Ocular manifestations of feline viral diseases

Replication kinetics and cytopathic effect of feline calicivirus in feline corneal epithelial cells

OBJECTIVE

To determine the replication kinetics and cytopathic effect (CPE) of feline calicivirus (FCV) in feline corneal epithelial cells (FCEC).

ANIMALS STUDIED

Seven archived FCV isolates and one archived feline herpesvirus type 1 (FHV-1) isolate, previously obtained from eight domestic short hair cats.

PROCEDURES

FCV RNA was extracted for sequencing using Illumina MiSeq, to identify three genomically diverse isolates for further testing. Following reference-based assembly, viral genomes were annotated and assessed. Superficial keratectomies were performed to isolate the corneal epithelium of cats and the cells were cultured in vitro. FCEC were infected with the three chosen FCV isolates and one FHV-1 isolate at two different multiplicity of infection ratios (MOIs, 0.1 and 0.01 PFU/cell) and virus titration was assessed at 0, 2, 6, 12, 24, and 48 h post-infection (hpi). Viral identity was confirmed by RT-qPCR.

RESULTS

Three genomically diverse FCV isolates were chosen for further assessment in the FCEC model. All infections of FCEC with FCV led to visible CPE, characterized by epithelial cell rounding and detachment from the plate by 24 hpi, while FHV-1 led to visible CPE within 48 hpi. All three of the FCV isolates replicated effectively in FCEC at both 0.1 and 0.01 MOI, with a peak increase in titer approximately 12-24 hpi.

CONCLUSIONS

The results support the possible role of FCV as a primary pathogen of the feline ocular surface. FCV replicates in FCEC in vitro, leading to profound CPE.

The Occurrence of Chlamydia felis in Cats and Dogs in Hungary

The World Health Organization (WHO) estimates that many human infections are zoonoses, creating a worldwide public health challenge. Among Chlamydia species, Chlamydia felis is the leading cause of conjunctivitis in cats and is a prominent zoonotic species. This study aimed to determine the occurrence and risk of chlamydiosis in cats and dogs in Szeged, Hungary, and surrounding areas. The total nucleic acids from conjunctival swab samples of symptomatic and asymptomatic animals were extracted using an automated nucleic acid extraction system. After that, DNA was amplified by pan-chlamydia PCR. Bacterial and fungal cultures were also performed to detect other microorganisms. Of the 93 animals, 32 (34.4%) were positive for pan-chlamydia PCR. The positivity rates were 33.3% (26/78) in cats and 40.0% (6/15) in dogs. Furthermore, the positivity rates were 37.2% (16/43) in the cat shelter, 42.4% (14/33) in the veterinary clinic, and 11.7% (2/17) in household pets. In total, 103 species were identified through culture-based examinations, including 97 (94.2%) bacterial and 6 fungal (5.8%) species. From both human and animal health perspectives, it is essential to have a detailed understanding of the circumstances of chlamydiosis, given the global impact of zoonotic diseases.

Green tea extract reduces viral proliferation and ROS production during Feline Herpesvirus type-1 (FHV-1) infection

BACKGROUND

Feline Herpesvirus type-1 (FHV-1) is a worldwide spread pathogen responsible for viral rhinotracheitis and conjunctivitis in cats that, in the most severe cases, can lead to death. Despite the availability of a variety of antiviral medications to treat this illness, mainly characterized by virostatic drugs that alter DNA replication, their use is often debated. Phytotherapeutic treatments are a little-explored field for FHV-1 infections and reactivations. In this scenario, natural compounds could provide several advantages, such as reduced side effects, less resistance and low toxicity. The purpose of this study was to explore the potential inhibitory effects of the green tea extract (GTE), consisting of 50% of polyphenols, on FHV-1 infection and reactive oxygen species (ROS) production.

RESULTS

Crandell-Reese feline kidney (CRFK) cells were treated with different doses of GTE (10-400 µg/mL) during the viral adsorption and throughout the following 24 h. The MTT and TCID50 assays were performed to determine the cytotoxicity and the EC50 of the extract, determining the amounts of GTE used for the subsequent investigations. The western blot assay showed a drastic reduction in the expression of viral glycoproteins (i.e., gB and gI) after GTE treatment. GTE induced not only a suppression in viral proliferation but also in the phosphorylation of Akt protein, generally involved in viral entry. Moreover, the increase in cell proliferation observed in infected cells upon GTE addition was supported by enhanced expression of Bcl-2 and Bcl-xL anti-apoptotic proteins. Finally, GTE antioxidant activity was evaluated by dichloro-dihydro-fluorescein diacetate (DCFH-DA) and total antioxidant capacity (TAC) assays. The ROS burst observed during FHV-1 infection was mitigated after GTE treatment, leading to a reduction in the oxidative imbalance.

CONCLUSIONS

Although further clinical trials are necessary, this study demonstrated that the GTE could potentially serve as natural inhibitor of FHV-1 proliferation, by reducing viral entry. Moreover, it is plausible that the extract could inhibit apoptosis by modulating the intrinsic pathway, thus affecting ROS production.

Investigation of eye flora in cats infected with Herpesvirus and Calicivirus

Background and Objectives

The ocular surface is perpetually exposed to the external environment, rendering it susceptible to microbial contamination. The ocular surface microbiota consists of non-pathogenic microorganisms that inhabit the conjunctiva and cornea. This study's objective was to extensively review the prevalence of bacterial and fungal organisms in the conjunctiva of healthy and diseased cats. (Herpes- and Calici-infected groups).

Materials and Methods

The current study was performed on 240 cats that had visited veterinary health centers (Tehran, Iran) for examination. Sterile swabs from each cat's eyes were investigated for microbiological assessment. After sample collection, viral pathogens (Herpes and Calici viruses) were isolated and identified using the PCR method. The ages of the investigated group were 3.76, 3.93, and 4.15 months.

Results

The highest frequency of bacteria in the normal, Herpes-infected/Calici-infected, and Herpes/Calici-infected groups were associated with Staphylococcus intermedius and Streptococcus agalactiae, Staphylococcus epidermidis, and Staphylococcus intermedius, respectively. In addition, it was found that the high prevalence of fungal microorganisms in the isolated samples was related to yeasts, Aspergillus (Aspergillus fumigatus, Aspergillus niger), and Penicillium species.

Conclusion

Bacterial prevalence was significantly higher in all groups than the prevalence of fungi in the eyes of cats. The statistical comparison between the study groups regarding microbial and fungal frequency showed that significant differences were found between them, such that the frequency was higher in all disease groups, against the control group. In addition, a significant relation was observed between the Herpes-infected and Calici-infected groups regarding microbial and fungal prevalence.

Detection of Mycoplasma spp. and feline calicivirus in cats with ocular surface disease

OBJECTIVE

To survey the prevalence of pathogens in shelter-housed cats with active ocular surface disease (OSD).

ANIMALS STUDIED

A total of 255 shelter-housed domestic cats with evidence of active OSD. No normal, unaffected cats were sampled.

PROCEDURE(S)

OSD scoring was performed on cats with active OSD. Combined oropharyngeal/conjunctival swabs were submitted for rt-PCR/PCR for feline herpesvirus (FHV-1), feline calicivirus (FCV), Chlamydia spp. (CHL), Bordetella bronchiseptica (BORD), and Mycoplasma spp. (MYC).

RESULTS

Pathogens were detected as follows: 76.4% (195/255) MYC, 57.6% (147/255) FHV-1, 42.7% (109/255) FCV, 26.7% (68/255) CHL, and 5.5% (14/255) BORD. Monoinfections affected 21.1% (54/255) animals, with MYC being the most common monoinfection (12.5%, 32/255), followed by FHV-1 (4.7%, 12/255), followed by CHL (2.4%, 6/255), followed by FCV (1.6%, 4/255), with no animals having a BORD monoinfection. Dual infections affected 36.4% of animals (93/255), with MYC detected in 30.1% (77/255) dual infections and FCV detected in 12.9% (33/255) dual infections. Dual infections with MYC and FCV together were detected in 9.8% (25/255) animals. Many animals (35.3%, 90/255) were found to be affected by 3 or more pathogens, and 7.1% (18/255) animals had no pathogens detected. OSD scores were not influenced by any variable assessed, including the number and type of pathogens detected.

CONCLUSION

MYC, FHV-1, FCV, and CHL were commonly detected in this group of animals with OSD. Both MYC and FCV (alone or in combination with each other) were detected in multiple animals with active OSD, supporting prior evidence that either may independently act as a primary ocular surface pathogen.

An ethogram of acute pain behaviors in cats based on expert consensus

An improved understanding of behaviors reflecting acute pain in cats is a priority for feline welfare. The aim of this study was to create and validate a comprehensive ethogram of acute pain behaviors in cats that can discriminate painful versus non-painful individuals. An inventory of behaviors (ethogram) with their respective descriptors was created based on a literature review of PubMed, Web of Science and CAB Abstracts databases. The ethogram was divided into ten behavior categories that could be evaluated by duration and/or frequency: position in the cage, exploratory behaviors, activity, posture and body position, affective-emotional states, vocalization, playing (with an object), feeding, post-feeding and facial expressions/features. Thirty-six behaviors were analyzed independently by four veterinarians with postgraduate qualifications in feline medicine and/or behavior as (1) not relevant, (2) somewhat relevant, (3) quite relevant or (4) highly relevant and used for content (I-CVI) and face validity. Items with I-CVI scores > 0.67 were included. Twenty-four behaviors were included in the final ethogram. Thirteen items presented full agreement (i.e., I-CVI = 1): positioned in the back of the cage, no attention to surroundings, feigned sleep, grooming, attention to wound, crouched/hunched, abnormal gait, depressed, difficulty grasping food, head shaking, eye squinting, blepharospasm and lowered head position. Seven descriptors were reworded according to expert suggestions. The final ethogram provides a detailed description of acute pain behaviors in cats after content and face validity and can be applied to the characterization of different acute painful conditions in hospitalized cats.

Development and application of a dual ERA method for the detection of Feline Calicivirus and Feline Herpesvirus Type I

Feline calicivirus (FCV) and feline herpesvirus type I (FHV-1) are the most common viral pathogens responsible for cat respiratory diseases, and coinfection with these two pathogens is often found. In veterinary clinics, the main diagnostic methods for FCV and FHV-1 are test strips and polymerase chain reaction (PCR). However, the sensitivity of test strips are not sufficient, and PCR is time-consuming. Therefore, developing a rapid and high-performance clinical diagnostic test is imperative for the prevention and treatment of these diseases. Enzymatic recombinase amplification (ERA) is an automated isothermal nucleic acid amplification technique that maintains a constant temperature, and is both rapid and highly accurate. In this study, a dual ERA method was developed using the Exo probe for a differential detection of FCV and FHV-1. This dual ERA method demonstrated high performance with the detection limit of 10¹ copies for both viruses, and no cross-reactions with feline parvovirus virus and F81 cells. To test the utility of the method for clinical applications, 50 nasopharyngeal swabs from cats with respiratory symptoms were collected and tested. The positive rates of FCV and FHV-1 were 40% (20/50, 95% confidence interval [CI], 26.4 to 54.8%) and 14% (7/50, 95% CI, 5.8 to 26.7%), respectively. The rate of coinfection with FCV and FHV-1 was 10% (5/50, 95% CI, 3.3 to 21.8%). These results were in agreement with those found using quantitative real-time PCR. Therefore, this dual ERA method is a novel and efficient clinical diagnostic tool for FCV and FHV-1 detection.

Comparison of five conjunctival cytology sampling methods in normal cat eyes

Background and Aim

Ophthalmological cytology is an easy, informative, rapid, and commonly-used low-cost diagnostic method, but sample collection and preparation are essential steps in obtaining qualitative material for cytological evaluation. This study aimed to evaluate cytological smear quality and animal discomfort after single or three serial conjunctival scrapings in normal cat eyes using five sampling methods.

Materials and Methods

Five cytology methods (mini brush, cotton swab, soft brush, Kimura spatula, and cytobrush) were used in 50 eyes (10 with one scraping and 10 with three consecutive scrapings for a particular method) in complete 25 clinically and ophthalmologically healthy cats of different ages, sexes, and breeds. Ocular discomfort (1 = eyes open, 2 = partially open, and 3 = eyes squinted), average cell count (ten 10× fields), cell distribution (ten 100× fields: 0 = all cells are aggregated, 1 = <25% cells are evenly distributed, 2 = 25-50% cells are evenly distributed, and 3 = >50% cells are evenly distributed) and sample quality - aggregates (two cells and more), mucus, and artifacts (1+ = fair, 2+ = moderate, and 3+ = high amount) were evaluated.

Results

The discomfort scores for the mini brush, cotton swab, soft brush, spatula, and cytobrush after a single and three scrapings were 1, 1, 1, 2, and 3, respectively. The average cell counts ± standard deviation after one and three scrapings were as follows: mini brush 11.15 ± 13.87 and 7.55 ± 12.7; cotton swab 7.17 ± 10.20 and 10.00 ± 16.44; soft brush 19.45 ± 22.22 and 8.55 ± 13.82; spatula 17.15 ± 32.94 and 13.85 ± 22.01; and cytobrush 13.35 ± 18.33 and 13.05 ± 19.29, respectively; the cell distributions were 3, 3, 3, 1, and 1 after single scraping and 3, 3, 2, 0, and 2 after three scrapings, respectively.

Conclusion

The mini brush was the optimal method since it produced less discomfort, fewer artifacts, and the highest smear quality. Spatula smears were difficult to evaluate due to material thickness. The highest mucus and aggregate amounts were found in cytobrush, cotton swab, and soft brush samples. In this study, small number of samples per each sampling method is a major limitation.

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.

Nanoparticle ocular immunotherapy for herpesvirus surface eye infections evaluated in cat infection model

Ocular herpes simplex type 1 (HSV-1) infections can trigger conjunctivitis, keratitis, uveitis, and occasionally retinitis, and is a major cause of blindness worldwide. The infections are lifelong and can often recrudesce during periods of stress or immune suppression. Currently HSV-1 infections of the eye are managed primarily with anti-viral eye drops, which require frequent administration, can cause irritation, and may take weeks for full resolution of symptoms. We therefore evaluated the effectiveness of an ocular immune activating nanoparticle eye drop as a novel approach to treating HSV-1 infection, using a cat feline herpesvirus -1 (FHV-1) ocular infection model. In vitro studies demonstrated significant induction of both type I and II interferon responses by the liposome-dual TLR 3/9 agonist nanoparticles, along with suppression of FHV-1 replication. In cats with naturally occurring eye infections either proven or suspected to involve FHV-1, ocular nanoparticle treated animals experienced resolution of signs within several days of treatment, including resolution of keratitis and corneal ulcers. In a cat model of recrudescent FHV-1 infection, cats treated twice daily with immune nanoparticle eye drops experienced significant lessening of ocular signs of infection and significantly fewer episodes of viral shedding compared to control cats. Treatment was well-tolerated by all cats, without signs of drug-induced ocular irritation. We concluded therefore that non-specific ocular immunotherapy offers significant promise as a novel approach to treatment of HSV-1 and FHV-1 ocular infections.

Ophthalmic effects of dexmedetomidine, methadone and dexmedetomidine-methadone in healthy cats and their reversal with atipamezole

OBJECTIVES

The aims of this study were to evaluate and compare the effects that dexmedetomidine and methadone, either alone or in combination, have on the ocular variables of healthy adult cats when administered intramuscularly, as well as their reversal with atipamezole.

METHODS

A randomized crossover blinded study of 10 healthy cats was used to assess the effect of 0.2 mg/kg methadone (MET), 7.5 μg/kg dexmedetomidine (D7), 10 μg/kg dexmedetomidine (D10), 7.5 μg/kg dexmedetomidine and 0.2 mg/kg methadone (DM7) and 10 μg/kg dexmedetomidine and 0.2 mg/kg methadone (DM10) on intraocular pressure (IOP), tear production and pupil diameter (PD). The animals were evaluated for 30 mins. Afterwards, atipamezole was administered and ocular variables were evaluated for 30 mins.

RESULTS

D10, DM7 and DM10 significantly decreased mean IOP but MET or D7 did not. Tear production decreased significantly in all treatments, corresponding to 18%, 59%, 63%, 86% and 98% in MET, D7, D10, DM7 and DM10, respectively. PD increased in all treatments, but MET showed the highest PD. Thirty minutes after atipamezole (RT30), IOP returned to baseline with no difference between groups, and there was a significant increase in tear production, but the means were still different from baseline.

CONCLUSIONS AND RELEVANCE

Dexmedetomidine decreases IOP and tear production but increases PD in healthy cats. Atipamezole can partly reverse those alterations. Low-dose dexmedetomidine (7.5 µg/kg) promotes sedation without changing the IOP. All protocols significantly decrease tear production, and Schirmer tear test after sedation is not representative of non-sedated values. Methadone induces quick onset mydriasis without changing the IOP.

Investigation of monotherapy and combined anticoronaviral therapies against feline coronavirus serotype II in vitro

OBJECTIVES

Feline infectious peritonitis (FIP), caused by genetic mutants of feline enteric coronavirus known as FIPV, is a highly fatal disease of cats with no currently available vaccine or US Food and Drug Administration-approved cure. Dissemination of FIPV in affected cats results in a range of clinical signs, including cavitary effusions, anorexia, fever and lesions of pyogranulomatous vasculitis and perivasculitis, with or without central nervous system or ocular involvement. The objectives of this study were to screen an array of antiviral compounds for anti-FIPV (serotype II) activity, determine cytotoxicity safety profiles of identified compounds with anti-FIPV activity and strategically combine identified monotherapies to assess compound synergy against FIPV in vitro. Based upon clinically successful combination treatment strategies for human patients with HIV and hepatitis C virus infections, we hypothesized that a combined anticoronaviral therapy approach featuring concurrent multiple mechanisms of drug action would result in an additive or synergistic antiviral effect.

METHODS

This study screened 90 putative antiviral compounds for efficacy and cytotoxicity using a multimodal in vitro strategy, including plaque bioassays, real-time RT-PCR viral inhibition and cytotoxicity assays.

RESULTS

Through this process, we identified 26 compounds with effective antiviral activity against FIPV, representing a variety of drug classes and mechanisms of antiviral action. The most effective compounds include GC376, GS-441524, EIDD2081 and EIDD2931. We documented antiviral efficacy for combinations of antiviral agents, with a few examined drug combinations demonstrating evidence of limited synergistic antiviral activity.

CONCLUSIONS AND RELEVANCE

Although evidence of compound synergy was identified for several combinations of antiviral agents, monotherapies were ultimately determined to be the most effective in the inhibition of viral transcription.

2022 AAFP/EveryCat Feline Infectious Peritonitis Diagnosis Guidelines

CLINICAL IMPORTANCE

Feline infectious peritonitis (FIP) is one of the most important infectious diseases and causes of death in cats; young cats less than 2 years of age are especially vulnerable. FIP is caused by a feline coronavirus (FCoV). It has been estimated that around 0.3% to 1.4% of feline deaths at veterinary institutions are caused by FIP.

SCOPE

This document has been developed by a Task Force of experts in feline clinical medicine as the 2022 AAFP/EveryCat Feline Infectious Peritonitis Diagnosis Guidelines to provide veterinarians with essential information to aid their ability to recognize cats presenting with FIP.

TESTING AND INTERPRETATION

Nearly every small animal veterinary practitioner will see cases. FIP can be challenging to diagnose owing to the lack of pathognomonic clinical signs or laboratory changes, especially when no effusion is present. A good understanding of each diagnostic test's sensitivity, specificity, predictive value, likelihood ratio and diagnostic accuracy is important when building a case for FIP. Before proceeding with any diagnostic test or commercial laboratory profile, the clinician should be able to answer the questions of 'why this test?' and 'what do the results mean?' Ultimately, the approach to diagnosing FIP must be tailored to the specific presentation of the individual cat.

RELEVANCE

Given that the disease is fatal when untreated, the ability to obtain a correct diagnosis is critical. The clinician must consider the individual patient's history, signalment and comprehensive physical examination findings when selecting diagnostic tests and sample types in order to build the index of suspicion 'brick by brick'. Research has demonstrated efficacy of new antivirals in FIP treatment, but these products are not legally available in many countries at this time. The Task Force encourages veterinarians to review the literature and stay informed on clinical trials and new drug approvals.

Updates on Coronavirus-Related Ocular Manifestations: From the Past to COVID-19 Pandemic

Context: Coronaviruses are the largest RNA viruses associated with some ocular manifestations. There are various contradictory reports about the ocular manifestations of coronaviruses in humans. Different ocular tissues can affect coronavirus-associated infectious diseases. Evidence Acquisition: All manuscripts were collected from PubMed, Google Scholar, and other relevant databases. All searches were done by specific keywords, including "coronavirus," "ocular disease," and "eye." Results: There are various contradictory reports about the ocular effects of coronaviruses in humans. Different ocular tissues are involved in coronavirus-associated infectious diseases. The ductal connection between the upper respiratory tract and eye mucosa through the nasolacrimal duct can be an entrance to respiratory viruses, such as coronaviruses. The coronavirus can infect the retina, conjunctiva, cornea, and uvea of the eye. The primary SARS-CoV-2 receptor, ACE2, is mainly expressed in the posterior tissues of the eye, such as the retina and RPE. Feline CoV, SARS-CoV, MERS-CoV, and infectious bronchitis virus (IBV) are responsible for conjunctiva involvement in coronavirus-related ocular pathogenesis. Also, various studies are held on COVID-19 and the impact of the conjunctiva on diagnosis and medical complications. Given that the cornea has an acceptable expression of ACE2 and TMPRSS2 genes compared to lung tissue, some studies were done on the impact of the cornea in COVID-19. Feline infectious peritonitis virus (FIPV) is also related to uvea complications. The experiments of human and animal models on the effects of coronaviruses on the retina and cornea in the event of various epidemics of coronaviruses and new and unknown ocular complications can be of great help to future studies. Conclusions: Given the importance of investigating the pathogenesis and other routes of SARS-CoV-2 infection, especially in areas other than the respiratory tract, this report attempts to highlight the importance of eye infections caused by the virus, its role in maintaining the virus transmission chain, and its impact on public health.

Virus de la leucemia e inmunodeficiencia felina: un estudio retrospectivo en clínicas veterinarias particulares en Bogotá y Chía (Colombia), 2015-2019

Los virus de inmunodeficiencia y leucemia felina representan un problema de gran envergadura para los felinos domésticos debido a la multiplicidad de sintomatologías que manifiestan. El objetivo del presente estudio fue establecer, retrospectivamente, la prevalencia en la presentación de ViLeF y VIF en pacientes de seis clínicas de pequeños animales en Bogotá y Chía, en relación con factores como su edad, raza y género. Se realizó un estudio transversal y retrospectivo, mediante la recopilación de datos de 1.014 historias clínicas de pacientes felinos que ingresaron a seis clínicas de la ciudad de Bogotá y Chía, para determinar la prevalencia de VIF y ViLeF y la asociación de estas con factores como edad, género y raza, entre 2015 y 2019, a través de la prueba OR. La detección de los virus se realizó mediante una prueba rápida basada en inmunocromatografía. La mayor prevalencia para cada enfermedad por año fue: 12,3% para VIF en 2012 y 18% para ViLeF en 2019. Los machos presentaron mayores seroprevalencias para ambas enfermedades durante la mayoría los años evaluados. Factores como raza (criolla: VIF: 1,85; ViLeF: 2,01), género (macho: VIF: 1,53 OR; ViLeF: 1,64) y edad (> 7 años: VIF: 3,82; ViLeF: 3,21) se relacionaron positivamente con la presentación de ambas enfermedades en la población felina evaluada.

Changes in Health Indicators of Welfare in Group-Housed Shelter Cats

The aim of this study was to detect changes in health-oriented welfare indicators of shelter cats housed in a shelter by means of long-term monitoring of health indicators of welfare in a population of group-housed cats in a private, no-kill shelter in the Czech Republic. The cat population housed in a large group was monitored for 1 year. The data recording took place at 2-week intervals. A total of 220 cats were evaluated using a protocol containing eight health-oriented welfare indicators: body condition, third eye visibility, eye discharge, eye irritation, nose discharge, the presence of pathologically induced respiratory sounds, coat condition, and lameness and abnormal posture. The assessment was performed based on the observation by two trained evaluators. The cats' condition was rated on a 5-point scale for each indicator, where the optimal condition was represented by the score of 1 and a severe deterioration by the score of 5 for the given indicator, except for the body condition indicator, where the optimal condition was represented by the score of 3. A deterioration in the score in at least one of the indicators during the stay in the shelter was recorded in 52 (41.6%) of 125 cats that were assessed at least twice. The effect of the LOS, sex and age on the scores for each health indicator was examined via a linear mixed model analysis, as this method allows for handling of dependencies in the data of repeated measurements. The effect of predictors on the third eye visibility scores was not found. The age of cats predicted the coat condition and body condition scores. The LOS predicted scores of the abnormal posture and lameness indicator and scores of a composite index composed of indicators related to upper respiratory tract disease. The results suggest that despite the fact that some improvement of health was documented during the cats' stay in the shelter, there were a non-negligible number of animals experiencing a permanent or long-term deterioration in health. Efforts to minimize the undesirable factors contributing to the deterioration of well-being of cats during their stay in a shelter should be made.

Autologous lamellar keratoplasty for the treatment of feline corneal sequestrum: A retrospective study of 35 eyes (2012-2020)

OBJECTIVE

To evaluate the use of autologous lamellar keratoplasty for the treatment of feline corneal sequestrum (FCS).

PROCEDURE

The medical records of cats diagnosed with FCS that underwent autologous lamellar keratoplasty between 2012 and 2020 with a minimum of 2 months of follow-up were reviewed. After keratectomy of FCS, a button adjacent to the corneal limbus was harvested on the same eye and sutured to the recipient bed. A nictitating membrane flap was left in place until the first recheck except for one patient. Postoperative treatment with topical and systemic antibiotics and systemic nonsteroidal anti-inflammatory medications was prescribed. Follow-up examinations were carried out 2 weeks, 1 month and 2 months post-operatively and consisted of a complete ophthalmic examination.

RESULTS

A total of 35 cats (35 eyes) were included. The median follow-up time was 3.2 months (range, 2-59 months). Brachycephalic cats were overrepresented (85.7%). The mean graft size was 6.5 mm (range, 6-9 mm). Minor complications consisting of melting and partial integration of the graft occurred in 2/35 eyes (5.7%). Recurrence was observed in 1/35 eyes (2.9%) and was managed by a superficial keratectomy. A good visual outcome was achieved in all eyes, and a faint or mild corneal opacification occurred in 15/35 (42.9%).

CONCLUSIONS

Autologous lamellar keratoplasty is an effective treatment for FCS, providing good tectonic support to the affected cornea and resulting in good visual and cosmetic outcomes. These results should be verified in future prospective studies that include a larger number of cases and longer-term follow-up.

SARS-CoV-2 on the ocular surface: is it truly a novel transmission route?

Since December 2019, the novel COVID-19 outbreak has spread rapidly around the globe and infected millions of people. Although the major transmission route of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is considered to be airborne droplets and close contact, the ocular transmission route has been reported with great concern. The current work summarises the characteristics of SARS-CoV-2, the ocular distribution of the major SARS-CoV-2 binding protein, and the experimental and clinical evidence of the ocular transmission route. Although it seems that the likelihood of the ocular surface being an infection gateway is low, SARS-CoV-2 infection or transmission via the ocular surface may cause conjunctivitis and other ocular discomfort. Therefore, good eye protection is an essential safeguard procedure, especially for medical staff.

Prevalence and type of ocular disease in a population of aged captive nondomestic felids

OBJECTIVES

Report of prevalence and type of ocular disease in a captive population of nondomestic felids.

METHODS

Medical records of 202 cats from 1993 to 2018 were reviewed. Species, age at diagnosis, sex, ocular examination abnormalities, systemic/physical examination abnormalities, type of examination (visual, sedated, or anesthetized), ocular structures affected, other diagnostics, therapy, and resolution of ocular disease were recorded.

RESULTS

A total of 202 nondomestic felids including 18 different species (bobcat, caracal, cougar, Fishing cat, Geoffroy's cat, jaguar, jungle cat, leopard, leopard cat, liger, lion, lynx, ocelot, Sand cat, Savannah cat, serval, snow leopard, and tiger) from a rescue facility were evaluated. Forty-six ocular lesions were diagnosed in 33 (16.3%) cats from 8 different species (bobcat, caracal, cougar, leopard, lion, ocelot, serval, and tiger) with a mean age of 16 ± 5.9 years at time of diagnosis. Ocular lesions included corneal disease (37%) (ulcerations, perforations, keratitis, corneal scars), cataracts (23.9%), hyphema (8.7%), lens luxation (6.5%), retinal detachment (6.5%), uveitis (4.3%), conjunctival disease (4.3%), retinal degeneration (2.1%), glaucoma (2.1%), and optic neuritis (2.1%). Therapies included medical (topical antibiotics, anti-inflammatories, serum, etc.) and/or surgical management (enucleation, intracapsular lens extraction, corneoconjunctival transposition, and corneal burr debridement).

CONCLUSIONS

To the authors' knowledge, this is the first report of the prevalence of ocular disease in a population of captive nondomestic felids. It is difficult to diagnose and treat ocular disease in nondomestic cats due to challenges related to handling, diagnostics, and therapeutics in nondomestic species. Ocular disease seen in this population is similar to that found in domestic cat populations.

Clinical and molecular aspects of veterinary coronaviruses

Coronaviruses are a large group of RNA viruses that infect a wide range of animal species. The replication strategy of coronaviruses involves recombination and mutation events that lead to the possibility of cross-species transmission. The high plasticity of the viral receptor due to a continuous modification of the host species habitat may be the cause of cross-species transmission that can turn into a threat to other species including the human population. The successive emergence of highly pathogenic coronaviruses such as the Severe Acute Respiratory Syndrome (SARS) in 2003, the Middle East Respiratory Syndrome Coronavirus in 2012, and the recent SARS-CoV-2 has incentivized a number of studies on the molecular basis of the coronavirus and its pathogenesis. The high degree of interrelatedness between humans and wild and domestic animals and the modification of animal habitats by human urbanization, has favored new viral spreads. Hence, knowledge on the main clinical signs of coronavirus infection in the different hosts and the distinctive molecular characteristics of each coronavirus is essential to prevent the emergence of new coronavirus diseases. The coronavirus infections routinely studied in veterinary medicine must be properly recognized and diagnosed not only to prevent animal disease but also to promote public health.

Ocular manifestations and clinical characteristics of 535 cases of COVID-19 in Wuhan, China: a cross-sectional study

PURPOSE

To investigate the ocular manifestations and clinical characteristics of COVID-19 patients caused by SARS-CoV-2 in Wuhan, China.

METHODS

A total of 535 COVID-19 patients were recruited at Mobile Cabin Hospital and Tongji Hospital. Information on demographic characteristics, exposure history, ocular symptoms, eye drop medication, eye protections, chronic eye diseases, systemic concomitant symptoms, radiologic findings and SARS-CoV-2 detection in nasopharyngeal swabs by real-time PCR was collected from questionnaires and electronic medical records.

RESULTS

Of 535 patients, 27 patients (5.0%) presented with conjunctival congestion and 4 patients had conjunctival congestion as the initial symptom. The average duration of conjunctival congestion was 5.9 ± 4.5 days (mean [SD]). The other ocular symptoms, including increased conjunctival secretion, ocular pain, photophobia, dry eye and tearing, were also found in patients with conjunctival congestion. Notably, hand-eye contact was independently correlated with conjunctival congestion in COVID-19 patients. We also found that some COVID-19 patients had chronic eye diseases, including conjunctivitis (33, 6.2%), xerophthalmia (24, 4.5%) and keratitis (14, 2.6%). Similar to the published studies, the most common clinical symptoms were fever, cough and fatigue. A total of 343 patients (64.1%) had positive SARS-CoV-2 detection in nasopharyngeal swabs.

CONCLUSIONS

Conjunctival congestion is one of the COVID-19-related ocular symptoms, which could occur as the initial symptoms. Frequent hand-eye contact may be the risk factor for conjunctival congestion in COVID-19 patients. Screening of patients with conjunctival congestion by ophthalmologists is advocated during the outbreak of COVID-19. It is essential to provide eye-care equipment and strengthen education on eye protection.

COVID-19 Disease and Ophthalmology: An Update

The worldwide outbreak of the severe and acute respiratory coronavirus disease (COVID-19) caused by the coronavirus strain SARS-CoV-2 is currently the focal point of discussion due to the suffering this syndrome is causing to humanity. However, the ophthalmological implications of this syndrome has not yet been well described. Both eyes and tears as portals of entry and sources of contagion have been the subject of debate by many authors. The purpose of this review is to summarize the evidence currently available on COVID-19 and its ocular implications and manifestations, in both animals and humans, with the aim to facilitate prevention and educate the ophthalmological community on this subject. A review of the literature revealed that the results of some studies suggest that ocular symptoms commonly appear in patients with severe COVID-19 pneumonia and that it is possible to isolate the virus from the conjunctival sac of these patients. Conjunctivitis is not a common manifestation of the disease, but contact with infected eyes could be one route of transmission. Consequently, ophthalmologists need to have correct prevention strategies in place. Some guidelines regarding the prevention and management of ophthalmology clinics are reviewed. However, well-designed trials should be conducted to rule out other ocular manifestations that may result from COVID-19 infection and to understand the transmission of the virus through the eyes.

The evidence of SARS-CoV-2 infection on ocular surface

This is a cross-sectional study of patients who received a COVID-19 diagnosis between December 30, 2019 and February 7, 2020 at Tongji Hospital. A total of 102 patients (48 Male [47%] and 54 Female [53%]) with clinical symptoms, Rt, and chest Computed Tomography (CT) abnormalities were identified with a clinical diagnosis of COVID-19. Patients had a mean [SD] gestational age of 57.63 [14.90] years. Of a total of 102 patients identified, 72 patients (36 men [50%] and 36 women [50%]; mean [SD] age, 58.68 [14.81] years) were confirmed to have COVID-19 by laboratory diagnosis with a SARS-CoV-2 RT-PCR assay. Only two patients (2.78%) with conjunctivitis were identified from 72 patients with a laboratory confirmed COVID-19. Of those two patients, SARS-CoV-2 RNA fragments were found in ocular discharges by SARS-CoV-2 RT-PCR in only one patient. Our findings suspect the incidence of SARS-CoV-2 infection through the ocular surface is extremely low, while the nosocomial infection of SARS-CoV-2 through the eyes after occupational exposure is a potential route. To lower the SARS-CoV-2 nosocomial infection, all health care professionals should wear protective goggles. The inefficient diagnostic method and the sampling time lag may contribute to the lower positive rate of conjunctival swab samples of SARS-CoV-2.

Effects of orally administered raltegravir in cats with experimentally induced ocular and respiratory feline herpesvirus-1 infection

OBJECTIVE

To determine the effects of orally administered raltegravir in cats with experimentally induced ocular and respiratory feline herpesvirus-1 (FHV-1) infection.

ANIMALS

14 healthy 6-month-old unvaccinated specific pathogen-free cats.

PROCEDURES

On day 0, all cats were experimentally inoculated by topical application of 0.1 mL of a solution containing 10⁶ plaque-forming units of FHV-1 strain FH2CS to the inferior conjunctival fornix of each eye. Cats were randomly assigned to receive either raltegravir (80 mg; n = 7) or lactose (250 mg; vehicle; 7), PO, every 12 hours for 14 days beginning on day 1. Cats were assigned clinical ocular and respiratory disease scores every other day from days 0 to 30. Conjunctival swab specimens were collected for detection of FHV-1 by virus isolation and real-time PCR assay at 3-day intervals from days 0 to 30. Confocal microscopy was performed on days 0 and 10 to assess corneal epithelial leukocyte infiltration. The assessed variables and duration of FHV-1 shedding were compared between the 2 treatment groups.

RESULTS

Cats in both groups developed moderate to severe conjunctivitis and ulcerative keratitis characteristic of FHV-1 infection. Median duration of FHV-1 shedding was shorter and signs of ocular and respiratory disease were less severe for raltegravir-treated cats than for vehicle-treated cats. However, the mean conjunctival FHV-1 titer and corneal epithelial leukocyte count did not differ between the 2 groups.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested orally administered raltegravir might be effective for alleviation of ocular and respiratory signs of FHV-1 infection in cats. (Am J Vet Res 2019;80:490-497).

Mapping the entire nerve architecture of the cat cornea

OBJECTIVE

To provide a complete nerve architecture and neuropeptide distribution in the cat cornea.

ANIMALS STUDIED

Two adult domestic cats.

PROCEDURE

The cat corneas were stained with protein gene product (PGP) 9.5 antibody-a pan marker for nerve fibers-and then divided into four quarters and double labeled with calcitonin gene-related peptide (CGRP) or substance P (SP) antibodies. Relative corneal nerve fiber densities and nerve terminals were evaluated in whole mount images by computer-assisted analysis.

RESULTS

An average of 21.5 ± 2.1 thick stromal nerves enters the cornea around the limbus where they split into many branches going up to the anterior stroma. Some branches link to each other, but most of them penetrate the basement membrane in the periphery to give origin to subbasal bundles, which run centripetally and merge to form a whirl-like structure (vortex) at the center. These nerve bundles send out many fine terminals that innervate the epithelial cells. Subbasal nerve density and nerve terminals were greater in the center than in the periphery of the cornea. Additionally, CGRP-positive central epithelial nerve fibers and terminals were more abundant than SP-positive nerves and terminals.

CONCLUSION

The architecture of cat corneal nerves shows similarities to human and mouse cornea innervation. This study provides useful data for researchers who use the cat model to assess corneal nerve pathological alterations, as well as in the veterinary field where corneal opacities, ulcerations, and infections damage the nerves and decrease sensitivity.

In vitro efficacy of povidone iodine and hydroxyethyl cellulose, alone and in combination, against common feline ocular pathogens

Infectious ocular disease, such as conjunctivitis, is common in cats and can be caused by several viruses and bacteria, either as a single infection or as co-infections. In this study, povidone-iodine (PVP-I), alone or compounded with hydroxyethyl cellulose (HEC), was investigated for its efficacy against these pathogens in vitro. Whilst PVP-I alone was effective at inhibiting feline herpesvirus type 1 (FHV-1), Chlamydia felis, and Mycoplasma felis, PVP-I with HEC exerted a synergistic inhibitory effect against FHV-1 and C. felis. In contrast, only minimal inhibition of feline calicivirus was observed. These results demonstrate that PVP-I, alone and in combination with HEC, is effective against some feline ocular pathogens when tested in cell lines in vitro. In vivo studies investigating the systemic safety, ocular tolerance, and clinical efficacy of this combination in cats would be necessary before it could be recommended as a therapy in affected cats.

Variation in the Reported Management of Canine Prolapsed Nictitans Gland and Feline Herpetic Keratitis

Treatment variation in medicine may be driven by evidence gaps, clinician factors, and patient preferences. Although well-documented in human medicine, variation in clinical management is relatively unexplored in veterinary practice. Clinical vignette questionnaires were administered to a cross section of general practitioners (GPs) and veterinarians with postgraduate training in ophthalmology (PGs) to survey recommended management of canine prolapsed nictitans gland (“cherry eye”, PNG) and feline herpesvirus (FHV-1) keratitis. The majority of veterinarians (96.2%) suggested surgical replacement of cherry eye, with a pocketing technique being the most frequently nominated procedure. GPs were more likely to suggest gland excision in the event of surgical failure, while PGs more frequently nominated techniques incorporating a periosteal anchor for salvage repair. Most respondents managed FHV-1 keratitis with topical antibiotics (76.4%), with a minority suggesting topical antivirals (32.2%). GPs favoured topical acyclovir whilst PGs more frequently recommended topical trifluorothymidine. A significantly larger proportion of PGs nominated systemic famciclovir and lysine supplement for FHV-1 keratitis. This survey revealed moderate treatment variation for these conditions, both between and within practitioner groups. Additional research is needed to assess the reasons for this variation, particularly for conditions in which high quality evidence is scant.

Isolation and phylogenetic analysis of three feline calicivirus strains from domestic cats in Jilin Province, China

Feline calicivirus (FCV) is a highly prevalent pathogen that can cause infectious felid upper respiratory tract disease. The majority of complete genome sequences of FCV strains reported to date are from the USA. In this study, three FCV strains, CH-JL1, CH-JL2 and CH-JL3, were isolated from domestic cats in Jilin Province, China. Sequence analysis revealed that except for strains HRB-SS, WZ-1, XH, 12Q087-1 and 12Q087-5, the 3' untranslated regions (UTRs) of CH-JL2 and CH-JL3 are more than 20 nucleotides longer than those of all other reference isolates. The complete sequences of the three CH-JLs were compared with other reference strains, with nucleotide sequence identity values in the range of 76.2%-82.2%, 76.8%-96.4 and 76.8%-96.4%. Phylogenetic analysis showed that CH-JL1 forms a branch with FB-NJ-13, GD, 12Q087-1 and 12Q087-5. CH-JL2 was found to be most closely related to CH-JL3, forming another branch together with the other isolates. CH-JL1 shares a long nucleotide span with CH-JL2 and CH-JL3. It can be inferred that many FCV strains are co-circulating in Jilin Province. The availability of complete genome sequences will serve as a reference for future epidemiological studies of FCV.

Electric Cell-Substrate Impedance Sensing To Monitor Viral Growth and Study Cellular Responses to Infection with Alphaherpesviruses in Real Time

Alphaherpesviruses, including those that commonly infect humans, such as HSV-1 and HSV-2, typically infect and cause cellular damage to epithelial cells at mucosal surfaces, leading to disease. The development of novel technologies to study the cellular responses to infection may allow a more complete understanding of virus replication and the creation of novel antiviral therapies. This study demonstrates the use of ECIS to study various aspects of herpesvirus biology, with a specific focus on changes in cellular morphology as a result of infection. We conclude that ECIS represents a valuable new tool with which to study alphaherpesvirus infections in real time and in an objective and reproducible manner.

Electric cell-substrate impedance sensing (ECIS) measures changes in an electrical circuit formed in a culture dish. As cells grow over a gold electrode, they block the flow of electricity and this is read as an increase in electrical impedance in the circuit. ECIS has previously been used in a variety of applications to study cell growth, migration, and behavior in response to stimuli in real time and without the need for cellular labels. Here, we demonstrate that ECIS is also a valuable tool with which to study infection by alphaherpesviruses. To this end, we used ECIS to study the kinetics of cells infected with felid herpesvirus type 1 (FHV-1), a close relative of the human alphaherpesviruses herpes simplex virus 1 (HSV-1) and HSV-2, and compared the results to those obtained with conventional infectivity assays. First, we demonstrated that ECIS can easily distinguish between wells of cells infected with different amounts of FHV-1 and provides information about the cellular response to infection. Second, we found ECIS useful in identifying differences between the replication kinetics of recombinant DsRed Express2-labeled FHV-1, created via CRISPR/Cas9 genome engineering, and wild-type FHV-1. Finally, we demonstrated that ECIS can accurately determine the half-maximal effective concentration of antivirals. Collectively, our data show that ECIS, in conjunction with current methodologies, is a powerful tool that can be used to monitor viral growth and study the cellular response to alphaherpesvirus infection.

IMPORTANCE Alphaherpesviruses, including those that commonly infect humans, such as HSV-1 and HSV-2, typically infect and cause cellular damage to epithelial cells at mucosal surfaces, leading to disease. The development of novel technologies to study the cellular responses to infection may allow a more complete understanding of virus replication and the creation of novel antiviral therapies. This study demonstrates the use of ECIS to study various aspects of herpesvirus biology, with a specific focus on changes in cellular morphology as a result of infection. We conclude that ECIS represents a valuable new tool with which to study alphaherpesvirus infections in real time and in an objective and reproducible manner.

A novel corneal explant model system to evaluate antiviral drugs against feline herpesvirus type 1 (FHV-1)

Feline herpesvirus type-1 (FHV-1) is the most common viral cause of ocular surface disease in cats. Many antiviral drugs are used to treat FHV-1, but require frequent topical application and most lack well-controlled in vivo studies to justify their clinical use. Therefore, better validation of current and novel treatment options are urgently needed. Here, we report on the development of a feline whole corneal explant model that supports FHV-1 replication and thus can be used as a novel model system to evaluate the efficacy of antiviral drugs. The anti-herpes nucleoside analogues cidofovir and acyclovir, which are used clinically to treat ocular herpesvirus infection in cats and have previously been evaluated in traditional two-dimensional feline cell cultures in vitro, were evaluated in this explant model. Both drugs suppressed FHV-1 replication when given every 12 h, with cidofovir showing greater efficacy. In addition, the potential efficacy of the retroviral integrase inhibitor raltegravir against FHV-1 was evaluated in cell culture as well as in the explant model. Raltegravir was not toxic to feline cells or corneas, and most significantly, inhibited FHV-1 replication at 500 µM in both systems. Importantly, this drug was effective when given only once every 24 h. Taken together, our data indicate that the feline whole corneal explant model is a useful tool for the evaluation of antiviral drugs and, furthermore, that raltegravir appears a promising novel antiviral drug to treat ocular herpesvirus infection in cats.

Causes of endogenous uveitis in cats presented to referral clinics in North Carolina

OBJECTIVE

To investigate the causes of endogenous uveitis in cats presenting to referral ophthalmology clinics in North Carolina.

PROCEDURE

Medical records of cats diagnosed with endogenous uveitis at North Carolina State University's College of Veterinary Medicine (NCSU-CVM) or Animal Eye Care Associates of Cary, NC between 2003 and 2015 were reviewed. Inclusion criteria were cats that had complete diagnostic workups, including clinical, clinicopathological, serological, and histopathological data, as well as imaging modalities. Serology was consistently completed for feline leukemia virus (FeLV), feline immunodeficiency virus (FIV), feline coronavirus (FCoV), Toxoplasma gondii, and Bartonella spp.

RESULTS

One hundred and twenty cats met the inclusion criteria. Seroprevalence of FeLV (2.7%), FIV (7.3%), FCoV (34.7%), T. gondii (23.7%), and Bartonella spp. (43.2%) was observed, with a combined seroprevalence of 59.2%. Nineteen cats (15.8%) were diagnosed with feline infectious peritonitis (FIP) based on clinical, hematological, serological, histopathological, and necropsy findings. The average age of all cases was 7.62 years, while the average age of cats diagnosed with FIP was 1.82 years. Neoplasia was diagnosed in six cats (5.0%). No underlying etiology was found in 49 cats (40.8%).

CONCLUSIONS

Both idiopathic and neoplastic causes of uveitis were less prevalent than previously reported in studies, while seropositivity was higher than previously reported for the study area. This may be due to improved diagnostic capabilities or that cats with infectious disease were more likely to be referred. Because of the high prevalence of FIP, young cats with uveitis should be evaluated for hyperglobulinemia and FCoV serology should be performed as minimal diagnostics.

In Vitro and In Vivo Evaluation of Cidofovir as a Topical Ophthalmic Antiviral for Ocular Canine Herpesvirus-1 Infections in Dogs

PURPOSE

The effects of cidofovir were investigated against canine herpesvirus-1 (CHV-1) in vitro and in dogs with experimentally induced recurrent ocular CHV-1 infection, a host-adapted pathogen animal model of ocular herpes simplex virus-1 (HSV-1) infection.

METHODS

The cidofovir EC50 was determined for CHV-1 and HSV-1. A randomized, masked vehicle-controlled trial was performed using beagles with experimentally induced recurrent ocular CHV-1 infection. Dogs received 1 drop of 0.5% cidofovir solution or 0.9% sodium chloride solution (vehicle) in both eyes 2 times daily for 14 days. Dogs were monitored at intervals for 30 days by a clinical ophthalmic examination, in vivo confocal microscopy of the cornea and conjunctiva, ocular sample CHV-1 polymerase chain reaction assay, hemogram, and serum biochemistry panel. Clinical ocular disease scores were calculated and infiltrating leukocytes detected by in vivo confocal microscopy quantified.

RESULTS

Cidofovir displayed similar in vitro antiviral activity against CHV-1 and HSV-1. Clinical ocular disease scores were significantly higher in the cidofovir group compared to the vehicle group. Marked conjunctival pigmentation and blepharitis were also detected in the cidofovir group, but not the vehicle group. Conjunctival and corneal leukocyte infiltration scores determined by in vivo confocal microscopy were significantly higher in the cidofovir group. Dogs administered cidofovir had significantly reduced durations of ocular viral shedding compared to the vehicle group. Hemogram and serum biochemistry panel values were unremarkable.

CONCLUSIONS

Twice-daily application of topical 0.5% cidofovir ophthalmic solution reduced the duration of ocular viral shedding in dogs with experimentally induced recurrent ocular CHV-1 infection, but was associated with local ocular toxicity.

Ex vivo modeling of feline herpesvirus replication in ocular and respiratory mucosae, the primary targets of infection

Feline herpesvirus 1 (FeHV-1) is a major cause of rhinotracheitis and ocular diseases in cats. In the present study, the viral replication at the primary infection sites was studied using feline respiratory and ocular mucosa explants. The explants of three cats were maintained in an air-liquid culture up to 96 hours without loss of viability. After inoculation with FeHV-1 (C27), no evidence of infection was noted in corneal epithelium, while plaque-wise replication was observed in conjunctival and tracheal mucosae beginning from 24 h post inoculation (hpi). The viral plaque diameters increased over time in trachea and conjunctiva and were larger in tracheal explants than in conjunctival explants at 48 hpi. FeHV-1 penetrated the basement membrane in conjunctival and tracheal explants between 24 and 48 hpi. At 48 and 72 hpi, viral invasion was going deeper in tracheal explants than in conjunctival explants. Our study indicates that FeHV-1 has a better capacity to invade the respiratory mucosa than the conjunctival mucosa, and prefers the conjunctiva, but not the cornea as a portal of entry during ocular infection.

Faecal virome of cats in an animal shelter

We describe the metagenomics-derived feline enteric virome in the faeces of 25 cats from a single shelter in California. More than 90 % of the recognizable viral reads were related to mammalian viruses and the rest to bacterial viruses. Eight viral families were detected: Astroviridae, Coronaviridae, Parvoviridae, Circoviridae, Herpesviridae, Anelloviridae, Caliciviridae and Picobirnaviridae. Six previously known viruses were also identified: feline coronavirus type 1, felid herpes 1, feline calicivirus, feline norovirus, feline panleukopenia virus and picobirnavirus. Novel species of astroviruses and bocaviruses, and the first genome of a cyclovirus in a feline were characterized. The RNA-dependent RNA polymerase region from four highly divergent partial viral genomes in the order Picornavirales were sequenced. The detection of such a diverse collection of viruses shed within a single shelter suggested that such animals experience robust viral exposures. This study increases our understanding of the viral diversity in cats, facilitating future evaluation of their pathogenic and zoonotic potentials.