Detection of equine herpesvirus 3 in equine skin lesions by polymerase chain reaction.
During a recent breeding season, ulcerative, pustular skin lesions were observed on the external genitalia of 2 mares and 1 stallion within a small herd. Based on the location and description of the skin lesions plus the clinical history, equine coital exanthema, caused by equine herpesvirus 3 (EHV3), was the primary differential diagnosis. Scrapings of skin lesions from the perineum of 2 mares were submitted for diagnostic evaluation. Virus isolation was attempted by inoculation of several cell lines of equine origin, but no cytopathic agent was detected. The skin scrapings were processed for DNA extraction, and polymerase chain reaction (PCR) amplification was performed for herpesvirus DNA polymerase and DNA-packaging protein (terminase) genes using nested, degenerate primers targeted to conserved regions of the herpesvirus genome. Products of the expected sizes were generated for both assays, and subsequent nucleotide sequencing of the amplification products established that EHV3 had been detected in DNA extracted from the skin lesions. Detection of EHV3 was confirmed using an EHV3-specific PCR assay targeted to the gC gene. Using the novel EHV3 nucleotide sequence identified in this report, a sensitive and specific PCR assay targeted to the highly conserved DNA polymerase gene was developed. (+info)
Occurrence of equine coital exanthema in pastured draft horses and isolation of equine herpesvirus 3 from progenital lesions.
During the period from 2001 to the following year, progenital diseases had been epidemic among the draft stallions and mares pastured together in Iwate Prefecture, the northeastern district of Japan. A stallion and 8 of 31 mares were affected in 2001, and 1 of 2 stallions and 10 of 36 mares in 2002. The clinical symptoms consisted of the formation of papules, pustules, ulcers and scabs on the progenital skin and mucosa in stallions and mares. In 2002, Equine herpesvirus 3 (EHV3) was isolated from 2 mares and the glycoprotein G gene of the virus detected from a stallion and 4 mares by polymerase chain reaction. Serum neutralizing tests showed that 12 of 38 horses, 10 clinically and 2 subclinically affected, changed to be positive for the EHV3 antibody. The results suggest that the horses were affected with equine coital exanthema (ECE) through coitus. Five mares with the antibody at the pre-pastured period may have been the possible origins of EHV3 infection in 2002, although the exact origin in 2001 remains unknown. The artificial insemination was performed for the prevention of ECE spreading through coitus on the pasture in 2003. There was no epidemic of the disease in 31 mares, although 3 mares with the antibody at the pre-pastured period showed the significant increase in the titers during the pastured period. (+info)
Herpesvirus-associated neurological disease in a donkey.
A 4-year-old donkey was evaluated for progressive neurological abnormalities consisting of depression, stupor, weakness, and recumbency. Diagnostic evaluation for viral involvement identified an asinine herpesvirus in DNA extracted from deep pharyngeal swabs. Specific primers were designed based on comparison with equine herpesviral DNA polymerase sequences and yielded an 875-base pair product from the donkey. This sequence had complete identity with short sequences of asinine herpesvirus previously identified in donkeys with interstitial pneumonia. Amino acid analysis of the entire sequence indicated high similarity with Equid herpesvirus 7 (91%), Zebra herpesvirus 1 (90%), and Equid herpesvirus 2 (89%). With supportive treatment and physical therapy, the donkey gradually recovered over 5 days of hospitalization and returned to normal function. The current case illustrates the potential of a novel asinine herpesvirus to induce neurological disease in donkeys and provides a large viral sequence allowing confident assignment of this virus to the subfamily Gammaherpesvirinae. (+info)
Genetic relatedness of equine herpesvirus types 1 and 3.
The genetic relatedness of two types of equine herpesviruses (EHVs), 1 (EHV-1) and 3 (EHV-3), was determined by DNA-DNA reassociation kinetics. Denatured, labeled viral DNA probe was allowed to reassociate in the presence or absence of the second unlabeled viral DNA. The initial rate of reassociation of either labeled viral DNA was increased by the presence of the heterologous viral DNA to an extent indicating only 2 to 5% homology between the two EHV genomes. Moreover, labeled RNA extracted from EHV-3-infected cells hybridized to filter-immobilized EHV-1 DNA only 2 to 3 percent as efficiently as to the homologous EHV-3 DNA. These results demonstrate that the genital (EHV-3) and nongenital (EHV-1) types of EHVs exhibit very little genetic homology. (+info)