Histopathological changes in testicular lesions in cats.

OBJECTIVES: The aim of this retrospective study was to describe the neoplastic and non-neoplastic lesions seen on histopathological examination of cat testes in Hong Kong between 2018 and 2024. METHODS: A total of 26 single or dual testes samples were collected from 18 cats by veterinarians at 14 veterinary clinics and submitted for histopathological examination. Laboratory records, including signalment, lesion location, age, breed and histopathological findings, were reviewed for each cat. RESULTS: Neoplastic testicular lesions were seen in three older cats (median age 8.5 years; range 3-17) compared with 18 non-neoplastic lesions in 15 cats (median age 1 year; range 0.5-3). The most common non-neoplastic lesions included inflammation (in the testes, epididymis, tunics and ductus deferens), cryptorchidism, and one case each of polyorchidism and epididymal cyst formation. Two of the testes with inflammation were identified on immunohistochemical staining as feline coronavirus-infected and one pair of testes was associated with the presence of extracellular Gram-negative bacteria at the lesion site. Three different neoplastic lesions were identified, one each of Sertoli cell tumour, leiomyoma and fibrosarcoma. CONCLUSIONS AND RELEVANCE: Non-neoplastic testicular lesions were most common, including inflammation, cryptorchidism, polyorchidism and epididymal cysts. To our knowledge, leiomyoma and fibrosarcoma have not been reported in cat testes before and represent important differential diagnoses for testicular lesions.

Most of the testicles examined from castrated cats because of disease noted by the owner had evidence of inflammation. Others were poorly developed because they had not descended correctly into the scrotum. Three cases of testicular cancer were noted and two of the types of cancer had not been reported in cats before but have been seen in humans.

Microsporum canis Causes Cutaneous and Extracutaneous Feline Dermatophytic Pseudomycetomas: Molecular Identification and Clinicopathological Characteristics.

Dermatophytic pseudomycetoma (DPM) is a rarely reported invasive fungal infection of humans and animals, especially cats. This study aimed to identify dermatophytes, breed associations, and the frequency of extracutaneous (EC) involvement in feline DPM. Electronic records and formalin-fixed paraffin-embedded tissue (FFPET) from 32 suspected DPM cases in 30 cats were retrieved from a diagnostic laboratory between 2018 and 2024. To confirm DPM and molecular identity, DNA was extracted from FFPET for ITS2 sequencing, and immunohistochemistry was performed on PCR-negative cases. All cases were confirmed as DPM. Microsporum canis was the only dermatophyte identified. The sensitivity and specificity of ITS2 sequencing for M. canis identification in FFPET were 22/32 (68.8%) and 21/22 (95.5%), respectively. Exotic (36.7%) and Persian (23.3%) but not British breeds (26.3%) were over-represented compared to feline admissions at an affiliated veterinary hospital (8.5%, p < 0.001; 3%, p < 0.001; 21.6%, p = 0.817, respectively). Five cases (16.7%) had EC lesions; two had intra-abdominal masses; two had oral cavity masses, including one which extended into the cranial vault; and one had superficial cervical lymph node invasion. Exotic and Persian breeds are over-represented for DPM and M. canis is the primary cause. EC lesions of DPM may occur more commonly than previously thought.

Neoplastic and non-neoplastic lesions in biopsy samples from pet rabbits in Hong Kong: a retrospective analysis, 2019-2022.

Rabbits are popular pets in the urban environment of Hong Kong, ranking third behind cats and dogs. Here we describe the frequency of neoplastic and non-neoplastic lesions in biopsies from pet rabbits submitted to the CityU Veterinary Diagnostic Laboratory between 2019 and 2022, comprising 247 tissue samples from 243 rabbits collected by veterinarians in 19 veterinary clinics. Among the 243 rabbits, there were 128 females (65 spayed), 114 males (54 castrated); sex information was not provided for 1 rabbit. The rabbit breeds included 45 Lionhead, 35 Dwarf, 14 Lop, 11 Dwarf Lop, 5 French Lop, 3 Angora, 2 Dutch, 2 Holland Lop, and 1 each of Netherland Dwarf, Velveteen, Mini Lop, and New Zealand White. The mean ages of rabbits with neoplastic and non-neoplastic lesions were 7.1 and 5.7 y, respectively. The most common neoplastic lesions were adenocarcinoma (26.4%), trichoblastoma (21.4%), sarcoma (9.4%), and thymoma (8.2%). The most common non-neoplastic lesion was uterine cystic endometrial hyperplasia (14.8%), followed by dermal abscess formation in the ventral abdomen or skin of the head (12.5%). Although a broad spectrum of other lesions was described, our findings in biopsies from pet rabbits in Hong Kong are consistent with those in other jurisdictions.

A Review: Haemonchus contortus Infection in Pasture-Based Sheep Production Systems, with a Focus on the Pathogenesis of Anaemia and Changes in Haematological Parameters.

Haemonchosis is an important cause of anaemia in sheep worldwide, particularly those that are kept in pasture-based systems in warm, high rainfall environments. Potential outcomes vary based on the severity of infection and the sheep's immune response, however, in some sheep infection can lead to death. The consequences of Haemonchus contortus infection mean that it has been well-studied in a range of different farming systems. However, to our knowledge, there has not been a recent review focused on the pathophysiology of anaemia caused by haemonchosis. Thus, this review provides an in-depth discussion of the literature related to the pathophysiology of haemonchosis and associated clinical signs for hyperacute, acute, and chronic haemonchosis. Additionally, haematological and biochemical findings are presented, and various diagnostic methods are assessed.

Absence of serological or molecular evidence of Leptospira infection in farmed swine in the Hong Kong Special Administrative Region.

Leptospirosis is an important zoonotic disease with several maintenance host species including swine. A cross sectional survey was undertaken between January to October 2020 to investigate the prevalence of leptospirosis in farmed swine in the Hong Kong Special Administrative Region (HKSAR) of China. Serum samples were collected from swine on seven farms (15 swine per farm; ten multiparous sows and five twelve-week-old weaners), while kidney samples were collected from 64 swine submitted for routine post-mortem (26 farms; average 2.4 swine per farm, range 1-6). Microscopic agglutination tests (MAT) to a panel of 24 Leptospira antigens did not reveal any evidence of seroconversion at a titre of 1:100. Polymerase chain reaction (PCR) testing of the kidney samples for Leptospira DNA did not detect any evidence of infection. Bayesian methods were used to compute the probability that the leptospirosis prevalence in farmed swine in the HKSAR was <3%, given none of the 105 swine sampled were positive on the MAT. The results of this study demonstrate no serological or molecular evidence of leptospirosis in farmed swine in the HKSAR. Subsequent statistical analysis supports the conclusion that the prevalence of leptospirosis in farmed swine in the HKSAR is negligible at present.

First case of feline cryptococcosis in Hong Kong, caused by Cryptococcus neoformans.

A nine-year-old domestic short hair cat was presented for a nasal planum mass, nasal discharge, hyporexia and weight loss. On physical examination nasal proliferative and ulcerative lesions and submandibular lymphadenopathy were identified. Cytology, histopathology, fungal culture, antigen serology and MALDI-TOF confirmed cryptococcal rhinitis with regional mandibular lymph node involvement due to Cryptococcus neoformans infection. This is the first reported case of cryptococcosis in a feline patient in Hong Kong.

Review of Diagnostic Procedures and Approaches to Infectious Causes of Reproductive Failures of Cattle in Australia and New Zealand.

Infectious causes of reproductive failure in cattle are important in Australia and New Zealand, where strict biosecurity protocols are in place to prevent the introduction and spread of new diseases. Neospora caninum ranks highly as an important cause of reproductive wastage along with fungal and bacterial infections. Brucella, a leading cause of abortion elsewhere in the world, is foreign, following successful programs to control and eradicate the disease. Leptospirosis in cattle is largely controlled by vaccination, while Campylobacter and Tritrichomonas infections occur at low rates. In both countries, Bovine Viral Diarrhea virus (BVDV) infection rates as the second most economically important disease of cattle and one that also has an effect on reproduction. Effective disease control strategies require rapid diagnoses at diagnostic laboratories. To facilitate this process, this review will discuss the infectious causes of reproductive losses present in both countries, their clinical presentation and an effective pathway to a diagnosis.

Perspectives on Current Challenges and Opportunities for Bovine Viral Diarrhoea Virus Eradication in Australia and New Zealand.

This review outlines the history of bovine viral diarrhoea virus (BVDV) and the current situation in Australia and New Zealand. BVDV has been reported as present in cattle from both countries for close to 60 years. It rates as the second most economically significant disease afflicting cattle, and is highly prevalent and spread throughout the beef and dairy industries. While other cattle diseases have been the subject of government control and eradication, infection with BVDV is presently not. Eradication has been undertaken in many other countries and been judged to be a good investment, resulting in positive economic returns. Presently, Australia and New Zealand have adopted a non-compulsory approach to control schemes, initiated and managed by farmers and veterinarians without the ultimate goal of eradication. Moving towards eradication is possible with the infrastructure both countries possess, but will require additional resources, coordination, and funding from stakeholders to move to full eradication.

Moving past serology: Diagnostic options without serum.

Detecting antibodies formed in serum in response to infection is the traditional function of serology. Diagnostic modalities have included complement fixation tests, agar gel immune-diffusion, radioimmunoassay, ELISA and immunofluorescence. More recent technology now allows for the direct detection of pathogens by PCR. This review details the options for diagnostic testing using specimen types other than serum, identifying the advantages and disadvantages of these options and providing evidence for more widespread use of these techniques and specimen types.

Interlaboratory and between-specimen comparisons of diagnostic tests for leptospirosis in sheep and cattle.

A study was performed to investigate interlaboratory test agreement between a research and a commercial veterinary diagnostic laboratory on blood and urine samples, and to investigate test agreement between blood, urine, and kidney samples (research laboratory) for leptospirosis diagnosis. Samples were sourced from 399 sheep and 146 beef cattle from a local abattoir. Interlaboratory agreement for real-time quantitative polymerase chain reaction (qPCR) results on urine samples was almost perfect (kappa = 0.90), despite the use of different amplification targets (DNA gyrase subunit B gene vs. 16s ribosomal RNA gene), chemistries (SYTO9 vs. TaqMan probe), and pre-PCR processing. Interlaboratory agreement for microscopic agglutination test (MAT) positivity was almost perfect (kappa = 0.93) for Leptospira borgpetersenii serovar Hardjo subtype Hardjobovis (Hardjobovis) but moderate (kappa = 0.53) for Leptospira interrogans serovar Pomona (Pomona). Among animals that had different titers recorded, higher Hardjobovis and lower Pomona titers were reported by the commercial laboratory than by the research laboratory (P < 0.005). These interlaboratory comparisons can assist researchers and diagnosticians in interpreting the sometimes discrepant test results. Within the research laboratory, the comparison of qPCR results on urine and kidney showed almost perfect agreement (kappa = 0.84), suggesting that the qPCR on these 2 specimens can be used interchangeably. The agreement between MAT positivity and urine and kidney qPCR results was fair (kappa = 0.32 and kappa = 0.33, respectively). However, the prevalence ratio of urine and kidney qPCR positivity in Hardjobovis-seropositive versus Hardjobovis-seronegative sheep indicated that Hardjobovis seropositivity found in sheep may be able to predict shedding or renal carriage.

Bovine viral diarrhoea: pathogenesis and diagnosis.

Bovine viral diarrhoea virus (BVDV) is the most prevalent infectious disease of cattle. It causes financial losses from a variety of clinical manifestations and is the subject of a number of mitigation and eradication schemes around the world. The pathogenesis of BVDV infection is complex, with infection pre- and post-gestation leading to different outcomes. Infection of the dam during gestation results in fetal infection, which may lead to embryonic death, teratogenic effects or the birth of persistently infected (PI) calves. PI animals shed BVDV in their excretions and secretions throughout life and are the primary route of transmission of the virus. These animals can usually be readily detected by virus or viral antigen detection assays (RT-PCR, ELISA), except in the immediate post-natal period where colostral antibodies may mask virus presence. PI calves in utero (the 'Trojan cow' scenario) currently defy detection with available diagnostic tests, although dams carrying PI calves have been shown to have higher antibody levels than seropositive cows carrying non-PI calves. Acute infection with BVDV results in transient viraemia prior to seroconversion and can lead to reproductive dysfunction and immunosuppression leading to an increased incidence of secondary disease. Antibody assays readily detect virus exposure at the individual level and can also be used in pooled samples (serum and milk) to determine herd exposure or immunity. Diagnostic tests can be used to diagnose clinical cases, establish disease prevalence in groups and detect apparently normal but persistently infected animals. This review outlines the pathogenesis and pathology of BVD viral infection and uses this knowledge to select the best diagnostic tests for clinical diagnosis, monitoring, control and eradication efforts. Test methods, types of samples and problems areas of BVDV diagnosis are discussed.

Osteogenic intraocular melanoma in an alpaca (Vicugna pacos).

A 10-year-old, female, pregnant alpaca (Vicugna pacos) presented with a discolored, swollen right eye. The eye did not respond to treatment and was enucleated. Sectioning of the fixed eye revealed an ocular mass replacing the aqueous and vitreous humors, with multiple regions of bone formation. Histopathological, immunohistochemical, and transmission electron microscopy confirmed the tumor was an intraocular melanoma with bone formation. Osteogenic melanoma is a rare variant of melanoma not reported in the eye before.

Amplification of three different papillomaviral DNA sequences from a cat with viral plaques.

A 3-year-old cat from New Zealand developed three small raised non-ulcerated plaques on the face. Serology detected antibodies against feline immunodeficiency virus (FIV). Histology of the plaque revealed epidermal hyperplasia with keratinocytes either distended with large blue-grey cytoplasmic bodies or with shrunken nuclei surrounded by a clear halo. Papillomavirus (PV) antigen was detected immunohistochemically and feline viral plaque was diagnosed. Swabs were taken of both lesional and non-lesional skin, and polymerase chain reactions were used to detect PV DNA. Three different PV DNA sequences were amplified, one from a Felis domesticus PV type 1 (FdPV-1) previously amplified from a feline viral plaque, a second (FdPV-JM) previously amplified from feline cutaneous squamous cell carcinomas, and a third FdPV-MY that was not reported previously. All three sequences were amplified from swabs of both lesional and non-lesional skin. These results extend the geographical range of FdPV-1 outside North America and also demonstrate the ability of FdPV-1 to asymptomatically infect feline skin. However, the detection of multiple PV sequences within both lesional and non-lesional samples makes it difficult to determine whether or not any of the PVs caused feline viral plaque development in this cat. This is the first time PV DNA has been detected in a feline skin swab sample. Additionally, it is the first report of multiple PVs being detected in a single sample from a cat. This may suggest that FIV infection predisposes cats to cutaneous PV infection.