Travel-Related Infections




HIGH-YIELD FACTS



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  • The most common cause of fever in the child returned from international travel is the nonspecific viral illness.



  • It is imperative to consider treatable causes of fever (e.g., malaria) or fever etiologies at risk for decompensation and the need for supportive care (e.g., dengue).



  • Diagnostic evaluation and differential diagnosis should be driven by the history of pre-travel immunizations and receipt of prophylactic medication, region of travel, activities undertaken while abroad, return date, physical examination findings (including severity and duration), and knowledge of the most common pathogens seen in a given area.



  • A population at considerable risk for travel infections is termed “visiting friends and relatives” (VFRs), as these families often opt not to seek medical attention prior to travel.



  • Thick and thin smears for malaria are indicated for any febrile child returning from a malaria-endemic region. Negative smears do not exclude malaria, and if strong clinical suspicion exists, smears should be repeated every 6 to 12 hours.



  • Malaria treatment often is empiric, and chloroquine resistance should be assumed in almost all regions. Therapy for children with high-grade parasitemia may involve blood transfusion (or exchange transfusion) and treatment with a combination of parenteral agents. These may include clindamycin in addition to quinidine or quinine.



  • Typhoid fever is very common in travelers (especially from the Indian subcontinent and Asia). Diarrhea is not always seen. Bacteremia may be common. Increasing antibiotic resistance in Salmonella typhi isolates makes microbiologic confirmation and antibiotic susceptibility testing important.



  • Obtain stool culture from the child with diarrheal disease returned from international travel. Fluid resuscitation is the mainstay of therapy. Antimicrobial therapy (often macrolide-based) can reduce disease severity, symptom duration, and secondary spread within the household.



  • Dengue is extending its geographical distribution and is now seen in southern portions of the United States. It is a biphasic illness, with an initial nonspecific febrile illness with or without a viral exanthema. After a few days, hemorrhagic manifestations and symptoms corresponding to capillary leak are manifest, lasting 2 to 3 days. Treatment is supportive.



  • Zika virus infection is asymptomatic in most children and adults, but can present as a self-limited fever, conjunctivitis, myalgias, joint pain, and an influenza-like illness.




The emergency department (ED) is a common venue of care for children who are ill after a recent international travel. At least three categories of pediatric travelers can be identified: children returning home after travel, international adoptees, and recently arrived immigrants. Barriers to access to care, severity of illness, timing of symptom onset (weekends, holidays), and community referral patterns may result in children in all the above-mentioned groups presenting to the ED.



Individual VFRs often neglect to seek travel advice prior to trips under the preconception that children have residual immunity when returning to the family’s country of origin. Waning immunity, failure to develop effective long-term immune responses to certain infections (e.g., malaria), and lack of preventive strategies result in many of these children becoming ill. In the Houston area, for example, the single greatest risk factor for childhood malaria is being a VFR traveling to Nigeria; few of these children had received adequate malarial prophylaxis.1



It is also important for the ED provider to recognize the regional flavor for what is considered “local” (Table 67-1).2 Endemic diseases in one part of the United States may represent a travel infection in another. Families may neglect to mention trips to a given area if they are taken frequently or do not require much travel time (e.g., hunting trips) but the relevant definition of travel from an infectious disease’s standpoint is not contingent upon distance. It is any activity that places a person in contact with a set of microbial flora to which the person is not exposed in their everyday life. A list of non-mammalian vectors for different diseases is listed in Table 67-2.3




TABLE 67-1Geographic Distribution of Selected Infectious Diseasesa




TABLE 67-2Non-Mammalian Vectors or Reservoirs for Selected Infectious Diseasesa



One way to conceptualize fever in the traveler is to subdivide diseases into three categories (Table 67-3).4–25 The first category represents diseases endemic to the United States, and thus the travel history represents a red herring. The most common cause of fever in returned travelers is a nonspecific viral illness or gastroenteritis.26 A subcategory is vaccine-preventable illness,27 such as hepatitis A, influenza, or measles. The latter specifically is very readily transmitted, and given the low vaccination rates in some portions of the United States28 may rapidly spread in a susceptible population. VFRs are more likely to have a vaccine-preventable disease than other groups.29 Another subcategory is disease seen in other parts of the country (e.g., babesiosis, Lyme). A final subcategory is sexually transmitted infections (STIs) acquired internationally (e.g., acute HIV infection), and should be on the differential diagnosis of the adolescent returning from abroad (see Chapter 89, Sexually Transmitted Diseases).




TABLE 67-3Travel Diseases



The second category reflects illnesses that are not endemic to the United States and are almost exclusively imported (e.g., malaria, yellow fever, most cases of typhoid, some cases of dysentery). The history both of travel and of activities performed and location within a given country are essential to identifying the cause of fever. The spectrum of symptoms may overlap with common domestic diseases (e.g., gastroenteritis) or the child may present with fever without localizing signs.



The third category is for illnesses seen both domestically and internationally (e.g., tuberculosis [TB], non-typhi Salmonella, and some diseases that are now emerging in the United States, such as dengue).30 These diseases may be more or less common in the region where the child resides. Finally, infectious diseases whose incubation period is long are unlikely to drive presentation to the ED with symptoms referable to a recent trip (e.g., TB in older children and adolescents).




HISTORY AND PHYSICAL EXAMINATION



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Historical elements that should be queried include use of prophylactic medications, receipt of vaccines prior to travel, activities, areas, and duration of travel, and timing of return.



It is insufficient to simply ask if a prophylactic medication was given prior to departure; specific questions regarding adherence should be asked. For example, a child may have been prescribed chloroquine and subsequently traveled to an area where all Plasmodium species are chloroquine resistant. Some antimalarial prophylaxis medications are administered daily, whereas others are given weekly, leading to a lower likelihood that a family will remember to administer the weekly medication. Finally, most antimalarials are intended to be started before arrival to the region of travel and continued after returning home for maximum efficacy.

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Jan 9, 2019 | Posted by in EMERGENCY MEDICINE | Comments Off on Travel-Related Infections

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