Graduation Year

2006

Document Type

Thesis

Degree

M.A.

Degree Granting Department

Public Health

Major Professor

Lillian M. Stark, Ph.D.

Keywords

Flaviviruses, Surveillance, Hai, Elisa, Prnt, Luminex

Abstract

West Nile virus (WNV) and St. Louis Encephalitis (SLEV) are arthropod-borne viruses belonging to the genus Flavivirus and are classified as significant human pathogens of global epidemiological importance. Since its introduction into the United States in 1999, WNV has spread throughout most of the country and has caused major epidemics of neuroinvasive disease (Hayes and Gubler, 2005). SLEV is endemic to the United States and is maintained in an enzootic transmission cycle in Florida.The Florida Sentinel Chicken Arboviral Surveillance Network was established in 1978 following a widespread rural epidemic of SLEV in central Florida to monitor the activity of arboviruses (Day and Stark, 1996). This program ultimately impacts vector control strategies and may warrant medical alerts to warn the population.

Current serological detection methods for sentinel chickens include hemagglutination inhibition antibody test (HAI), IgM antibody capture enzyme-linkedimmunosorbent assay (MAC-ELISA), and Plaque Reduction Neutralization Test (PRNT).These serological assays may take over three weeks to generate a final result. A more rapid and equally sensitive test to replace these current serological methods would be of benefit. Microsphere-based immunoassays (MIAs) are a more rapid serological option for laboratory diagnosis of many diseases (Kellar et al, 2001). The objective of this study was to develop and validate a protocol for a MIA to detect antibodies to WNV and SLEV in sentinel chicken sera. A total of 385 sentinel chicken sera from 2005 were assayed using the MIA for WNV and 424 sera from multiple years were assayed for SLEV. The capability of the MIA to multiplex allowed for simultaneous detection of antibodies to WNV and SLEV in sentinel chicken sera.

The MIA was found to be more sensitive and specific than both the HAI and MAC-ELISA for the detection of antibodies to WNV, and just as sensitive and specific as the MAC-ELISA for the detection of antibodies to SLEV in sentinel chicken sera. These results indicate that there is a potential of the MIA to decrease turn-around time and allow for earlier detection and improvement to the current surveillance system.

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