"Presencia de infecciones por el virus de la lengua azul en predios con elevada mortalidad en bovinos del cantón Chone de la provincia de Manabì"

Abstract

The objective of the investigative work was to demonstrate the presence of the Bluetongue Virus (BLV) in cattle from farms with high mortality in the Chone canton of the Manabí province. In the first place, it was evaluated whether there were risk factors for the presentation of virus infections in 364 farms of four of the livestock parishes of Chone, by analyzing the data of an epidemiological survey carried out by AGROCALIDAD in 364 farms of the parishes. San Antonio, Boyacá, Canuto and Ricaurte of the Chone canton. From this analysis it was obtained that there was a high proportion of farms, where there were risk factors for bluetongue, such as: a humid climate with subtropical temperatures and an abundance of wetlands, which favor the presence of the culicoid vector in the first two quarters of the year. In addition, that in all farms there had been increased mortality in cattle, without a proven diagnosis and that there is a total ignorance of bluetongue. Subsequently, six of the surveyed farms were selected to investigate the circulation of the Bluetongue Virus (BLV). In these studied farms, a wide circulation of the virus was found, since 98.2% of the bovines sampled, were seroreactors to VLA by ELISA. To determine the presence of active infections of this virus, a longitudinal study was carried out using sentinel calves serologically negative to VLA, in which the presence of VLA in blood was diagnosed by RT-PCR in the 2nd and 5th weeks after arriving at the farm and seroconversion by ELISA, between the 3rd and 8th weeks after its introduction. After having demonstrated the presence of active VLA infections in these farms, it is recommended that investigations be carried out to determine the circulating VLA serotypes, the knowledge of which is relevant for a vaccination control program.