Bartonella species, feline herpesvirus-1, and Toxoplasma gondii PCR assay results from blood and aqueous humor samples from 104 cats with naturally occurring endogenous uveitis

Use of selected samples to diagnose a tricky feline viral disease in a cat with uveitis and neurological signs

This case involved a 2-year-old neutered male domestic mixed-breed cat that was rescued from the street eight months earlier. The animal presented with weakness, hyporexia, progressive weight loss, fatigue, uveitis, pale mucous membranes, dehydration (7%), and pelvic limb paresis. Aqueous humor was collected for molecular analysis for the differential diagnosis of potential etiological agents [Feline coronavirus (FCoV), Feline leukemia virus (FeLV), Feline immunodeficiency virus (FIV), Toxoplasma gondii, Cryptococcus spp., Felid herpesvirus-1 (FHV-1) and Bartonella spp.] of feline uveitis. The sample was positive by real-time reverse transcription-polymerase chain reaction (RT-qPCR) for FCoV and RT-qPCR and real-time polymerase chain reaction (qPCR) for FeLV and qPCR FIV. The cat was euthanized due to poor clinical outcomes and prognosis. A cerebrospinal fluid (CSF) sample was collected and tested, and the same pathogens were found in the aqueous humor. Small-cell follicular multicenter lymphoma and multifocal pyogranulomatous meningoencephalitis were observed upon histopathological analysis. In this study, aqueous humor and cerebrospinal fluid samples were efficient for the detection of coinfection with FIV, FeLV, and FCoV.

Histoplasma capsulatum, Toxoplasma gondii, Bartonella henselae and Bartonella clarridgeiae coinfections in an indoor-only Siamese cat

Case summary

A 6-year-old male castrated Siamese cat was referred for acute-onset blindness and mydriasis. Physical examination revealed serous retinal detachment with panuveitis and systemic hypertension. Abdominal ultrasound showed suspected dilation of the cisterna chyli and abdominal lymphadenopathy. Aspirates of mesenteric lymph nodes revealed intrahistiocytic yeast organisms with mild-to-moderate pyogranulomatous inflammation. Fungal culture and ITS1 sequencing of the lymph node aspirates confirmed infection with Histoplasma capsulatum. PCR performed on whole blood was positive for Bartonella henselae and Bartonella clarridgeiae, and Toxoplasma gondii IgG and IgM antibodies were detected in serum. The cat was prescribed prednisolone (0.5 mg/kg PO q24h), itraconazole (10 mg/kg PO q24h), clindamycin (13 mg/kg PO q12h), amlodipine (0.625 mg PO q24h), prednisolone acetate 1% drops (q6h) and ophthalmic lubricant for both eyes (q6h). The cat was doing well at home after 2 weeks of prednisolone, itraconazole and clindamycin administration, and no abnormalities were detected on repeat abdominal ultrasound 3 months later. The retinal detachment showed mild-to-moderate improvement at that time, but vision was not regained.

Relevance and novel information

This is the first report of coinfection of H capsulatum, T gondii, B henselae and B clarridgeiae in an indoor-only cat living in a H capsulatum non-enzootic area with no known travel history.

Wild Rabbit Exposure to Leishmania infantum, Toxoplasma gondii, Anaplasma phagocytophilum and Babesia caballi Evidenced by Serum and Aqueous Humor Antibody Detection

Wild rabbits (Oryctolagus cuniculus) can be important sentinel species for the presence of zoonotic pathogens. Therefore, we collected blood samples from wild rabbits harvested by hunters during the hunting season 2019–2020 on the island of Lemnos, to determine exposure of wild rabbits to the zoonotic pathogens Leishmania infantum, Toxoplasma gondii, Anaplasma phagocytophilum and Babesia caballi, as well as aqueous humor to assess its diagnostic performance in terms of sensitivity, specificity, positive and negative likelihood ratios. Antibodies against these pathogens were detected by Indirect Immunofluorescence Antibody (IFA) assay. Out of the 72 wild rabbits included in the study, 4.2%, 5.5%, 18% and 9.7% were seropositive to L. infantum, T. gondii, A. phagocytophilum and B. caballi, respectively. Although less frequently, antibodies were also detected in aqueous humor of wild rabbits. The antibody detection in aqueous humor presented 100% specificity but decreased sensitivity compared to serum suggesting that aqueous humor could be successfully used in epidemiological studies to confirm exposure at the population level but has little diagnostic value at the individual level. This is the first report on the seropositivity of wild rabbits to A. phagocytophilum and B. caballi and the detection of antibodies against A. phagocytopylum, L. infantum, T. gondii and B. caballi in the aqueous humor.

An unusual case of eosinophilic uveitis in a cat

An 8-year-old female spayed domestic short-haired cat was examined for recurrent unilateral anterior uveitis of 5 month's duration. No underlying cause was found on infectious disease screening. The cat also had a 4-year history of allergic or immune-mediated skin disease that was controlled with corticosteroid injections followed by long-term oral cyclosporine therapy. Medical management with frequent topical anti-inflammatory drugs (prednisolone acetate 1% suspension, diclofenac 0.1% solution) controlled the intraocular inflammation; however, the uveitis would relapse when therapy was discontinued. Eventually, secondary glaucoma developed OD and the eye was enucleated. At the time of surgery, a complete blood count showed a mild eosinophilia. Histopathology revealed a marked panuveitis characterized by an abundant accumulation of mixed inflammatory cells, with a predominantly eosinophilic infiltrate in the anterior chamber, iris, ciliary body, and choroid. No etiologic agents were found on serial sections, and there were no cellular criteria for malignancy noted. Nine months after enucleation, the chronic dermatitis appeared to be in remission despite no further medical management. This is the first known report of a primarily eosinophilic uveitis in a cat with chronic allergic skin disease and may be considered an ocular variant of feline eosinophilic granuloma complex.

A multicenter retrospective study into endogenous causes of uveitis in cats in the United Kingdom: Ninety two cases

PURPOSE

The purpose of this study was to investigate the most common causes of endogenous feline uveitis in a UK referral population and to investigate associations based on signalment.

METHODS

Retrospective multicenter cross-sectional study from 2010 to 2019 including cats presented to the Animal Health Trust and the Royal Veterinary College with clinical signs consistent with uveitis. Cats were included in analyzes if they had a full physical examination including an ophthalmic examination, complete blood count, serum biochemistry, and infectious disease testing for at least two diseases unless the diagnosis was found on clinical examination (eg, neoplasia).

RESULTS

A total of 92 cats were included in the study. The majority of cats presenting with uveitis were male (66.3%). The most common causes of endogenous uveitis were idiopathic uveitis (42/92 45.7%), feline infectious peritonitis (FIP) 15/92 16.3%), and lymphoma (10/92 10.9%). Fisher's exact test showed differences in breed across diagnosis groups (p = .002) with purebred cats being overrepresented in the lymphoma and FIP groups. Kruskal-Wallis test showed differences in median age across diagnosis groups (p < .001) with cats in the FIP group having the youngest age (median 1.4 years, interquartile range (IQR) 0.4-1.8 years) and cats in the neoplasia (primary or paraneoplastic) group having the oldest age (median 12.8 IQR 10.8-13.8). Idiopathic uveitis was unilateral in 56.1% of cases, and infectious causes were unilateral in 47.8% of cases.

CONCLUSIONS

The most common cause of endogenous uveitis in a population of cats in the UK was idiopathic uveitis, followed by FIP and lymphoma.

Molecular Detection of Bartonella spp. and Hematological Evaluation in Domestic Cats and Dogs from Bangkok, Thailand

(1) Background: Bartonella spp. are Gram-negative, facultative, intracellular bacteria transmitted by hematophagous insects. Several species cause zoonotic diseases such as cat-scratch disease. Bartonella henselae and Bartonella clarridgeiae are the main species found in Thailand, however, there have been few studies on Bartonella spp. In addition, the hematological evaluation of Bartonella-infected animals is limited in Thailand. The aims of this study were prevalence investigation and hematological evaluation of Bartonella-infected dogs and cats residing in Bangkok, Thailand. (2) Methods: In total, 295 dogs and 513 cats were molecularly evaluated to detect Bartonella spp. using PCR with primers targeting the partial gltA, rpoB, ftsZ, ribC, and groEL genes. In total, 651 domestic animals were evaluated for hematological parameters compared between Bartonella-positive and Bartonella-negative animals. (3) Results: Overall, the prevalence of Bartonella spp. was 1.61% which was found only in free-ranging cats (2.83%). Bartonella henselae and B. clarridgeiae were confirmed from a concatenated phylogenetic tree of partial gltA and ribC genes, with 100% bootstrapping replication. For other housekeeping gene sequences, mixed infection was expected from the amplicons of rpoB, ftsZ, and groEL. Importantly, the mean corpuscular volume (MCV) was significantly increased in Bartonella-positive cats. (4) Conclusions: We suggest that B. henselae and B. clarridgeiae are important species and are still circulating in domestic animals, especially cats. The evaluation of blood parameters, especially a raised MCV, should be of concern in Bartonella infection in asymptomatic cats. Additionally, the knowledge of how to prevent Bartonella-related diseases should be promoted with people in at-risk situations.

All about toxoplasmosis in cats: the last decade

Toxoplasma gondii infections are common in humans and animals worldwide. Toxoplasmosis continues to be of public health concern. Cats (domestic and wild felids) are the most important host in the epidemiology of toxoplasmosis because they are the only species that can excrete the environmentally resistant oocysts in feces. Cats can excrete millions of oocysts and a single cat can spread infection to many hosts. The present paper summarizes information on prevalence, persistence of infection, clinical signs, and diagnosis of T. gondii infections in domestic and wild cats for the past decade. Special emphasis is paid to genetic diversity of T. gondii isolates from cats. Review of literature indicates that a unique genotype (ToxoDB genotype #9 or Chinese 1) is widely prevalent in cats in China and it has been epidemiologically linked to outbreaks of clinical toxoplasmosis in pigs and deaths in humans in China; this genotype has rarely been detected in other countries. This review will be of interest to biologists, parasitologists, veterinarians, and public health workers.

Prevalence of antibody seroconversion to Toxoplasma gondii in uveitis and non-uveitis dogs

Objectives

To evaluate the prevalence of seroconversion to Toxoplasma gondii in dogs with uveitis and dogs without uveitis.

Methods

In total, 135 dogs were evaluated: 51 dogs were diagnosed with uveitis, and 84 dogs were without uveitis. Latex agglutination tests were performed on all sera, and the results were evaluated.

Results

Overall, 7.8 and 6.0 per cent of sera were positive for the presence of anti-T gondii antibodies (dilution ≥1:64) in the groups with uveitis and non-uveitis dogs, respectively. The frequency distribution of variables (positive and negative results in the uveitis and the non-uveitis group of dogs) was tested with Fisher’s exact test. There was no statistically significant difference between groups (P=0.73).

Clinical significance

These findings suggest that evidence of exposure to T gondii was not significantly different between uveitis and non-uveitis groups of dogs and that the possible association between exposure to T gondii and canine uveitis requires further investigation. This study is the first to report the seroprevalence of anti-T gondii antibodies in dogs in the UK population and the first to report the seroprevalence of anti-T gondii antibodies in dogs with uveitis.

Effect of a Pheromone on Stress-Associated Reactivation of Feline Herpesvirus-1 in Experimentally Inoculated Kittens

Background

Stress contributes to reactivation of feline herpesvirus‐1 (FHV‐1). The usage of pheromones to decrease stress in FHV‐1 experimentally inoculated kittens has not previously been investigated.

Hypothesis/Objectives

To determine whether a feline pheromone would lessen stress, resulting in decreased recurrence of FHV‐1‐associated illness in kittens.

Animals

Twelve 5‐month‐old, purpose‐bred kittens.

Methods

Randomized, double‐blind, placebo‐controlled clinical trial. Kittens previously infected with the same dose of FHV‐1 were randomized into 2 separate but identical group rooms. After a 2‐week equilibration period, a diffuser containing either the pheromone or placebo was placed in each of the rooms, and the kittens acclimated for an additional 2 weeks. Every 2 weeks thereafter, for the 8‐week study period, housing was alternated between kennel‐ and group housing. Blinded observers applied a standardized clinical and behavioral scoring rubric daily. After each 2‐week period, serum cortisol concentrations and quantitative PCR for FHV‐1 and glyceraldehyde 3‐phosphate dehydrogenase (GAPDH) ratios were evaluated. Clinical, behavioral, and laboratory test results were compared between groups within individual and combined study periods.

Results

Sneezing occurred more frequently in the placebo group during individual (P = 0.006) and combined study periods (P = 0.001). Sleep at the end of observation periods occurred more frequently in the pheromone group during individual (P = 0.006) and combined study periods (P < 0.001).

Conclusions and Clinical Importance

The findings suggest that the pheromone decreased stress, and the decrease in stress response may have resulted in decreased sneezing associated with FHV‐1.

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.

Bartonella henselae as a cause of acute-onset febrile illness in cats

Case series summary

At different time points spanning 6 months, three adopted feral flea-infested cats, residing in the household of a veterinary technician, became acutely anorexic, lethargic and febrile. Enrichment blood culture/PCR using Bartonella alpha Proteobacteria growth medium (BAPGM) confirmed initial infection with the same Bartonella henselae genotype in all three cases. With the exception of anemia and neutropenia, complete blood counts, serum biochemical profiles and urinalysis results were within reference intervals. Also, tests for feline leukemia virus, feline immunodeficiency virus, Toxoplasma gondii and feline coronavirus antibodies were negative. Serial daily temperature monitoring in one case confirmed a cyclic, relapsing febrile temperature pattern during 1 month, with resolution during and after treatment with azithromycin. Bartonella henselae Western immunoblot (WB) results did not consistently correlate with BAPGM enrichment blood culture/PCR results or B henselae indirect fluorescent antibody (IFA) titers, and WB titration results were not informative for establishing antibiotic treatment failure. During the respective follow-up periods, no illnesses or additional febrile episodes were reported, despite repeat documentation of B henselae bacteremia in two cats available for follow-up (one with the same genotype and the other with a different B henselae genotype); one cat was, unfortunately, killed by dogs before follow-up testing.

Relevance and novel information

We conclude that microbiological diagnosis and treatment of B henselae infection in cats can be challenging, that antibody titration results and resolution of clinical abnormalities may not correlate with a therapeutic cure, and that fever and potentially neutropenia should be differential diagnostic considerations for young cats with suspected bartonellosis.

Biomarkers for neural injury and infection in small animals

Cross-sectional imaging techniques have facilitated diagnosis of central nervous system (CNS) diseases. However, there is still frequently a lack of definition of the cause of neurologic lesions, because tissue sampling from the pathologic site is often difficult and there are few clinical diagnostic tools to assist diagnosis. Biomarkers can assist in understanding the cause, diagnosis, severity, and prognosis for neural injury. Integration of conventional testing and new diagnostic techniques will overcome shortcomings in understanding infectious diseases of the CNS. Diagnostic tests may be limited by poor positive and negative predictive values, which must be recognized when interpreting test results.

Concurrent administration of an intranasal vaccine containing feline herpesvirus-1 (FHV-1) with a parenteral vaccine containing FHV-1 is superior to parenteral vaccination alone in an acute FHV-1 challenge model

The administration of intranasal (IN) or subcutaneous (SC) vaccines containing modified live feline herpesvirus 1 (FHV-1) offers some level of protection against FHV-1 challenge, but relative efficacy is <100%. In this study, clinical signs and viral shedding in kittens were compared among three groups: (1) kittens vaccinated concurrently with IN and SC vaccines containing FHV-1 (Group 1, n = 8); (2) kittens vaccinated with a SC FHV-1 vaccine alone (Group 2, n = 8), and (3) unvaccinated control kittens (Group 3, n = 8). All kittens were FHV-1 naïve at enrolment, and challenge with a virulent strain of FHV-1 was performed 1 week after vaccination. Daily clinical signs and pharyngeal FHV-1 shedding were recorded over a 21-day infection period. Overall, kittens in Group 1 had significantly less severe clinical illness than those in Group 2 (P < 0.05). Additionally, significantly less FHV-1 DNA was detected on pharyngeal swabs from kittens in Group 1 compared to those in Group 2 (P < 0.001). Concomitant administration of IN and SC FHV-1 vaccines was superior to administration of the SC FHV-1 vaccine alone in this challenge model of FHV-1 naïve kittens.

Diagnostic utility of aqueocentesis and aqueous humor analysis in dogs and cats with anterior uveitis

Objective

To evaluate diagnostic utility of aqueous humor analysis in animals with anterior uveitis.

Animals

Client‐owned dogs (n = 12) and cats (n = 10).

Procedures

Examination findings and diagnostic test results including aqueous humor cytology were compared.

Results

Disease duration prior to aqueocentesis was not significantly different between dogs with idiopathic anterior uveitis and those with an etiologic diagnosis, but was shorter in cats with feline infectious peritonitis (FIP) than those with idiopathic uveitis. Microbial nucleic acids, antigens, or antibodies against them were seldom found in blood/serum; however, serum feline coronavirus titers ≥1:6400 were detected only in cats with FIP. Aqueous humor cytology was diagnostic in no cats and two dogs, both with neoplasia. Although aqueous humor contained predominantly neutrophils in cats with FIP and large reactive lymphocytes and plasma cells appeared more frequent in cats with idiopathic uveitis, neither clinical nor cytologic assessment of anterior chamber contents differed significantly between cats with idiopathic or FIP‐associated uveitis. Cytologically assessed plasma cell number was correlated with keratic precipitates and disease duration. Clinically detectable hyphema and cytologic erythrocyte number were correlated. However, cytologic cell grades and clinical grade of flare or cell numbers within the anterior chamber were not correlated.

Conclusions

Aqueous humor cytology permitted diagnosis of neoplasia in dogs with anterior uveitis but was generally not helpful in cats. Poor correlation between clinical and cytologic assessment of cell numbers and type within the anterior chamber dictates that clinical grading should not be the sole criterion for electing to perform aqueocentesis.