Nidovirus-Associated Proliferative Pneumonia in the Green Tree Python (Morelia viridis)

Area of Science:

• Veterinary Pathology
• Virology
• Herpetology

Background:

• Sudden deaths and respiratory disease outbreaks have been observed in green tree pythons (Morelia viridis).
• Previous studies identified nidoviruses causing severe respiratory illness in other python species.

Purpose of the Study:

• To characterize the cause and pathogenesis of mucinous pneumonia in green tree pythons.
• To identify and isolate the causative agent of the observed respiratory disease.

Main Methods:

• Necropsy and histological examination of affected pythons.
• Next-generation sequencing (NGS) for viral genome identification.
• Virus isolation in cell culture and molecular detection (RT-PCR, in situ hybridization).

Main Results:

• A novel nidovirus, Morelia viridis nidovirus (MVNV), was identified as the causative agent.
• Histopathology revealed airway epithelial hyperplasia and excessive mucus production.
• MVNV was detected in respiratory tissues, suggesting respiratory transmission.

Conclusions:

• MVNV infection leads to severe pneumonia and high mortality in green tree pythons.
• The virus causes significant respiratory tract damage, likely leading to death by impaired gas exchange.
• Nidoviruses represent a significant threat to captive python populations.