Electron microscopy of equine respiratory viruses in organ cultures of equine fetal respiratory tract epithelium.

This study examines the effects of various equine respiratory viruses on organ cultures of horse fetal tracheal and nasal tissues. The researchers observed how the structure of these tissues changed upon infection with equine influenza virus-A1, equine herpesvirus-1, and equine rhinovirus-1 using advanced electron microscopy tools.

Experimental Methodology

• The scientists grew organ cultures of equine fetal tracheal and nasal tissues in a controlled lab setting.
• These cultures were then exposed to three different equine respiratory viruses: equine influenza virus-A1 (EIV-A1), equine herpesvirus-1 (EHV-1), and equine rhinovirus-1 (ERV-1).
• Both inoculated and control (non-inoculated) cultures were examined under scanning and transmission electron microscopes at different time points to view the conditions of cells.

Observations and Findings

• Organ cultures exposed to ERV-1 showed minimal changes, with only occasional island-like lesions in the nasal turbinate. No virus particles were visible in the thin sections of these infected cultures.
• Tissues exposed to EHV-1 had a significant reduction in the epithelial layer. The various stages of herpesvirus morphogenesis (the progression of the virus’ life cycle) were visible in these cultures.
• Exposure to EIV-A1 resulted in the sporadic loss of cilia, filament-like structures responsible for the movement of particles over cell surfaces. This effect was primarily seen in tracheal organ cultures. The virus particles were visible, budding from the base of microvilli (small, finger-like extensions from the cell surface).

Conclusion

• This study offers valuable information on how equine respiratory viruses affect the morphological structure of equine fetal tracheal and nasal tissues.
• The results depict the varying degrees of tissue damage and virus particle visibility across different virus types. ERV-1 led to minor visible changes, while EHV-1 and EIV-A1 caused more significant structural changes, including cell layer loss and cilia disruption.
• This research could serve as a basis for further studies to understand the pathogenicity and virulence of these viruses and may contribute to the development of more effective treatments and prevention strategies.