Oral vesicular lesions in horses without evidence of vesicular stomatitis virus infection.

The research article discusses the study of oral vesicular lesions in horses that appear to be consistent with Vesicular Stomatitis (VS), but unrelated to Vesicular Stomatitis Virus (VSV) infection.

Study Overview

• The study investigated horses with oral vesicular lesions that were clinically similar to those found in Vesicular Stomatitis (VS). However, these horses did not show evidence of Vesicular Stomatitis Virus (VSV) infection, leading to this detailed analysis.
• The research involved eight horses, which were quarantined following the appearance of the oral lesions. The severity of the clinical signs was measured and recorded every two to five days over a period of three months.

Methods and Techniques

• Serum samples from the horses were tested for antibodies using techniques such as competitive enzyme-linked immunosorbent assay (cELISA), capture ELISA for IgM, serum neutralization, and complement fixation (CF). These methods determine the presence of antibodies that react against VSV.
• The researchers also attempted virus isolation, involving swab specimens taken from active lesions on the horses to identify the possible causative virus.

Results

• Two horses, which had oral lesions on day one, showed positive for antibodies against VSV through cELISA and CF. However, CF results turned negative by the nineteenth day.
• The other six horses were seronegative initially, but developed oral vesicular lesions by day 23. These lesions were clinically similar to VS, yet the horses were seronegative, suggesting the absence of VSV infection.
• All attempts at virus isolation from the lesions were unsuccessful, which further indicated no VSV infection.

Conclusions

• The horses were kept isolated for 75 days as per state and federal regulations because the symptoms could imply a VSV infection, which is of substantial economic and regulatory concern.
• Despite the quarantine and symptoms similar to VSV, the study suggests that the oral vesicular lesions were not associated with a VSV infection.
• This significant finding implies that the presence of a non-VSV vesicular disease could complicate efforts to control VS in the United States and could potentially impact foreign trade due to misdiagnosis.