Decreased Virus-Neutralizing Antibodies Against Equine Herpesvirus type 1 In Nasal Secretions of Horses After 12-hour Transportation.
Authors: Bannai Hiroshi, Takahashi Yuji, Ohmura Hajime, Ebisuda Yusaku, Mukai Kazutaka, Kambayashi Yoshinori, Nemoto Manabu, Tsujimura Koji, Ohta Minoru, Raidal Sharanne, Padalino Barbara
Journal: Journal of equine veterinary science
Summary
Transportation stress impairs mucosal immunity to equine herpesvirus type 1 (EHV-1), potentially increasing disease susceptibility during the critical post-transport period. Six healthy, transport-experienced Thoroughbreds underwent repeated 12-hour transportation while researchers monitored stress markers (cortisol), viral replication via PCR, and antibody responses in both serum and nasal secretions. Although systemic immune responses remained largely intact and no active viral replication occurred, virus-neutralising antibody titres in nasal wash concentrates dropped significantly (≥4-fold) in four of the six horses, with geometric mean titres declining from 202 to 57 (P < 0.05), whilst serum neutralising titres against EHV-1 remained stable in five animals. This dissociation between maintained systemic and suppressed mucosal immunity suggests that transportation stress creates a window of vulnerability at the respiratory mucosa specifically—the primary entry point for EHV-1—despite adequate circulating antibodies. For practitioners managing transported horses, these findings underscore the importance of minimising additional stressors, optimising ventilation and hydration during transit, and considering preventative measures (including vaccination review and isolation protocols) during the first week post-transport, when mucosal defences appear compromised.
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Practical Takeaways
- •Transportation stress suppresses local mucosal immunity to EHV-1 in the nasal cavity, potentially increasing susceptibility to respiratory infection despite maintained systemic antibodies—consider isolation or preventive measures for 2-6 days post-transport
- •Monitor transported horses closely for respiratory signs even if they have prior EHV-1 exposure, as mucosal protection is transiently compromised
- •The increase in nasal IgA after transport suggests an immune response to stress, but this doesn't prevent the decline in specific EHV-1 neutralizing capacity, indicating a qualitative rather than quantitative antibody problem
Key Findings
- •12-hour transportation significantly increased cortisol concentrations, confirming acute stress response in horses
- •Virus-neutralizing antibodies against EHV-1 in nasal secretions declined ≥4-fold in 4 of 6 horses post-transportation (geometric mean 202 to 57, P<0.05), despite stable serum titers
- •No evidence of viral replication or lytic infection was detected by real-time PCR in nasal swabs or PBMCs
- •Nasal wash total IgA concentration increased significantly after transportation, but VN capacity against EHV-1 was suppressed