Transmission patterns of St. Louis encephalitis and eastern equine encephalitis viruses in Florida: 1978-1993.
Abstract: Sentinel chickens were maintained at field sites in 40 Florida counties for varying periods between 1978 and 1993. For each county, the total number of St. Louis encephalitis virus (SLE) or eastern equine encephalitis (EEE) virus seroconversions were divided by the number of chickens exposed to calculate a mean annual seroconversion rate. These rates were used to evaluate the annual and geographical distributions of these viruses within Florida. For SLE, the rates in counties that reported human SLE cases during a widespread epidemic in 1990 were compared with adjusted mean annual seroconversion rates calculated by excluding the epidemic year seroconversion data. In general, actual rates were higher than adjusted rates in counties where human SLE cases were reported in 1990. Similar calculations were made for EEE virus that was unusually abundant in northern Florida during the spring and summer of 1991. In general, EEE virus was distributed in the panhandle and northern regions and SLE virus in the central and southern regions of the state. However, this distribution was not exclusive, and during years of high transmission, either virus can extend beyond its normal range. The annual distribution of SLE and EEE viruses was sporadic, ranging from years with little detectable activity to years with widespread, high-level transmission.
Publication Date: 1996-01-01 PubMed ID: 8906917DOI: 10.1093/jmedent/33.1.132Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
- Alphavirus
- Arboviruses
- Disease Outbreaks
- Disease Prevalence
- Disease Surveillance
- Disease Transmission
- Encephalitis
- Encephalomyelitis
- Epidemiology
- Equine Health
- Geographical Differences
- Horses
- Infectious Disease
- Mosquito-borne Diseases
- Public Health
- Serological Surveys
- Seroprevalence
- Vector-borne disease
- Veterinary Medicine
Summary
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The research paper examines the distribution and transmission patterns of St. Louis encephalitis and Eastern equine encephalitis viruses in Florida from 1978 to 1993, using sentinel chickens as indicators.
Methodology
- Sentinel chickens were used as bioindicators and were maintained at various field sites across 40 counties in Florida for different periods spanning from 1978 to 1993.
- The researchers calculated a mean annual seroconversion rate for SLE and EEE viruses in each county. The term “seroconversion” refers to the process of developing detectable antibodies in the blood due to infection or immunization.
- The rates were calculated by dividing the number of SLE or EEE virus seroconversions by the number of chickens exposed to these viruses.
Results and Analysis
- The researchers assessed the geographical and annual distributions of SLE and EEE viruses in Florida using the calculated seroconversion rates.
- For SLE, the researchers compared the rates in counties that reported human SLE cases during a major epidemic in 1990 with adjusted mean annual seroconversion rates. These adjusted rates were calculated after excluding the epidemic year seroconversion data.
- In general, the actual rates were reported to be higher than the adjusted rates in counties where human SLE cases were reported in 1990.
- Similar calculations were made for the EEE virus, which was found to be unusually prevalent in the northern regions of Florida during spring and summer of 1991.
Conclusion
- The researchers found that the distribution of SLE virus was generally in the central and southern regions of Florida, while EEE virus was commonly found in the northern regions and the panhandle.
- This distribution pattern, however, was not exclusive, and during high-transmission years, either virus could extend beyond its usual range.
- They also noted that the annual distribution of these viruses was sporadic and could range quite dramatically from little detectable activity to years marked by widespread, high-level transmission.
Cite This Article
APA
Day JF, Stark LM.
(1996).
Transmission patterns of St. Louis encephalitis and eastern equine encephalitis viruses in Florida: 1978-1993.
J Med Entomol, 33(1), 132-139.
https://doi.org/10.1093/jmedent/33.1.132 Publication
Researcher Affiliations
- Florida Medical Entomology Laboratory, Institute of Food and Agricultural Sciences, University of Florida, Vero Beach 32962, USA.
MeSH Terms
- Animals
- Bird Diseases / virology
- Chickens / virology
- Encephalitis Virus, Eastern Equine / isolation & purification
- Encephalitis Virus, St. Louis / isolation & purification
- Florida
Citations
This article has been cited 11 times.- Fish D, Tesh RB, Guzman H, Travassos da Rosa APA, Balta V, Underwood J, Sither C, Vasilakis N. Emergence potential of mosquito-borne arboviruses from the Florida Everglades.. PLoS One 2021;16(11):e0259419.
- Heberlein-Larson LA, Tan Y, Stark LM, Cannons AC, Shilts MH, Unnasch TR, Das SR. Complex Epidemiological Dynamics of Eastern Equine Encephalitis Virus in Florida.. Am J Trop Med Hyg 2019 May;100(5):1266-1274.
- Lord CC. The Effect of Multiple Vectors on Arbovirus Transmission.. Isr J Ecol Evol 2010 Jan 1;56(3-4):371-392.
- Estep LK, McClure CJ, Vander Kelen P, Burkett-Cadena ND, Sickerman S, Hernandez J, Jinright J, Hunt B, Lusk J, Hoover V, Armstrong K, Stark LM, Hill GE, Unnasch TR. Risk of exposure to eastern equine encephalomyelitis virus increases with the density of northern cardinals.. PLoS One 2013;8(2):e57879.
- Kelen PT, Downs JA, Burkett-Cadena ND, Ottendorfer CL, Hill K, Sickerman S, Hernandez J, Jinright J, Hunt B, Lusk J, Hoover V, Armstrong K, Unnasch RS, Stark LM, Unnasch TR. Habitat associations of eastern equine encephalitis transmission in Walton County Florida.. J Med Entomol 2012 May;49(3):746-56.
- Jacob BG, Burkett-Cadena ND, Luvall JC, Parcak SH, McClure CJ, Estep LK, Hill GE, Cupp EW, Novak RJ, Unnasch TR. Developing GIS-based eastern equine encephalitis vector-host models in Tuskegee, Alabama.. Int J Health Geogr 2010 Feb 24;9:12.
- Vitek CJ, Richards SL, Robinson HL, Smartt CT. A model to assess the accuracy of detecting arboviruses in mosquito pools.. J Am Mosq Control Assoc 2009 Sep;25(3):374-8.
- Vitek CJ, Richards SL, Mores CN, Day JF, Lord CC. Arbovirus transmission by Culex nigripalpus in Florida, 2005.. J Med Entomol 2008 May;45(3):483-93.
- Gibbs SE, Hoffman DM, Stark LM, Marlenee NL, Blitvich BJ, Beaty BJ, Stallknecht DE. Persistence of antibodies to West Nile virus in naturally infected rock pigeons (Columba livia).. Clin Diagn Lab Immunol 2005 May;12(5):665-7.
- Shaman J, Day JF, Stieglitz M, Zebiak S, Cane M. Seasonal forecast of St. Louis encephalitis virus transmission, Florida.. Emerg Infect Dis 2004 May;10(5):802-9.
- Cupp EW, Klingler K, Hassan HK, Viguers LM, Unnasch TR. Transmission of eastern equine encephalomyelitis virus in central Alabama.. Am J Trop Med Hyg 2003 Apr;68(4):495-500.
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