Pathology in Practice. Necrotizing leukoencephalitis (NLE)

Investigation of astrovirus and bornavirus in the cerebrospinal fluid of dogs clinically diagnosed with meningoencephalitis of unknown etiology

BACKGROUND

Non-suppurative encephalitides in a variety of species, including humans and dogs, have been linked to infection by astroviruses and bornaviruses.

HYPOTHESIS/OBJECTIVES

To determine whether or not ribonucleic acid of astroviruses or bornaviruses was present in the cerebrospinal fluid (CSF) of dogs with clinically diagnosed meningoencephalomyelitis of unknown etiology (MUE).

ANIMALS

Twenty-five client-owned dogs evaluated by CSF analysis at a single university referral hospital.

METHODS

Prospective case-control study. Cerebrospinal fluid was collected from clinically diagnosed MUE and control cases and evaluated by reverse-transcriptase polymerase chain reaction for the presence of astrovirus and bornavirus.

RESULTS

Neither astrovirus nor bornavirus nucleic acids were identified in CSF collected from 20 clinically diagnosed MUE and 5 control cases.

CONCLUSIONS AND CLINICAL IMPORTANCE

The negative results of this investigation suggest that astrovirus and bornavirus are not commonly detectable in CSF of dogs with MUE.

Prognostic Factors for Recovery of Vision in Canine Optic Neuritis of Unknown Etiology: 26 Dogs (2003-2018)

Optic neuritis (ON) is a recognized condition, yet factors influencing recovery of vision are currently unknown. The purpose of this study was to identify prognostic factors for recovery of vision in canine ON of unknown etiology. Clinical databases of three referral hospitals were searched for dogs with presumptive ON based on clinicopathologic, MRI/CT, and fundoscopic findings. Twenty-six dogs diagnosed with presumptive ON of unknown etiology, isolated (I-ON) and MUE-associated (MUE-ON), were included in the study. Their medical records were reviewed retrospectively, and the association of complete recovery of vision with signalment, clinicopathologic findings, and treatment was investigated. Datasets were tested for normality using the D'Agostino and Shapiro-Wilk tests. Individual datasets were compared using the Chi-squared test, Fisher's exact test, and the Mann-Whitney U-test. For multiple comparisons with parametric datasets, the one-way analysis of variance (ANOVA) was performed, and for non-parametric datasets, the Kruskal-Wallis test was performed to test for independence. For all data, averages are expressed as median with interquartile range and significance set at p < 0.05. Twenty-six dogs met the inclusion criteria. Median follow-up was 230 days (range 21–1901 days, mean 496 days). Six dogs (23%) achieved complete recovery and 20 dogs (77%) incomplete or no recovery of vision. The presence of a reactive pupillary light reflex (p = 0.013), the absence of fundoscopic lesions (p = 0.0006), a younger age (p = 0.038), and a lower cerebrospinal fluid (CSF) total nucleated cell count (TNCC) (p = 0.022) were statistically associated with complete recovery of vision. Dogs with I-ON were significantly younger (p = 0.046) and had lower CSF TNCC (p = 0.030) compared to the MUE-ON group. This study identified prognostic factors that may influence complete recovery of vision in dogs with ON. A larger cohort of dogs is required to determine whether these findings are robust and whether additional parameters aid accurate prognosis for recovery of vision in canine ON.