The Post-Travel Period

The most frequent health problems in ill returned travellers are persistent gastrointestinal illness, 10%; skin lesions/rashes, 8%; respiratory infections, 5%-13% (depending on season of travel); and fever in up to 3%. Although gastrointestinal upset is the most frequent problem, febrile illness is the most serious since the infection may be life threatening to the patient (malaria) or a pose a serious public health hazard (viral haemorrhagic fever). The most frequent "tropical" causes of fever are malaria, dengue fever, invasive bacterial diarrhoea, hepatitis A, typhoid fever, and rickettsial infections. However, nontropical entities such as respiratory or urinary tract infections account for a large proportion of febrile illnesses in returned travellers. The most frequent causes of persistent gastrointestinal illness are postinfectious irritable bowel syndrome and postinfectious lactose intolerance. The former often presents as intermittent diarrhoea but may actually be a manifestation of constipation associated with episodic, rapid expulsions of loose stool. Although infections such as giardiasis or cyclosporiasis are often treated on the basis of clinical findings (without the benefit of laboratory confirmation), intestinal parasitic infections are uncommon causes of persistent diarrhoea. Most post-travel skin ailments are insect bites, pyoderma, scabies, and cutaneous larva migrans.

Some diseases might not manifest themselves immediately on return. Most travellers infected abroad become ill within 12 weeks after returning to the United States. However, some diseases, such as malaria, may not cause symptoms for as long as 6-12 months after exposure. If travellers become ill after they return home, even many months after travel, they should be advised to tell their physician where they have traveled. Fever in a traveller returned from a malarious area should be considered a medical emergency; malaria should be evaluated urgently by appropriate laboratory tests, which should be repeated if the initial result is negative. Since most primary-care physicians have little expertise in tropical diseases, a newly returned, ill international traveller should be evaluated by an infectious disease or tropical medicine practitioner. For assistance in finding a provider who practices clinical tropical medicine, one may access the American Society of Tropical Medicine website for a listing by state at www.astmh.org/scripts/clinindex.asp.

It may be prudent for asymptomatic international travellers who have been abroad for many months or longer, particularly in developing countries, to be screened for certain diseases. The decision to screen for particular pathogens will depend on the travel and exposure history. For example, travellers who have engaged in unprotected sex or have received an injection, a body piercing, or a tattoo may be screened for HIV, hepatitis C and other STDs, and, if not immune, hepatitis B. Travellers who have been exposed to freshwater in areas endemic for schistosomiasis should be screened for this infection by serology and stool and/or urine tests. Eosinophilia in a returned traveller suggests the possibility of a helminth infection, of which the most important is strongyloidiasis. If left untreated, this infection may last for the lifetime of the host, and in an immunocompromised person it has the potential to disseminate. Serology is the most sensitive diagnostic test.

• Spira AM. Assessment of travellers who return home ill. Lancet. 2003;361:1459-69.
• Ryan ET, Wilson ME, Kain KC. Illness after international travel. N Engl J Med. 2002;347:505-16.
• Wilson ME, Chen LH. Dermatologic infectious diseases in international travellers. Curr Infect Dis Rep. 2004;6:54-62.
• Suh KN, Kozarsky PE, Keystone JS. Evaluation of fever in the returned traveller. Med Clin North Am. 1999;83:997-1017.
• Connor BA, Landzberg BR. Persistent travellers' diarrhoea. In: Keystone JS, Kozarsky PE, Freedman DO, Nothdurft H, Connor BA, eds. Travel Medicine. Philadelphia: Mosby; 2004. p. 503-15.
• Leder K, Sundararajan V, Weld L, et al; GeoSentinel Surveillance Group. Respiratory tract infections in travellers: a review of the GeoSentinel surveillance network. Clin Infect Dis. 2003;36:399-406.

- Jay Keystone