Diagnosing the Tropical Traveller

oPatientPlus articles are written by UK doctors and are based on research evidence, UK and European Guidelines. They are designed for health professionals to use, so you may find the language more technical than the condition leaflets.

Global travel trends have meant a huge increase in the numbers of people travelling abroad and, increasingly, to remote countries. Travel is cheaper, and people generally have a greater proportion of disposable income. There is a greater awareness of different cultures through the medium of television and more opportunities to travel related to study or work.

  • In 2009 international tourist arrivals fell for the first time in over a decade - from 920 to 880 million arrivals.
  • The only region which had a growth in tourism during 2009 was Africa (+5%). A worldwide increase of 3-4% is forecast for 2010.
The patient who returns unwell provides a considerable challenge to the practitioner. You will not be able to cover, or think of, every possibility.

If in doubt, the National Travel Health Network and Centre (NaTHNaC) can be contacted on 0845 602 6712 or advice found on http://www.nathnac.org/.

  • Travel departure and return dates
  • Countries visited, including stop-overs
  • Destinations within the countries; rural or urban
  • Climatic conditions; season
  • Exposure to bites: insect, arachnid, reptile, mammal
  • Exposure to animals, including bites and licks
  • Exposure to ill people
  • Unprotected intercourse and partners
  • Type of food and liquids consumed, how and where prepared
  • Vaccination history: review certificate and compliance
  • Type of travel
  • Quality of travel
  • Medications (specific for trip and routine)
  • Injuries or illnesses (how and where treated: injections given, blood taken, blood transfused, surgery, sterility of equipment and supplies)
  • Timing and sequence of symptoms

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Fever

  • Malaria:
    • This should be considered in any patient presenting with fever, who has been to a malaria endemic area within the last year.[2][3]
    • Clinically the patient may complain of fever, chills, sweats, headaches, muscle pains, nausea and vomiting.
    • Gold standard diagnosis is finding malarial parasites on a slide.
  • Hepatitis A:
    • This takes approximately one month before symptoms appear.
    • There is generally sudden onset of fever, fatigue, nausea and then jaundice.
  • Typhoid fever:
    • This is reported from virtually all countries, but is concentrated in developing countries and in areas with inadequate sanitation.
    • Fever is the hallmark of the disease, with relative bradycardia, dry cough, constipation and splenomegaly. Rash (rose spots) headache, and diarrhoea may occur.
  • Cholera:
    • Incidence is 2 cases per million travellers.
    • It is actually quite difficult to catch.
  • Yellow fever:
    • This is found in parts of South America and Africa. Vaccination is available and certification required for entry to some countries.
    • Features include fever, exudative sore throat, facial oedema and prostration. Diagnosis is made on serology.
  • Dengue fever:
    • Arbovirus infections are the main cause of viral fevers in returned travellers, and tend to have short incubation periods, typically less than 2 weeks.[4]
    • Dengue fever is the most common arbovirus in travellers and is transmitted by Aedes mosquitoes, which tend to be urban and to bite during the day.
  • Typhus:
    • Marburg and Ebola viruses:
      • They are found in the Sudan, Zaire and Kenya.
      • Patients present with fever, myalgia, diarrhoea and vomiting, pleuritic pain, shock and bleeding tendency.
    • Lassa fever
      • Consider in travellers from Nigeria, Sierra Leone and Liberia.
    • Rabies:
      • This presents as a nonspecific fever ±pharyngitis.
      • The bite site may itch. Common sources are bats and dogs.
    • Plague:
      • Is carried by rodent fleas and is common worldwide.
      • The most common is bubonic, which features tender swelling of the lymph nodes - buboes.
    • Brucellosis:
      • Is carried in farm animals and their products. Beware unpasteurised cheeses in countries with poor public health systems.
      • Symptoms are like flu.
    • Histoplasmosis:
      • Is transmitted by fungal spore, but recent cases have been through bat caves with guano.
      • Pre-existing lung disease increases the risk to the traveller.
      • The fever is accompanied by chest pain and cough.
    Also consider septicaemia and meningitis.

    Early referral to the local infectious diseases unit will provide the most useful, up-to-date advice on management.

    Diarrhoea

    The most frequent problem is travellers' diarrhoea. Up to 40% of short-term travellers to developing countries, and up to 70% of long-term travellers will experience at least one bout of diarrhoea.[5] Most cases of diarrhoea are mild, of short duration and do not require antibiotic treatment. Because it is caused by eating and drinking contaminated food and water, people travelling in primitive conditions will experience more problems. The highest risk is found with travel to Asia, Africa and Latin America.

    Where the diarrhoea is severe, bloody and/or prolonged, then laboratory investigation is necessary. Where the patient is severely ill and possibly septicaemic, blood culture is mandatory.[5]

    Initial investigation should include:
    • Stool for microscopy, culture and sensitivity to look for enteric pathogens. A separate sample may be needed for occult blood testing.
    • Request stool serology for giardia antigens.
    • In cases of chronic diarrhoea, consider a lactose tolerance test or a Schilling test with intrinsic factor.
    • Advise patients on the reduced efficacy of the combined oral contraceptive pill.
    • Endoscopy with biopsy and duodenal aspirate or colonoscopy with biopsies and cultures should follow if initial testing is non-diagnostic; also consider ultrasonography and computerised or magnetic imaging studies as well.

    Respiratory disease

    This is spread through cough and close respiratory contact.
    • Influenza:
      • This occurs in the winter season in temperate areas, and year-round in the tropics.
    • Tuberculosis (TB):
      • This has a worldwide distribution.
      • Risk of exposure is likely to be related to duration of stay in high-prevalence areas.
      • The nature and circumstances of contact with local people are likely to be important determinants of risk; work in a healthcare setting is particularly high-risk.
      • Comorbidity, such as diabetes, long-term steroidal therapy, chronic renal failure and malignant lymphoma also increase the risk.
      • However, co-infection with human immunodeficiency virus (HIV) carries the greatest risk of developing active TB - approximately 7-10% per year.[6]
    • Pandemic respiratory illness:
    First-line investigations should include:
    • Sputum sample for microscopy, culture and sensitivities.
    • CXR.

    Lymphadenopathy

    Consider plague, HIV, rickettsial infection, brucellosis, leishmaniasis, dengue fever, lymphogranuloma venereum and Lassa fever.

    Jaundice

    Consider viral hepatitis, cholangitis, liver abscess, leptospirosis (90% anicteric), typhoid fever, dengue fever, yellow fever and haemoglobinopathies.

    Hepatosplenomegaly

    Viral hepatitis, malaria, brucellosis, typhoid fever, leishmaniasis, schistosomiasis and toxoplasmosis should be considered.

    Gross splenomegaly

    Malaria, visceral leishmaniasis, trypanosomiasis, typhoid, brucellosis, typhus and dengue fever should be considered.

    Anaemia

    Exclude hookworm, malaria and visceral leishmaniasis as potential causes.

    Skin rashes

    • Meningococcal disease, yellow fever, dengue fever, rickettsial infection and viral haemorrhagic fevers can cause petechiae or ecchymosis.
    • Prickly heat is a sun sensitivity which gives an intensely itchy erythematous rash, usually in a skin fold.
    • Dengue fever presents with generalised rash after travel from the tropics and Indonesia. Transmission from person to person and mosquito. Severe headaches and fever with intense joint and muscle pain.
    • Trypanosomiasis presents with rash, fever and tender lymph glands. It follows travel to South and East Africa, South America, Angola, Sudan, Congo, and Uganda. There is a variable incubation period.
    • Cutaneous larva migrans is uncommon but may be found after travel to Thailand and Southeast Asia. There are red, itchy, mobile lesions which may move up to 1 cm per hour. They are most common on limbs.
    • Leprosy or Hansen's disease is characterised by multiple symmetrical lesions. Spread is via respiratory droplet from person to person.
    • Leishmaniasis results from the bite of an infected sandfly. The bite becomes pruritic and painful. The traveller may present with nasal obstruction and bleeding.
    • The majority (56%) of Western travellers having a new sexual relationship whilst travelling, have sex with travellers from other developed countries.[7]
    • 25% begin a relationship with a new partner, and 66% do not, or inconsistently use a condom.[8]
    The big 4 to remember are gonorrhoea, syphilis, chlamydia and HIV.
    • Any symptomatic patient should be referred to your local genitourinary medicine clinic for further management.
    • Advice required may include future prevention advice and advice on sex whilst waiting for results.

    HIV

    This is a particular problem in Sub-Saharan Africa, the Far East and, recently, there have been increased cases from India, Latin America and the Caribbean.[9]
    • Exposure prophylaxis for HIV is controversial. Three anti-retroviral drugs need to be commenced within 72 hours of exposure.
    • Initial investigations should also consider hepatitis B, hepatitis markers and probably hepatitis C also.
    • Testing should be repeated at 6 months.
    • If the patient is presenting within 2 weeks of contact, an active vaccination course for hepatitis B may provide some protection.

Further reading & references

  1. Spira AM; Assessment of travellers who return home ill. Lancet. 2003 Apr 26;361(9367):1459-69.; Includes useful management algorithms
  2. Leggat PA; Assessment of febrile illness in the returned traveller. Aust Fam Physician. 2007 May;36(5):328-32.
  3. Smith AD, Bradley DJ, Smith V, et al; Imported malaria and high risk groups: observational study using UK surveillance BMJ. 2008 Jul 3;337:a120. doi: 10.1136/bmj.a120.
  4. Senanayake S; Dengue fever and dengue haemorrhagic fever--a diagnostic challenge. Aust Fam Physician. 2006 Aug;35(8):609-12.
  5. Goldsmid JM, Leggat PA; The returned traveller with diarrhoea. Aust Fam Physician. 2007 May;36(5):322-7.
  6. Selwyn PA, Hartel D, Lewis VA, et al; A prospective study of the risk of tuberculosis among intravenous drug users with human immunodeficiency virus infection. N Engl J Med. 1989 Mar 2;320(9):545-50.
  7. Hawkes S, Hart G; Men's sexual health matters: promoting reproductive health in an international context. Trop Med Int Health. 2000 Jul;5(7):A37-44.
  8. Gillies P, Slack R, Stoddart N, et al; HIV-related risk behaviour in UK holiday-makers. AIDS. 1992 Mar;6(3):339-41.
  9. The Yellow Book - Section 9; Sexually transmitted and blood-borne infections, including HIV and hepatitis B, and overseas travel

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.

Original Author:
Dr Hayley Willacy
Current Version:
Last Checked:
21/05/2010
Document ID:
2057 (v22)
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