Submitted to: American Journal of Veterinary Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/15/2010
Publication Date: 2/1/2011
Citation: Arroyo, M., Perez, A.M., Rodriguez, L.L. 2011. Characterization of the temporal and spatial distribution and reproductive ration of vesicular stomatitis outbreaks in Mexico in 2008. American Journal of Veterinary Research. 2011(72):233-238. Interpretive Summary: Vesicular Stomatitis (VS) is a disease of livestock caused by vesicular stomatitis virus (VSV). The disease is characterized by the appearance of vesicles and ulceration of tongue, mouth, feet, and teats. The disease affects horses, cattle, and pigs, lesions in the later two species resemble those caused by foot-and-mouth disease a devastating disease of livestock. Occassionally humans and some wildlife species may become infected. The United States is regularly affected by VSV incursions and genetic evidence suggests that viruses associated with such incursions likely originate from enzootic areas of Mexico. The study here was aimed at characterizing the temporal and spatial distribution and reproductive ratio of VS outbreaks reported in Mexico in 2008. Such knowledge will help to prevent and control the occurrence of VS epidemics in both Mexico and the United States and will help to improve the efficiency of the national surveillance systems for the disease.
Technical Abstract: Objective--- To quantify the temporal and spatial distribution and reproductive ratio of vesicular stomatitis (VS) outbreaks reported in Mexico in 2008. Population--- Mexican herds in which VS outbreaks were officially reported and confirmed from January 1st through December 31st, 2008. Procedure--- The Poisson model of the space-time scan statistic was used to identify periods of time and geographical locations at highest risk for VS in Mexico in 2008. The herd reproductive ratio (Rh) of the epidemic was computed using the doubling-time method. Results--- One significant time-space cluster of VS was detected in the State of Michoacan from September 4th through December 10th,2008. The temporal extent of the VS outbreaks and the value and pattern of decrease of the RH was different in the endemic zone of Tabasco and Chiapas compared to the region included in the time-space cluster. Conclusions and Clinical Relevance--- The large number of VS outbreaks reported in Mexico in 2008 was associated with the spread of the disease from the endemic zone in southern Mexico to areas sporadically affected by the disease. Results suggest that implementation of a surveillance system in the endemic zone of Mexico aimed at early detecting changes in the value of Rh and time-space clustering of the disease will help to prevent VS spread into regions of Mexico and neighboring countries that are only sporadically affected by the disease.