# Encephalitozoonosis in Pet Rabbits: Epidemiology, Pathogenesis, Immunology and Consensus on Clinical Management

## TL;DR

This review discusses the challenges of diagnosing and treating Encephalitozoon cuniculi in pet rabbits and proposes guidelines for better clinical management.

## Contribution

The paper provides a consensus on diagnostics and treatment for E. cuniculi in rabbits, addressing gaps in current veterinary practices.

## Key findings

- E. cuniculi has a high seroprevalence in rabbits, up to 85%.
- Clinical signs include neurological, renal, and ocular manifestations.
- There is a lack of high-sensitivity diagnostic tools for ante mortem detection.

## Abstract

Encephalitozoon cuniculi infection in rabbits is challenging due to the high seroprevalence, treatment regimens based on older literature, and the paucity of active research. Given the lack of agreement in the veterinary community and modern robust studies, there is both high variance in the base knowledge of this agent and the disease processes as well as considerable variability in the application of therapies. The aim of this review is to provide a focused presentation regarding the biology and clinical presentations with a consensus on the use of diagnostics and treatment regimens.

Members of the microsporidial genus Encephalitozoon have the capacity to infect both mammals and birds, and E. cuniculi is most commonly found in rabbits. With a seroprevalence ranging up to 85%, E. cuniculi can be a problem in pet rabbits as well as in food production and laboratory animal science. While most infections are likely subclinical, there are three main clinical presentations: neurological, renal, and ocular. Typical clinical signs including vestibular disease and phacoclastic uveitis may develop with initial or relapsing infection, while renal infection is usually progressive and associated with non-specific clinical signs. High-sensitivity/specificity ante mortem diagnostic options are lacking, and serological testing most often provides adjunct rather than definitive information such that physical examination and other diagnostics are used more so for ruling out other differentials and comorbidities, rather than confirming infection. In the veterinary community, treatment regimens are variable given the lack of thorough studies and a consensus. The aim of this document is to present the available literature to give a concise review of this organism and its infection of rabbits as well as to propose guidelines and protocols for diagnostics and treatment regimens. In addition, the current challenges and recommendations for further studies are discussed.