Solid phase immune electron microscopy for diagnosis of transmissible gastroenteritis in pigs

Area of Science:

• Veterinary Virology
• Immunoelectron Microscopy
• Animal Diagnostics

Background:

• Transmissible gastroenteritis (TGE) is a significant swine disease.
• Detecting TGE virus in faeces is challenging due to sample complexity.
• Conventional electron microscopy has limitations in sensitivity and specificity for faecal samples.

Purpose of the Study:

• To develop and optimize a solid phase immune electron microscopy (SPIEM) technique for TGE virus detection.
• To compare the sensitivity of SPIEM with conventional negative staining electron microscopy (NSEM).
• To evaluate SPIEM as a diagnostic tool for TGE virus shedding in pigs.

Main Methods:

• Coating electron microscope grids with Protein A and TGE virus antiserum.
• Optimizing Protein A concentration (250 µg/ml), antiserum dilution (1:100), and incubation time (overnight).
• Comparing SPIEM with NSEM for detecting TGE virus in faecal samples from infected pigs.

Main Results:

• SPIEM significantly improved TGE virus detection in crude faeces by specifically trapping the virus and reducing contaminant adsorption.
• The sensitivity of SPIEM was at least 100-fold higher than NSEM.
• TGE virus was detected in faecal samples from infected pigs using SPIEM, showing improved specimen clarity compared to NSEM.

Conclusions:

• Solid phase immune electron microscopy is a highly sensitive and practical method for detecting TGE virus in pig faeces.
• SPIEM offers a significant improvement over conventional electron microscopy for diagnosing TGE.
• This technique may serve as a valuable diagnostic test for TGE virus in living animals, complementing immunofluorescence.