Experimental Reptarenavirus Infection of Boa constrictor and Python regius

Area of Science:

• Veterinary Virology
• Herpetology
• Infectious Diseases

Background:

• Boid inclusion body disease (BIBD) is a significant global threat to captive snakes, characterized by cytoplasmic inclusion bodies (IBs) primarily composed of reptarenavirus nucleoprotein (NP).
• Previous research established a causative link between reptarenavirus infection and BIBD by reproducing the disease in boas and pythons.

Purpose of the Study:

• To experimentally infect Ball pythons (Python regius) and Boa constrictors (Boa constrictor) with reptarenavirus isolates.
• To investigate the efficacy of different virus delivery routes (intraperitoneal injection, tracheal instillation) and vaccination strategies.
• To develop an animal model for studying BIBD transmission and pathogenesis, and to compare antibody responses between experimental and natural infections.

Main Methods:

• Experimental infection of pythons (n=16) and boas (n=16) with three reptarenavirus isolates using intraperitoneal injection and tracheal instillation.
• Monitoring for clinical signs, viral RNA detection, and inclusion body formation over several months.
• Testing vaccination efficacy using recombinant protein or inactivated virus preparations, followed by homologous and heterologous virus challenge.

Main Results:

• Tracheal instillation and intraperitoneal injection led to reptarenavirus infection in pythons, with transient central nervous system signs observed in some individuals.
• Experimental infections did not result in the formation of characteristic inclusion bodies (IBs) in either pythons or boas.
• Boas developed persistent reptarenavirus infections (11/12) lasting at least 10 months post-inoculation.
• Vaccination protected three of four snakes against homologous virus challenge, but not against heterologous virus challenge.
• Differences were observed in antibody responses between experimentally and naturally infected snakes.

Conclusions:

• Experimental reptarenavirus infection can be established in pythons and boas via multiple routes, with tracheal instillation potentially mimicking natural infection.
• The absence of inclusion bodies in experimentally infected snakes suggests that BIBD pathogenesis is complex and may require additional factors beyond initial infection.
• Vaccination strategies show potential for controlling homologous reptarenavirus infections, warranting further investigation for BIBD prevention.