59 percent were neuroinvasive disease cases, which occurred more often with increasing age
THURSDAY, March 4, 2021 (HealthDay News) — From 2009 to 2018, there were 21,869 confirmed or probable cases of West Nile virus (WNV) disease, 59 percent of which were neuroinvasive disease cases, according to a surveillance summary published in the March 5 issue of the U.S. Centers for Disease Control and Prevention Morbidity and Mortality Weekly Report.
Noting that WNV is a nationally notifiable condition, Emily McDonald, M.D., from the CDC in Atlanta, and colleagues describe cases of WNV in the United States during 2009 to 2018.
The researchers identified 21,869 confirmed or probable cases of WNV disease during 2009 to 2018, including 12,835 (59 percent) neuroinvasive disease cases. Illness onset occurred during July to September for 89 percent of all WNV patients. With increasing age, the incidence of neuroinvasive disease and case fatalities increased, with the highest incidence seen among those aged 70 years and older (1.22 cases per 100,000 population). Hospitalization rates were >85 percent in all age groups among the neuroinvasive cases, with the highest rates seen among patients aged 70 years and older (98 percent). In 2012, the national incidence of WNV neuroinvasive disease peaked (0.92 cases per 100,000 population). From 2013 to 2018, the national incidence was relatively stable (average annual incidence, 0.44), but there was variation noted at the state level from year to year.
“Public health education programs should focus prevention messaging on older persons, because they are at increased risk for severe neurologic disease and death,” the authors write.
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