Anti-Leishmania spp. antibody detection in domestic cats from a visceral leishmaniasis transmission area

Feline leishmanial infection is reported worldwide, but the epidemiological role of domestic cats in the leishmaniasis cycle remains unclear, and cats might act as cryptic reservoir hosts in endemic areas with no feline leishmaniosis cases. Considering that, a serological screening for anti-Leishmania spp. antibodies was performed by indirect immunofluorescence antibody test (IFAT) in 389 necropsied cats' serum samples from a new visceral leishmaniasis transmission area with no feline leishmanial infection reported to unveil if the cats are being exposed to the parasite. The overall seroprevalence for Leishmania spp. was 11.05% (43/389). No association was found between sex, neutering status, age group, breed, coat length, feline immunodeficiency virus (FIV) infection, and Leishmania spp. antibody detection. A positive association was found with coat color (cats within the orange spectrum with white [particolor]) (OR = 2.47, CI 95% 1 - 6.13, P = 0.044) and a negative association (OR = 0.38, CI 95% 0.18 - 0.79, P = 0.01) between feline leukemia virus (FeLV) infection and IFAT positivity for Leishmania spp. Therefore, it is concluded that the seroprevalence found was greater than 10%, indicating contact of the protozoan with cats in the region served.

Isolation and characterization of Buchananella hordeovulneris from feline pyothorax

A 1-year-old female mixed-breed cat was admitted to a veterinary hospital in Southern Brazil with tachypnea, low thoracic amplitude, restrictive breathing pattern, and cyanotic mucous membranes 2 days after elective castration surgery. Radiography revealed pleural effusion, and approximately 100-200 mL of fluid was collected by thoracocentesis. The reddish purulent exudate contained large numbers of yellowish-white granules with branched filamentous structures on cytological examination. The fluid was plated on blood agar and incubated under aerobiosis at 37 °C. On the third day of incubation, circular, dry, and opaque colonies, measuring < 0.5 mm in diameter, were observed. Their phenotypic and molecular characteristics were compatible with Buchananella hordeovulneris (basonym: Actinomyces hordeovulneris), a pathogenic actinomycete rarely detected in cats. Our findings indicate that B. hordeovulneris should be included in the differential diagnosis of pyothorax in cats together with Actinomyces spp. and Nocardia spp. Taxonomic confirmation of disease-causing microorganisms in animals is important to understand the course of infection and its association with disease epidemiology.

Hemolytic Crisis in a Dog with Copper-Associated Chronic Hepatitis

Background: Copper is an essential micronutrient for the body to function properly. However, although it is a vital element, an excess of copper in the body is extremely toxic. Copper toxicity has been reported mainly in sheep. In dogs, clinicopathological signs of toxicity are characterized by chronic liver failure. This means that the hemolytic crisis so common in sheep is a condition rarely associated with toxicity in dogs, so there are very few descriptions of this condition in the veterinary literature. The purpose of this report is to describe a case of hemolytic crisis in a dog with copper-associated chronic hepatitis.Case: A medium-sized 6-year-old bitch was brought to the Veterinary Hospital of the Federal University of Santa Maria, with clinical presentation of apathy, anorexia and red urine. A physical examination revealed mildly jaundiced mucosa and dark brown urine. A urinalysis indicated the presence of protein, bilirubin and occult blood. The blood count revealed hypochromic macrocytic anemia, leukocytosis due to left shift neutrophilia and thrombocytopenia. Serum biochemistry showed elevated levels of alanine aminotransferase and alkaline phosphatase. The animal was given a blood transfusion due to the severity of her anemia, but her clinical condition worsened and she died, whereupon her body was sent for necropsy. This necropsy revealed conspicuous signs of jaundice, splenomegaly and altered liver and kidney color. The liver was brownish, with its natural surface firm and slightly irregular. The kidneys were diffusely blackened. The urine was dark brown. Fragments of different organs were collected, fixed in 10% buffered formalin solution, routinely processed for histopathology and stained with hematoxylin and eosin. A histological dissection of the liver showed the hepatic lobes dissected by fibrosis, forming islands of hepatocytes and numerous lymphocytes and plasmocytes. Brown granular pigment was observed in periportal hepatocytes. Perls Prussian blue and rubeanic acid staining techniques were performed to characterize this pigment. Most of the pigment reacted strongly to rubeanic acid and but not to Perls’ Prussian blue, thus characterizing it as copper. Random hepatic necrosis was visible. The kidneys contained hemoglobin and necrotic epithelial cells obstructing the renal tubules. Based on the clinical and anatomopathological aspects, a diagnosis of hemolytic crisis due to copper-associated chronic hepatitis was established.Discussion: The most accepted mechanism to explain the occurrence of hemolysis is that copper long stored in hepatocytes is massively released into the bloodstream due to some stressful condition. When too much copper circulates in the bloodstream it inhibits enzymes that act on the energy metabolism of red blood cells, thereby lowering the synthesis of energy and nucleotides needed for glutathione activity, and causing hemoglobin to transform into methemoglobin. In the case reported here, copper toxicosis presumably originated from the animal’s diet since, according to the literature, the periportal distribution of copper revealed during histology suggests that the event resulted from excessive copper intake or was secondary to previous cholestatic liver injury. This paper describes a case of hemolytic crisis in a dog with copper-associated chronic hepatitis and, emphasizes the importance of including copper toxicity as a differential diagnosis for dogs presenting hemolytic crisis, in order to assist veterinarians in managing their patients. 

Melanocytoma-acanthoma in a Dog

Background: Melanocytic neoplasms are skin tumors that often occur in dogs.  However, melanocytoma-acanthoma, also called melanoacanthoma, is a benign melanocytic neoplasm rarely reported in this species, which has been described only three times in the veterinary literature. Briefly, this tumor is characterized by a single, painless, darkly pigmented and firm cutaneous papule or nodule. Histologically, it is composed of mixed populations of well-differentiated melanocytes and keratinocytes, unlike traditional melanocytic tumors (melanoma and melanocytoma). These cells are arranged in lobules surrounded by collagenous stroma. Melanocytes are large epithelioid cells containing varying amounts of melanin. Keratinocytes form anastomosing trabeculae with peripheral palisading, and small cysts containing amorphous or laminated keratin. The definitive diagnosis of melanocytoma-acanthoma is based on histopathological findings. This report describes a case of melanocytoma-acanthoma in a dog in Brazil.Case: A 9-year-old female miniature Schnauzer dog was examined at the Veterinary Hospital of the Federal University of Santa Maria, where a single, firm, pigmented papule was found in the auricle. The lesion had started 15 days earlier. Hematological tests and serum biochemistry profile were normal. An excisional biopsy of the papule was surgically removed and subjected to histopathological examination. The tissue was fixed in 10% neutral buffered formalin, processed routinely and embedded in paraffin wax. Sections were stained with hematoxylin and eosin (HE). A histopathological examination revealed a nonencapsulated, well-defined, extensive, densely cellular proliferation located in dermis. This proliferation was composed of lobules and nests of well-differentiated stratified squamous epithelium closely associated with neoplastic melanocytes, surrounded by thin bundles of fibrous stroma. A diagnosis of melanocytoma-acanthoma was established based on these histological features.Discussion: The first description of melanocytoma-acanthoma in humans was as melano-epithelioma, classified into subtypes I and II. Both subtypes are benign neoplasms composed of well-differentiated melanocytes and keratinocytes, which are distinguished from one another based on the amount and distribution of melanocytes. Type I melano-epithelioma is characterized by proliferative lobules of melanocytes and keratinocytes, including melanocytes scattered diffusely among keratinocytes. Type II melano-epithelioma involves only the proliferation of keratinocytes, while melanocytes are limited to the basal layer of keratinocyte lobules. To clarify this condition, some authors use the term “melanoacanthoma” to indicate the above-described type I melano-epithelioma, and seborrheic keratosis to indicate type II melano-epithelioma. However, other authors use the term melanoacanthoma to denote the two conditions (types I and II melano-epithelioma). On the other hand, veterinary medicine does not recognize subtypes, instead using the term melanocytoma-acanthoma, and more recently, melanoacanthoma, to denote this cutaneous neoplasm. Melanocytoma-acanthoma in dogs was first reported in Spain, and involved a 2-year-old German shepherd dog. Later, two other cases were described in adult mixed-breed dogs, one in South Korea and the other in Libya. This is the first report of melanocytoma-acanthoma in a dog in Brazil. The gross and histopathological appearance of this case matches that described in the previous cases (a single, well-defined, pigmented cutaneous papule or nodule). Histologically, the differential diagnosis for melanocytoma-acanthoma includes melanoma, melanocytoma, trichoepithelioma, and sebaceous epithelioma.