Barbara Nell

Clinical symptoms and diagnosis of encephalitozoonosis in pet rabbits.

Infections with Encephalitozoon cuniculi in rabbits are observed at increasing frequency and are known as opportunistic infections in immunocompromised humans. 191 pet rabbits with suspected encephalitozoonosis, presented at the Animal Hospital of the Veterinary University of Vienna (Austria), were included in this study. Rabbits were serologically examined for antibodies against E. cuniculi (144 positive out of 184 rabbits with suspected encephalitozoonosis compared to 14 positive out of 40 clinically healthy rabbits tested as part of a standard health check) and Toxoplasma gondii (8 positive out of 157). Of the 144 seropositive rabbits with clinical signs, 75% showed neurological symptoms, 14.6% demonstrated phacoclastic uveitis and 3.5% suffered from renal failure. 6.9% of the animals had combined symptoms. Vestibular disease dominated within the rabbits that showed neurological symptoms. Polymerase chain reaction (PCR) could not detect parasite DNA in urine or cerebrospinal fluid (CSF), but did so in 4 out of 5 samples of liquefied lens material in cases with phacoclastic uveitis due to lens capsule rupture. Additionally further diagnostic procedures, such as inspection of the external ear canal (N=69), radiography of the tympanic bullae (N=65) were performed to rule out differential diagnosis. 54.2% of the patients exhibiting neurological symptoms recovered within a few days, while 87.5% of the rabbits suffering from renal failure died or had to be euthanized.

Correlation between corneal sensitivity and quantity of reflex tearing in cows, horses, goats, sheep, dogs, cats, rabbits, and guinea pigs.

OBJECTIVE Guinea pigs have a very low threshold of corneal sensitivity and at the same time nearly no reflex tearing compared to dogs, cats, and horses. The question arose whether there is a general correlation between corneal sensitivity and the quantity of reflex tearing. ANIMALS STUDIED Totally 160 animals of 8 different species (20 animals per species) were investigated. PROCEDURES The corneal touch threshold (CTT) was measured with a Cochet-Bonnet esthesiometer. The palpebral fissure length (PFL) was measured with a calliper ruler. The Schirmer tear test (STT) was modified by adapting the width of the STT strip to the PFL of every species. For the STT II, 0.4% oxybuprocaine was applied. RESULTS Corneal touch threshold: Cows (1.67 g/mm(2)), horses (1.23 g/mm(2)), sheep (1.13 g/mm(2)), goats (1.44 g/mm(2)), dogs (2.16 g/mm(2)), and cats (1.33 g/mm(2)) show similar CTT values. In contrast, rabbits (6.21 g/mm(2)) and guinea pigs (7.75 g/mm(2)) show a significantly lower CTT. Tear Production Difference STT I - STT II: Rabbits have the greatest decline in tear production with 38.4%, followed by sheep (33.3%), dogs (31.1%), cats (24.7%), cows (23.7%), horses (18.0%), and goats (14.0%). Guinea pigs have no decline, but a slight increase of -16.0%. Correlation CTT and STT II - STT I Difference: Pearsons correlation coefficient shows a small, but significant correlation. The coefficient of determination can only forecast a value with 7.1% certainty. CONCLUSIONS The high variance and low reproducibility of results suggest that the measuring devices are inappropriate to assess the evaluated parameters. Therefore, no assured correlation between the corneal sensitivity and the quantity of reflex tearing could be found.

Detection of Encephalitozoon cuniculi in the feline cataractous lens

PURPOSE Identification of Encephalitozoon cuniculi (E. cuniculi) as a possible causative agent for cataracts and uveitis in cats. METHODS Within a 12-month study period, cats that were presented with focal anterior cortical or mature cataract and secondary uveitis underwent a complete ophthalmic examination, complete blood count, serum biochemistry, serologic tests for E. cuniculi and tests for feline immunodeficiency virus (FIV), feline infectious peritonitis (FIP), feline leukemia virus (FeLV) and Toxoplasma gondii (T. gondii). PCR for DNA detection of E. cuniculi and T. gondii as well as cytologic examination of aqueous humor after paracentesis and phacoemulsified lens material were also performed. In addition histopathologic examination of the resected anterior lens capsule and attached lens epithelial cells was performed. Serologic testing for antibodies against E. cuniculi was also performed in 100 ophthalmologically healthy cats. RESULTS Eleven (19 eyes) European shorthair cats with a median age of 3.5 years were included. Nine of 11 cats had bilateral cataracts, with 12/19 eyes having focal anterior cortical cataracts and 7/19 eyes having mature cataracts. In 14/19 eyes anterior uveitis was present. All cats had a positive antibody titer (1:80-1:10,000) for E. cuniculi. Encephalitozoon cuniculi DNA was detected by PCR and sequencing in 18/19 lenses and in 10/19 aqueous samples. Five tentative positive results were detected by cytologic examination. Spores were detected in 15/19 samples of lens material with histopathologic staining. Only 2/100 ophthalmologically healthy cats showed a positive antibody titer for E. cuniculi. CONCLUSION Encephalitozoon cuniculi is a cause of focal anterior cortical cataract and anterior uveitis in cats.

Detection of equid herpesviruses 2 and 5 in a herd of 266 Lipizzaners in association with ocular findings.

A herd of Lipizzaners (n=266) in three locations [Federal stud Piber (Styria), Heldenberg (Lower Austria) and the Spanish Riding School Vienna (Vienna)] were examined for ocular diseases and tested for herpesviruses (HVs) in PBMCs, nasal- and conjunctival swabs. In 167 (62.8%) horses equid herpesvirus-2 (EHV-2) nucleic acid was identified in at least one of the investigated samples, and 136 (51.1%) horses were positive for equid herpesvirus-5 (EHV-5) nucleic acid in at least one of the samples. One hundred and five (39.5%) of the horses mentioned above were identified with EHV-2/EHV-5 double infections. The results were correlated with potential influence factors such as age, gender, location, and housing. Statistical analysis demonstrated a significantly higher percentage of horses diagnosed with HV infections stabled in one location (Piber); also, housing in free stalls was associated with a higher rate of HV infections. Horses carrying EHV-2 or EHV-5 nucleic acid were significantly younger than the negative group. Statistical analysis of PCR results and ophthalmic findings did not prove a significant association between any disease pattern and presence of the equid gammaherpesviruses EHV-2 and EHV-5. The results of this herd survey indicate that horses younger than eight years of age, housed in free stalls with high population densities have a significantly increased risk for infection with EHV-2 and EHV-5. However no prediction can be made whether this results in ophthalmic disease. This is the first ophthalmic-virologic survey of this magnitude in a single horse breed.

Investigations on the conjunctival goblet cells and on the characteristics of glands associated with the eye in the guinea pig.

OBJECTIVE To investigate the distribution and density of conjunctival goblet cells (GC) and to study the anatomy and microscopic characteristics of glands associated with the eye in the guinea pig. PROCEDURES Twenty-five guinea pigs were used. Meibomian gland openings were counted using biomicroscopy. Conjunctiva, eyelids and glands were embedded in glycol methacrylate and paraffin. Sections were stained with hematoxylin and eosin (H&E), periodic acid Schiffs reaction (PAS) and Alcian blue (AB). RESULTS Highest GC densities were found in the bulbar and palpebral region of the nasal conjunctiva (GC index: 13.7-16.4%). Lowest GC densities (GC index: 0.0-1.0%) were found in 3/4 limbal regions (nasal and temporal upper eyelid, temporal lower eyelid). Guinea pigs have 27.1±3.0 (mean±SD) meibomian gland openings in the upper lid and 25.7±2.3 in the lower lid. Difference between upper and lower lid was significant (P=0.037). Two subconjunctival sebaceous glands occur temporal to each eye. The Harderian gland is very large. In the lacrimal gland three different cell types were distinguished both according to the cell structure and histochemical staining. CONCLUSIONS Goblet cell densities are lower in guinea pigs than in dogs and horses. Positive staining with PAS and AB could be an indication that mucins are produced in the lacrimal gland. If so, they may contribute to the mucin layer of the tear film. Both the extraordinarily large Harderian gland and the subconjunctival sebaceous glands produce lipids and may contribute to the lipid layer of the tear film.

Impression cytology: a novel sampling technique for conjunctival cytology of the feline eye

OBJECTIVE Impression cytology is a noninvasive investigation of the ocular surface. It uses the adhesive features of different filter papers to collect a monolayer of epithelial cells from the cornea and/or conjunctiva. Samples obtained by impression cytology exhibit all characteristics of an ideal cytology specimen. The aim of this study was to test the feasibility of impression cytology and determine the most appropriate filter paper to achieve maximum diagnostic value of the feline eye. ANIMALS STUDIED Ten healthy cats. PROCEDURES The study was conducted in two phases. In the first phase, eight different filter papers (FPs) with various pore sizes were tested: 3.0-, 1.2-, 0.8-, 0.45-, 0.22-, 0.05- and 0.025-μm cellulose acetate papers and a 0.4-μm Biopore membrane (BM). Samples were obtained from the superior bulbar and from the inferior palpebral conjunctiva. In the second phase, three different sampling methods - with and without topical anesthesia, and with topical anesthesia and drying of the conjunctiva - were compared employing the BM encased in the intended BM device (BMD). Samples were evaluated for cellularity and quality of cells. RESULTS In the first phase, samples obtained from the superior bulbar conjunctiva with the BM had the most sufficient cellularity and quality. In the second phase, BMD with topical anesthesia and additional drying of the conjunctiva was the most ideal method. CONCLUSION The BMD may prove to be a suitable diagnostic tool for clinicians. Sampling is quick, processing is simple, and a large area of intact cells can be harvested.

Ophthalmological findings in a closed herd of Lipizzaners.

REASONS FOR PERFORMING THE STUDY There are no studies on the ophthalmic health status in the Lipizzaner breed. OBJECTIVE To perform an ophthalmological survey in a closed herd in 3 housing systems. MATERIALS All horses at the Federal Stud Piber, Heldenberg and the Spanish Riding School Vienna were subjected to ophthalmological examination. Findings were documented and correlated with factors such as age, gender, location and housing situation. The interrelation of abnormalities of different regions was determined by calculating accuracy. Pedigree analysis of horses affected by cataract was performed. RESULTS A total of 267 horses met the inclusion criteria of this study. Of these, 172 horses were stabled in Piber, 72 in Vienna and 23 in Heldenberg. Ophthalmological examination revealed 203 cases with ocular findings, predominantly involving the conjunctiva (44.6%), cornea (21.7%) and fundus (37.5%). In 24 (8.9%) horses a diagnosis of cataract was made. There was no interrelation between different eye diseases. Horses stabled at Piber were significantly more affected by conjunctival and fundic abnormalities. Fewer abnormalities were found in horses stabled in open boxes. Access to free stalls resulted in more cases of conjunctivitis. Pedigree analysis showed no evidence of inbreeding as a cause of cataract formation. CONCLUSION AND POTENTIAL RELEVANCE Acquired corneal abnormalities were over-represented in this study. This survey may serve as a basis for further research on the pathogenesis of ophthalmic diseases in Lipizzaners.

Investigations on the conjunctival goblet cells and the characteristics of the glands associated with the eye in chinchillas (Chinchilla Laniger)

OBJECTIVE To investigate the density and distribution of conjunctival goblet cells (GC) and study the anatomy and microscopic characteristics of glands associated with the eye in chinchillas (Chinchilla Laniger). PROCEDURE 12 chinchillas were included in the study. Conjunctiva (divided into four regions), eyelids, and glands were embedded in paraffin wax, sectioned, stained, and analyzed. RESULTS Highest GC densities were found in the palpebral region of the nasal and temporal conjunctiva of both eyelids (GC index: 25.1-18.2%), and lowest densities, in the bulbar and marginal region of the nasal and temporal conjunctiva of both eyelids (GC index: 1.5-0.0%). Meibomian glands extend along the entire length of both eyelids, and the whole glandular complex broadens toward the temporal canthus. This is macroscopically visible through the conjunctiva. The openings of the Meibomian glands are macroscopically not discernible. The light pink, smooth, and crescent-shaped lacrimal gland lies next to the aforementioned broadened part of the Meibomian glands in the temporal canthus. The whitish, 0.9-cm-long, smooth Harderian gland is firmly attached to the posterior part of the globe and extends nasally from the optic nerve to the equator. Furthermore, chinchillas possess two lacrimal puncta, situated on the inner conjunctival surface of both eyelids near the medial canthus. A pigmented lacrimal canaliculus originates from each punctum. The vestigial nictitating membrane is supported by a hyaline cartilage and is pigmented at its free margin. CONCLUSIONS Chinchillas possess a Harderian gland, a lacrimal gland, and Meibomian glands. The GC density in the nasal and temporal palpebral conjunctiva is higher than in guinea pigs.

Review of the measuring precision of the new Meibometer® MB550 through repeated measurements in dogs

OBJECTIVE A meibometer is a device to measure the delivery rate of lipids on the eyelid margin. The aim of this study is to determine the measuring precision of the new Meibometer MB550 (Courage-Khazaka electronic GmbH, 50829, Cologne, Germany), linked to a computer, by means of repeated measurements in dogs by different examiners. PROCEDURE Two investigators measured the lipid rate on the eyelid margin in 10 healthy dogs for 10 days. One examiner measured the right eye (OD) and the other measured the left eye (OS) for 5 days. After 5 days, the eyes to be measured were switched between the examiners. The new device was able to record all measurement values as charts and curves in comparison to the previous Meibometer, which displayed only one value. RESULTS Mean meibomium lipid level +/- SD in the OD and OS of 10 dogs in 10 days was 211 +/- 48 MU and 205 +/- 41 MU (meibometer units), respectively. There was no significant difference between OD and OS, but a broad distribution of the values could be found. Gender did not influence the measurements. A significant difference was determined between the measurements in the first 5 days to those in the following 5 days. There was, therefore, also a significant difference in the measurements of the 2 examiners. CONCLUSION Meibometry is a minimally invasive lipid measuring method on the eyelid margin. Repeated measurement results obtained by two examiners, with the new device Meibometer MB550 linked to a computer, showed a wide range of values. The measuring precision of the new Meibometer MB550 is therefore questionable.

Clinical course of ophthalmic findings and potential influence factors of herpesvirus infections: 18 month follow-up of a closed herd of lipizzaners

Background To date the influence of herpesviruses on the development of equine ocular diseases has not been clearly determined. Objective The purpose of this study was to illustrate the course of equine ocular findings over a period of 18 months at 6 month intervals, in correlation with the results of herpesvirus detection. Methods 266 Lipizzaners in 3 federal states of Austria underwent complete ophthalmologic examination 4 times. Blood samples, nasal- and conjunctival swabs were obtained at the same time and used for the detection of the equid gammaherpesviruses EHV-2 and EHV-5 using consensus herpesvirus PCR and type-specific qPCRs. Ophthalmic findings and results of herpesvirus PCRs were recorded and statistically analysed using one-way ANOVA, and multiple logistic regression analysis to determine the influence of herpesvirus infections and other contributing factors on the presence of ophthalmic findings. Results In the first, second, third and fourth examination period 266, 261, 249 and 230 horses were included, respectively. Ophthalmic findings consistent with herpesvirus infections included conjunctival- and corneal pathologies. Statistical analysis revealed that the probability of positive herpesvirus PCR results decreased with progressing age; however the presence of corneal findings increased over time. At the time of each examination 45.1%, 41.8%, 43.0%, and 57.0% of horses with conjunctival or corneal findings, respectively, were positive for EHV-2 and/or EHV-5. However, 31.6%, 17.6%, 20.1%, and 13.0% of clinically sound horses were positive for these herpesviruses at each examination period, too. Conclusion Based on the results of our study there is a significant influence of young age on EHV-2 and/or EHV-5 infection. Corneal pathologies increased over time and with progressing age. Whether the identified findings were caused by herpesviruses could not be unequivocally determined.