Quantification of Equid herpesvirus 5 DNA in clinical and necropsy specimens collected from a horse with equine multinodular pulmonary fibrosis.

The research article presents a case study of a 15-year-old horse with chronic interstitial pneumonia, initially diagnosed as equine multinodular pulmonary fibrosis (EMPF), associated with Equid herpesvirus 5 (EHV-5). The research shows a correlation between high viral load in tissues and the severity of the disease. Furthermore, it suggests the usefulness of quantitative real-time PCR in understanding the relationship between EMPF and EHV-5.

Case Description and Initial Diagnosis

• The study investigated a case of a 15-year-old Belgian gelding horse displaying symptoms of fever, depression, and respiratory distress.
• Upon conducting a lung biopsy, the horse was discovered to have interstitial fibrosis consistent with chronic interstitial pneumonia.
• The presence of Equid herpesvirus 5 (EHV-5) DNA was detected in bronchoalveolar lavage and biopsy specimens via polymerase chain reaction (PCR).
• Based on these findings, a presumptive diagnosis of equine multinodular pulmonary fibrosis (EMPF), a disease believed to be associated with EHV-5, was made.

Treatment and Further Developments

• Following the presumptive diagnosis of EMPF, the horse underwent systemic treatment involving corticosteroids and antiviral medications.
• Although the horse showed initial improvement, its condition rapidly deteriorated after four weeks and, as a result, was euthanized.

Postmortem Examination and Findings

• A postmortem examination was conducted, confirming the presumptive diagnosis of EMPF.
• The EHV-5 DNA load across different tissues was ascertained using a quantitative real-time PCR technique.
• The highest viral load was found within the horse’s lung, particularly within the pulmonary fibrotic nodules. This suggests a potential link between the severity of the disease and the viral load in organ tissues.

Conclusion and Implications of the Research

• This case study highlighted the potential of quantitative real-time PCR as a tool in determining EHV-5 load in different organ tissues.
• The findings underline the link between high EHV-5 viral load and the severity of the disease in the most affected tissues.
• Moreover, the bronchoalveolar lavage proved to be an effective clinical sample for estimating EHV-5 load in the lungs.
• The results contribute significantly to understanding the relationship between EHV-5 and EMPF, offering valuable insights for diagnostic processes and potential therapeutic approaches for EMPF in horses.