Feline Herpesvirus 1 and Mycoplasma spp. Conventional PCR Assay Results From Conjunctival Samples From Cats in Shelters With Suspected Acute Ocular Infections

Relationship between the bacterial ocular surface microbiota and outcomes for cats with feline herpesvirus type 1 ocular surface disease

OBJECTIVE

Feline herpesvirus 1 (FHV-1) causes ocular surface disease in domestic cats. The purpose of this study was to assess the relationship between bacterial ocular surface microbiota and outcomes for cats with FHV-1 ocular surface disease.

ANIMALS STUDIED

Twenty-two shelter-housed cats with confirmed FHV-1 ocular surface disease.

PROCEDURES

Animals were grouped according to FHV-1 shedding and ocular clinical scores following intervention: worsened outcome (WorOut, n = 11) or improved outcome (ImpOut, n = 11). Scoring and conjunctival sampling were completed on Days 1 and 8 of twice daily antiviral treatment. Bacterial DNA was extracted and submitted for 16S rRNA gene sequencing. Real-time polymerase chain reaction was performed for selected bacterial species. Overall DNA concentration between groups was assessed.

RESULTS

Bacterial microbiota relative abundance composition was significantly different between ImpOut and WorOut groups (weighted UniFrac p = .006). Alpha diversity was significantly higher in the ImpOut group compared with the WorOut group (Shannon p = .042, Simpson's p = .022, Pielou's p = .037). Differences in the relative abundance of various phyla and species were detected between groups. Total DNA concentration was higher in the WorOut group compared with the ImpOut group (p = .04). Feline GAPDH (p = .001) and Bilophila wadsworthia (p = .024) copy number was significantly higher in the ImpOut group compared with the WorOut group.

CONCLUSIONS

The results highlight the important relationship between the bacterial ocular surface microbiota and FHV-1 infection outcomes in cats treated with antiviral medications. Low bacterial species diversity, higher overall DNA (presumed predominantly bacterial) load, and certain bacterial phyla/species were associated with poor outcomes for cats with FHV-1 ocular disease.

A review of evidence-based management of infectious ocular surface disease in shelter-housed domestic cats

Infectious ocular surface disease (IOSD) is a common problem in shelter-housed domestic cats and has a widespread negative impact on animal welfare. While the common etiological agents are well-described, addressing IOSD in large groups of animals presents a management challenge to the clinician and logistical challenges to shelter employees. Treatments, diagnostics, and prevention strategies that are effective in privately owned or experimental animals may be impractical or ineffective in the shelter environment. This review article focuses on the relative prevalence of etiological agents in feline IOSD, practical diagnostic testing protocols, prevention strategies, and treatment of IOSD in shelter-housed cats. Discrepancies between experimental laboratory-based studies and clinical trials assessing therapeutics for treatment of feline herpes virus are highlighted. Further high-quality clinical trials are necessary to determine optimal preventative and therapeutic protocols for IOSD in shelter-housed cats.

Comparative Efficacy of Topical Ophthalmic Ganciclovir and Oral Famciclovir in Cats with Experimental Ocular Feline Herpesvirus-1 Epithelial Infection

Purpose: To determine the comparative efficacy of ganciclovir ophthalmic gel and famciclovir oral tablets in cats with experimentally induced ocular feline herpesvirus-1 (FHV-1) epithelial infection. Methods: A randomized, placebo-controlled trial was performed using 16 nonvaccinated, specific pathogen-free cats with experimental FHV-1 infection induced by topical ocular inoculation. Cats received topical ganciclovir 0.15% ophthalmic gel (1 drop 3 times daily, n = 6 cats), oral famciclovir (90 mg/kg twice daily, n = 6), or topical artificial tear gel (1 drop 3 times daily, n = 4) for 14 days. Cats were monitored after inoculation for 30 days. Ophthalmic examinations were performed every 2 days and ocular disease scores calculated. In vivo confocal microscopy was performed, and corneal leukocyte infiltrates quantified. Ocular samples for FHV-1 quantitative polymerase chain reaction (qPCR) and virus isolation assays were collected every 3 days. Hemograms and serum biochemistry panels were performed at intervals. Results: Clinical ocular disease scores and corneal leukocyte infiltrates were significantly lower in the ganciclovir and famciclovir groups compared with placebo, but no significant differences were detected between the antiviral treatment groups. Ocular viral loads determined by qPCR were significantly lower in the ganciclovir group compared with the placebo group, but there were no significant differences between the other study groups. Hemograms and biochemistry panels were unremarkable. Conclusion: Topical application of ganciclovir gel 3 times daily was well-tolerated and displayed similar efficacy at reducing clinical ocular disease scores and corneal inflammation as twice daily oral famciclovir treatment in cats with experimental ocular FHV-1 infection.

Prevalence and characteristics of ocular diseases in Sphynx cats: A retrospective assessment (2012-2021) and comparison with non-Sphynx cats

PURPOSE

To describe the prevalence of ocular diseases in Sphynx cats, and compare disease characteristics with other feline breeds.

METHODS

Medical records of Sphynx cats presented to an ophthalmology referral center between 1/2012 and 4/2021 were examined. Cats of other breeds examined during the same period served as controls.

RESULTS

One hundred ten Sphynx cats were examined during the study period, diagnosed with corneal sequestrum (n = 42 cats), lower eyelid entropion (n = 25), presumed herpetic keratoconjunctivitis (n = 19), conjunctivitis (n = 7), corneal ulcers (n = 6), nasolacrimal duct atresia/obstruction (n = 6), corneal dystrophy (n = 3), eosinophilic keratitis (n = 2), uveitis (n = 2), non-ulcerative keratitis (n = 1), and cataract (n = 1). Corneal sequestrum was significantly more common in Sphynx versus non-Sphynx cats (odds ratio = 8.0, 95% CI = 5.3-12.2, p < .001), and age of diagnosis was significantly younger in Sphynx cats (2.0 ± 1.5 years vs. 5.9 ± 4.0 years, p < .001). Corneal sequestrum recurrence was noted in 19.4% Sphynx eyes and 6.4% non-Sphynx eyes undergoing surgery (p = .015). Lower eyelid entropion-most often bilateral (80%)-was significantly more common in Sphynx versus non-Sphynx cats (odds ratio = 4.1, 95% CI = 2.3-7.1, p < .001), and age of diagnosis was significantly younger in Sphynx cats (0.9 ± 1.4 years vs. 3.5 ± 3.3 years, p < .005).

CONCLUSIONS

Corneal sequestrum and entropion were overrepresented and diagnosed at an earlier age in Sphynx cats when compared with the general feline population. Given the high prevalence, early age of onset, and relatively high recurrence of corneal sequestrum in Sphynx cats, further studies are warranted to better understand etiopathogenesis and preferred therapies.

First Report of Isolation and Molecular Characterization of Felid Herpesvirus-1 from Symptomatic Domestic Cats in Egypt

Feline herpesvirus 1 (FHV-1) is one of the main causes of upper respiratory tract infection in cats. Despite its veterinary importance, no previous studies investigated the occurrence of this virus in Egypt. In the present work, a total number of one hundred forty (N = 140) conjunctival and/or oropharyngeal swabs were collected from symptomatic cats during veterinary clinic visits located in two Egyptian provinces. Virus isolation was performed in the Chorioallantoic membranes (CAMs) of 12-days-old SPF eggs. Interestingly, the embryos showed stunting growth and abnormal feathering and infected CAMs showed edematous thickening and cloudiness with characteristic white opaque pock lesions. Polymerase chain reaction (PCR) amplification of the thymidine kinase gene (TK) was successful in 16/140 (11.4%) of the suspected cases. Two of the amplified genes were sequenced and the TK gene sequences of the FHV-1 isolates were highly similar to other reference strains in the GenBank database. Given the above information, the present study represents the first report of feline herpesvirus type 1 (FHV-1) in domestic cats in Egypt. Further studies on the causes of upper respiratory tract infections in cats as well as vaccine efficacy are needed.

Serum 25-hydroxyvitamin D concentration and infectious respiratory disease complex in shelter dogs

Background

Hypovitaminosis D is a risk factor for the development of respiratory infections in humans and repletion can be protective.

Objectives

Determine if serum 25‐hydroxyvitamin (OH)D concentrations are lower in shelter dogs and if 25(OH)D concentrations are associated with clinical signs of canine infectious respiratory disease complex (CIRDC) or with time in the shelter.

Animals

One hundred forty‐six shelter dogs (clinically ill n = 36, apparently healthy n = 110) and 23 nonshelter control dogs.

Methods

Prospective cohort study. Shelter dogs were grouped as clinically ill or apparently healthy based on the presence or absence, respectively, of clinical signs associated with CIRDC. Serum 25(OH)D concentrations were measured with a competitive chemiluminesence immunoassay. Nucleic acids of agents associated with the CIRDC were amplified by polymerase chain reaction assays.

Results

The concentration of 25(OH)D was 7.3 ng/mL (4.5‐9.9, 95% confidence interval [CI]) lower in dogs with signs of CIRDC than apparently healthy shelter dogs (t(142) = 2.0, P = .04). Dogs positive for DNA of canine herpesvirus (CHV)‐1 had serum 25(OH)D concentrations 14.9 ng/mL (−3.7 to 29.6, 95% CI) lower than dogs that were negative (t(137) = 2.0, P = .04). Serum 25(OH)D concentrations in shelter dogs were not different from control dogs (t(45) = −1.4, P = .17). Serum 25(OH)D concentration was not associated with duration of time in the shelter (F(1, 140) = 1.7, P = .2, R² = 0.01).

Conclusion and Clinical Importance

Vitamin D could have a role in acute respiratory tract infections in shelter dogs.

Effects of famciclovir in cats with spontaneous acute upper respiratory tract disease

OBJECTIVES

The aim of this study was to assess the effects of famciclovir administration in cats with spontaneously acquired acute upper respiratory tract disease.

METHODS

Twenty-four kittens with clinical signs of acute upper respiratory tract disease were randomly allocated to receive doxycycline (5 mg/kg PO q12h) alone (group D; n = 12) or with famciclovir (90 mg/kg PO q12h; group DF; n = 12) for up to 3 weeks. Clinical disease severity was scored at study entry and daily thereafter. Oculo-oropharyngeal swabs collected at study entry and exit were assessed using quantitative PCR for nucleic acids of feline herpesvirus type 1 (FHV-1), feline calicivirus (FCV), Chlamydia felis, Bordetella bronchiseptica and Mycoplasma felis.

RESULTS

The median (range) age of cats was 1.5 (1-6) months in group D vs 1.6 (1-5) months in group DF (P = 0.54). Pathogens detected in oculo-oropharyngeal swabs at study entry included FCV (n = 13/24; 54%), M felis (n = 8/24; 33%), FHV-1 (n = 7/24; 29%), C felis (n = 7/24; 29%) and B bronchiseptica (n = 3/24; 12%). Median (range) duration of clinical signs was 11.5 (3-21) days in group DF and 11 (3-21) days in group D (P = 0.75). Median (range) total disease score at the end of the study did not differ between groups (group D 1 [1-1] vs group DF 1 [1-3]; P = 0.08).

CONCLUSIONS AND RELEVANCE

This study revealed no significant difference in response to therapy between cats treated with doxycycline alone or with famciclovir; cats improved rapidly in both groups. However, identification of FHV-1 DNA was relatively uncommon in this study and clinical trials focused on FHV-1-infected cats are warranted to better evaluate famciclovir efficacy.