Endemic malaria was effectively wiped out in the United States in the 1950s. However, the number of cases imported by travelers returning to the United States and by foreign visitors continues to pose a public health threat, according to a study published online April 24 in the American Journal of Tropical Medicine and Hygiene.
"Imported cases pose the potential threat for reintroduction of malaria into the naturally present Anopheles population in the United States," write Diana Khuu, PhD, MPH, from the department of epidemiology at the Fielding School of Public Health, University of California, Los Angeles, and colleagues. They note that with protection before travel most malaria infections are preventable.
Malaria symptoms include fever, shaking, chills, and muscle pain, and in severe cases jaundice, acute kidney failure, severe anemia, and acute respiratory distress syndrome, which can quickly lead to death.
Using data from the National (Nationwide) Inpatient Sample, the authors found that between 2000 and 2014, there were 22,029 malaria-related hospitalizations (4.88 per 1 million people). Of those, there were 4823 severe malaria cases and 182 in-hospital deaths. Hospitalizations occurred more often in the Mid-Atlantic and South Atlantic states.
Malaria-related hospitalizations far outnumbered hospitalizations for other travel-related diseases. On average, there were 1469 malaria cases per year in the United States compared with an average of 98 to 397 cases each of leishmaniasis, trypanosomiasis, schistosomiasis, dengue, filariasis, and strongyloidiasis.
"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," Dr Khuu said in a press release.
Men had a higher rate of malaria hospitalizations than women (60.1% vs 39.4). Researchers write that that may indicate fewer men are asking about preventive measures or adhering to them.
Researchers found that 14% of the women hospitalized for malaria were pregnant, which is concerning as malaria in pregnancy can cause maternal anemia, death of the mother or fetus, low birth weight, and delayed intrauterine growth.
By race, African Americans made up more than half of the hospitalizations (52.5%), followed by whites (24%), Hispanics (6.3%), Asian/Pacific Islanders (5.9%), and Native Americans (0.9%).
The researchers also note that the disease adds substantial costs to the healthcare system. They found that the average length of stay was 4.36 days with average charges per hospitalization of $25,789
The Centers for Disease Control and Prevention offers guidance on malaria risk and prevention by region.
Am J Trop Med and Hyg. Published online April 24, 2017. abstract
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Cite this: Malaria Tops Travel-Related Diseases for US Hospitalizations - Medscape - Apr 24, 2017.