The fluorescent antibody technique in the diagnosis of equine rhinopneumonitis virus abortion.

The research article discusses the application and efficiency of the fluorescent antibody technique in diagnosing equine viral rhinopneumonitis, a significant cause of horse abortions, by detecting its presence in various foal tissues.

Technique and Materials

• The given study relied on the fluorescent antibody technique, where antibodies are tagged with a fluorescent dye, to trace the presence of equine viral rhinopneumonitis (EVR).
• Fluorescein isothiocyanate, a fluorescent tagging compound, was linked to two known positive EVR sera to create conjugates, which were tested on EVR-infected tissue culture cells for accuracy.
• The researchers applied these conjugates to the selected tissues from 32 aborted foetus and foals during a natural outbreak of EVR.

Results

• The researchers found antigen in various tissues in 20 out of 32 cases (62.5%) using immunofluorescence.
• Furthermore, they were able to isolate the EVR virus from 15 out of 24 cases (62.5%) by inoculating bovine fetal kidney cell monolayers with a pool of lung and liver.
• A histological investigation of different tissues from 29 cases led to the diagnosis of EVR in 19 cases (65.5%), based on the existence of focal areas of necrosis and intranuclear inclusion bodies.

Discrepancies in Diagnosis

• However, the study also reveals two cases where the results did not correlate. One case was histologically positive but negative on fluorescence. The other case was histologically negative and also negative by virus isolation but showed fluorescence.

Outcome of the Research

• The research concluded that the distribution of fluorescence across the infected fetal tissues suggested that to receive a positive diagnosis, a combined examination of lung and thymus gland was the most likely and efficient approach.