Relative Risk Estimation for Mycoplasma synoviae in Backyard Chickens in Paraguay
DOI:
https://doi.org/10.3923/ijps.2009.842.847Keywords:
Choropleth map, data visualization, respiratory diseaseAbstract
Poultry production is a growing industry in Paraguay, in southern South America. The insufficient farm management methods frequently applied in backyard chickens make them a possible reservoir for economically important diseases such as Mycoplasma synoviae that can influence commercial poultry operations. There are no former studies on a survey of Mycoplasma synoviae among backyard chickens in Paraguay. The objectives of this study were: (1) to observe the seroprevalence of MS in backyard chickens in Paraguay and (2) to generate maps for the estimated Relative Risk (RR) for MS in the study chickens, in place of using the observed seroprevalence. Paraguay is divided into 17 departments. A department-stratified random sampling was arranged and conducted. The required total sample size of 1537 from a chicken population of 17 million was sufficient to produce a 95% confidence interval with a desired precision of ±2.5% when the estimated seroprevalence was 50%. Sera were examined using a commercial indirect ELISA. The overall observed seroprevalence was 53%. The resulting maps for the estimated RR for Mycoplasma synoviae in the study chickens at department level were drawn. Departments with notably high or low disease risks were confirmed. Different types of epidemiological parameters can be calculated to take account of probable risk factors. Therefore, additional detailed investigations into those risk factors relating to Mycoplasma synoviae occurrence with respect to spatially epidemiological dissimilarities would be of interest.
References
Hernandez-Divers, S.M., P. Villegas, F. Prieto, J.C. Unda and N. Stedman et al., 2006. A survey of selected avian pathogens of backyard poultry in Northwestern Ecuador. J. Avian Med. Surg., 20: 147-158.
Kelley, P.J., D. Chitauro, C. Rohde, J. Rukwava, A. Majok, F. Davelaar and P.R. Mason, 1994. Diseases and management of backyard chicken flocks in Chitungwiza, Zimbabwe. Avian Dis., 38: 626-629.
Lumley, T., 2004. Analysis of complex survey samples. J. Stat. Software, 9: 1-19.
Lunn, D.J., A. Thomas, N. Best and D. Spiegelhalter, 2000. WinBUGS-a Bayesian modelling framework: Concepts, structure and extensibility. Stat. Comput., 10: 325-337.
McBride, M.D., D.W. Hird, T.E. Carpenter, K.P. Snipes, C. Danayeelmi and W.W. Utterback, 1991. Health survey of backyard poultry and other avian species located within one mile of commercial California meat-turkey flocks. Avian Dis., 35: 403-407.
Newcombe, R.G., 1998. Two-sided confidence intervals for the single proportion: Comparison of seven methods. Stat. Med., 17: 857-872.
Rogan, W.J. and B. Gladen, 1978. Estimating prevalence from results of a screening-test. Am. J. Epidemiol., 107: 71-76.
Wunderwald, C. and R.K. Hoop, 2002. Serological monitoring of 40 Swiss fancy breed poultry flocks. Avian Pathol., 31: 157-162.
Bailey, T.C. and A.C. Gatrell, 1995. Interactive Spatial Data Analysis. Longman Scientific & Technical, Harlow, Essex, UK., ISBN: 9780582244931, Pages: 413.
CIP, 2005. GIS Download Data Server. Centro Internacional de la Papa (CIP), Lima, Peru.
DGEEC, 2008. Anuario Estadistico del Paraguay 2006. DGEEC, Asuncion,.
Dohoo, I., W. Martin and H. Stryhn, 2003. Veterinary Epidemiologic Research. AVC Inc., Charlottetown, pp: 706.
FAO, 2001. Faoclim 2: World-Wide Agroclimatic Data (CD-ROM Database). FAO, Rome, Italy.
FAO, 2005. New LocClim: Local Climate Estimator. FAO, Rome, Italy.
Kleven, S.H., 2003. Mycoplasma Synoviae Infection. In: Diseases of Poultry, Saif, Y.M., H.J. Barnes, J.R. Glisson, A.M. Fadly, L.R. McDougald and D.E. Swayne (Eds.). Iowa State University Press, Ames, pp: 756-765.
Kleven, S.H., 2005. Poultry Mycoplasmosis. In: The Merck Veterinary Manual, Kahn, C.M. (Ed.). Merck and Co., UK., pp: 2242-2246.
Lewin-Koh, N.J. and R. Bivand, 2009. Maptools: Tools for reading and handling spatial objects. R Package Version 0.7-20. http://cran.r-project.org/web/packages/maptools/index.html
Lumley, T., 2009. Survey: Analysis of complex survey samples. http://www.jstatsoft.org/v09/a08/paper.
R Development Core Team, 2008. R: A Language and Environment for Statistical Computing. R Foundation for Statistical Computing, Vienna, Austria, ISBN 3-900051-07-0, Pages: 2673.
SENACSA, 2006. Vigilancia epidemiologica de newcastle e influenza aviar muestreo nacional segun departamento ano 2006. Anuario 2006: Estadistica Pecuaria, Servicio Nacional de Calidad y Salud Animal (SENACSA), Asuncion.
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