The pathogenicity of two Neospora caninum goat strains in a BALB/c mouse model

Goats are frequently described as an intermediate host for the protozoan Neospora caninum, manifesting the disease mainly by recurrent abortions with placentitis and encephalitis in fetuses. Several reports of natural and experimental infections in cattle and mice show differences in the immune response, and the outcome of the infection can be variable depending on the species affected and by the behavior of the infective strain. This study describes for the first time two Neospora caninum strains isolated from naturally infected goats from the state of Minas Gerais, Brazil. One placenta and one brain from different goats were processed for a first bioassay in gerbils (Meriones unguiculatus). Subsequently, a second bioassay was performed by inoculating the processed brain samples from gerbils into Interferon gamma (IFN-γ) knockout mice (KO mice). Tachyzoites collected from the peritoneal fluid of the KO mice were inoculated into VERO cell monolayers, where they presented a very slow growth rate. The tachyzoites were also inoculated into BALB/c mice with a dose of 10⁶ tachyzoites per animal. After a 5-week follow up, the animals infected with both of the strains developed a strong polarized Th1 response with increased serum and spleen gene expression levels of pro-inflammatory cytokines (mainly IFN-γ and TNF-α) in the first week. Tissue lesions were mild in the animals infected with both strains. Despite the strong immune response preventing an infection in the visceral organs, the parasite was able to reach the brain, causing progressive brain lesions from the second to fifth week post infection. The NC-goat1-infected mice presented with severe meningoencephalitis, but the NC-goat2-infected animals had considerable histological brain lesions only at week 5. Immunohistochemical analysis of the mouse brains revealed a different pattern of inflammatory cells compared to the naturally infected goats. A severe inflammatory infiltrate of CD3⁺ T lymphocytes was found in the NC-goat1-infected mice. A more discrete infiltrate of CD3⁺ T cells was found in the NC-goat2-infected animals. Additionally, IBA1 IHC revealed an intense microglial reaction and monocyte perivascular cuffs in the NC-goat1-infected animals and lower microglia/monocyte infiltrates in the NC-goat2-infected mice. This work contributes knowledge on the pathogenicity of new Neospora caninum strains in mice, comparable with other well-established mouse models of the disease, and demonstrates the importance of studying goats as an intermediate host of this parasite.

Multiple infarcts and hemorrhages in the central nervous system of a dog with cerebral amyloid angiopathy: a case report

Background

β-amyloid (Aβ) can accumulate in the brain of aged dogs, and within vessels walls, the disease is called cerebral amyloid angiopathy (CAA). In humans, Alzheimer’s disease and CAA are strongly correlated with cerebrovascular disease. However, in dogs, this association has not been extensively studied yet. The present report highlights the pathological and clinical features of a concomitant cerebrovascular disease and amyloid precursor protein (APP) accumulation in the brain of a dog.

Case presentation

A female, 16-year-old, Standard Poodle with a one-year history of cognitive deficits presented with an acute onset of right-sided postural reaction deficit and circling, left-sided head tilt, positional nystagmus, and ataxia. Due to poor prognosis the dog was euthanized, and pathological examination of the brain revealed an acute lacunar infarction within the thalamus extending to rostral colliculus. Additional findings included subacute and chronic areas of ischemia throughout the brain and areas of hemorrhage within the medulla. Immunolabeling revealed APP deposition within intraparenchymal vessels of frontal, temporal and occipital cortex, hippocampus, diencephalon, mesencephalon and myelencephalon, besides meningeal vessels walls. Glial fibrillary acidic protein (GFAP) immunolabeling showed marked astrocytosis around the acute area of infarction and within chronic areas of ischemia. Histological examination of the brain along with immunohistochemistry results showed a concomitant APP, which is an Aβ precursor, accumulation within the neuroparenchyma and vessels (CAA) with histological evidences of a cerebrovascular disease in an aged dog.

Conclusions

This report shows that APP accumulation in the brain can occur concomitantly to a severe cerebrovascular disease in a dog. Further studies are necessary to elucidate if cerebrovascular disease is associated with Aβ accumulation in the brain of dogs.

Benefits of Fish Oil Consumption over Other Sources of Lipids on Metabolic Parameters in Obese Rats

This study evaluated the effect of the consumption of different levels and sources of lipids on metabolic parameters of Wistar rats. Animals were fed with high-fat diet (HFD) containing 20% of lard for 12 weeks to cause metabolic obesity. Subsequently, the animals were divided into six groups and were fed diets with lipid concentrations of 5% or 20% of lard (LD), soybean oil (SO) or fish oil (FO), for 4 weeks. Data were submitted to analysis of variance (two-way) followed by Tukey post hoc test (p < 0.05). The groups that consumed FO showed less weight gain and lower serum levels of triacylglycerol (TAG), total cholesterol and fractions, aspartate aminotransferase (AST) activity, atherogenic index, less amount of fat in the carcass, decreased Lee index and lower total leukocyte counting (p < 0.05). These same parameters were higher in LD treatment (p < 0.05). In the concentration of 20%, carcass fat content, blood glucose levels, as well as alanine aminotransferase (ALT) and gamma glutamyl transferase (GGT) decreased in FO groups (p < 0.05). The SO group had intermediate results regarding the other two treatments (FO and LD). We concluded that fish oil intake was able to modulate positively the metabolic changes resulting from HFD.

Diagnoses of Ovine Infection by the Serotype-4 Bluetongue Virus on Minas Gerais, Brazil

Background: Bluetongue (BT) is a viral disease transmitted by hematophagous vectors of the genus Culicoides. In Brazil, the identifcation of antibodies against the virus has been held for over thirty years, however clinicopathological diagnosis of the disease are scarce. The frst reported case occurred in the state of Paraná in 2001, confrmed by isolation and identifcation of serotype 12 of BTV. In the state of Rio Grande do Sul, in 2009, two outbreaks confrmed and was identifed the serotype 12. Serotype 4 was isolated during an outbreak in the state of Rio de Janeiro in 2013. This study describes the Diagnoses of ovine infection by the serotype-4 bluetongue virus in Minas Gerais, Brazil. Case: In a farm in the Southern region of the state of Minas Gerais, a group of 28 male sheep, was sent for necropsy at the Setor de Patologia Veterinária of Universidade Federal de Lavras (SPV-UFLA). In a flock of 80 male sheep 28 died with clinical signs of respiratory distress, whereas other showed signs of anemia and hypoproteinemia, cough, sneezing, prostration, fever, mucopurulent nasal discharge, anemia and submandibular edema. At necropsy, the main changes observed were cranioventral pulmonary consolidation, hemorrhage at the base of the pulmonary artery and ulcerating lesions in the hard palate mucosa, rumen and reticulum. The histological changes consisted of bacterial bronchopneumonia, papillary necrosis associated with bacterial structures, multifocal vasculitis in the submucosa and thrombi in blood vessels of the serosa in the rumen and reticulum, hyaline and flocculate necrosis in esophageal muscle, skeletal and cardiac muscle fbers were also observed, associated with moderate mononuclear inflammatory infltrate between fbers and around blood vessels. Discussion: The diagnosis of BT was confrmed by the identifcation of nucleic acids of the virus in blood samples and from tissues of animals from the herd by RT-PCR and by the detection of antibodies against Bluetongue virus with the agar gel immunodiffusion (AGID) test using serum samples from the remaining herd animals. Serotype 4 was identifed in three of the samples inoculated into KC cells. The hemorrhage at the base of the pulmonary artery, one characteristic fndings, was found in three of the necropsied sheep. The pulmonary lesions observed in the present study strongly suggest the occurrence of pneumonia caused by opportunistic bacteria, especially Mannheimia haemolytica, which is commonly associated with pneumonia in sheep infected with BTV. This work is the frst in the state of Minas Gerais and the fourth in Brazil to report an outbreak of the disease with clinical signs. The economic impact of bluetongue results not only from the direct losses of animals to the disease, but also to the correlation among BTV infection and other problems including pneumonia, abortion and verminoses. In a study focused on the characteristics of ovine farming in Minas Gerais, farmers from the center-southwest reported that abortion and pneumonia were among their main problems. Thus, further epidemiological studies on BTV may improve the level of identifcation of infected herds and may help promote prophylactic measures. Necropsies and histopathology exams constitute crucial tools for diagnosis, because most cases present at a sub-clinical stage or in association with other, concomitant diseases. Keywords: BTV 4, viral diseases, sheep, RT-PCR e IDGA