Comparison of methods for the diagnosis of equine herpesvirus type 1 infection.

This research investigated occurrence and diagnosis methods for equine herpesvirus type 1 (EHV-1) in aborted horse fetuses and newborn foals. The reliability and sensitivity of virus isolation, immunohistochemistry, histology, and fetal serology were compared and evaluated, revealing immunohistochemical methods to be slightly more sensitive than virus isolation for diagnosing EHV-1.

Objective of the Research

• The researchers aimed to study the prevalence of EHV-1 infections in aborted horse fetuses and newborn foals.
• They also sought to compare the sensitivity of various diagnostic methods – virus isolation, immunohistochemistry, histology, and fetal serology – for detecting the infection.

Methodology

• 101 cases comprising of 93 aborted fetuses and 8 weak foals were scrutinized using virus isolation, immunohistochemistry, and histology.
• 68 cases were examined using fetal serology.
• The team noted the presence of common microscopic changes in multiple organs in all cases.
• The existence of intranuclear inclusion bodies, a characteristic of viral infections, was confirmed only in 25 (35.2%) of the 71 virus-positive tissue samples.

Findings

• Out of the total cases, 15 (14.9%) were confirmed to have EHV-1 infection through immunohistochemistry and 13 (12.9%) through virological investigation.
• Fetal serology identified EHV-1 infection in 4 (5.9%) cases but these did not exhibit EHV-1 specific lesions, nor could the virus be detected through virus isolation or immunohistochemistry in these cases.

Conclusions

• The results indicated that fetal serology does not fully endorse its usefulness in virus-positive cases for identifying EHV-1.
• Immunohistochemistry was identified as a slightly more sensitive and reliable method than virus isolation in diagnosing EHV-1, given its higher detection rate.