopheles mosquitoes thick-and-thin blood film examination

Investigations

  • First-line
    • CBC
    • Liver enzymes and function, for viral hepatitides
    • Electrolytes, urea, and creatinine
    • Urinalysis, for proteinuria that would suggest Leptospirosis
    • Blood cultures x2, for enteric/typhoid fever
    • Thick and thin smears x3 over 3 days, for malaria
  • Based on history and lab results
    • Urine culture
    • Stool culture and O&P
    • Hepatitis serologies
    • Serology for zika, chikungunya, and dengue viruses, with repeat in 14 days if negative
    • C. difficile toxin
    • NP swab

Further Reading