Illness in Returned Traveller

A structured approach to the returned traveller with a new health problem — most often fever, but also GI, respiratory or dermatological presentations. Complements Fever of unknown origin.

Background

Illness on return from travel spans a spectrum from minor and self-limiting to life-threatening. Fever in the returned traveller may be a symptom of a minor self-limiting illness or the onset of a life-threatening disease — and disease unrelated to travel can still occur after exotic travel, so don’t anchor on an exotic diagnosis alone.

• Common: non-specific viral infection, respiratory tract infection, gastroenteritis, giardiasis, UTI.
• Less common but important: malaria, measles, typhoid fever, dysentery, dengue fever, hepatitis.

First rule: exclude malaria

Malaria must be excluded in every febrile traveller returning from an endemic area. Any patient who has been to a malarious region and gives a history of fever should be tested — send thick and thin blood films on 2 separate occasions, plus a rapid diagnostic test (e.g. Rapimal™) where available (note: RDTs are only reliably sensitive for P. falciparum, not the other Plasmodium species). An initial negative blood smear does not exclude malaria — repeat if suspicion remains. Falciparum malaria can kill within days; fever within the first few weeks of return is malaria until proven otherwise.

Returned travellers who were visiting friends and relatives (VFR) overseas are more likely to have a serious cause for their illness — e.g. malaria and typhoid fever — often because they under-estimated their own risk and skipped prophylaxis/vaccination.

Structured history

• Where (urban vs rural, specific destination, altitude), when (departure/return dates), and what exposures — food/water, freshwater contact, insect/tick bites, sexual contacts, animal contact, occupation/ hobbies, healthcare received abroad, unwell travel companions.
• Prophylaxis and vaccines taken — which drug, when started, adherence, whether still taking it.
• Drug history (prescription, complementary, illicit).
• Incubation period of the possible infections narrows the differential (see table below) — see also the CDC destination-specific disease reference.

Examination

A full examination is required. Key findings that may localise the cause:

• Jaundice, hepatosplenomegaly
• Cough, coryza, conjunctivitis ± rash (measles)
• Rashes — rose spots (typhoid), macular/maculopapular (dengue, rickettsia)
• Purpura/petechiae (meningococcal)
• Regional lymphadenopathy
• Insect bites (e.g. ticks)

Differential by incubation period

Incubation	Infection
Short (<10 days)	Malaria, influenza, arboviral infections (dengue, yellow fever), plague, enteric bacterial infections (incl. paratyphoid), African tick bite fever, spotted fever group (incl. Rocky Mountain spotted fever)
Intermediate (10–21 days)	Malaria, viral haemorrhagic fevers, typhoid fever, scrub typhus, Q fever, relapsing fever (Borrelia spp.), African trypanosomiasis, brucellosis, leptospirosis
Long (>21 days)	Malaria, hepatitis A/B/C/E, schistosomiasis (Katayama fever), leishmaniasis, amoebic liver abscess, tuberculosis, filariasis

Specific incubation periods (days)

Infection	Incubation
Malaria (P. falciparum)	7 days (min) – 12 weeks (usual max)
Malaria (other Plasmodium spp.)	Weeks to several years
Measles*	7–18 days
Dengue	3–14 days
Hepatitis A*	14–50 days
Hepatitis B	45–180 days
Typhoid*	3 days – 3 months
Campylobacter	1–10 days
Shigella	12 hours – 4 days
Viral haemorrhagic fevers*	2–21 days
Influenza	2–5 days
Cholera* (V. cholerae O1/O139)	Hours – 5 days (usually 2–3 days)

* Urgent notifiable diseases — the rest are routine notifiable.

Physical findings can also localise the cause: jaundice (dengue, typhoid, rickettsial infections, syphilis, gonorrhoea, viral hepatitis, brucellosis), hepatomegaly (rickettsial infection, brucellosis, dengue, HIV, visceral leishmaniasis), splenomegaly (amoebiasis, malaria, typhoid, hepatitis, leptospirosis), haemorrhage (rickettsial infections, Crimean-Congo/ Marburg/Ebola/Rift Valley/yellow fever, epidemic louse-borne typhus, Rocky Mountain spotted fever).

Red flags — act immediately

• Suspected viral haemorrhagic fever (endemic-area exposure + bleeding or high-risk contact) → isolate and notify public health urgently — see Viral haemorrhagic fevers/Ebola.
• Any patient in whom measles is clinically suspected should be nursed in a negative-pressure room with airborne precautions.
• Features of sepsis/meningococcaemia, altered consciousness, or severe malaria → urgent hospital transfer.

Investigations

• FBC (anaemia and thrombocytopenia more likely with malaria)
• Thick and thin malaria films ×2 (or rapid antigen test) — as above
• Measles PCR (nasopharyngeal swab, prodrome to day 6) or serology (IgM/IgG appear day 1–3 post-rash) if measles suspected
• LFTs (if suspecting hepatitis or malaria)
• Blood cultures — routine in all febrile returned travellers
• CXR
• Urine M+C (if suspect UTI)
• Stool culture ± O/C/P (e.g. bacillary dysentery, giardiasis, viral gastroenteritis); consider storing serum if dengue/other arbovirus suspected
• Serology/PCR guided by specific exposures (dengue NS1, arboviral, enteric, HIV)

Management

Treatment targets the likely cause (empirical antibiotics for pneumonia/UTI as indicated), with contact tracing and notification of notifiable diseases where relevant — most travel-acquired infections listed above are notifiable (see your state/territory health department, e.g. Victoria’s notifiable conditions list).

• Remember non-infectious causes of fever (e.g. thrombophlebitis).
• Consider referral to Infectious Diseases if the patient is unwell or no cause is identified.

From https://www.rch.org.au/clinicalguide/guideline_index/Illness_in_the_returned_traveller/.