Viruses associated with respiratory disease of horses in New Zealand: an update

Abstract

Viruses causing or associated with respiratory disease in horses worldwide are reviewed. Results are presented from a serological survey of 121 New Zealand foals and horses that had been affected by respiratory disease, determining the prevalence of antibodies in this country to the major viruses associated with similar disease overseas. To date there is no evidence of equine influenza virus in New Zealand. Both equine herpesvirus type 1 and 2 have been frequently isolated and show high serological prevalences. Serological evidence of equine rhinovirus type 1 and type 2 is presented with a prevalence of 12.3% and 41.2% respectively observed in foal sera, and 37.7% and 84.9% in adult horse sera. Antibody reacting to equine viral arteritis virus antigen was detected in 3/121 test sera. Equine adenovirus has been isolated on occasions and has shown a 39% serological prevalence in one study reviewed. Progress in New Zealand equine virus research is discussed.

Equine herpesvirus infections in yearlings in South-East Queensland

“…Purewal et al [34], Welch et al [45], Fortier et al [21], Jolly et al [28] and Nordengrahn et al [31] have linked EHV-2 with Streptococcus zooepidemicus, Rhodococcus equi, and S. equi. In our study, we could not establish a link between gammaherpesvirus infection and bacterial colonization as all swabs were transported to the laboratory in virus transport medium containing antibiotics and therefore unsuitable for bacteriology testing.…”

Association of Two Newly Recognized Herpesviruses with Interstitial Pneumonia in Donkeys (Equus Asinus)

“…4,9,19,20,28,[39][40][41] However, infection with EHV2 appears to be widespread, and several studies have also found EHV2 in the respiratory tract and peripheral blood leukocytes of horses without clinical disease, with isolation and/ or PCR detection rates ranging from 31 to 89%. 4,19,33,35,39 Following experimental inoculation of EHV2 into both juvenile and adult horses, chronic pharyngitis was observed in the young horses while the adult horses remained clinically normal. 3 As with other gammaherpesviruses, latency in lymphocytes has been demonstrated for EHV2.…”

Transmission of equine herpesvirus 2 to the mouse: characterization of a new laboratory infection model.

“…Previously, these viruses had been thought to be similar to other known cytomegaloviruses based on their biological properties (Roizman et al, 1992). However, the precise role of any of the current isolates of EHV-2 in relation to disease production in the horse is unknown and the viruses have been isolated from clinically normal horses as well as those showing clinical signs including upper respiratory tract disease, pneumonia, enlarged lymph nodes, conjunctivitis or general malaise (Studdert, 1971 ;Blakeslee et al, 1975 ;Sugiura et al, 1983 ;Jolly et al, 1986 ;Browning & Studdert, 1988).…”