Chronic sialodacryoadenitis virus (SDAV) infection in athymic rats

Area of Science:

• Veterinary Virology
• Immunology
• Pathology

Background:

• Sialodacryoadenitis virus (SDAV) is a common rodent pathogen.
• Athymic rats are often used in research due to their compromised immune systems.
• The interaction between SDAV and athymic rats, especially in the context of co-infections, requires further investigation.

Purpose of the Study:

• To investigate the detection and effects of Sialodacryoadenitis virus (SDAV) in athymic rats implanted with human tumor cell lines.
• To characterize the clinical signs, pathological changes, and viral persistence of SDAV in this model.
• To assess the potential for SDAV transmission and seroconversion in sentinel rats.

Main Methods:

• Athymic rats implanted with human tumor cell lines were monitored for clinical signs and necropsied.
• Histopathology and immunohistochemistry were used to identify SDAV lesions and viral antigens in salivary and respiratory tissues.
• Rat antibody production tests and sentinel rat housing were employed to assess SDAV seroconversion and transmission.

Main Results:

• SDAV was detected in athymic rats, leading to sneezing, dyspnea, weight loss, and death.
• Suppurative rhinitis and bronchopneumonia were observed, with recovery of secondary bacterial pathogens.
• Characteristic SDAV lesions and viral antigens were found in salivary and respiratory tracts; infection persisted for at least 6 months.

Conclusions:

• Spontaneously acquired SDAV infection can cause significant morbidity and mortality in athymic rats.
• Athymic rats can serve as a model for studying SDAV pathogenesis and persistence.
• The study highlights the importance of monitoring for viral infections, including SDAV, in immunocompromised research animals.