Fever in the returned traveller

• Incidence of Fever in Travelers
  • About 2-3% of travelers experience febrile illness.
  • Fever accounts for roughly 25% of post-travel medical consultations.
  • The illnesses range from minor, self-limiting to serious, life-threatening.
  • Late presentations can occur, with some infections manifesting months or years later.

• Diverse Causes of Fever
  • Common diagnoses:
    • systemic febrile illness – 35% (malaria, dengue, typhoid, rickettsia)
    • unspecified febrile illness – 22%
    • acute diarrhoea – 15%
    • respiratory illness – 14% (pneumonia, bronchitis, sinusitis)
    • vaccine-preventable illness – 3% (hepatitis A and B, typhoid)
  • Serious conditions like malaria, meningococcal disease need early recognition.
  • Infectious causes may also be a public health concern.

• Diagnostic Process
  • A thorough history including medical, travel, and exposure details is essential.
  • Physical examination should be comprehensive, checking for signs like lymphadenopathy, hepatomegaly, splenomegaly, and jaundice.
  • History specifics: patient’s age, past surgeries, medications, allergies, vaccinations, immune status.

Particular exposures and possible infections
EXPOSURE	DISEASE
Drinking unclean water	Viral diarrhoea, shigella, salmonella, hepatitis A and E, giardia, polio, cryptosporidium, Guinea-worm
Skin contact in unclean water	Leptospirosis, schistosomiasis, free-living amoeba
Eating raw or improperly cooked food	Food-borne viruses and bacteria, wide range of parasites, brucellosis, listeriosis
Animal bites	Rabies, rat-bite fever, wound infections, simian herpes B-virus, cat-scratch fever
Animal contact	Q-fever, anthrax, toxoplasma, Hanta viruses, Nipah/Hendra viruses, severe acute respiratory syndrome, plague
Bird contact	Psittacosis, avian influenza
Mosquito bites	Malaria, dengue, yellow fever, arboviruses, viral encephalitis, filariasis
Tick bites	Rickettsia, borrelia, tick-born encephalitis, Q-fever, Crimean-Congo haemorrhagic fever, tularaemia, babesiosis
Fly bites	African trypanosomiasis, onchocerciasis, leishmaniasis, loa loa, sandfly fever, bartonella
Flea bites	Plague, murine typhus, tungiasis
Lice bites	Relapsing fever, epidemic typhus, trench fever
Mite bites	Scrub typhus, rickettsial pox
Triatomine bug bite	Chagas disease
Soil-skin contact	Hookworm, strongyloides, melioidosis, fungal infections, mycobacteria
Sexual contact	HIV, hepatitis A, B and C, sexually transmitted diseases
Injections, body-piercing	Hepatitis B and C, HIV, malaria, mycobacteria, leishmaniasis

Checklist for taking a history in returned travellers
QUESTIONS	EXAMPLES
Country of origin and country of travel	Latent disease, possible exposures
Occupation, hobbies, activities	Farmer, abattoir worker, cave explorer
Prophylaxis	Immunisations, malaria prophylaxis, insect repellents
Treatments or procedures	Blood transfusions, injections, splenectomy, gastrectomy, tattoos
Drugs	Prescribed, over-the-counter, illicit
Diet	Seafood, raw food, traditional or homemade food
Sex	Unprotected sex, HIV partner, multiple partners, commercial sex
Allergies	Antibiotics, food, insect bites, plant
Bites	Insects, snake, animal, spider, human
Pets	Birds, dogs, cats, other
Family history	Diabetes, sickle-cell anaemia, tuberculosis

Average incubation periods for selected diseases
INCUBATION	DISEASES
Short (<10 days)	Arboviruses including dengue, chikungunya, bacillary dysentery, influenza, legionella, meningococcal, Marburg/Lassa fevers, plague, relapsing fever, rickettsial spotted fevers, scrub typhus
Intermediate (10–21 days)	African trypanosomiasis, brucellosis, hepatitis A and E, leptospirosis, malaria, typhoid, polio, epidemic typhus, Q-fever
Long (>21 days)	Hepatitis B, malaria, amoebic liver disease, visceral leishmaniasis, melioidosis, rabies, tuberculosis, filariasis, HIV, schistosomiasis

Key physical findings suggestive of cause of fever
CLINICAL FINDING	POSSIBLE DIAGNOSES
Rash, maculopapular	Dengue, rickettsia, acute HIV, typhoid, scarlet fever, gonococcal, syphilis
Rash, petechial	Rickettsia, meningococcal, viral haemorrhagic fevers, leptospirosis
Eschars	Scrub typhus, tick-bite fever, anthrax, spider bites
Ulcers	Leishmaniasis, mycobacteria, anthrax
Jaundice	Hepatitis, malaria, leptospirosis, relapsing fever
Lymphadenopathy	Leishmaniasis, plague, rickettsia, brucellosis, toxoplasmosis, HIV, Lassa fever
Hepatomegaly	Malaria, leishmaniasis, schistosomiasis, liver abscess, typhoid, hepatitis, leptospirosis
Splenomegaly	Malaria, leishmaniasis, relapsing fever, trypanosomiasis, typhus, dengue, schistosomiasis, brucellosis

Unusual diseases present in Australia
EXPOSURE	DISEASES
Mosquito	Alphaviruses – Ross River virus, Barmah Forest virus Flaviviruses – Murray Valley encephalitis, Kunjin virus, dengue, Japanese encephalitis
Tick	Queensland tick typhus, Flinders Island spotted fever
Mite	Scrub typhus
Soil and water	Melioidosis, leptospirosis
Animal	Australian bat lyssavirus, Hendra virus, Q-fever, brucellosis
Various	Mycobacteria – Bairnsdale ulcer, tuberculosis, leprosy, avian complex, trachoma

• Laboratory Investigations
  • Routine tests include blood examination, liver function tests, malaria smears, blood cultures, urinalysis.
  • Malaria smears may be repeated if suspicion persists despite negative results.
    • Negative smears can be due to
      • low parasitaemia or
      • can occur despite a high load with P. falciparumdue to sequestration.
    • Malaria should always be reconsidered if a traveller has returned from an area where transmission occurs, regardless of whether they took chemoprophylaxis, or whether they are afebrile at the time of assessment
  • Additional testing depends on clinical presentation and history.

• Management Approaches
  • Focus on identifying life-threatening and treatable conditions.
  • Avoid overdiagnosis, common in certain diseases like malaria and typhoid fever in specific regions.
  • Managing potential communicable disease spread is crucial.

• Referral and Hospitalization Guidelines
  • Unclear or complex cases should be referred to infectious disease specialists or hospitals.
  • Outpatient management is possible for less severe cases.
  • Severe, atypical, or worsening cases may require hospitalization.

• Public Health Aspects in Australia
  • Clinicians must report certain communicable diseases.
  • Quarantinable diseases demand extensive public health responses.

Quarantinable diseases in Australia are those that are subject to strict control measures under the Quarantine Act 1908 and the Biosecurity Act 2015. Quarantinable Diseases in Australia

1. Cholera
2. Plague
3. Yellow Fever
4. Rabies
5. Smallpox
6. Viral Hemorrhagic Fevers (including Ebola, Marburg, Lassa, and Crimean-Congo)
7. Severe Acute Respiratory Syndrome (SARS)
8. Middle East Respiratory Syndrome (MERS)
9. Human Influenza caused by a new subtype (such as H5N1 or H7N9)
10. Poliomyelitis (Polio)

• Conclusion and Recommendations
  • Systematic evaluation involving history, examination, and testing is vital.
  • Excluding malaria is critical in febrile individuals from endemic areas.
  • Specialist consultation is advised for cases without a clear diagnosis.