Feline intralenticular Encephalitozoon cuniculi: three cases from California

Area of Science:

• Veterinary Ophthalmology
• Feline Infectious Diseases
• Parasitology

Background:

• Ocular manifestations of Encephalitozoon cuniculi (E. cuniculi) infection are increasingly recognized in cats.
• Immunocompromised status in cats can predispose them to opportunistic infections like E. cuniculi.

Observation:

• Three immunocompromised domestic shorthair cats in California presented with immature cataracts and signs of anterior uveitis.
• Clinical signs included corneal edema, anisocoria, elevated intraocular pressure, blepharospasm, and lethargy.
• Diagnostic workup involved comprehensive ophthalmic examinations, ocular ultrasound, electroretinography, and specific testing for E. cuniculi.

Findings:

• Serological testing for E. cuniculi was positive in two cats (1:64-1:4096).
• Intraocular E. cuniculi was confirmed via lens histopathology or PCR of ocular fluids/tissues in all cases.
• Surgical interventions included enucleation, phacoemulsification with intraocular lens placement, and phacoemulsification with ciliary body ablation and IOL implantation.

Implications:

• Encephalitozoon cuniculi should be considered a differential diagnosis for cataracts and uveitis in cats, particularly in immunocompromised individuals.
• Early diagnosis and prompt treatment, including surgical intervention like phacoemulsification, can lead to better visual outcomes.
• This case series highlights the importance of considering E. cuniculi in feline ocular disease, extending its relevance globally.