Pathological findings and patterns of feline infectious peritonitis in the respiratory tract of cats.

Feline infectious peritonitis (FIP) is an important cause of death in cats. Thoracic manifestations are less common than abdominal manifestations, and FIP-associated respiratory disease is poorly documented. This study aimed to investigate pathological findings in the respiratory tract of cats with FIP and the occurrence and distribution of feline coronavirus antigen in the respiratory tract using immunohistochemistry. A retrospective study was carried out on 112 cats with FIP, of which 66 had inflammatory histological lesions in the respiratory tract (58.9%) and were included in this study. Three major gross patterns were defined: marked fibrin deposition in the thoracic cavity with lung atelectasis; marked fibrin deposition in the thoracic cavity with lung pyogranulomas; and lung pyogranulomas without thoracic effusion. Histological analysis revealed primary lesions in the visceral pleura and lung parenchyma at a similar frequency, with multifocal to diffuse presentations. Marked lesions were commonly observed. Five major histological patterns were defined: pleuritis; pleuritis and vasculitis/perivascular injury in the lung parenchyma; pleuritis and pneumonia; perivascular injury in the parenchyma without pleuritis; and pneumonia without pleuritis. In the pleura and pulmonary parenchyma, FIP virus antigen was detected in perivascular and peribronchial macrophages and in macrophages within bronchial-associated lymphoid tissue and foci of necrosis and inflammation in the pleura and lung parenchyma. Co-infections with retroviruses were detected in 47 cats (71.2%), mainly with feline leukemia virus (62.2%). Although FIP is a systemic disease, some cats developed significant lesions in the thoracic cavity, including involvement of the upper respiratory tract and presenting respiratory signs, without other classic signs of FIP. This work advances our knowledge of FIP in the respiratory system, helping veterinarians to recognize the various presentations of this disease.

Ophthalmic and immunopathological characterization of systemic infectious diseases in cats.

Ocular involvement in systemic diseases is frequent in cats; however, without concurrent clinical and ophthalmic examinations with gross and/or histologic analysis of the eye, these findings can be underdiagnosed. This article aims to provide gross, histologic, and immunohistochemical characteristics of ocular lesions from cats submitted to necropsy, focusing on those caused by systemic infectious agents. Cats that died due to a systemic infectious disease were selected based on necropsy diagnosis and presence of ocular lesions. Gross, histologic, and immunohistochemical findings were recorded. From April 2018 to September 2019, 849 eyes of 428 cats were evaluated. Histologic abnormalities were seen in 29% of cases, which were classified as inflammatory (41%), neoplastic (32%), degenerative (19%), and metabolic/vascular (8%). Macroscopic changes were present in one-third of eyes with histologic lesions. Of these, 40% were attributed to inflammatory or neoplastic diseases associated with infectious agents. The most important infectious agents causing ocular disease in this study were feline leukemia virus, feline infectious peritonitis virus, and Cryptococcus sp. The most common ocular abnormalities associated with infectious agents were uveitis (anterior, posterior, or panuveitis), optic neuritis, and meningitis of the optic nerve. Ocular lesions secondary to systemic infections in cats are frequent; however, these are not always diagnosed because gross lesions are less common than histologic lesions. Therefore, both gross and histologic evaluation of the eyes of cats is recommended, mainly for cases in which the clinical suspicion or necropsy diagnosis suggests that an infectious agent might be related to the cause of death.

Causes of death in neotropical primates in Rio Grande do Sul State, Southern Brazil.

BACKGROUND: Anthropogenic disturbances are the main threats to nonhuman primates conservation, and infectious diseases may also play a key role in primate population decline. This study aimed to determine the main causes of death in neotropical primates. METHODS: A retrospective study of post-mortem examinations was conducted on 146 neotropical primates between January 2000 and December 2018. RESULTS: Conclusive diagnoses were obtained in 68.5% of the cases, of which 59 corresponded to non-infectious causes and 41 to infectious diseases. Trauma was the main cause of death (54/100), with anthropogenic stressors caused by blunt force trauma injuries (collision with vehicles) and puncture wound injuries associated with interspecific aggression (dog predation) were the most common factors. Other causes of death included bacterial diseases (27%), followed by parasitic diseases (12%), neoplasms (2%), and viral diseases (2%). CONCLUSIONS: Free-ranging primates were mostly affected by non-infectious causes, while captive primates were by infectious conditions.

Rangelia vitalii molecular and histological quantification in tissues comparing crab-eating foxes (Cerdocyon thous) and domestic dogs.

Rangeliosis is a condition transmitted by the tick Amblyomma aureolatum and caused by the protozoan parasite Rangelia vitalii in canids. In domestic dogs, the disease causes a severe hemolytic disease, while in wild canids the piroplasm is often detected without any clinical abnormality. This study aimed to detect and quantify the number of copies of the R. vitalii Hsp70 gene (indirect parasite burden) in several organs of domestic and South American wild canids (Cerdocyon thous and Lycalopex gymnocercus) to elucidate distinct clinical presentations of rangeliosis in these species. A total of seven domestic dogs that died due to rangeliosis and 38 wild foxes were initially included, with all dogs presenting histological and molecular features of rangeliosis, while eight C. thous were positive at the molecular analysis for R. vitalii. Fragments of 22 organs collected from domestic (n = 7) and wild foxes (n = 8) were employed for histological and molecular quantification using real-time polymerase chain reaction aiming at the Hsp70 gene. Histologically, parasitophorous vacuoles were constantly detected in the dogs, while these were detected only in two C. thous. Parasitic burden was significantly higher in the digestive, cardiorespiratory, endocrine, genitourinary, and skeletal-muscle systems of domestic dogs when compared to wild foxes. In the hematopoietic system of wild canids, some organs, such as the lymph nodes and tonsils, presented significantly lower amounts of R. vitalii, while other organs (spleen, bone marrow, and blood) had results similar to those of domestic dogs. Additionally, the central nervous system of both domestic and wild canids presented a similar quantity of R. vitalii. The etiological agent is possibly maintained through an asexual reproductive process (merogony) in both domestic and wild species. Nonetheless, a limited or short-duration schizogony phase occurs in C. thous, which would designate this species as a possible reservoir host for the agent. Dogs, in contrast, would most likely act as accidental hosts, presenting a severe and more pathogenic schizogony phase, resulting in characteristic clinical and pathological rangeliosis.

Feline giant-cell pleomorphic sarcoma: cytologic, histologic and immunohistochemical characterization.

OBJECTIVES: This study aimed to characterize the cytologic, pathologic and immunohistochemical (IHC) aspects of feline giant-cell sarcoma. METHODS: Biopsy and necropsy reports from the Department of Veterinary Pathology were retrieved, and 13 cases of pleomorphic sarcoma (PS) were selected according to the established epidemiologic, pathologic and IHC criteria. All samples were fixed in 10% formalin, routinely processed for histology, and stained with hematoxylin and eosin. Samples also underwent IHC testing for vimentin, ionized calcium-binding adaptor molecule 1 (Iba-1), desmin, actin and S-100. RESULTS: The mean age of the affected cats was 9.5 years, and females were over-represented. Most neoplasms were observed in the flank, lateral thorax, limbs and interscapular region, and were >2 cm in diameter. Cytology analysis revealed highly cellular preparations with three distinct populations (spindle cells, small round cells and multinucleated giant cells) in a dense eosinophilic stroma. Histologically, PS was composed of a combination of these three populations. IHC labeling for vimentin and Iba-1 was strongly positive for spindle cells and multinucleated giant cells, respectively. Desmin/actin showed variable labeling among the samples. S-100 was negative in all samples. CONCLUSIONS AND RELEVANCE: PS is a neoplasm of mesenchymal origin, also known as malignant fibrous histiocytoma. The predominant subtype in this study that affected the cats was the giant-cell type, characterized by the presence of multinucleated giant cells among spindle-shaped cells. These findings are similar to those described in human patients; thus, a comparison between the neoplasms seen in these species might be useful, and the knowledge of biologic behavior and overall treatment approach for humans could be extrapolated to cats.

Relationship Between Clinicopathological Features and Prognosis in Appendicular Osteosarcoma in Dogs.

Osteosarcoma is the most common primary bone neoplasm in dogs and often involves the appendicular skeleton. We report the clinicopathological and prognostic features of appendicular osteosarcomas diagnosed in 153 dogs from 2008 to 2018. The survival data for 22 dogs that underwent surgery and chemotherapy were statistically compared with the clinical, histopathological and immunohistochemical data for correlation with prognosis. The affected dogs had a mean age of 9.1 years and a mean body weight of 33.4 kg. No sex predilection was detected, although the incidence was slightly higher in females (52%). Large mixed and purebred dogs were most commonly affected. Long bones were affected in 124 cases (92.5%; 124/134). The extremities affected within long bones were the metaphysis of the proximal humerus (29%), distal radius (17.7%), distal femur (15.3%) and proximal tibia (7.2%). Histologically, osteoblastic osteosarcoma was most commonly detected (56.9%), followed by chondroblastic (13.7%), telangiectatic (11.8%), fibroblastic (7.8%), giant cell-rich (5.2%) and poorly differentiated neoplasms (4.6%). Regional lymph nodes were available for analysis in 28 out of 70 excisional biopsies from amputated entire limbs. Metastases to regional lymph nodes were observed in 14.3% (4/28) of these cases. Distant metastases were found in 75% (39/52) of cases in which diagnostic imaging or necropsy was carried out. The lungs were the most common site of metastasis (87.2%; 34/39 cases). Weight, age, sex, affected limb or bone, histological classification, mitotic count or histological grade did not influence survival (P >0.05). Neoplasms located at proximal extremities (n = 7) of affected limbs had a tendency for a poorer prognosis than those at distal extremities (n = 15) (P = 0.06). For these cases, the 1-year survival rate was 14.3% compared with 40% for neoplasms at distal extremities. There was no significant difference in the survival rate when amputation (n = 16) or limb preservation (n = 6) techniques were employed with chemotherapy (P = 0.20). The survival period of dogs that had undergone limb amputation, or limb preservation surgery, and chemotherapy was 73-1,185 days, with a mean and median of 376 and 256 days, respectively. Mild to marked cytoplasmic immunolabelling of osteopontin was found in all cases but the intensity (P = 0.66) and percentage of neoplastic cells labelled (P = 0.49) did not influence survival.

Molecular and pathological characterization of teat papillomatosis in dairy cows in southern Brazil.

Teat papillomatosis is caused by different bovine papillomavirus (BPV) types and is especially important for dairy cows, because it results in severe damage to the health and structure of the mammary gland. This work describes the molecular and pathological aspects of teat papillomatosis in dairy cows in southern Brazil. Samples of teat papillomas were collect from 73 slaughtered dairy cows. Fragments of the lesions were collected in individual pools per animal and subjected to PCR using the FAP primer pair and sequencing of the amplification products. Teats with the remaining lesions were fixed in 10% neutral buffered formalin, routinely processed for histopathology, and stained with hematoxylin and eosin (H&E). Papillomatous lesions were characterized by three macroscopic patterns, namely exophytic (5 [6.9%]), flat (29 [39.7%]), and mixed (39 [53.4%]). Histologically, all samples were identified as squamous papillomas. Partial sequencing of the L1 gene resulted in the detection of 8 classical BPV types (BPVs 4, 6, 7, 8, 9, 10, 11, and 12) in 27 samples, 6 previously reported putative BPV types in 17 samples, and 10 putative new BPV types in 15 samples. Four sequences could not be classified, and 10 were negative in the PCR. There was no correlation between the gross pattern and the BPV type identified, and all the samples were characterized by squamous papillomas under histological examination. However, 24 different BPV types were identified, demonstrating high genetic diversity among BPVs associated with teat papillomatosis in dairy cows in southern Brazil.

Pathological and microbiological characterization of mastitis in dairy cows.

Mastitis may be caused by a wide range of microorganisms able to induce distinct lesions in mammary tissues. This study aims to characterize the gross and microscopic features of mastitis in dairy cows and to correlate them with the pathogens involved. The udders of slaughtered dairy cows were inspected and milk samples from each mammary quarter or fragments of the parenchyma were sent for microbiological analysis, and tissue collected for histopathological evaluation. A total of 148 cows and 592 mammary quarters were collected. From these, 432 quarters (73%) had mastitis and in 160 (27%), no changes were observed. Mastitis was classified into seven patterns based on the histopathological findings, of which mixed, lymphoplasmacytic, and suppurative mastitides were the most prevalent with 35.9% (155/432), 27.1% (117/432), and 14.3% (62/432) of the cases, respectively. These patterns were associated with the same set of pathogens: Streptococcus spp., coagulase-negative Staphylococcus (CNS), Staphylococcus aureus, Streptococcus agalactiae, Streptococcus uberis, and Corynebacterium bovis. The pyogranulomatous pattern represented 7.2% (31/432) of the cases with distinct distribution based on the agent involved, mostly S. aureus and Nocardia sp. Abscedative mastitis accounted for 6.0% (26/432) of the cases; it was characterized by multiple abscesses in the parenchyma and was mainly caused by Trueperella pyogenes. Necrosuppurative mastitis represented 5.8% (25/432) of the cases which were characterized by severe parenchyma necrosis and were caused by bacteria such as CNS and Escherichia coli. The granulomatous pattern represented 3.7% (16/432) of the cases and was occasionally associated with Mycobacterium sp.