Struvite Urolithiasis in Long-Evans Rats.

Area of Science:

• Veterinary Pathology
• Urolithiasis Research
• Rodent Health

Background:

• Struvite urinary calculi (magnesium, ammonium, phosphate) can lead to severe complications like sepsis and renal failure in rats.
• A sudden increase in struvite calculi cases was observed in a shipment of Long-Evans rats.

Purpose of the Study:

• To investigate the cause and characteristics of struvite urinary calculi in a population of laboratory rats.
• To identify contributing factors and recommend management strategies for similar outbreaks.

Main Methods:

• Physical examination, radiography, and ultrasonography were used for screening affected rats.
• Necropsy, urinalysis (pH, cell counts, crystal analysis), and bacterial culture (Proteus mirabilis) were performed.
• Vendor investigation identified additional affected rats from the same colony.

Main Results:

• Struvite calculi were found in multiple rats, associated with alkaline urine, bacteria (Proteus mirabilis), leukocytes, and crystals.
• Affected rats exhibited metabolic disturbances and bacterial infections.
• The outbreak was linked to a specific breeding area, suggesting potential genetic or environmental factors.

Conclusions:

• Metabolic disturbances combined with bacterial infection predisposed rats to struvite calculi formation.
• Prompt urine culture, surgical intervention, and antibiotic therapy are recommended for sudden increases in cases.
• Dietary factors warrant further investigation as a potential contributing element.