West Nile Virus Southeast Conference1

than 60 scientists, public health officials , and clinicians from throughout the southeastern United States gathered in Atlanta to present data from the 2001 and 2002 West Nile virus (WNV) epidemics. The aim of the daylong conference, hosted by the Southeastern Center for Emerging Biological Threats at Emory University, was to assemble a diverse perspective on WNV by sharing knowledge, identifying key questions for research about the disease and prevention , and fostering collaborations between epidemiologists, veterinarians , laboratorians, and clinicians. In the overview presentation, the experiences of state health officials, clinical spectrum and pathogenesis, laboratory diagnostics, veterinary issues, surveillance, and vector control were discussed. The 2002 epidemic produced the largest annual number of cases to date, and four novel modes of transmission were discovered: 1) transplanted organs or tissue, including blood; 2) breast milk from an infected mother; 3) percutaneous exposure to infected tissue or serum among laboratory and hospital workers ; and 4) transplacental exposure to fetuses in utero, resulting in birth defects. In addition, WNV-associated acute flaccid paralysis was discussed; the paralysis is caused by localized infection of the anterior horn cells of the spinal cord, resulting in signs and symptoms similar to poliomyelitis. State epidemiologists or their representatives presented information about the state epidemics in the southeastern United States. The experiences in four states (Florida, Georgia, Louisiana, and Mississippi) were common in their themes of expansion of WNV epidemics, concentrated nature of outbreaks, importance of protection from mosquito bites, limitations of diagnostic methods, and dynamics of WNV spread in the United States from 2001 to 2002. Significant differences also emerged regarding the observed benefits of mosquito control activities and the value of animal surveillance as an early detection system. Also, while the states unanimously agreed that collaboration among local, state, and federal public health agencies, academic research institutions, and other nongovernmental organizations is critical to responding effectively to WNV, the degree to which such collaborations actually occurred and the existence of previously established relationships varied. Several clinicians discussed the pathogenesis and clinical aspects of the disease. The pathogenesis of WNV was reviewed; clinicians suggested that infections of the central nervous system can demonstrate any or all of three distinct characteristics: neuroinvasiveness (the ability to enter the nervous system), neurotropism (the ability to infect neural cells), and neurovirulence (the ability to cause neurologic disease). WNV possesses all three. The virus can enter the nervous system, as shown …