Fever in the Returning Traveler

Approach to acute illness in a traveler:

Important questions to consider:

Where did the patient reside? Those visiting family and friends are at greater risk for local infection, as they tend to stay in areas with less robust infection control measures, and may also eschew prophylaxis
Travel history, including layovers
Characteristics of areas visited: altitude can shed light on potential pathogens

Exposure history, particularly sexual
Animals, including insect bites
Needle/blood exposure
Food
Soil and water, particularly freshwater (risk for leptospirosis, schistosomiasis, amoeba)

Incubation period of fever
Localizing symptoms
Duration of fever
Immunization status (hepatitis A/B, yellow fever, typhoid)
Adherence of prophylaxis
Immune status: those with history of malaria are less susceptible to complicated disease, whereas as Devin pointed out, a history of dengue places one at increased risk for hemorrhagic fever

Ddx for fever in the returning traveler:

Helpful to classify based on incubation period (<14 days, 14 days-6 weeks, > 6 weeks since return from travel)
Also helpful to classify based on fever +/- other systemic symptoms (hemorrhage, diarrhea, CNS or respiratory sxs)
Undifferentiated fever (<14 days):

Malaria: must be ruled out in any febrile traveler to an endemic area (p. falciparum can be rapidly fatal and can occur up to 1 month after exposure; p. vivax p. ovale can remain quiescent for weeks to years)
Dengue fever: accounts for up to 10% of post-travel febrile illnesses according to GeoSentinel data; most common febrile illness in travelers to Southeast Asia, the Carribean and South America
Rickettsia: including spotted fever, African tick typhus, Mediterranean tick typhus, scrub typhus; transmitted by arthropods, most frequently after camping, hiking, safari
Leptospirosis: spirochete infxn, related to fresh water exposure to (usually contaminated w animal urine/feces)
Typhoid and paratyphoid fever: due to Salmonella typhi, most commonly in India, the Phillipines and Latin America. Vaccines are only partially protective.
EBV/CMV infection
Acute HIV
African trypanosomiasis (sleeping sickness)

Associated with other systemic symptoms (ie. hemorrhage, respiratory, CNS, etc.): meningococcal meningitis, rabies, arboviruses, Q fever, legionella etc.
Long incubation period (>6 weeks): leishmaniasis, Hepatitis B, amebic lever abscess, schistosomiasis, filariasis, malaria (non-falciparum sp.), TB, etc.

(Christopher Woo MD, 1/20/11)

(Victoria Kelly MD, 11/29/10)