West nile virus disease and other arboviral diseases – United States, 2011.

The researchers conducted a study on arboviruses, primarily the West Nile virus, in the United States in 2011. They found that these viruses, which are transmitted through mosquito and tick bites, have been leading to severe illness and local outbreaks.

Research Overview

• The research focuses on Arthropodborne viruses (arboviruses) which are primarily transmitted to humans via the bites of infected mosquitoes and ticks.
• The most commonplace manifestation of these symptomatic infections is typically a systemic febrile illness, while less common manifestations include neuroinvasive diseases like meningitis, encephalitis, or acute flaccid paralysis.

West Nile Virus (WNV)

• The West Nile Virus (WNV) is the leading cause of domestically acquired arboviral disease within the United States. Despite WNV leading the pack, there are several other arboviruses also responsible for seasonal outbreaks and sporadic cases.
• In 2011, the Centers for Disease Control and Prevention (CDC) received reports of 871 cases of nationally notifiable arboviral diseases, excluding dengue, with etiological agents including WNV (712 cases), La Crosse virus (LACV) (130), Powassan virus (POWV) (16), St. Louis encephalitis virus (SLEV) (six), Eastern equine encephalitis virus (EEEV) (four), and Jamestown Canyon virus (JCV) (three).

Classification of Arboviral Diseases

• Out of the total reported cases, 624 or about 72% were classified as neuroinvasive disease, translating to a national incidence rate of 0.20 per 100,000 population.
• The research concludes that WNV and other arboviruses continue to be the cause of severe illnesses to considerable numbers of persons in the United States, leading to focal outbreaks.