Survival Analysis, Long-Term Outcomes, and Percentage of Recovery up to 8 Years Post-Infection among the Houston West Nile Virus Cohort

Abstract

In 2012, we witnessed a resurgence of West Nile virus (WNV) in the United States, with the largest outbreak of human cases reported since 2003. WNV is now endemic and will continue to produce epidemics over time, therefore defining the long-term consequences of WNV infection is critical. Over a period of eight years, we prospectively followed a cohort of 157 WNV-infected subjects in the Houston metropolitan area to observe recovery over time and define the long-term clinical outcomes. We used survival analysis techniques to determine percentage of recovery over time and the effects of demographic and co-morbid conditions on recovery. We found that 40% of study participants continued to experience symptoms related to their WNV infection up to 8 years later. Having a clinical presentation of encephalitis and being over age 50 were significantly associated with prolonged or poor recovery over time. Since the health and economic impact as a result of prolonged recovery, continued morbidity, and related disability is likely substantial in those infected with WNV, future research should be aimed at developing effective vaccines to prevent illness and novel therapeutics to minimize morbidity, mortality, and long-term complications from infection.

Granular Hyperreflective Specks by Spectral Domain Optical Coherence Tomography as Signs of West Nile Virus Infection: The Stardust Sign

“…In a survival analysis of WNV cases in metropolitan Houston, TX, between 2002 and 2009, 381 cases were reported of which 157 were followed to assess symptoms associated with infection. 12 The study found that full recovery of initial symptoms averaged approximately 2 years while those presenting with encephalitis continued to experience symptoms more than 5 years after infection. Ten of 13 deaths reported over the course of the study were cases that initially presented with encephalitis.…”

“…One year after infection, 7% of patients reported persistent blurred vision and 2% still reported blurred vision 8 years after infection. 12 From an ocular perspective, Garg and Jampol 10 identified the following five categories of intraocular manifestations of WVN infection based on clinical experience with 4 patients and literature review of 10 additional cases: chorioretinitis with lesions (widely scattered or linear arrays), uveitis without focal lesion, occlusive vasculitis, congenital chorioretinal scarring, and optic neuritis. Of these categories, the most common and most characteristic ocular manifestation of WNV infection is chorioretinitis.…”

Evaluation of Prolonged Fatigue Post–West Nile Virus Infection and Association of Fatigue with Elevated Antiviral and Proinflammatory Cytokines

“…Subjectively, participants continued to report prolonged fatigue following infection, with 20% of study participants reporting fatigue up to 8 years later (20). Additionally, we recently reported the persistence of anti-WNV IgM antibodies in 23% of study participants 8 years following infection (19).…”

Long‐term outcomes of Murray Valley encephalitis cases in Western Australia: what have we learnt?

“…Despite this, a number of patients with WNV encephalitis develop cognitive and psychological sequelae in the longer term, including memory loss, fatigue, anorexia and depression. These sequelae also occur in patients with WNV fever but no neuroinvasive disease . However, this is not a consistent finding, with another study finding that physical and mental outcomes following WNV encephalitis returned to US population norms approximately 1 year post‐infection.…”