An Outbreak in Pigeons Caused by the Subgenotype VI.2.1.2 of Newcastle Disease Virus in Brazil

Newcastle disease virus (NDV) can infect over 250 bird species with variable pathogenicity; it can also infect humans in rare cases. The present study investigated an outbreak in feral pigeons in São Paulo city, Brazil, in 2019. Affected birds displayed neurological signs, and hemorrhages were observed in different tissues. Histopathology changes with infiltration of mononuclear inflammatory cells were also found in the brain, kidney, proventriculus, heart, and spleen. NDV staining was detected by immunohistochemistry. Twenty-seven out of thirty-four tested samples (swabs and tissues) were positive for Newcastle disease virus by RT-qPCR test, targeting the M gene. One isolate, obtained from a pool of positive swab samples, was characterized by the intracerebral pathogenicity index (ICPI) and the hemagglutination inhibition (HI) tests. This isolate had an ICPI of 0.99, confirming a virulent NDV strain. The monoclonal antibody 617/161, which recognizes a distinct epitope in pigeon NDV strains, inhibited the isolate with an HI titer of 512. A complete genome of NDV was obtained using next-generation sequencing. Phylogenetic analysis based on the complete CDS F gene grouped the detected isolate with other viruses from subgenotype VI.2.1.2, class II, including one previously reported in Southern Brazil in 2014. This study reports a comprehensive characterization of the subgenotype VI.2.1.2, which seems to have been circulating in Brazilian urban areas since 2014. Due to the zoonotic risk of NDV, virus surveillance in feral pigeons should also be systematically performed in urban areas.

Surveillance and Genetic Characterization of Virulent Newcastle Disease Virus Subgenotype V.3 in Indigenous Chickens from Backyard Poultry Farms and Live Bird Markets in Kenya

Kenyan poultry consists of ~80% free-range indigenous chickens kept in small flocks (~30 birds) on backyard poultry farms (BPFs) and they are traded via live bird markets (LBMs). Newcastle disease virus (NDV) was detected in samples collected from chickens, wild farm birds, and other domestic poultry species during a 2017–2018 survey conducted at 66 BPFs and 21 LBMs in nine Kenyan counties. NDV nucleic acids were detected by rRT-PCR L-test in 39.5% (641/1621) of 1621 analyzed samples, of which 9.67% (62/641) were NDV-positive by both the L-test and a fusion-test designed to identify the virulent virus, with a majority being at LBMs (64.5%; 40/62) compared to BPFs (25.5%; 22/62). Virus isolation and next-generation sequencing (NGS) on a subset of samples resulted in 32 complete NDV genome sequences with 95.8–100% nucleotide identities amongst themselves and 95.7-98.2% identity with other east African isolates from 2010-2016. These isolates were classified as a new sub-genotype, V.3, and shared 86.5–88.9% and 88.5–91.8% nucleotide identities with subgenotypes V.1 and V.2 viruses, respectively. The putative fusion protein cleavage site (¹¹³R-Q-K-R↓F ¹¹⁷) in all 32 isolates, and a 1.86 ICPI score of an isolate from a BPF chicken that had clinical signs consistent with Newcastle disease, confirmed the high virulence of the NDVs. Compared to genotypes V and VI viruses, the attachment (HN) protein of 18 of the 32 vNDVs had amino acid substitutions in the antigenic sites. A time-scaled phylogeographic analysis suggests a west-to-east dispersal of the NDVs via the live chicken trade, but the virus origins remain unconfirmed due to scarcity of continuous and systematic surveillance data. This study reveals the widespread prevalence of vNDVs in Kenyan backyard poultry, the central role of LBMs in the dispersal and possibly generation of new virus variants, and the need for robust molecular epidemiological surveillance in poultry and non-poultry avian species.

Protection conferred by commercial NDV live attenuated and double recombinant HVT vaccines against virulent California 2018 Newcastle disease virus (NDV) in chickens

Vaccines against virulent Newcastle disease virus (NDV) are widely available and can be protective, but improved vaccination protocols are needed to prevent clinical disease and reduce virus circulation. The present study evaluated the efficacy of two commercial vaccines alone or in combination: a live attenuated NDV vaccine (LV) and a recombinant herpesvirus of turkeys vector expressing the fusion protein of NDV and the virus protein 2 of infectious bursal disease virus (rHVT-ND-IBD). Chickens were vaccinated with one of four vaccination protocols: live vaccine (LV) at 1 and 11 days of age (DOA), rHVT ND-IBD and LV at 1 DOA, rHVT ND-IBD at 1 DOA boosted with an LV at 11 DOA, and rHVT ND-IBD at 1 DOA. The vaccinated birds were challenged at different time points (3 or 4 weeks of age) with the California 2018 virus. The mortality, clinical signs, mean death time (MDT), humoral response before and after vaccination, and virus shedding after challenge were evaluated. All vaccination protocols were able to prevent mortality, reduce virus shedding, and induce antibody levels before the challenge at 3 and 4 weeks-old. Overall, the antibody levels before the challenge at 4 weeks were significantly higher in all groups vaccinated with the rHVT ND-IBD when compared to levels in 3 week old birds. The combination of recombinant rHVT ND-IBD with a live vaccine at one-day-old seems to be a better combination, due to the absence of clinical signs, higher antibody levels pre and post-challenge, and reduced virus shedding at any time point after the challenge at 3 or 4 weeks of age with the California 2018 virus.

Single-Nucleotide Polymorphism Analysis to Select Conserved Regions for an Improved Real-Time Reverse Transcription-PCR Test Specific for Newcastle Disease Virus

A bioinformatics approach using single-nucleotide polymorphism (SNP) analysis was performed to improve the current real-time reverse transcription-PCR (RRT-PCR) tests for the rapid detection of Newcastle disease virus (NDV). In total, 422 NDV complete genomes were analyzed using the Virus Pathogen Resource to compare the conservation of the primer and probe sequences and to select regions to develop new RRT-PCR tests. The sensitivity and specificity of the three new RRT-PCR tests targeting the nucleoprotein (NP) and polymerase (L) genes were optimized and were compared with established tests for NDV detection. The SNP analysis was also used to identify the number of mismatches between selected primers/probes and the NDV complete genome sequences. The SNP analysis, averaged over the entire primer or probe, showed the primer/probe sequences of three new tests were more conserved than the primer/probe sequences of the commonly used test targeting the matrix (M) gene. The M RRT-PCR test was compared with the new tests on a panel of 46 viruses, comprising 31 NDV isolates. Limit of detection (LOD) varied from 1.3 to 3.7 log 50% egg-infective doses using five isolates from different genotypes by all tests. The two RRT-PCR tests targeting the L and M genes detected three out of five isolates with the lowest LOD. The NP and M RRT-PCR tests had the lowest and highest rates of genetic variants, respectively, among all probes. Because currently used tests are likely to miss some isolates, the availability of validated alternative tests provides alternatives for detection of viral variants that can be rapidly deployed to diagnostic laboratories.

Retraction Note to: Comparative analysis of the replication of bovine herpesvirus 1 (BHV1) and BHV5 in bovine-derived neuron-like cells

The Editor-in-Chief has retracted this article.

Retraction Note to: Mitochondrial bioenergy alterations in avian HD11 macrophages infected with infectious bronchitis virus

The Editor-in-Chief has retracted this article [1]. Figures 1A, 1D and 2B (bottom right) are identical with Figures 1A, 1H and 1B respectively in another article [2] which reports a study in a different species. In addition, Table 1 contains data presented in a third article [3], which also reports a study in a different species. The Editor-in-Chief therefore no longer has confidence in the validity of the data and the conclusions drawn. Tereza C. Cardoso disagrees with this retraction. Helena L. Ferreira agrees with this retraction. Sergio E. L. da Silva, Andrea F. Garcia, Felipe E. S. Silva, Roberto Gameiro, Carolina U. F. Fabri and Dielson S. Vieira have not responded to any correspondence about this retraction.

Genetic characterization and pathogenesis of the first H9N2 low pathogenic avian influenza viruses isolated from chickens in Kenyan live bird markets

Poultry production plays an important role in the economy and livelihoods of rural households in Kenya. As part of a surveillance program, avian influenza virus (AIV)-specific real-time RT-PCR (RRT-PCR) was used to screen 282 oropharyngeal swabs collected from chickens at six live bird markets (LBMs) and 33 backyard poultry farms in Kenya and 8 positive samples were detected. Virus was isolated in eggs from five samples, sequenced, and identified as H9N2 low pathogenic AIV (LPAIV) G1 lineage, with highest nucleotide sequence identity (98.6-99.9%) to a 2017 Ugandan H9N2 isolate. The H9N2 contained molecular markers for mammalian receptor specificity, implying their zoonotic potential. Virus pathogenesis and transmissibility was assessed by inoculating low and medium virus doses of a representative Kenyan H9N2 LPAIV isolate into experimental chickens and exposing them to naïve uninfected chickens at 2 -days post inoculation (dpi). Virus shedding was determined at 2/4/7 dpi and 2/5 days post placement (dpp), and seroconversion determined at 14 dpi/12 dpp. None of the directly-inoculated or contact birds exhibited any mortality or clinical disease signs. All directly-inoculated birds in the low dose group shed virus during the experiment, while only one contact bird shed virus at 2 dpp. Only two directly-inoculated birds that shed high virus titers seroconverted in that group. All birds in the medium dose group shed virus at 4/7 dpi and at 5 dpp, and they all seroconverted at 12/14 dpp. This is the first reported detection of H9N2 LPAIV from Kenya and it was shown to be infectious and transmissible in chickens by direct contact and represents a new disease threat to poultry and potentially to people.

Rapid evolution of Mexican H7N3 highly pathogenic avian influenza viruses in poultry

Highly pathogenic avian influenza (HPAI) virus subtype H7N3 has been circulating in poultry in Mexico since 2012 and vaccination has been used to control the disease. In this study, eight Mexican H7N3 HPAI viruses from 2015–2017 were isolated and fully sequenced. No evidence of reassortment was detected with other avian influenza (AI) viruses, but phylogenetic analyses show divergence of all eight gene segments into three genetic clusters by 2015, with 94.94 to 98.78 percent nucleotide homology of the HA genes when compared to the index virus from 2012. The HA protein of viruses from each cluster showed a different number of basic amino acids (n = 5–7) in the cleavage site, and six different patterns at the predicted N-glycosylation sites. Comparison of the sequences of the Mexican lineage H7N3 HPAI viruses and American ancestral wild bird AI viruses to characterize the virus evolutionary dynamics showed that the nucleotide substitution rates in PB2, PB1, PA, HA, NP, and NS genes greatly increased once the virus was introduced into poultry. The global nonsynonymous and synonymous ratios imply strong purifying selection driving the evolution of the virus. Forty-nine positively selected sites out of 171 nonsynonymous mutations were identified in the Mexican H7N3 HPAI viruses, including 7 amino acid changes observed in higher proportion in North American poultry origin AI viruses isolates than in wild bird-origin viruses. Continuous monitoring and molecular characterization of the H7N3 HPAI virus is important for better understanding of the virus evolutionary dynamics and further improving control measures including vaccination.

Updated unified phylogenetic classification system and revised nomenclature for Newcastle disease virus

Several Avian paramyxoviruses 1 (synonymous with Newcastle disease virus or NDV, used hereafter) classification systems have been proposed for strain identification and differentiation. These systems pioneered classification efforts; however, they were based on different approaches and lacked objective criteria for the differentiation of isolates. These differences have created discrepancies among systems, rendering discussions and comparisons across studies difficult. Although a system that used objective classification criteria was proposed by Diel and co-workers in 2012, the ample worldwide circulation and constant evolution of NDV, and utilization of only some of the criteria, led to identical naming and/or incorrect assigning of new sub/genotypes. To address these issues, an international consortium of experts was convened to undertake in-depth analyses of NDV genetic diversity. This consortium generated curated, up-to-date, complete fusion gene class I and class II datasets of all known NDV for public use, performed comprehensive phylogenetic neighbor-Joining, maximum-likelihood, Bayesian and nucleotide distance analyses, and compared these inference methods. An updated NDV classification and nomenclature system that incorporates phylogenetic topology, genetic distances, branch support, and epidemiological independence was developed. This new consensus system maintains two NDV classes and existing genotypes, identifies three new class II genotypes, and reduces the number of sub-genotypes. In order to track the ancestry of viruses, a dichotomous naming system for designating sub-genotypes was introduced. In addition, a pilot dataset and sub-trees rooting guidelines for rapid preliminary genotype identification of new isolates are provided. Guidelines for sequence dataset curation and phylogenetic inference, and a detailed comparison between the updated and previous systems are included. To increase the speed of phylogenetic inference and ensure consistency between laboratories, detailed guidelines for the use of a supercomputer are also provided. The proposed unified classification system will facilitate future studies of NDV evolution and epidemiology, and comparison of results obtained across the world.

Virulent Newcastle disease viruses from chicken origin are more pathogenic and transmissible to chickens than viruses normally maintained in wild birds

Five, class II, virulent Newcastle disease virus (vNDV) isolates of different genotypes from different host species were evaluated for their ability to infect, cause disease, and transmit to naïve chickens. Groups of five birds received a low, medium, or high dose, by the oculonasal route, of one of the following vNDV: three chicken-origin, one cormorant-origin, and one pigeon-origin. Three naïve birds were added to each group at two days post-inoculation (DPI) to evaluate transmission. Virus shedding was quantified from swabs (2/4/7 DPI), and seroconversion was evaluated at 14 DPI. All inoculated and contact birds in the chicken-origin vNDV groups succumbed to infection, displaying clinical signs typical of Newcastle disease and shed virus titers above 6 log₁₀ EID₅₀/ml. Birds receiving a high and medium dose of the cormorant virus showed primarily neurological clinical signs with 80% and 60% mortality, respectively. The chickens showing clinical disease shed virus at titers below 4 log₁₀ EID₅₀/ml, and the remaining bird in the high dose group seroconverted with a high HI titer. For the pigeon-origin virus, no clinical signs were observed in any of the birds, but all 5 chickens in the high challenge dose and one bird in the medium challenge group shed virus at mean titers of 3.1 and 2.2 log₁₀ EID₅₀/ml, respectively. Overall, the chicken-origin viruses infected chickens and efficiently transmitted to naïve birds, while the cormorant- and pigeon-origin viruses infected chickens only at the higher doses and did not transmit to other birds.

Presence of Newcastle disease viruses of sub-genotypes Vc and VIn in backyard chickens and in apparently healthy wild birds from Mexico in 2017

Virulent Newcastle disease viruses (NDV) have been present in Mexico since 1946, and recently, multiple outbreaks have been reported in the country. Here, we characterized eleven NDV isolated from apparently healthy wild birds and backyard chickens in three different locations of Jalisco, Mexico in 2017. Total RNA from NDV was reverse-transcribed, and 1285 nucleotides, which includes 3/4 of the fusion gene, was amplified and sequenced using a long-read MinION sequencing method. The sequences were 99.99-100% identical to the corresponding region obtained using the Illumina MiSeq. Phylogenetic analysis using MinION sequences demonstrated that nine virulent NDV from wild birds belonged to sub-genotypes Vc and VIn, and two backyard chicken isolates were of sub-genotype Vc. The sub-genotype Vc viruses had nucleotide sequence identity that ranged from 97.7 to 98% to a virus of the same sub-genotype isolated from a chicken in Mexico in 2010. Three viruses from pigeons had 96.3-98.7% nucleotide identity to sub-genotype VIn pigeon viruses, commonly referred to as pigeon paramyxovirus, isolated in the USA during 2000-2016. This study demonstrates that viruses of sub-genotype Vc are still present in Mexico, and the detection of this sub-genotype in both chickens and wild birds suggests that transmission among these species may represent a biosecurity risk. This is the first detection and complete genome sequencing of genotype VI NDV from Mexico. In addition, the utilization of an optimized long-read sequencing method for rapid virulence and genotype identification using the Oxford nanopore MinION system is demonstrated.

RETRACTED: Bovine Herpesvirus 5 promotes mitochondrial dysfunction in cultured bovine monocyte-derived macrophages and not affect virus replication

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Editors-in-Chief and Authors. Fig 1A is a duplicate of a figure that has already been published in da Silva SEL et al. Archives of Virology 2018;163:1043-1049; 10.1007/s00705-018-3704-2. These two papers report studies performed with cells from two different animal species (bovine cells for the Veterinary Microbiology paper and chicken cells for the Archives of Virology paper). The reuse of the same figure in the Veterinary Microbiology paper to describe cells that were supposed to be from a different species is thus inappropriate and also puts into question the reliability of the other results presented in this paper. In addition, the Editors-in-Chief have remaining concerns about the strong similarities of other data presented in the two papers. Even if these concerns were addressed, the re-use of any data has to be clearly indicated and appropriately cited. As such this article represents a misuse of the scientific publishing system. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process.

Molecular and serological detection of Leishmania spp. in horses from an endemic area for canine visceral leishmaniasis in southeastern Brazil

ABSTRACT: This study aimed to verify the occurrence of Leishmania spp. and Leishmania (Leishmania) infantum in horses from a visceral leishmaniasis endemic area in Brazil. DNA samples from blood and conjunctival swab (CS) were tested by PCR and Indirect Immunofluorescence Antibody Test (IFAT). Although none of the horses was clinically sick, animals infected by Leishmania spp. were found and some could be characterized as infected by L. (L.) infantum. From 40 horses, 100% of the animals were positive by blood PCR, 90% (36/40) by CS PCR, and 2.5% (01/40) in serodiagnosis, by IFAT. Six from these 40 horses were L. (L.) infantum positive by blood PCR. Direct sequencing and analysis of amplicons resulted in a sequence to evolutionary analysis. Results indicate the presence of Leishmania spp. and L. (L.) infantum infecting healthy horses in Brazil. The presence of Leishmania spp. and L. (L.) infantum DNA in asymptomatic horses suggests that they can be important reservoirs of these parasites, a highly relevant finding for the epidemiological surveillance of the diseases they cause.

Avian coronavirus isolated from a pigeon sample induced clinical disease, tracheal ciliostasis, and a high humoral response in day-old chicks

The detection of avian coronaviruses (AvCoV) in wild birds and the emergence of new AvCoV have increased in the past few years. In the present study, the pathogenicity of three AvCoV isolates was investigated in day-old chicks. One AvCoV isolated from a pigeon, which clustered with the Massachusetts vaccine serotype, and two AvCoV isolated from chickens, which grouped with a Brazilian genotype lineage, were used. Clinical signs, gross lesions, histopathological changes, ciliary activity, viral RNA detection, and serology were evaluated during 42 days post infection. All AvCoV isolates induced clinical signs, gross lesions in the trachea, moderate histopathological changes in the respiratory tract, and mild changes in other tissues. AvCoV isolated from the pigeon sample caused complete tracheal ciliostasis over a longer time span. Specific viral RNA was detected in all tissues, but the highest RNA loads were detected in the digestive tract (cloacal swabs and ileum). The highest antibody levels were also detected in the group infected with an isolate from the pigeon. These results confirm the pathogenicity of Brazilian variants, which can cause disease and induce gross lesions and histopathological changes in chickens. Our results suggest that non-Galliformes birds can also play a role in the ecology of AvCoV.

Mitochondrial bioenergy alterations in avian HD11 macrophages infected with infectious bronchitis virus

To establish an association between mitochondrial dysfunction and apoptosis following infectious bronchitis virus (IBV) infection, HD11 avian macrophage cells were infected with the Massachusetts 41 (M41) strain. Our results show that the M41 strain of IBV induced cytopathic effects followed by the release of new viral particles. Elevated numbers of apoptotic cells were observed at 24, 48 and 72 h post-infection (p.i.). Viral infection was associated with mitochondrial membrane depolarization and reactive oxygen species (ROS) production at all of the examined timepoints p.i. In summary, IBV M41 replication in infected HD11 macrophages seems to induce mitochondrial bioenergy failure, acting as a respiratory chain uncoupler, without compromising viral replication.

Brucella canis infection in dogs from commercial breeding kennels in Brazil

Canine brucellosis caused by Brucella canis is a neglected zoonosis worldwide and is a leading cause of reproductive failure in dogs, often causing substantial economic losses in breeding kennels. This study aimed to investigate the occurrence of B. canis infection in dogs of commercial breeding kennels located in São Paulo State, Brazil. A total of 753 dogs (183 males and 570 females) from 38 commercial kennels were clinically examined, and blood samples were collected for brucellosis diagnosis through blood culture. The association between clinical manifestations suggestive of brucellosis and positive results through blood culture was determined. Of the 753 dogs tested, 166 (22.0%) had at least one clinical sign suggestive of brucellosis and 158 (20.9%) had positive blood cultures. Seventy-two dogs had positive blood culture and had at least one clinical sign suggestive of brucellosis, while 91 dogs showed at least one clinical manifestation suggestive of brucellosis although blood culture was negative. Of the 38 kennels, 16 (42.1%) had at least one positive dog. The prevalence of infection in each kennel varied from 3.8% to 62.6%. Abortion/stillbirth, failure to conceive and enlargement of lymph nodes were significantly associated with brucellosis in female. No association of clinical signs and positive results in blood culture was observed in males. None of the kennels has been carrying out programmes to control brucellosis, and the sale of infected dogs was considered a common practice yielding risks to the public health, in view of the zoonotic potential of the infection.

Cellular response markers and cytokine gene expression in the central nervous system of cattle naturally infected with bovine herpesvirus 5

The present study reports an investigation on the phenotype of inflammatory and immune cells, cytokine and viral gene expression in the brains of cattle naturally infected with bovine herpesvirus 5 (BHV5). Brain sections of 38 affected animals were analysed for the nature and extent of perivascular cuffs in the Virchow-Robin space and parenchyma. Histopathological changes were severe in the olfactory bulbs (Obs), hippocampus, piriform, frontal, temporal and parietal cortices/lobes and were characterized by inflammatory infiltrates in Virchow-Robin spaces. The histopathological changes correlated positively with the distribution of BHV5 antigens (r = 0.947; P < 0.005). Cells of CD3+ phenotype were predominant in areas with severe perivascular cuffs. Viral antigens and genomic viral DNA were detected in the Obs and piriform lobe, simultaneously (r = 0.987; P < 0.005). Similarly, pro-inflammatory cytokine genes INFG, IL2, TNF and LTBR were expressed in the same brain areas (P < 0.005). These results provide important information on the inflammatory and immunological events accompanying BHV5 neurological infections. Our findings provide the first evidence for increased immune activation followed by inflammatory cytokine expression, positively correlated with viral replication in the cranial areas of the brain. Taken together, these results suggest that the host immune response and inflammation play a crucial role in the pathogenesis of acute encephalitis by BHV5 in cattle.

Isolation, characterization and immunomodulatory-associated gene transcription of Wharton's jelly-derived multipotent mesenchymal stromal cells at different trimesters of cow pregnancy

The possibility of isolating bovine mesenchymal multipotent stromal cells (MSCs) from fetal adnexa is an interesting prospect due to the potential use of these cells in biotechnological applications. However, little is known about the properties of these progenitor cells in bovine species. Wharton's jelly (WJ) MSC cells were obtained from the umbilical cord of bovine fetuses at three different stages of pregnancy and divided into groups 1, 2 and 3 according to gestational trimester. Cell morphology, from the three stages of pregnancy, typically appeared fibroblast-like spindle-shaped, presenting the same viability and number. Moreover, the proliferative ability of T-cells in response to a mitogenic stimulus was suppressed when WJMSC cells were added to the culture. Multilineage properties were confirmed by their ability to undergo adipogenic, osteogenic/chondrogenic and neurogenic differentiation. Mesenchymal phenotyping, CD105+, CD29+, CD73+ and CD90+ cell markers were detected in all three cell groups, yet these markers were considered more expressed in MSCs of group 2 (p < 0.005). Expression of cytokines IL2, IL6RR, INFAC, INFB1, IFNG, TNF and LTBR were downregulated, whereas IL1F10 expression was upregulated in all tested WJMSCs. The present study demonstrated that WJMSCs harvested from the bovine umbilical cord at different gestational stages showed proliferative capacity, immune privilege and stemness potential.

Presence of Vaccine-Derived Newcastle Disease Viruses in Wild Birds

Our study demonstrates the repeated isolation of vaccine-derived Newcastle disease viruses from different species of wild birds across four continents from 1997 through 2014. The data indicate that at least 17 species from ten avian orders occupying different habitats excrete vaccine-derived Newcastle disease viruses. The most frequently reported isolates were detected among individuals in the order Columbiformes (n = 23), followed in frequency by the order Anseriformes (n = 13). Samples were isolated from both free-ranging (n = 47) and wild birds kept in captivity (n = 7). The number of recovered vaccine-derived viruses corresponded with the most widely utilized vaccines, LaSota (n = 28) and Hitchner B1 (n = 19). Other detected vaccine-derived viruses resembled the PHY-LMV2 and V4 vaccines, with five and two cases, respectively. These results and the ubiquitous and synanthropic nature of wild pigeons highlight their potential role as indicator species for the presence of Newcastle disease virus of low virulence in the environment. The reverse spillover of live agents from domestic animals to wildlife as a result of the expansion of livestock industries employing massive amounts of live virus vaccines represent an underappreciated and poorly studied effect of human activity on wildlife.

Bovine herpesviruses induce different cell death forms in neuronal and glial-derived tumor cell cultures

Oncolytic viruses have the ability to infect tumor cells and leave healthy cells intact. In this study, bovine herpesvirus 1 (BHV1; Los Angeles, Cooper, and SV56/90 strains) and bovine herpesvirus 5 (BHV5; SV507/99 and GU9457818 strains) were used to infect two neuronal tumor cell lineages: neuro2a (mouse neuroblastoma cells) and C6 (rat glial cells). BHV1 and BHV5 strains infected both cell lines and positively correlated with viral antigen detection (p < 0.005). When neuro2a cells were infected by Los Angeles, SV507/99, and GU9457818 strains, 40 % of infected cells were under early apoptosis and necroptosis pathways. Infected C6 cells were >40 % in necroptosis phase when infected by BHV5 (GU9457818 strain). Blocking caspase activation did not interfere with cell death. However, when necroptosis was blocked, 60-80 % of both infected cells with either virus switched to early apoptosis pathway with no interference with virus replication. Moreover, reactive oxygen species production and mitochondrial membrane dysfunction were detected at high levels in both infected cell lines. In spite of apoptosis and necroptosis blockage, tumor necrosis factor alpha (TNFA) and virus transcription were positively correlated for all viral strains studied. Thus, these results contribute to the characterization of BHV1 and BHV5 as potential oncolytic viruses for non-human cells. Nonetheless, the mechanisms underlying their oncolytic activity in human cells are still to be determined.

A three-dimensional cell culture system as an in vitro canine mammary carcinoma model for the expression of connective tissue modulators

In this study, derived complex carcinoma (CC) and simple carcinoma (SC) cell lines were established and cultured under two-dimensional (2D) and three-dimensional (3D) conditions. The 3D was performed in six-well AlgiMatrix™ (LifeTechnologies®, Carlsbad, CA, USA) scaffolds, resulting in spheroids sized 50-125 µm for CC and 175-200 µm for SC. Cell viability was demonstrated up to 14 days for both models. Epidermal growth factor receptor (EGFR) was expressed in CC and SC in both systems. However, higher mRNA and protein levels were observed in SC 2D and 3D systems when compared with CC (P < 0.005). The connective tissue modulators, metalloproteinases-1, -2, -9 and -13 (MMPs), relaxin receptors 1 and 2 (RXR1 and RXR2) and E-cadherin (CDH1) were quantitated. All were upregulated similarly when canine mammary tumour (CMT)-derived cell lines were cultured under 3D AlgiMatrix, except CDH1 that was downregulated (P < 0.005). These results are promising towards the used of 3D system to increase a high throughput in vitro canine tumour model.

Evaluation of an Immunochromatographic Test to the Diagnosis of Canine Brucellosis Caused by Brucella canis

This study evaluated the performance of an immunochromatographic test (ICT) for the diagnosis of canine brucellosis caused by Brucella canis, comparing its results with that of the rapid slide agglutination test with and without the use of 2-mercaptoethanol and the agar gel immunodiffusion test (AGID). The microbiological culture, PCR and clinical examination were used as reference. According to the results obtained in clinical examination, blood culture, culture of semen and vaginal swab and PCR in blood, semen and vaginal swab, a total of 102 dogs were divided into three groups: B. canis-infected dogs (Group 1), B. canis-non-infected dogs (Group 2) and dogs with suspected brucellosis (Group 3). The diagnostic sensitivity of RSAT, 2ME-RSAT, AGID and ICT in Group 1 was, respectively, 75%, 37.5%, 27.8% and 89.58%. The diagnostic specificity of RSAT, 2ME-RSAT, AGID and ICT in Group 2 was, respectively, 91%, 100%, 100%, and 100%. In dogs with suspected brucellosis, 9.67% were RSAT positive, none was positive by 2ME-RSAT, 3.22% were AGID positive and 6.45% were ICT positive. The main drawback concerning canine brucellosis diagnosis is the lack of a highly sensitive serological assay to be used as a screening test to the rapid identification of infected animals. The ICT showed a high diagnostic specificity and a diagnostic sensitivity value greater than that observed in the RSAT, 2ME-RSAT and AGID. However, 10.41% of infected dogs had negative results by ICT. These dogs were positive by microbiological culture and/or PCR, indicating active infection and consequently a higher potential of spreading Brucella. Although rapid and simple to perform, the ICT lacked sensitivity to be used as a screening test.

Tumour necrosis factor-alpha-induced protein 8 (TNFAIP8) expression associated with cell survival and death in cancer cell lines infected with canine distemper virus

Oncolytic virotherapy is a novel strategy for treatment of cancer in humans and companion animals as well. Canine distemper virus (CDV), a paramyxovirus, has proven to be oncolytic through induction of apoptosis in canine-derived tumour cells, yet the mechanism behind this inhibitory action is poorly understood. In this study, three human mammary tumour cell lines and one canine-derived adenofibrosarcoma cell line were tested regarding to their susceptibility to CDV infection, cell proliferation, apoptosis, mitochondrial membrane potential and expression of tumour necrosis factor-alpha-induced protein 8 (TNFAIP8). CDV replication-induced cytopathic effect, decrease of cell proliferation rates, and >45% of infected cells were considered death and/or under late apoptosis/necrosis. TNFAIP8 and CDVM gene expression were positively correlated in all cell lines. In addition, mitochondrial membrane depolarization was associated with increase in virus titres (p < 0.005). Thus, these results strongly suggest that both human and canine mammary tumour cells are potential candidates for studies concerning CDV-induced cancer therapy.

Experimental infection of inbred BALB/c and A/J mice with Massachusetts and Brazilian strains of infectious bronchitis virus (IBV)

The ability of avian coronaviruses to replicate in mice was investigated to investigate interspecies transmission. Two inbred mouse strains (BALB/c and A/J) with different genetic backgrounds were inoculated with the avian coronavirus strains Mass and BR-I and monitored for at least 10 days. Analysis of viral RNA, histopathological examinations, immunohistochemistry and serology were performed. After virus inoculation, neither clinical signs nor evident gross lesions were observed. Viral RNA, histopathological changes, and viral nucleoprotein were observed in the lung, trachea and sinus of all inoculated mice. Our study demonstrates the importance of elucidating the epidemiology of coronaviruses, including in rodents that are pests in poultry production.

Prevalence of newcastle disease virus in broiler chickens (Gallus gallus) in Brazil

This study was carried out during 2002/2003, aiming to determine the prevalence of virulent Newcastle disease virus strains (NDV) in Brazilian commercial poultry farms. Clinical samples were obtained from the Southeastern, Southern and Central-Western regions, which comprise the main area of the Brazilian poultry production. Serum samples and tracheal and cloacal swabs of 23,745 broiler chickens from 1,583 flocks, including both vaccinated chickens and those with no vaccination information, were tested for NDV using a diagnostic ELISA kit. The seropositivity was 39.1%, and the isolation percentage by flock varied from 1.0 to 7.6%, and by region from 6.5 to 58.4%. Higher isolation rates (74.3-83.3%) were obtained after three passages in embryonated chicken eggs. All isolates preliminarily identified as NDV were characterized as nonpathogenic strains, as their Intracerebral Pathogenicity Index (ICPI) was below 0.7. Based on results of this study, Brazil can claim a virulent NDV-free status for commercial flocks.

Infectious bronchitis virus replication in the chicken embryo related cell line

The susceptibility of the chicken embryo related (CER) cell line to infectious bronchitis virus (IBV M41) was characterized after five consecutive passages in CER cells. Virus replication was monitored by cytopathic effect observation, electron microscopy, indirect immunofluorescence, and reverse transcription polymerase chain reaction (RT-PCR). At 96 h post-infection (p.i.), the cytopathic effect was graded 75% by cell fusion, rounding up of cells and monolayer detachment, and the electron microscopy image characterized by coronavirus morphology. Cytoplasmic fluorescence was readily observed by from 24 h p.i. onwards, and at all times the respective viral RNA from IBV-infected monolayers was demonstrated by RT-PCR. Extra-cellular virus was measured by virus titration performed on chicken kidney cells and embryonated chicken eggs, and respective titres ranged from 4.0 to 6.0 log10 EID50/ml on embryonated chicken eggs, and from 2.0 to 6.0 log10 TCID50/ml on both CER cells and chicken kidney cells studied from 24 to 120 h p.i. These results confirmed that the M41 strain replicated well in the CER cell line.

A Universal Avian Endogenous Real-Time Reverse Transcriptase–Polymerase Chain Reaction Control and Its Application to Avian Influenza Diagnosis and Quantification

Real-time reverse transcriptase-polymerase chain reaction (RRT-PCR) is becoming an established first-line diagnostic assay as well as a precise quantification tool for avian influenza virus detection. However, there remain some limitations. First, we show that the sensitivity of RRT-PCR influenza detection can be 10- to 100-fold inhibited in oropharyngeal and cloacal swabs. Adding 0.5 U of heat-activated Taq DNA polymerase successfully reverses PCR inhibition. Second, an excellent strategy for detecting false negative samples is the coamplification of an internal control from each sample. We developed a universal avian endogenous internal control (bird beta-actin) and apply it to influenza A diagnosis. Moreover, this internal control proves useful as a normalizer control for virus quantification, because beta-actin gene expression does not change in infected vs. uninfected ducks. A combined panel of wild bird cloacal swabs, wild bird tissue samples, experimental duck swabs, and experimental duck and chicken tissue samples was used to validate the endogenous control. The application of an endogenous internal control proves an excellent strategy both for avoiding false negative diagnostic results and for standardizing virus quantification studies.

Comparative Study of Three Different ELISA to Measure the Antibodies Against Infectious Bronchitis Virus in Vaccinated and Unvaccinated Broilers

Broilers were spray-vaccinated (n=150) with H120 serotype at one-day-old, challenged after 28 days with M41 IBV serotype and after bled at day 28, 34 and 46 after challenged. The respective sera were tested by the indirect ELISA (I-ELISA), sandwich ELISA (S-ELISA), liquid phase blocking ELISA (LPB-ELISA) and the standard serum neutralization test (SNT). For this purpose, a total of 300 sera samples, 150 from non vaccinated and 150 from vaccinated broilers were titrated by all the serological methods and the correlation coefficients were determined. The correlation values (r) between LPB-ELISA x SNT, S-ELISA x SNT, I-ELISA x SNT found werer = 0.98, r = 0.79, and r = 0.74, respectively. Nevertheless, the r between LPB-ELISA x S-ELISA, LPB-ELISA x I-ELISA and S-ELISA x I-ELISA were r = 0.75, r = 0.69 and r = 0.79. In fact , the I-ELISA and the S-ELISA had almost the same correlation with S-ELISA and LPB-ELISA, in contrast with the I-ELISA and LPB-ELISA. It was concluded that LPB-ELISA showed better sensitivity than I-ELISA and S-ELISA, also after 46 days challenge with the heterologous serotype. However, these two last techniques demonstrated similar specificity when the titers were compared with those obtained in SNT, even though after the heterologous serotype challenge the SNT produced better results. This study demonstrated the close relationship between LPB-ELISA and SNT assays.