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Travel Medicine: Emerging Pathogens and New Recommendations, Part 2

Travel Medicine: Emerging Pathogens and New Recommendations, Part 2

ABSTRACT: Most travelers to Third World countries encounter health-related problems during their stay and may require medical attention on returning home. Although malaria is still the most common diagnosis among travelers to the developing world, several other infectious diseases, such as dengue fever, chikungunya fever, and leishmaniasis, are growing in importance. Clinicians need to stay informed about travel requirements and vaccine recommendations for US citizens.


Key words: chikungunya fever, leishmaniasis, dengue fever


More than half of travelers to the developing world experience a health-related problem during their trip, with 8% requiring medical attention on their return because of persistent symptoms.1 The GeoSentinel database, a collaborative effort among 31 travel medicine clinics on 6 different continents, suggests that the most common diagnoses in these persons continue to be malaria (24%), dengue fever (DF) (6%), acute traveler’s diarrhea (4%), and typhoid fever (2%).2 In recent years, however, the changing epidemiology of several pathogens has posed new risks to travelers. Among these are avian influenza, novel H1N1 (swine) influenza, multidrug-resistant tuberculosis (MDRTB), chikungunya virus (CHIKV) infection (ie, chikungunya fever), leishmaniasis, and DF.

In our 2-part series, we discuss these emerging infections and summarize new travel requirements and vaccine recommendations. Here we focus on CHIKV infection, leishmaniasis, and DF; in a previous article (Travel Medicine: Emerging Pathogens and New Recommendations, CONSULTANT, September 2009, page 549), we discussed avian influenza, novel H1N1 influenza, and MDR-TB.

CHIKUNGUNYA FEVER
CHIKV, an arbovirus transmitted by the Aedes aegypti mosquito, was first identified in Tanzania in 1953.3 Chikungunya is derived from the local word kungunyala meaning “contorted,” and refers to the severe joint pain experienced by infected patients. 4

Acute infection is characterized by fever; headache; myalgias; and a subacute, bilateral polyarthralgia that typically affects the distal joints of the fingers, toes, ankles, and wrists.5 Rash is frequently observed; among 47 French patients returning from the Indian Ocean islands with CHIKV infection, 24 noted an evanescent pruritic rash over the face, trunk, or extremities accompanied by edema (Figure 1).6 Among 46 persons in this group of travelers, less common clinical manifestations were bilateral conjunctivitis in 2 patients (4%) and large joint effusions in 7 patients (15%). Common laboratory findings include elevation of liver and muscle enzyme levels, mild thrombocytopenia, and leukopenia. Hematological abnormalities in the acute phase may be associated with bleeding. Affected patients may suffer from a protracted illness characterized by persistent polyarthralgias and a limited ability to perform activities of daily living. Tenosynovitis also may exacerbate these late-stage symptoms.6,7

Figure 1 – Clinical manifestations of chikungunya fever include a blanching, evanescent rash (A, B) and peripheral edema (C). (From Simon F et al. Medicine [Baltimore]. 20076; used with permission.)

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