Description and Characterization of Different Types of Lymphoma in Cats in Hong Kong.

This study aimed to characterize and describe the different lymphoma types and anatomical forms in cats in Hong Kong. The clinical and histopathological data of cats diagnosed with lymphoma by cytology and/or histopathology were collected from a large diagnostic laboratory in Hong Kong. In total, 444 cats were diagnosed with lymphoma over four years (2019-2022). Like other countries where there is a low prevalence of FeLV infection, the predominant form of lymphoma was gastrointestinal (abdominal). Nasopharyngeal and peripheral nodal lymphoma were the second and third most common forms of lymphoma. The large cell/high-grade lymphoma type was much more common than the low-grade/small cell lymphoma in the study population. Domestic short hair was the most commonly affected breed in our study (n = 259/444). Among the cats with identified T/B-cell status, B-cell lymphoma (n = 61/81) prevailed as the most common phenotype. This study describes and characterizes the different types of feline lymphoma in cats in Hong Kong, adding valuable information to the body of knowledge.

Splenic Myelolipomas in the Domestic Cat-To Operate or Not to Operate?

Myelolipoma is a benign, typically inert neoplasm of uncertain aetiology that is rarely reported in cats. Although commonly asymptomatic, in some cases, myelolipomas can cause abdominal discomfort or present with rupture and haemorrhage. Here, we describe a rare case of a splenic myelolipoma in a Domestic Long Hair cat in which, after extensive diagnostic investigations, clinical signs of hyporexia and weight loss were attributable to the presence of an intra-abdominal mass. The patient was treated by splenectomy and unexpectedly died during the post-operative period. Although splenectomy appears to be a sensible intervention in symptomatic patients, the optimal management of splenic myelolipomas in cats remains unknown. The risk-benefit ratio of surgical management needs to be carefully considered, and therapeutic intervention should be tailored individually to each patient.

L-LOP/LOPP for the treatment of canine gastrointestinal/hepatosplenic lymphoma.

Canine gastrointestinal (GI) and hepatosplenic (HS) high-grade (large cell) lymphomas are uncommon forms of canine lymphomas, with a very poor response to chemotherapy and a very poor prognosis. Currently, there are no established effective chemotherapy protocols for canine GI/HS lymphomas. This case series aimed to retrospectively evaluate the efficacy of lomustine-based protocols L-LOP (L-asparaginase, lomustine, vincristine, and prednisolone) and L-LOPP (with the addition of procarbazine) for treatment of canine GI/HS lymphomas. Medical records of dogs with cytologically or histologically diagnosed lymphoma at CityU Veterinary Medical Centre from 2019 to 2022 were retrospectively reviewed. The L-LOP/LOPP treatment protocol was well tolerated with rare severe adverse events. Median progression-free survival for GI and HS lymphoma was 56 days (range, 10-274 days) and 57 days (range 8-135 days) respectively; while median survival time for GI and HS lymphoma was 93 days (range 10-325 days) and 210 days (range 8-240 days) respectively.

Babesia gibsoni Infection in a Cat with Immune-Mediated Haemolytic Anaemia and Thrombocytopenia.

Tick-borne haemoparasite Babesia gibsoni has been detected rarely in cats, in surveys of apparently healthy animals. In stored blood from a 6-year-old male-neutered domestic shorthair cat in Hong Kong, B. gibsoni DNA was detected retrospectively using PCR for Babesia spp. 18S rRNA and mitochondrial cytochrome B genes, followed by sequencing and basic local alignment search tool (BLAST) analysis. The cat presented with severe haemolytic anaemia and thrombocytopenia. The cat responded to supportive care and glucocorticoids and was clinically normal despite persistent subclinical thrombocytopenia until six months after presentation, when it succumbed to a fatal haemorrhagic episode. Necropsy revealed severe intestinal and pulmonary haemorrhage and hypocellular bone marrow with megakaryocytosis but no other causes of immune-mediated thrombocytopenia (IMTP) or immune-mediated haemolytic anaemia (IMHA). Blood stored on days 158 and 180 tested PCR negative for Babesia spp. This report demonstrates that geographic range of B. gibsoni detection in cats includes Hong Kong. The exclusion of other causes suggests that B. gibsoni might have potentially played a role in triggering immune-mediated disease in this case.

First molecular confirmation of multiple zoonotic vector-borne diseases in pet dogs and cats of Hong Kong SAR.

In recent years, the incidence of vector-borne diseases (VBDs) has increased throughout the globe. In particular, tick-borne diseases (e.g., caused by Ehrlichia canis, E. ewingii, Anaplasma phagocytophilum, A. platys, Borrelia burgdorferi sensu stricto (s.s.) and Babesia gibsoni) and mosquito-borne diseases (e.g., caused by Dirofilaria immitis) diseases pose a burden on animal health. Nevertheless, there have been no studies undertaken on the occurrence of VBDs in pet dogs and cats in Hong Kong SAR. This study fills this gap, and is the first to determine the seroprevalence of major VBDs, such as those caused by D. immitis, E. canis, E. ewingii, A. phagocytophilum, A. platys and B. burgdorferi s.s, in dogs and cats through commercially available SNAP 4Dx plus testing. Infection by all these pathogens and Babesia sp. was further assessed through PCR and DNA sequencing. A total of 224 blood samples were collected from domestic dogs (n = 159) and cats (n = 65) in Hong Kong SAR during summer 2022. Hematocrit and platelet counts were determined in each blood sample and other hematological parameters were assessed using an automatic hematology analyzer and vortex the specimen for one to two minutes at or near the highest setting to minimize the clumping. All cat sera samples were negative for tested pathogens, but antibodies against some of the pathogens were detected in dog sera samples. Here, the highest figures were recorded for seroprevalence of E. canis/E. ewingii (10.7%), followed by D. immitis (5.7%), and A. phagocytophilum/A. platys (2.5%). No B. burgdorferi s.s. antibodies were detected in any of the dogs tested. Through molecular diagnostics, we detected the presence of B. gibsoni (3.7%), E. canis (3.1%), D. immitis (5.7%), and A. phagocytophilum (1.3%). Neighbor-Joining phylogenetic trees for vector-borne pathogens (i.e., genus Anaplasma sp.) showed 100% clustering to Japan, the USA and Germany, whereas genus Ehrlichia sp. showed 100% clustering to China, Turkey, Cuba, and Greece. Similarly, genus Babesia sp. clustered 100% to India, Sri Lanka and Austria, while D. immitis clustered in Iraq, South Korea, Portugal, France, the USA and Italy. This study provides the first evidence on the occurrence of tick-borne pathogens in pet dogs in Hong Kong SAR. Based on these findings, it is recommended that appropriate screening should be undertaken in domestic dogs to evaluate the prevalence of these pathogens and promote the timely control of VBDs.

Retrospective Evaluation of a Combination of Carboplatin and Bleomycin for the Treatment of Canine Carcinomas.

Carboplatin is a chemotherapy agent widely used in veterinary oncology to treat various types of tumors including carcinomas. Carboplatin has previously been used in combination with 5-Fluoro uracil (5-FU) or gemcitabine for the treatment of various carcinomas. Bleomycin is a chemotherapy drug commonly used in humans, but its use has been uncommonly reported in dogs. The combination of carboplatin and bleomycin chemotherapy treatment has never been reported in dogs. Dogs diagnosed with carcinoma and treated with a combination of carboplatin and bleomycin, at a single veterinary referral center, were retrospectively evaluated. Thirty patients met the inclusion criteria. The dose of carboplatin ranged from 200-250 mg/m2 (median 240 mg/m2) and the dose of bleomycin from 15-20 IU/m2 (median 15 IU/m2). The treatment with carboplatin and bleomycin was well tolerated, with sixteen patients (53%) developing side effects. Thirteen patients (46%) developed gastrointestinal signs and nine dogs (30%) developed hematological abnormalities. The most common side effects were grade-1 hyporexia and grade-1 neutropenia. Grade-2 neutropenia was rarely observed, and only one patient developed grade-3 neutropenia. None of the dogs developed grade-4 adverse events, or required hospitalization, or died due to the treatment. No signs of chronic side effects, including pulmonary toxicity, were observed. Objective response was observed in 24% of the cases (six partial responses) and 76% of cases achieved clinical benefit (partial response+ stable disease). Clinical signs improved in 24 of the 30 cases (80%). The main aim of this study was to evaluate the safety of bleomycin and carboplatin in combination for the treatment of various types of carcinomas. The combination of bleomycin and carboplatin appears safe and potentially effective for some types of carcinomas. Larger prospective studies are needed to confirm the safety and efficacy of combined carboplatin and bleomycin.

Eosinophilic pulmonary granulomatosis resembling a pulmonary carcinoma in a dog in Hong Kong.

Background: Canine Eosinophilic Pulmonary Granulomatosis (EPG) is a severe form of eosinophilic pulmonary disease that carries a guarded prognosis, responds poorly to therapy and recurs frequently. Most studies have reported a caudal lobar pulmonary distribution and a poorer prognosis in idiopathic cases. Case Description: A 7-year-old dog was presented for persistent cough, hyporexia, and weight loss. Eosinophilia and basophilia were transiently present, and an antigen test for heartworm disease was negative. Radiographic studies, followed by a computed tomography (CT) scan revealed nodular lesions and a large mass in the left cranial lobar region suggestive of neoplasia. Cytological and histopathological evaluation was consistent with EPG. The dog responded positively to corticosteroids and has since remained free of disease. Conclusion: EPG in dogs can resemble primary pulmonary neoplasia with secondary intra-pulmonary metastasis. Contrary to previous reports, idiopathic EPG can present with a cranial pulmonary distribution and respond positively to therapy.

Use of a pleural access port for the treatment of pyothorax in a cat.

Background: Pyothorax in cats is treated with intravenous fluids and antibiotics, and while thoracotomy and debridement are less commonly necessary, thoracostomy tubes are the treatment of choice when repeated drainage of the pleural cavity is needed. Case Description: An 11-month-old British short-haired cat was presented for a sudden onset of lethargy, dyspnea, and tachypnea, following an ovariohysterectomy 10 days prior to the treatment process. Pyrexia and muffled cardiac sounds on the left hemithorax were noted. A hemogram indicated the development of anemia and neutrophilia with a left shift. Radiography and ultrasonography confirmed a pleural effusion, and a CT scan ruled out the presence of any masses or perforating foreign bodies. A PCR on the pleural effusion ruled out feline coronavirus infection, and fluid analysis was confirmed as a septic exudate with Pasteurella multocida infection. A pleural access port was used to treat the pyothorax that successfully reduced hospitalization time and lowered overall financial outlay despite surgical implantation. Conclusion: The present report describes the successful use of a pleural port to treat pyothorax in one cat. This is the first time such a device has been reported for the treatment of pyothorax.

An alternative combination therapy with metronidazole, clindamycin and doxycycline for Babesia gibsoni (Asian genotype) in dogs in Hong Kong.

Babesia spp. are globally distributed hemoparasites that cause disease in many mammalian species. The species Babesia gibsoni (Asian genotype) is prevalent and endemic in many Asian countries but has also been reported in growing numbers in countries outside of Asia. Standard therapies for the treatment of B. gibsoni often fail to result in consistent and successful clearance of the organism. This study evaluated the use of a combination of three antibiotics: metronidazole, clindamycin and doxycycline after atovaquone and azithromycin failed to eliminate the infection on a polymerase chain reaction (PCR) test. The aim of this study was to determine whether the triple antibiotic combination was an appropriate alternative or additional treatment for the elimination of B. gibsoni. The medical records of 24 patients treated from December 2012 to July 2015 were retrospectively analyzed. The diagnosis of B. gibsoni was confirmed with a PCR test that was also used to assess treatment response. All patients were initially treated with the standard therapy, atovaquone and azithromycin with a 25% success rate clearing B. gibsoni. Dogs that remained positive on PCR using the standard therapy were then treated with the triple antibiotic protocol achieving an 87% success rate. The inclusion of an alternative and potentially effective protocol for the treatment of B. gibsoni would increase the options for the current therapeutic options, could aid in clearance of the organism and offer a more affordable option for clients.

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.