Genetic and antigenic characterization of Brazilian SRLV strains: Natural small ruminant interspecies transmission from mixed herds.

Cross-species transmission events and mixed infection of small ruminant lentiviruses (SRLVs) were studied in seven goats and two sheep from three small ruminant mixed flocks from Northeast and Southeast Brazil. Genetic and antigenic analyses with gag/env genes and ELISA multiepitope SU1/SU5 recombinant antigens were carried out, respectively. The genetic analysis of gag and env sequences showed high viral diversity in both species, MVV-like (subtype A1) and CAEV-like B1 in goats, and CAEV-like (subtype B1) in sheep, revealing SRLV interspecies transmission from sheep to goats and vice versa in Brazilian farms. Two Brazilian caprine lentiviruses were segregated in two new genetic clades based on gag analyses, which suggests a new classification into heterogenic genotype A. Furthermore, goat isolates were grouped into subtype A1 and B1 clusters. Cross-reactive antibodies were detected in goats using ELISA with a recombinant antigen carrying SU1 and SU5 immunodominant epitopes; the results showed anti-CAEV and MVV antibodies in goats and anti-CAEV antibodies in sheep. This result can be associated with the high divergence in the V4 region due to SRLV variability. All results confirm cross-species infection of SRLV in Brazilian mixed herds.

Age-dependent pathogenesis of clade 2.3.4.4A H5N2 HPAIV in experimentally infected Broad Breasted White turkeys.

Highly pathogenic avian influenza (HPAI) is a viral disease with devastating consequences to the poultry industry as it results in high morbidity, mortality and international trade restrictions. In the present study, we characterized age-related differences in terms of pathology in commercial white broad breasted turkeys inoculated with A/turkey/Minnesota/12582/2015 (H5N2) HPAIV clade 2.3.4.4A, a virus from the largest HPAI poultry outbreak that affected the Unites States in 2014-2015. Turkeys infected at 6-weeks of age showed inapparent to little clinical signs with rapid disease progression, reaching 100% mortality at 3 days post infection (dpi). In contrast, turkeys infected at 16-weeks of age developed ataxia and lethargy and reached 100% mortality by 5 dpi. Infection in the 6-weeks old turkeys resulted in peracute lesions consistent of extensive hemorrhages, edema and necrosis, but inflammation was not prominent. In the 16-weeks old turkeys, necrosis and hemorrhages in tissues were accompanied by a more prominent subacute inflammatory infiltrate. Both age groups showed presence of avian influenza virus (AIV) nucleoprotein (NP) in multiple cell types including neurons, glial cells, ependymal cells, respiratory epithelial cells, air capillary epithelium and pulmonary macrophages, cardiac myocytes, smooth muscle fibers, pancreatic acini and ductal cells. Cells of the vascular walls stained strongly positive for viral antigens, but no positivity was found in the endothelial cells of any organs. These findings indicate that age is a determinant factor in the progression of the disease and delay of mortality during infection with the H5N2 clade 2.3.4.4A HPAI virus in naïve white broad breasted turkeys.

Genetic variability and phylogeny of the 5' long terminal repeat from Brazilian bovine leukemia virus.

We conducted a phylogenetic analysis of 22 strains of bovine leukemia virus obtained by polymerase chain reaction to amplify a 582-base pair fragment of the transcriptional regulatory region 5' long terminal repeat (LTR). Twenty-two samples of proviral DNA from peripheral blood mononuclear cells containing bovine leukemia virus from naturally infected bovine from 4 distinct geographic regions in Brazil were investigated. The products obtained by polymerase chain reaction were subjected to direct sequencing and sequence alignment. Fragments of 422 nucleotides were obtained, located between positions -118 and +303 base pairs of the 5'LTR. These fragments corresponded to 80% of the LTR region and included 56% of sub-region U3, 100% of R, and 82.5% of U5. Phylogenetic analysis of these sequences showed a high conservation degree in the 5'LTR region, with 5 well defined groups. However, a hotspot occurrence in the R-U5 region was also observed, which contained 40% of all nucleotide variability observed.

Genetic variation of bovine leukemia virus (BLV) after replication in cell culture and experimental animals.

This article reports the selection of bovine leukemia virus (BLV) variants after continuous passage in cell lines or experimental animals. Two wild BLV strains isolated from 2 naturally infected Holstein dairy cows in Brazil (cow codes: 485 and 141) were used for the experimental infection of 1 sheep and FLK cells, and 1 rabbit and CC81 cells. Viral DNA was isolated several months after infection, and env gene nucleotide and amino acid sequences of the "passaged" variants were compared against the 2 original infecting wild strains. The sequences of the original infecting wild strains were not recovered after their replication in the cell lines or experimental animals. These results indicate that genetic variation occurred after BLV replication in vivo and in vitro, with new variants being selected.

Vero cells infected with the Lederle strain of canine distemper virus have increased Fas receptor signaling expression at 15 h post-infection.

We evaluated the expression of the Fas receptor gene in Vero cells infected with the Lederle vaccine strain of canine distemper virus using RT-PCR. Vero cells were plated, and after being grown for 24 h in MEM with 5% FBS, 80-90% confluent monolayer cultures were infected with the virus. The cells were harvested at 3, 6, 9, and 15 h post-infection. Uninfected Vero cells were used as a control. Total RNA was isolated from Vero cells using 1 mL Trizol(®) LS, and RT was performed using 2 µg total RNA. Primer pairs for RT-PCR amplification for the canine distemper virus nucleocapsid gene, the S26 reference gene, and the Vero rFas gene were used to analyze expression in Vero cells. RT-PCR results revealed virus activity at 3, 6, 9, and 15 h in the virus-infected Vero cells. The S26 housekeeping gene was amplified in virus infected and control samples. However, expression of the cell death receptor Fas was detected in Vero cells only at 15 h post-infection. We suggest that the Lederle vaccine induces apoptosis by Fas receptor signaling, possibly through caspase-8 signaling rather than through mitochondrial signaling in the infected cells.

Ocorrência do vírus da imunodeficiência felina e do vírus da leucemia felina em gatos domésticos mantidos em abrigos no município de Belo Horizonte / Occurrence of feline immunodeficiency virus and feline leukemia virus in Sheltered domestic cats of Belo Horizonte

Investigou-se a ocorrência da infecção pelo vírus da imunodeficiência felina (FIV) e pelo vírus da leucemia felina (FeLV) em gatos domésticos, provenientes de dois abrigos, no município de Belo Horizonte. Amostras de sangue de 145 animais foram coletadas e testadas para detecção do FIV pela reação em cadeia da polimerase (PCR). Destas amostras, 40 foram testadas para o antígeno p26 de FeLV por meio de ELISA. Observaram-se duas fêmeas (1,4 por cento) e quatro machos (2,8 por cento) positivos para FIV e nove fêmeas (22,5 por cento) e quatro machos (10,0 por cento) positivos para FeLV

The occurrence of the feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) was investigated in domestic cats from two shelters of Belo Horizonte. Samples from 145 cats were collected and tested for FIV by the polymerase chain reaction (PCR). Forty out of 145 samples were tested for FeLV p27 antigen by a commercial ELISA kit. Two females (1.4 percent) and four males (2.8 percent) were positive for FIV. For FeLV tests, 13 cats (32.5 percent) were positive, being nine females (22.5 percent) and four males (10.0 percent)