Phylogenetic characterisation of the G(L) sequences of equine arteritis virus isolated from semen of asymptomatic stallions and fatal cases of equineviral arteritis in Denmark

The study describes for the first time the phylogenetic relationship betwee n equine arteritis virus (EAV) isolated from asymptomatic virus-shedding st allions and fatal cases of equine viral arteritis (EVA) in an European coun try. EAV was isolated from three dead foals and an aborted foetus during th ree different outbreaks of EVA. From these fatalities, the complete open re ading frame 5, encoding the EAV GL protein, was amplified by reverse transc ription-polymerase chain reaction and subjected to nucleotide sequence anal ysis. Furthermore, DNA sequences were obtained from virus isolated from sem en samples of seven virus-shedding, but clinically healthy, Danish stallion s. DNA sequence alignment revealed an overall divergence of 0-14 and 0-10% at the nucleotide and amino acid levels, respectively. Phylogenetic analysi s including 24 previously published sequences revealed that European as wel l as North American "types" of EAV were present in the semen of asymptomati c carrier stallions and in fatal cases of EVA. Our results reveal that the presence of EAV-shedding stallions in Denmark represents a potential source of severe EVA. (C) 2001 Elsevier Science B.V. All rights reserved.