In the JournalsPerspective

Malaria hospitalizations in US more common than realized

Malaria hospitalizations in the United States are more common than previously thought, possibly due to increased travel to regions where the disease is endemic, researchers said.

As more infected travelers return to the U.S., clinicians must develop strategies to combat the potentially fatal disease, the researchers wrote in the American Journal of Tropical Medicine and Hygiene.

“It appears more and more Americans are traveling to areas where malaria is common and many of them are not taking preventive measures, such as using anti-malarial preventive medications and mosquito repellents, even though they are very effective at preventing infections,” researcher Diana Khuu, PhD, MPH, an epidemiology analyst with the Los Angeles County Department of Public Health, said in a news release.

Khuu and colleagues searched hospital records in the Nationwide Inpatient Sample database for malaria-related hospitalizations from 2000 to 2014. They estimated that there were 22,029 malaria hospitalizations in the U.S., with an average of 1,469 cases per year, during that period.

Of six other common travel-associated diseases, strongyloidiasis was the next most common, with an estimated 5,953 cases in the 15-year period and an average of 397 per year.

Men accounted for about 60% of patients with malaria. Blacks made up 52.5% of patients, whites 24%, Hispanics 6.3%, Asians and Pacific Islanders 5.9% and Native Americans 0.9%.

The disease-causing species was known in 52.9% of cases. Plasmodium falciparum — which is known to cause a strong majority of severe and fatal cases — accounted for 72.9% of those, the researchers found.

An estimated 4,823 (22%) cases were deemed severe malaria. The most common complication was renal failure (9.6%), followed by severe anemia (7.2%), cerebral malaria (4.3%), acute respiratory distress syndrome (4.1%) and jaundice (3.7%). One hundred eighty-two (0.8%) patients died in the hospital.

The researchers said the average cost per malaria case was nearly $25,800, and the total cost over the 15-year period was roughly $555 million.

They further estimated that a total of about 2,100 people in the U.S. are infected with malaria per year, and about 69% of them need hospital care. The number exceeds the CDC’s high-end estimate of 1,500 to 2,000 yearly cases.

The Southern region of the U.S. had the most malaria hospitalizations (37.1%), followed by the Northeast (34.2%), the West (14.6%) and the Midwest (14.2%). The Middle Atlantic and South Atlantic census divisions had more than half of all hospitalizations, with 27.2% and 24.9%, respectively.

The researchers said high rates of immigration to the Northeast could account for the heavy concentration of malaria cases there. Increased immigration to the region, they said, could mean increased travel to malaria-endemic areas to visit family and friends.

“Additional provider training for malaria awareness, diagnosis and management may be warranted in these areas,” the researchers wrote. – by Joe Green

Disclosure: The authors report no relevant financial disclosures.

Malaria hospitalizations in the United States are more common than previously thought, possibly due to increased travel to regions where the disease is endemic, researchers said.

As more infected travelers return to the U.S., clinicians must develop strategies to combat the potentially fatal disease, the researchers wrote in the American Journal of Tropical Medicine and Hygiene.

“It appears more and more Americans are traveling to areas where malaria is common and many of them are not taking preventive measures, such as using anti-malarial preventive medications and mosquito repellents, even though they are very effective at preventing infections,” researcher Diana Khuu, PhD, MPH, an epidemiology analyst with the Los Angeles County Department of Public Health, said in a news release.

Khuu and colleagues searched hospital records in the Nationwide Inpatient Sample database for malaria-related hospitalizations from 2000 to 2014. They estimated that there were 22,029 malaria hospitalizations in the U.S., with an average of 1,469 cases per year, during that period.

Of six other common travel-associated diseases, strongyloidiasis was the next most common, with an estimated 5,953 cases in the 15-year period and an average of 397 per year.

Men accounted for about 60% of patients with malaria. Blacks made up 52.5% of patients, whites 24%, Hispanics 6.3%, Asians and Pacific Islanders 5.9% and Native Americans 0.9%.

The disease-causing species was known in 52.9% of cases. Plasmodium falciparum — which is known to cause a strong majority of severe and fatal cases — accounted for 72.9% of those, the researchers found.

An estimated 4,823 (22%) cases were deemed severe malaria. The most common complication was renal failure (9.6%), followed by severe anemia (7.2%), cerebral malaria (4.3%), acute respiratory distress syndrome (4.1%) and jaundice (3.7%). One hundred eighty-two (0.8%) patients died in the hospital.

The researchers said the average cost per malaria case was nearly $25,800, and the total cost over the 15-year period was roughly $555 million.

They further estimated that a total of about 2,100 people in the U.S. are infected with malaria per year, and about 69% of them need hospital care. The number exceeds the CDC’s high-end estimate of 1,500 to 2,000 yearly cases.

The Southern region of the U.S. had the most malaria hospitalizations (37.1%), followed by the Northeast (34.2%), the West (14.6%) and the Midwest (14.2%). The Middle Atlantic and South Atlantic census divisions had more than half of all hospitalizations, with 27.2% and 24.9%, respectively.

PAGE BREAK

The researchers said high rates of immigration to the Northeast could account for the heavy concentration of malaria cases there. Increased immigration to the region, they said, could mean increased travel to malaria-endemic areas to visit family and friends.

“Additional provider training for malaria awareness, diagnosis and management may be warranted in these areas,” the researchers wrote. – by Joe Green

Disclosure: The authors report no relevant financial disclosures.

    Perspective

    Photo of Patricia Walker
    Patricia F. Walker

    This study confirms that infectious diseases do not respect borders. Given the number of people traveling internationally and the speed of international travel, we must have a physician and public health work force prepared to deal with global infectious diseases. That is why we need to continue medical education, research and funding for such activities both internationally and in the U.S.

    Patients should always see a travel medicine clinician before international travel to less developed countries. Patients can check the CDC web page at www.cdc.gov/travel, but they should see a doctor even if they are not going to a malarial area.

    Clinicians should do a better job of identifying which patients may be traveling within the next year and referring them to travel clinics for expert consultation. This can easily be done by asking at an annual examination, “Are you planning on traveling internationally within the next year?”

    This is particularly pertinent for primary care clinicians who are seeing immigrant travelers. The immigrant traveler returning home — called the “visiting friends and relatives” (VFR) traveler — is in the highest risk group for contracting malaria and bringing it back to the United States.

    There are many reasons for this — last-minute travel for a family emergency, staying in more rural areas, staying for longer periods of time and perhaps not understanding their degree of risk for contracting malaria, as they assume they have immunity or partial immunity. The CDC and others are working on connecting to higher risk communities with appropriate messages for VFR travelers about being seen for pre-travel consultation.


    Patricia F. Walker, MD

    Medical director for HealthPartners Travel and Tropical Medicine Center, Minneapolis-St. Paul

    President of the American Society of Tropical Medicine & Hygiene

    Disclosure: Walker reports no relevant financial disclosures.