This article is more than 5 years old. Information may no longer be current.
What is the greatest infectious disease threat to Americans traveling overseas?
Click Here to Manage Email Alerts
Experts agree that Americans who travel to countries in which certain infectious diseases are endemic face a variety of dangers. They range from age-old threats like malaria to those discovered more recently like Zika virus.
Infectious Disease News asked David O. Freedman, MD, a professor of medicine in the division of infectious diseases at the University of Alabama at Birmingham, and medical director at Shoreland Travax, about the greatest infectious disease threat to Americans traveling abroad.
Malaria remains the top infectious disease threat to travelers. High-profile emerging infections such as Ebola, MERS/SARS coronaviruses, chikun-gunya and Zika tend to present short-term risks to travelers with specific destinations and risk exposures. Few travelers have died during these outbreaks.
However, new zoonotic influenza strains have remained largely geographically restricted and in ecologic niches not intersected by travelers, although a once-in-a-century recombination event with a strain with high human infectivity is inevitable.
Malaria, nonetheless, has remained stubbornly persistent through human history and, despite some recent successes on the eradication front, remains in a seesaw battle with modern drug and vaccine developers. An average of 1,600 imported cases of malaria are officially reported annually in the United States, and at least 50,000 cases have been imported into rich countries in the last decade.
Although nationally notifiable in most countries, malaria is underreported by a factor of at least three- to fivefold because many cases are treated empirically without final laboratory confirmation. At times, resources for laboratory diagnosis are not available.
In the U.S., 70% of malaria patients are hospitalized, and 17% meet criteria for severe, life-threatening disease. If not recognized, diagnosed and appropriately treated early, infection with Plasmodium falciparum can evolve from a nonspecific febrile illness to coma, shock and death in as little as 24 hours. During 2000 to 2014, an average of 6.1 deaths from malaria occurred per year, with a high of 11 deaths in 2001.
Appropriate chemoprophylaxis is almost fully effective, yet 20% to 80% of travelers do not seek pre-travel health consultation.
Travelers visiting friends and relatives in their countries of origin constitute by far the group with the highest morbidity. Special approaches to illness prevention and education in this group have been elusive. Certainly, every medical encounter of any kind with this population should include a question of upcoming travel plans.
All travelers should see a qualified travel medicine specialist. Directories can be found at www.istm.org and www.astmh.org. No traveler should leave the pre-travel consultation without understanding the importance of seeking expert medical advice immediately if fever develops after the return home.
Malaria is a medical emergency. If stat testing is not available, the patient should be sent to a facility where it is. CDC experts are available for consultation at 1-770-488-7788, or at 1-770-488-7100 after hours.
Disclosure: Freedman reports that he is employed by Shoreland Travax and that he has provided consulting services for, or received honoraria or writing fees from, Antimicrobial Therapy, Shoreland, UptoDate, Elsevier and CDC/OUP.