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Published on: June 9, 2011
The pathology of human West Nile Virus infection
B A Sampson1, C Ambrosi, A Charlot
1Office of Chief Medical Examiner of the City of New York, NY 10016, USA.
Abstract:
West Nile Virus (WNV) was identified by immunohistochemistry (IHC) and polymerase chain reaction (PCR) as the etiologic agent in 4 encephalitis fatalities in New York City in the late summer of 1999. The fatalities occurred in persons with a mean age of 81.5 years, each of whom had underlying medical problems. Cardinal clinical manifestations included fever and profound muscle weakness. Autopsy disclosed encephalitis in 2 instances and meningoencephalitis in the remaining 2. The inflammation was mostly mononuclear and formed microglial nodules and perivascular clusters in the white and gray matter. The brainstem, particularly the medulla, was involved most extensively. In 2 brains, cranial nerve roots had endoneural mononuclear inflammation. In addition, 1 person had acute pancreatitis. Based on our experience, we offer recommendations for the autopsy evaluation of suspected WNV fatalities.
Insights
West Nile Virus (WNV) caused four fatal encephalitis cases in elderly New York City residents in 1999. Autopsies revealed widespread brain inflammation, particularly in the brainstem, guiding WNV fatality autopsy evaluations.
Area of Science:
- Neurology
- Virology
- Pathology
Background:
- West Nile Virus (WNV) emerged as a significant public health concern in New York City in 1999.
- Encephalitis fatalities in elderly individuals with comorbidities presented a diagnostic challenge.
Observation:
- Four elderly patients with underlying conditions died from WNV encephalitis.
- Clinical signs included fever and severe muscle weakness.
- Autopsies revealed mononuclear inflammation in the brain, predominantly in the brainstem.
Findings:
- Immunohistochemistry (IHC) and polymerase chain reaction (PCR) confirmed WNV as the causative agent.
- Pathological findings included encephalitis, meningoencephalitis, microglial nodules, and perivascular clusters.
- Cranial nerve root inflammation and acute pancreatitis were noted in some cases.
Implications:
- This study highlights the neuropathological features of WNV encephalitis.
- Recommendations are provided for autopsy evaluation in suspected WNV fatalities.
- Understanding WNV's impact on the central nervous system is crucial for public health.
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