Pathological findings associated with Dipetalonema spp. (Spirurida, Onchocercidae) infection in two species of Neotropical monkeys from Brazil

Among vector-borne helminths, filarioids of the genus Dipetalonema (Spirurida: Onchocercidae) localize in several tissues and body cavities of several animal species, causing mild to moderate lesions. The pathological findings associated with Dipetalonema spp. infection in Neotropical monkeys from southern Brazil are herein described, along with a fatal case due to filarial polyserositis and entrapment of an intestinal segment. At necropsy, nematodes were observed in abdominal and thoracic cavities, or in the pericardium of 37 (31.3%) out of the 118 individuals examined (i.e., 35 Alouatta guariba clamitans and two Sapajus nigritus). In addition, at histology, 27.0% of positive animals presented microfilarie (inside blood vessels of lung, spleen, liver, and brain) and 8.1% presented adult nematodes in the heart, lung, and liver. In two cases, cross-sections of filarioids were associated with areas of epicardial thickening with intense fibrosis and pyogranulomatous inflammation in the brain, heart, liver, lungs, or spleen. The DNA fragment was amplify using the cox1 gene, sequenced and analyzed to identify the nematode species collected; presence of Wolbachia was assessed in the filarioids using the 16S rRNA gene. At BLAST analysis of the cox1 gene, 10 sequences showed 91.7% nucleotide identity with Dipetalonema gracile, and two with D. gracile (98.5%) and Dipetalonema graciliformis (98.3%). Phylogenetic analyses clustered sequences of the cox1 obtained in this study in two clades corresponding with the host species. Wolbachia sp. endosymbiont was detected in four samples. Data herein reported provide a description of pathological lesions associated with the infection by Dipetalonema spp., suggesting that they may cause disease in Neotropical monkeys. In addition, a better understanding of diversity and biology of Dipetalonema spp. in South America is needed to assess the impact they may cause in native non-human primates from Brazil.

Generalized and fatal felid alphaherpesvirus-1 natural infection with liver involvement in a feline leukaemia virus-positive adult cat: a case report

Generalized and fatal felid alphaherpesvirus-1 (FeHV-1) natural infection with liver involvement is rarely reported in cats, and the occurrence of herpesvirus viraemia with internal organ histologic lesions in adult cats is unknown. A 1.5-year-old cat, female, mixed breed, positive for feline leukaemia virus (FeLV) presented in a veterinary teaching hospital with sneezing, nasal discharge, anorexia, and diarrhoea after two weeks, evolving to inspiratory dyspnoea. Complete blood count and serum biochemistry analysis showed marked leukopenia and thrombocytopenia. After clinical worsening and lack of treatment response, the cat was euthanized. Pathological findings included hepatic necrosis, fibrinonecrotic tracheitis, and bronchointerstitial pneumonia. Marked amounts of coccobacillary bacteria were observed covering the necrotic tracheal and bronchial mucosa, at the cytoplasm of alveolar macrophages, and free in alveoli lumen, mimicking a primary bacterial tracheitis and pneumonia. Both lung and tracheal bacteria exhibited marked immunolabeling in anti-Escherichia coli immunohistochemistry. In addition, rare epithelial cells of bronchi contained round, eosinophilic, intranuclear viral inclusion bodies (4-7 µm) that marginate the chromatin, characteristic of FeHV-1 infection. Strong multifocal anti-FeHV-1 immunolabeling was observed in necrotic epithelial cells of the liver, trachea, and lungs. Generalized herpesvirus infection with the occurrence of acute hepatic necrosis and severe respiratory illness is a potential differential diagnosis in FeLV-positive cats with respiratory signs. The immunodepression in these cats probably favours a FeHV-1 viraemia in addition to the development of opportunistic bacterial infections, such as Escherichia coli, and it is associated with a poor outcome.

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.

Mycobacterium tuberculosis var. tuberculosis infection in two captive black capuchins (Sapajus nigritus) in Southern Brazil

Tuberculosis is a common zooanthroponosis in humans with a high incidence in Brazil, but it may also affect non-human primates (NHPs), of which Old World primates are most commonly involved. Nonetheless, its occurrence in New World primates is unknown, and therefore, this study aimed to describe the infection by Mycobacterium tuberculosis variant tuberculosis in two captive black capuchin monkeys (Sapajus nigritus) in Southern Brazil. The primates were housed in the same enclosure, wherein close contact with humans frequently occurred, and presented apathy, anorexia, and death in a clinical course of 15 days to 2 months. At the necropsy, the tracheobronchial lymph nodes were markedly enlarged and firm to hard and on the cut surface had a caseous aspect. The lungs exhibited two injury patterns: multifocal and disseminated. Microscopically, the lungs exhibited multifocal to coalescing necrotic granulomas and non-necrotic granulomas, with multiple acid-fast bacilli within the cytoplasm of epithelioid macrophages and multinucleated giant cells. Bacilli were also labeled upon immunohistochemistry (IHC) for Mycobacterium tuberculosis. Microbiological culture of lung samples from both cases yielded colonies compatible with M. tuberculosis. The isolates were identified as M. tuberculosis var. tuberculosis through polymerase chain reaction (PCR). Although tuberculosis is poorly described in New World primates, M. tuberculosis var. tuberculosis may cause a highly contagious and progressive disease with high mortality in black capuchin monkeys (S. nigritus).

Rhizopus microsporus segmental enteritis in a cow

A ten year-old Holstein cow had an intermittent bloody diarrhea, evolving to anorexia and recumbency, followed by death. Mycotic segmental enteritis was diagnosed based on the pathological and immunohistochemical findings. Rhizopus microsporus was identified as the causal agent through fungal culture and PCR analysis. Intestinal mucormycosis is poorly described in cattle and should, therefore, be included as a differential diagnosis in cases of diarrhea and death in ruminants, especially when there is disruption of the normal balance of the alimentary microbiota.

Cats with Central Nervous System Cryptococcosis

Background: Cryptococcosis is a serious fungal infection contracted by humans and animals, and the most common systemic mycosis found in cats. This disease is often contracted through inhalation of fungal propagules. The Central Nervous System (CNS) may be infected through local extension (nasal and frontal sinuses) or via hematogenous route. Similarly to CNS bacterial infection, the clinical signs of neurological dysfunction may be attributed to mass effect (gelatinous mass of fungal microorganisms and fungal granuloma formation) or to a more disseminated inflammatory response to invading microorganisms. The objective of this study is to report one case of a patient with cryptococcal granulomas in the central nervous system and one case of a patient with neurological signs associated to cryptococcosis.Cases: A 3-year-old male mixed breed feline was admitted Veterinary Clinic, located in Porto Alegre, RS, Southern Brazil. The patient presented unsourced behavioral changes, vestibular ataxia and dysphagia caused by inability of coordination. The following tests were performed: complete blood count test, biochemical analysis, computed tomography scan (CT scan), fluid analysis, radiography and toxoplasmosis test. The following medicine were administrated for treatment: fluconazole, dexamethasone, mannitol, phenobarbital and levetiracetam. Fluid therapy was also part of the treatment. Immediately after death, the cat was submitted for necropsy, and a fungal granulomatous meningoencephalomyelitis was diagnosed.  Cryptococcus sp. was identified as the causal agent through pathological findings, fungal culture and PCR analysis.  One year later, another feline was admitted to the same clinic (a 2-year-old female mixed breed) presenting hypersalivation, tremors and excessive vocalization. The patient had contact with the deceased feline. The following tests were performed: complete blood count test, biochemical analysis, computed tomography scan (CT scan), cerebrospinal fluid analysis, and radiography. The following medicine were administrated for treatment: fluconazole, prednisolone, phenobarbital, potassium citrate and cefalotine. This patient is frequently monitored by a veterinarian and presents adequate health conditions after the occurrence.  Cryptococcus sp. was identified as the causal agent through fungal culture and cytology (cerebrospinal fluid).Discussion: Cats are the most frequently infected animals with the involvement of the upper and or lower respiratory tract, subcutaneous granuloma, and disseminated infections. These animals present a higher quality of life when the disease is diagnosed and treated early. Peripheral enhancement of intracranial cryptococcal granulomas has been demonstrated in felines. These fungal granulomas often present evidence of significant perilesional edema. The most substantial evidence for diagnosis of cryptococcosis is the identification of the microorganism in Cerebrospinal fluid (CSF) samples. The mechanism of the lesion is cellular death, probably caused by secondary atrophy from distortion and tissue compression due to the expansion of Cryptococcus cysts in the cerebral parenchyma. There are several reports of long-lasting remission or cure of CNS cryptococcosis treated with medicine combinations, including flucytosine and/or triazole antifungal agents (itraconazole and fluconazole.) The isolated use of flucytosine may contribute to development of drug resistance. One controversial alternative that may be beneficial to the patient is the administration of low prednisolone doses to counter perilesional edema in the initial stages of treatment. The utilization of glucocorticoids after diagnosis was associated to higher survival rates in animals.

Epidemiologic and Pathologic Aspects of Feline Eosinophilic Granuloma Complex

Background: The feline eosinophilic granuloma complex (FEGC) includes a group of lesions that affect the skin, mucocutaneous junctions, and oral cavity of cats.  It comprises three distinct clinical entities: the eosinophilic ulcer (EU), the eosinophilic plaque (EP) and the eosinophilic granuloma (EG). The EU is usually found in the upper lip. Lesions of EP occur most commonly on the abdomen and medial thigh. The EG lesions usually appear on the tongue and hard palate. The aim of this study is to describe the localization and pathological findings of FEGC through a retrospective study and testing by immunohistochemistry if feline herpesvirus type 1 (FHV-1) infection may be associated.Materials, Methods & Results: The records of biopsy specimens from the Department of Veterinary Pathology of the Universidade Federal do Rio Grande do Sul were recovered and cats diagnosed with FEGC were selected since January 2006 to December 2017. General data, such as age, sex, breed and distribution lesions, were analyzed and compiled. The histological slides were reviewed by optical microscopy and the microscopic findings were detailed. Sections of tissue were used in immunohistochemistry to investigate the presence of feline herpesvirus-1 (FHV-1) using anti-FHV-1 antibody.  In this study, 30 cats were diagnosed with FEGC. Most part of the cats were mixed breed (27/30), and there were no sex predisposition. The age of the cats ranged from seven months to 13 years old, and the median was three years. The lesion distribution of FEGC was 40% in oral cavity, 33.3% in skin and 26.6% in mucocutaneous junction. Histologically, the main lesion of all distributions was characterized by diffuse dermal/submucosa inflammatory infiltrate composed of eosinophils. Within the inflammation there were large irregular foci of collagen fibers and degranulated and degenerating eosinophil (“flame figures”). Oftentimes these foci were surrounded by macrophages and fewer multinucleated histiocytic giant cells. There were mild to moderate inflammatory infiltrate of mast cells, lymphocytes and plasm cells in dermis and submucosa. Ulceration of epidermis and mucosa were observed in majority of FEGC lesions with inflammatory infiltrate of neutrophils. All cases were negative for FHV-1 in the immunohistochemical evaluation.Discussion: In this study, feline eosinophilic granuloma complex was uncommon, accounting 0.96% of the feline cases diagnosticated in 15 years. Agreeing with the other authors, there was no sex and breed predilection. The median of age were three years old, some authors report higher occurrence in young animals and associated with genetic predisposition. Histologically, the most frequent findings were submucous and dermal inflammatory infiltrate composed primarily of eosinophils associated with areas of “flame figures”. Surrounded these areas, there were intense inflammatory infiltrate composed of macrophages, palisading macrophages and fewer multinucleated histiocytic giant cells as previously described by other authors. The ulceration of epidermis and mucosa was a common finding of eosinophilic granuloma complex lesions especially in cases where the oral cavity was affected. In this study, we could not evaluate the presence of FHV-1 in feline cases of eosinophilic granuloma complex. The area commonly affected in cases of FEGC was the oral mucosa. It may be due to differentiate from other diseases that affect the same area.  Feline eosinophilic granuloma complex are important differential diagnosis for other diseases that include neoplasms, especially squamous cell carcinoma.

Anatomopathological and Immunohistochemical Apects of Distemper Virus in Crab-Eating-Foxes and Pampa-Foxes

Background: Distemper is a contagious disease with worldwide distribution, which is caused by a single-stranded RNA virus of the genus Morbillivirus. The Crab-eating fox (Cerdocyon thous) and the Pampas fox (Lycalopex gymnocercus), wild canids commonly found in the state of Rio Grande do Sul, are highly susceptible to the disease. Distemper virus infection often shows a multisystemic presentation. Central nervous system lesions are frequently reported, and may lead to death of wild canids. Distemper virus infection affecting these species has been cited by several studies; nonetheless, case descriptions involving the Crab-eating fox and the Pampas fox are infrequent. Therefore, the objective of the present study is to describe the anatomopathological and immunohistochemical aspects of distemper in the referred species, aiming to assist with the diagnosis of the disease.Materials, Methods & Results: A retrospective study was performed, and the necropsy reports of Crab-eating foxes and Pampas foxes admitted to SPV-UFRGS from 2010 to 2016 were reviewed. Necropsy reports were revised in order to obtain information related to the clinical history and anatomopathological findings, and cases compatible with distemper were selected.  Data regarding the affected species, sex, approximate age, origin and clinical signs were compiled and analyzed. Selected histological sections of brain and cerebellum were submitted for immunohistochemistry (IHC) for monoclonal antibody canine distemper virus. In the studied period, 20 animals of the referred species were subjected to necropsy, of which four were diagnosed with distemper as a cause of death. Of the affected animals, two were female and two were male. Three were juvenile and one was an adult animal. Clinical signs reported included myoclonia, opisthotonos, forelimb paresis and nystagmus. No significant gross changes were noted. Histopathological findings were restricted to the central nervous system, especially in the cerebellum, and the main lesion was demyelination, as well as gemistocytic astrocytes, malacia with Gitter cells, gliosis and perivascular cuffing. Inclusion bodies were observed in only one case. Diffuse and marked viral antigen positive immunostaining was detected, mainly in the cytoplasm of astrocytes, predominantly in the cerebellum.  Discussion: The diagnosis of distemper affecting the Crab-eating fox and Pampas fox was based on the clinical and histopathological findings, along with viral antigen identification through immunohistochemistry. Clinical signs were restricted to the central nervous system and were associated with the affected area. Significant gross changes in the central nervous system were not observed, similarly to what has been described by other authors. The main histological lesion was demyelination in the cerebellum, which is in agreement with previous reports in wild canids. Similarly to the findings reported in dogs and mustelids, positive immunostaining was observed mainly in the cytoplasm of astrocytes in the cerebellum; however, in our cases diffuse marked staining was noted. Although some authors have reported that viral antigens disappear in demyelinating lesions, due to the inflammation associated with the host immune response, the opposite was observed in the present study, suggesting viral persistency linked to a weak immune response in these species. The clinical and pathological changes observed were compatible with the neurologic phase of distemper; therefore, it is important to include this agent among the differential diagnosis in the referred wild canids, mainly in animals presenting neurological signs. Immunohistochemichal evaluation was important to the establishment of postmortem diagnosis of distemper, since characteristic viral inclusion bodies were rarely observed through histopathology.