The equine arteritis virus isolate from the 2010 Argentine outbreak

METZ GE; SERENA M; PANEI CJ; NOSETTO EDGARDO; ECHEVERRIA MG

REVUE SCIENTIFIQUE ET TECHNIQUE DE L4OFFICE INTERNATIONAL DES EPIZOOTIES

OFFICE INT EPIZOOTIES

Año: 2014 vol. 33 p. 937 - 946

0253-1933

A semen sample from a stallion infected during the 2010 equine arteritis virus (EAV) outbreak was received for viral isolation prior to castration. EAV was identified using an immunofluorescence test, using polyclonal antibodies. RT-PCR to amplify a region of the GP5 gene was performed with primers GL105F and GL673R. The PCR products were purified and sequences of both strands were determined in a MegaBACE TM 1000 with inner primers CR2 and EAV32. The phylogenetic dataset was built with the five strains isolated in Argentina and the sequences reported previously and a group of selected sequences obtained from GenBank. The unrooted neighbor-joining tree was constructed using MEGA and bootstrap analyses were conducted using 1000 replicate datasets. The evolutionary distances were computed using the Maximum Composite Likelihood method. To predict N-glycosylation in GP5 sequences, the NetNGlyc Server analysis by Technical University of Denmark (http://www.cbs.dtu.dk/services/NetNGlyc/) was performed. The phylogenetic analysis revealed that, together with other strains previously isolated in our laboratory, the new strain (named GLD-LP-ARG) belongs to the European group EU-1 but another branch. The new strain had 99% of nucleotide identity with strain A1 and 98.1% with the Belgian strain 08P178. The persistently infected stallions and their cryopreserved semen constitute the reservoir of EAV, which ensures its persistence in the horse population around the world. These findings reinforce the importance of carefully monitoring EAV persistent infected stallions, as well as semen straws, by RT-PCR or Test mating, according to National regulations.