Equine Rotavirus diagnosis and molecular characterization in diarrheic foals of Argentina between 1992 and 2008.

GARAICOECHEA, LORENA; MIÑO, SAMUEL; BOK, KARIN; BARRANDEGUY, MARIA; PARREÑO, VIVIANA

Hamilton Island, Australia

Simposio; X International Symposium on Double-Stranded RNA Viruses; 2009

Double-Stranded RNA Viruses commetee

Group A Equine Rotavirus ERV. is the main cause of neonatal diarrhoea in foals. Based on the genetic variation of the proteins VP7 and VP4, group A RV are classified into 18 G-types and 27 P-types, respectively. Only the combinations P[12]G3 and P[12]G14 are epidemiologically important in equine. In Argentina, t he prevalent strain was antigenically characterized as G3 and an inactivated vaccine with the strains H2, P[12]G3; SA11. P[3]G3 and Lincoln, P[1]G6, has been applied. The aim of this study was to report the detection and characterization of the ERV strains circulating in Argentinean foals during 17 years 1992-2008.. Additionally, the phylogenetic analyses of the VP7, VP4 and NSP4 encoding genes of Argentinean representative strains, were conducted. ERV was detected in 39% 45/116. of the cases and 21% of the samples 165/771. by ELISA. From the positive cases, 42% were G3, 31% were G14, and in a 4%, G3+G14 were detected in the same sample by RT-PCR-Heminested-Multiplex. ERV G3 has been detected during the whole period, while G14 became the prevalent strain in the last three years. All the analyzed strains belonged to P[12], except for one case in which P[3] was detected. This constituted the first report of an ERV with the combination P[3]G3 in a diarrheic foal. In the phylogenetic study of VP7 the Argentinean G14, clustered with ERV G14 reference strains from USA and Japan while the Argentinean G3 clustered with other equine VP7 G3. The NSP4 of the ERV Argentinean strains constituted the E12 genotype together with NSP4 of Argentinean Guanaco and Bovine RV, suggesting the geographical evolution of this gene in RV Argentinean strains. The results of this study evidenced the switch in the prevalent strain during the period 1992-2008 and suggested that the ERV vaccine should be updated according to the circulating G14 strains.