Incursion of Highly Pathogenic Avian Influenza A(H5N1) Clade 2.3.4.4b Virus, Brazil, 2023

We report 4 highly pathogenic avian influenza A(H5N1) clade 2.3.4.4.b viruses in samples collected during June 2023 from Royal terns and Cabot's terns in Brazil. Phylodynamic analysis revealed viral movement from Peru to Brazil, indicating a concerning spread of this clade along the Atlantic Americas migratory bird flyway.

Genetic diversity of adenovirus in neotropical bats from Brazil

Bats can harbor a diversity of viruses, such as adenovirus. Ten different species of bat adenoviruses (BtAdV A to J) have been previous described worlwide. In Brazil, BtAdV was described in three species of phyllostomid species: Artibeus lituratus, Desmodus rotundus, and Sturnira lilium. There are around 180 bat species in Brazil, with 67% inhabiting the Atlantic Forest, with few information about the circulation of BtAdV in this biome. We aimed to describe the molecular detection and the phylogenetic characterization and suggest a classification of BtAdVs circulating in bats from the Brazilian Atlantic Forest. We collected 382 oral and rectal swabs from 208 bats between 2014-2015 and 2020-2021 from São Paulo, Pernambuco, and Santa Catarina Brazilian states. The adenovirus detection was done by a nested PCR targeting the DNA polymerase gene, and all positive samples were sequenced by the Sanger method. The phylogenetic analyses were based on the amino acid sequences using the MEGA 7 and BEAST software. We obtained 16 positive animals (detection rate 7.7%) belonging to seven bat species: Artibeus lituratus, Carollia perspicillata, Sturnira lilium, Molossus molossus, and the first record of Phyllostomus discolor, Eptesicus diminutus, and Myotis riparius. The phylogenetic analysis based on partial amino acid sequences showed that all obtained AdV sequences belong to the Mastadenovirus genus. We observed a high genetic diversity of BtAdV and identified eleven potential BtAdV species circulating in Brazil (BtAdV K to U). Our results contribute to the epidemiological surveillance of adenovirus, increasing the knowledge about the viral diversity and the distribution of AdV in bats from the Atlantic Forest.

33rd Brazilian Society for Virology (SBV) 2022 Annual Meeting

Each year, the Brazilian Society for Virology promotes a national meeting during the second semester of the year. In October 2022, the 33rd meeting took place at Arraial da Ajuda, Porto Seguro, Bahia, in-person:.this was the first in-person meeting since 2019, as the 2020 and 2021 events occurred online due to the issues imposed by COVID-19. It was a great pleasure for the whole audience to return to an in-person event, which certainly improved the interactions between the attendees in all ways. As usual, the meeting involved massive participation of undergraduate, graduate, and postdoc students, and several noteworthy international researchers were present. During five afternoons and evenings, attendees could discuss and learn about the most recent data presented by distinguished scientists from Brazil and other countries. In addition, young virology researchers from all levels could present their latest results as oral presentations and posters. The meeting covered all virology areas, with conferences and roundtables about human, veterinary, fundamental, environmental, invertebrate, and plant virology. The costs associated with attending the in-person event caused a slight reduction in the number of attendees compared to the two online events. However, even with this issue, the attendance was impressive. The meeting successfully achieved its most important goals: inspiring young and senior scientists and discussing high-quality, up-to-date virology research.

SARS-CoV-2 Spillback to Wild Coatis in Sylvatic-Urban Hotspot, Brazil

We tested coatis (Nasua nasua) living in an urban park near a densely populated area of Brazil and found natural SARS-CoV-2 Zeta variant infections by using quantitative reverse transcription PCR, genomic sequencing, and serologic surveillance. We recommend a One Health strategy to improve surveillance of and response to COVID-19.

H6N8 avian influenza virus in Antarctic seabirds demonstrates connectivity between South America and Antarctica

Wild aquatic birds are the natural reservoirs of avian influenza viruses (AIVs). It is estimated that 100 million seabirds live in the Antarctic Peninsula and adjacent islands, regularly encountering migratory birds that use the islands to nest. Between 2010 and 2013, we collected samples from 865 seabirds in Elephant, King George and Livingston islands, around Antarctica Peninsula: chinstrap penguin (n = 143); gentoo penguin (n = 208); Adelie penguin (n = 46); brown skua (n = 90); Cape petrel (n = 115) and southern giant petrel (n = 263). Serum (n = 673) samples were analysed by competitive ELISA and swabs (n = 614) were tested by one step real-time RT-PCR for avian influenza virus (AIV). Sera from 30 chinstrap penguins, 76 brown skuas and a single Adelie penguin were seropositive for AIV. Thirteen swab samples were AIV positive by RT-PCR, and complete genome sequences of H6N8 AIVs isolated from brown skua and chinstrap penguin in 2011 were obtained. Phylogenetic analyses indicated that all gene segments of the H6N8 viruses were closely related to Argentinian and Chilean AIVs. The prevalence with which we identified evidence for AIVs infection in various Antarctic seabirds suggest viral circulation in Antarctic avifauna and interspecies viral transmission in the sub-Antarctic region.

Long-Term Wastewater Surveillance for SARS-CoV-2: One-Year Study in Brazil

Wastewater-based epidemiology (WBE) is a tool involving the analysis of wastewater for chemicals and pathogens at the community level. WBE has been shown to be an effective surveillance system for SARS-CoV-2, providing an early-warning-detection system for disease prevalence in the community via the detection of genetic materials in the wastewater. In numerous nation-states, studies have indicated the presence of SARS-CoV-2 in wastewater. Herein, we report the primary time-course monitoring of SARS-CoV-2 RNA in wastewater samples in São José do Rio Preto-SP/Brazil in order to explain the dynamics of the presence of SARS-CoV-2 RNA during one year of the SARS-CoV-2 pandemic and analyze possible relationships with other environmental parameters. We performed RNA quantification of SARS-CoV-2 by RT-qPCR using N1 and N2 targets. The proportion of positive samples for every target resulted in 100% and 96.6% for N1 and N2, respectively. A mean lag of -5 days is observed between the wastewater signal and the new SARS-CoV-2-positive cases reported. A correlation was found between the air and wastewater temperatures and therefore between the SARS-CoV-2 viral titers for N1 and N2 targets. We also observed a correlation between SARS-CoV-2 viral titers and media wastewater flow for the N1 target. In addition, we observed higher viral genome copies within the wastewater samples collected on non-rainy days for the N1 target. Thus, we propose that, based on our results, monitoring raw wastewater may be a broadly applicable strategy that might contribute to resolving the pressing problem of insufficient diagnostic testing; it may represent an inexpensive and early-warning method for future COVID-19 outbreaks, mainly in lower- and middle-income countries.

Hemorrhagic fever viruses: Pathogenesis, therapeutics, and emerging and re-emerging potential

Hemorrhagic fever viruses (HFVs) pose a threat to global public health owing to the emergence and re-emergence of highly fatal diseases. Viral hemorrhagic fevers (VHFs) caused by these viruses are mostly characterized by an acute febrile syndrome with coagulation abnormalities and generalized hemorrhage that may lead to life-threatening organ dysfunction. Currently, the events underlying the viral pathogenicity associated with multiple organ dysfunction syndrome still underexplored. In this minireview, we address the current knowledge of the mechanisms underlying VHFs pathogenesis and discuss the available development of preventive and therapeutic options to treat these infections. Furthermore, we discuss the potential of HFVs to cause worldwide emergencies along with factors that favor their spread beyond their original niches.

First detection of Psittacid alphaherpesvirus 5 and coinfection with beak and feather disease virus in naturally infected captive ringneck parakeets (Psittacula krameri) in Brazil

This study describes a case report in captive rose-ringed parakeets (Psittacula krameri) that developed clinical signs and eventually died after introducing new birds without quarantine. Bronchopneumonia and airsacculitis with syncytial cells associated with intranuclear inclusion bodies were found. Herpesvirus was detected in lungs and liver by PCR, and a nearly complete genome sequence of a Psittacid alphaherpesvirus 5 was obtained from the lung of a bird. Metagenomic analysis also identified beak and feather disease virus in the same samples. The study also highlights the importance of quarantine for avoiding the introduction of new diseases in captive aviaries.

High genetic diversity of alphacoronaviruses in bat species (Mammalia: Chiroptera) from the Atlantic Forest in Brazil

Bat coronaviruses (Bat-CoV) represent around 35% of all virus genomes described in bats. Brazil has one of the highest mammal species diversities, with 181 species of bats described so far. However, few Bat-CoV surveillance programs were carried out in the country. Thus, our aim was to evaluate the Bat-CoV diversity in the Atlantic Forest, the second biome with the highest number of bat species in Brazil. We analyzed 456 oral and rectal swabs and 22 tissue samples from Atlantic Forest bats, detecting Alphacoronavirus in 44 swab samples (9.64%) targeting the RdRp gene from seven different bat species, three of them that have never been described as Bat-CoV hosts. Phylogenetic analysis of the amino acid (aa) sequences coding the RdRp gene grouped the sequences obtained in our study with Bat-CoV previously detected in identical or congeneric bat species, with high aa identity (over 90%). The RdRp gene was also detected in three tissue samples from Diphylla ecaudata and Sturnira lilium, and the partial S gene was successfully sequenced in five tissues and swab samples of D. ecaudata. The phylogenetic analysis based on the partial S gene obtained here grouped with the sequence of D. ecaudata with CoV from Desmodus rotundus previously detected in Peru and Brazil, with aa identity ranging from 73.6% to 88.8%. Our data reinforce the wide distribution of Coronaviruses in bats from Brazil and the novelty of three bats species as Bat-CoV hosts and the co-circulation of four Alphacoronavirus subgenera in Brazil. This article is protected by copyright. All rights reserved.

Impact of SARS-CoV-2 Gamma lineage introduction and COVID-19 vaccination on the epidemiological landscape of a Brazilian city

Background

The emergence of the Brazilian variant of concern, Gamma lineage (P.1), impacted the epidemiological profile of COVID-19 cases due to its higher transmissibility rate and immune evasion ability.

Methods

We sequenced 305 SARS-CoV-2 whole-genomes and performed phylogenetic analyses to identify introduction events and the circulating lineages. Additionally, we use epidemiological data of COVID-19 cases, severe cases, and deaths to measure the impact of vaccination coverage and mortality risk.

Results

Here we show that Gamma introduction in São José do Rio Preto, São Paulo, Brazil, was followed by the displacement of seven circulating SARS-CoV-2 variants and a rapid increase in prevalence two months after its first detection in January 2021. Moreover, Gamma variant is associated with increased mortality risk and severity of COVID-19 cases in younger age groups, which corresponds to the unvaccinated population at the time.

Conclusions

Our findings highlight the beneficial effects of vaccination indicated by a pronounced reduction of severe cases and deaths in immunized individuals, reinforcing the need for rapid and massive vaccination.

The 32nd Brazilian Society of Virology (SBV) 2021 Annual Meeting

The Brazilian Society of Virology has been organizing annual meetings for 32 years now. The 32nd annual meeting, which occurred in 2021, was once again an online meeting in consequence of the issues imposed by COVID-19, even with the vaccination advances. As in the 2020 meeting, the number of attendees was high, with considerable participation by undergraduate, graduate, and postdoc students. Distinguished scientists from different countries offered high-quality conferences, and oral presentation sessions were presented by young scientists showing their newest research results. For almost five hours a day during five days, attendees discussed high-quality science related to all areas of virology. Even with the difficulties imposed by another pandemic year, the 32nd SBV annual meeting achieved its most important goal-to inspire young scientists and discuss high-quality virology research.

In situ cytokine gene expression in early stage of virulent Newcastle disease in chickens

Selected lymphoid and reproductive tissues were examined from groups of 3-week-old chickens and 62-week-old hens that were inoculated choanally and conjunctivally with 10⁶ EID₅₀ of a virulent Newcastle disease virus (NDV) isolate from the California 2018-2020 outbreak, and euthanized at 1, 2, and 3 days postinfection. In the 3-week-old chickens, immunohistochemistry for NDV and for T and B cell lymphocytes, as well as in situ hybridization for IL-1β, IL-6, IFN-γ, and TNF-α revealed extensive expression of IL-1β and IL-6 in lymphoid tissues, often coinciding with NDV antigen. IFN-γ was only expressed infrequently in the same lymphoid tissues, and TNF-α was rarely expressed. T-cell populations initially expanded but by day 3 their numbers were below control levels. B cells underwent a similar expansion but remained elevated in some tissues, notably spleen, cecal tonsils, and cloacal bursa. Cytokine expression in the 62-week-old hens was overall lower than in the 3-week-old birds, and there was more prolonged infiltration of both T and B cells in the older birds. The strong pro-inflammatory cytokine response in young chickens is proposed as the reason for more severe disease.

The Emergence of the New P.4 Lineage of SARS-CoV-2 With Spike L452R Mutation in Brazil

The emergence of several SARS-CoV-2 lineages presenting adaptive mutations is a matter of concern worldwide due to their potential ability to increase transmission and/or evade the immune response. While performing epidemiological and genomic surveillance of SARS-CoV-2 in samples from Porto Ferreira—São Paulo—Brazil, we identified sequences classified by pangolin as B.1.1.28 harboring Spike L452R mutation, in the RBD region. Phylogenetic analysis revealed that these sequences grouped into a monophyletic branch, with others from Brazil, mainly from the state of São Paulo. The sequences had a set of 15 clade defining amino acid mutations, of which six were in the Spike protein. A new lineage was proposed to Pango and it was accepted and designated P.4. In samples from the city of Porto Ferreira, P.4 lineage has been increasing in frequency since it was first detected in March 2021, corresponding to 34.7% of the samples sequenced in June, the second in prevalence after P.1. Also, it is circulating in 30 cities from the state of São Paulo, and it was also detected in one sample from the state of Sergipe and two from the state of Rio de Janeiro. Further studies are needed to understand whether P.4 should be considered a new threat.

Case Study of Two Post Vaccination SARS-CoV-2 Infections with P1 Variants in CoronaVac Vaccinees in Brazil

The rapid development of efficacious and safe vaccines against coronavirus disease 2019 (COVID-19) has been instrumental in mitigating the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Moreover, the emergence of SARS-CoV-2 variants raised concerns on the efficacy of these vaccines. Herein, we report two cases of breakthrough infections with the P1 variant in patients vaccinated with CoronaVac, which is one of the two vaccines authorized for emergency use in the Brazilian immunization program. Our observations suggest that the vaccine reduced the severity of the disease and highlight the potential risk of illness following vaccination and subsequent infection with the P1 variant as well as for continued efforts to prevent and diagnose infection in vaccinated persons.

Oncolytic effect of Newcastle disease virus is attributed to interferon regulation in canine mammary cancer cell lines

Canine mammary carcinoma (CMC) is one of the major health threats in dogs. The oncolytic virotherapy is a promising strategy to treat canine as well as human cancer patients with non-pathogenic replicating viruses. Here, we evaluated the antitumor activity of one lentogenic, non-lytic Newcastle disease virus (NDV) LaSota strain expressing GFP (NDV-GFP) on five different CMCs and one non-tumorigenic cell line, regarding cell viability, cell death, selectivity index, morphology, global and target gene expression analysis. As evidenced by the selectivity index, all CMC cell lines were more susceptible to NDV-GFP in comparison with the non-tumorigenic cells (~3.1× to ~78.7×). In addition, the oncolytic effect of NDV-GFP was more evident in more malignant CMC cells. Also, we observed an inverse association of the IFN pathway expression and the susceptibility to NDV. The downregulated genes in NDV-GFP-sensitive cells were functionally enriched for antiviral mechanisms by interferon and immune system pathways, demonstrating that these mechanisms are the most prominent for oncolysis by NDV. To our knowledge, this is the first description of oncolysis by an NDV strain in canine mammary cancer cells. We also demonstrated specific molecular pathways related to NDV susceptibility in these cancer cells, opening the possibility to use NDV as a therapeutic-targeted option for more malignant CMCs. Therefore, these results urge for more studies using oncolytic NDVs, especially considering genetic editing to improve efficacy in dogs.

Detection of Leishmania infantum DNA in blood samples of horses (Equus caballus) and donkeys (Equus asinus) by PCR

Visceral leishmaniasis (VL) is a neglected tropical disease caused by the Leishmania infantum parasite. The protozoan is able to infect several domestic and wild mammals. Since the first report on Leishmania spp. infection in horses in South America, leishmaniasis in equids has been highlighted in Brazil. A molecular epidemiological survey was carried out to verify the occurrence of Leishmania spp. DNA in horses and donkeys, in leishmaniases endemic areas in Sao Paulo State, Brazil. To this end, blood samples were obtained from 107 horses and 36 donkeys and subjected to DNA extraction followed by PCR targeting the ITS-1 region. Among the horses and donkeys, 1.87% (2/107) and 8.33% (3/36) were positive by PCR, respectively. The DNA sequencing of the ITS-1 amplification products confirmed L. infantum DNA in these animals. Our results suggest that horses and donkeys from non-VL and VL endemic areas of São Paulo State may be infected by the parasite.

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.

Molecular detection of Leishmania spp. in cattle from Brazil by means of PCR using internal transcribed spacer 1

Leishmania spp. are important agents of human and animal leishmaniases that have an important impact on public health. In this study, we aimed to detect the circulation of Leishmania spp. in cattle from a visceral leishmaniasis non-endemic area of the state of São Paulo, Brazil. DNA was extracted from blood samples from 100 heifers in the municipality of Pirassununga and was amplified using primers specific for the first internal transcriber spacer (ITS1), to assess the presence of trypanosomatids. The assays revealed that one sample presented bands of between 300 and 350 base pairs. In GenBank, this sample matched 100% with Leishmania infantum (314 base pairs). The results suggest that cattle can be infected by Leishmania infantum in Brazil.

Molecular detection of Leishmania infantum DNA according to clinical stages of leishmaniasis in dog

The aim of this study was to compare molecular tests used to diagnose Leishmania spp. in dogs with different stages of infection. Blood and conjunctival swab (CS) samples from dogs classified in four clinical stages were subjected to different PCR protocols (13A/13B, MC1/MC2, LITSR/L5.8S and LEISH-1/LEISH-2 primers). To the study, 22.3% (48/215) of dogs were classified as without clinical signs, 67.5% (145/215) stage I (mild disease), 7.0% (15/215) stage II (moderate disease) and 3.2% (7/215) stage III (severe disease). The results showed that in blood samples, 13A/13B detected a significant higher number of positive dogs in stage I (25/145) and in total (42/215) (p≤0.05). However, when CS samples were tested, no difference was observed (p>0.05). On the other hand, in blood samples, MC1/MC2 detected significantly fewer positive dogs classified as without clinical signs (0/48), in stage I (0/145) and in total (1/215) (p≤0.05). Likewise, in CS samples, this primers showed also lower detection (1/215) (p≤0.05). So than, we can conclude that PCR on blood samples with 13A/13B primers has greater capacity to detect positive dogs, mainly at the initial of clinical disease than do other primers and MC1/MC2 are not a good choice to detect Leishmania infantum infection in dogs.

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.

Evidence of heterozygosity and recombinant alleles in single cysts of Giardia duodenalis

Giardia duodenalis is divided into eight assemblages (named A to H). Isolates of assemblage A are divided into four sub-assemblages (AI, AII, AIII and AIV). While isolates of sub-assemblage AII are almost exclusively detected in human hosts, isolates of assemblage B are encountered in a multitude of animal hosts and humans. Here, we isolated single cysts of G. duodenalis from a human stool sample and found that one of them had overlaps of assemblage AII and B alleles and an unexpectedly high number of variants of the beta-giardin (Bg) and GLORF-C4 (OrfC4) alleles. In addition, one of the Bg alleles of that cyst had a fragment of sub-assemblage AII interspersed with fragments of assemblage B, thus indicating that this allele may be a recombinant between sequences A and B. Our results are unprecedented and put a check on the statement that different assemblages of G. duodenalis represent species with different host specificities.

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.

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.

Molecular phylogeny of Toxoplasmatinae: comparison between inferences based on mitochondrial and apicoplast genetic sequences

Phylogenies within Toxoplasmatinae have been widely investigated with different molecular markers. Here, we studied molecular phylogenies of the Toxoplasmatinae subfamily based on apicoplast and mitochondrial genes. Partial sequences of apicoplast genes coding for caseinolytic protease (clpC) and beta subunit of RNA polymerase (rpoB), and mitochondrial gene coding for cytochrome B (cytB) were analyzed. Laboratory-adapted strains of the closely related parasites Sarcocystis falcatula and Sarcocystis neurona were investigated, along with Neospora caninum, Neospora hughesi, Toxoplasma gondii (strains RH, CTG and PTG), Besnoitia akodoni, Hammondia hammondiand two genetically divergent lineages of Hammondia heydorni. The molecular analysis based on organellar genes did not clearly differentiate between N. caninum and N. hughesi, but the two lineages of H. heydorni were confirmed. Slight differences between the strains of S. falcatula and S. neurona were encountered in all markers. In conclusion, congruent phylogenies were inferred from the three different genes and they might be used for screening undescribed sarcocystid parasites in order to ascertain their phylogenetic relationships with organisms of the family Sarcocystidae. The evolutionary studies based on organelar genes confirm that the genus Hammondia is paraphyletic. The primers used for amplification of clpC and rpoB were able to amplify genetic sequences of organisms of the genus Sarcocystisand organisms of the subfamily Toxoplasmatinae as well.

Differential Viral Fitness Between H1N1 and H3N8 Avian Influenza Viruses Isolated from Mallards (Anas platyrhynchos)

Homosubtypic and heterosubtypic immunity in mallards (Anas platyrhynchos) play an important role in the avian influenza virus (AIV) diversity. The mechanisms of AIV replication among wild birds and the role of immunity in AIV diversity have thus not been completely clarified. During the monitoring of AI circulation among wild waterfowl in 2007-2008, two viruses (H3N8 and H1N1) were isolated from ducks caught in a funnel trap located in La Hulpe wetland in Belgium. H3N8 viruses were revealed to be more prevalent in the mallard population than was H1N1, which might suggest a better adaptation to this species. In order to investigate this hypothesis, we characterized both isolated viruses biologically by experimental inoculation. Virus excretion and humoral response induced by both isolated viruses were evaluated in mallards after a first infection followed by a homo- or heterosubtypic reinfection under controlled experimental conditions. The H1N1 virus had a delayed peak of excretion of 4 days compared to the H3N8, but the virus shedding was more limited, earlier, and shorter after each reinfection. Moreover, the H3N8 virus could spread to all ducks after homo- or heterosubtypic reinfections and during a longer period. Although the humoral response induced by both viruses after infection and reinfection could be detected efficiently by competitive ELISA, only a minimal H1 antibody response and almost no H3-specific antibodies could be detected by the HI test. Our results suggest that the H3N8 isolate replicates better in mallards under experimental controlled conditions.

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.

Comparison of single 1-day-old chick vaccination using a Newcastle disease virus vector with a prime/boost vaccination scheme against a highly pathogenic avian influenza H5N1 challenge

Avian influenza (AI) vaccines should be used as part of a whole comprehensive AI control programme. Vectored vaccines based on Newcastle disease virus (NDV) are very promising, but are so far licensed in only a few countries. In the present study, the immunogenicity and protection against a highly pathogenic H5N1 influenza challenge were evaluated after vaccination with an enterotropic NDV vector expressing an H5 haemagglutinin (rNDV-H5) in 1-day-old specific pathogen free chickens inoculated once, twice or once followed by a heterologous boost with an inactivated H5N9 vaccine (iH5N9). The heterologous prime/boost rNDV-H5/iH5N9 combination afforded the best level of protection against the H5N1 challenge performed at 6 weeks of age. Two rNDV-H5 administrations conferred a good level of protection after challenge, although only a cellular H5-specific response could be detected. Interestingly, a single administration of rNDV-H5 gave the same level of protection as the double administration but without any detectable H5-specific immune response. In contrast to AI immunity, a high humoral, mucosal and cellular NDV-specific immunity could be detected up to 6 weeks post vaccination after using the three different vaccination schedules. NDV-specific mucosal and cellular immune responses were slightly higher after double rNDV-H5 vaccination when compared with single inoculation. Finally, the heterologous prime/boost rNDV-H5/iH5N9 combination induced a broader detectable immunity including systemic, mucosal and cellular AI and NDV-specific responses.

Isolation and molecular characterization of Brazilian turkey reovirus from immunosuppressed young poults

In this study, we investigated turkey reovirus (TReoV) in tissue samples from young birds, aged 15 days. RT-PCR for TReoV detected 3.3 % positive samples and TReoV was successfully isolated in Vero cells. Histological analysis of positive bursa of Fabricius (BF) revealed atrophied follicles and lymphocyte depletion. The number of CD8+, CD4+ and IgM+ cells was lower in infected BF. Phylogenetic analysis based on S3 gene showed that the Brazilian TReoV isolates clustered in a single group with 98-100 % similarity to TReoV strains circulating in the United States. This is the first indication that TReoV infection may be a contributing factor to immunosuppression in young birds.

Immune responses and protection against H5N1 highly pathogenic avian influenza virus induced by the Newcastle disease virus H5 vaccine in ducks

Ducks play an important role in the epidemiology of avian influenza, and there is a need for new avian influenza vaccines that are suitable for mass vaccination in ducks. The immune responses as well as highly pathogenic avian influenza (HPAI) H5N1 protection induced by a Newcastle disease virus (NDV) vector expressing an H5N1 hemagglutinin (rNDV-H5) were investigated in mule ducks, a hybrid between Muscovy (Cairina moschata domesticus) males and Pekin (Anas platyrhynchos domesticus) females. Immunological tools to measure NDV and H5-specific serum antibody, mucosal, and cell-mediated immune (CMI) responses in ducks have been validated after infection with the vector NDV and an H5N1 low pathogenic avian influenza virus. The effect of maternally-derived antibodies (MDAs) to NDV on the humoral and CMI responses after NDV-H5 vaccination was also investigated. Our results showed the rNDV-H5 vaccine elicits satisfactory humoral and cellular responses in 11-day-old ducks correlating with a complete clinical and virological protection against the H5N1 strain. However, vaccination with rNDV-H5 in the presence of NDV MDA induced lower NDV-specific serum antibody, mucosal, and CMI responses than in ducks with no MDA, while interestingly the H5-specific serum antibody and duodenal IgY response were higher in ducks with NDV MDA. To our knowledge, this is the first report of the use of an NDV vector in ducks and of an HPAI H5N1 challenge in mule ducks, which appeared to be as resistant as Pekin ducks.

Intranasal DNA vaccination induces potent mucosal and systemic immune responses and cross-protective immunity against influenza viruses

The induction of potent virus-specific immune responses at mucosal surfaces where virus transmission occurs is a major challenge for vaccination strategies. In the case of influenza vaccination, this has been achieved only by intranasal delivery of live-attenuated vaccines that otherwise pose safety problems. Here, we demonstrate that potent mucosal and systemic immune responses, both cellular and humoral, are induced by intranasal immunization using formulated DNA. We show that formulation with the DNA carrier polyethylenimine (PEI) improved by a 1,000-fold the efficiency of gene transfer in the respiratory track following intranasal administration of luciferase-coding DNA. Using PEI formulation, intranasal vaccination with DNA-encoding hemagglutinin (HA) from influenza A H5N1 or (H1N1)2009 viruses induced high levels of HA-specific immunoglobulin A (IgA) antibodies that were detected in bronchoalveolar lavages (BALs) and the serum. No mucosal responses could be detected after parenteral or intranasal immunization with naked-DNA. Furthermore, intranasal DNA vaccination with HA from a given H5N1 virus elicited full protection against the parental strain and partial cross-protection against a distinct highly pathogenic H5N1 strain that could be improved by adding neuraminidase (NA) DNA plasmids. Our observations warrant further investigation of intranasal DNA as an effective vaccination route.

Fine quantification of avian influenza H5N1 escape mutant quasispecies populations using mutation-specific real-time PCR

Influenza viruses have a rapid replication cycle, using enzymes without proofreading capacity and generating multiple virus quasispecies during replication. The identification and quantification of these quasispecies populations require time-consuming and expensive cloning and sequencing approaches. In the present study, we developed mutation-specific real-time PCR (RT-PCR) tests for the fine quantification of mutations in a background of wild-type sequences. As a proof-of-concept model, we developed mutation-specific RT-PCR tests to quantify antibody escape mutations during passage under monoclonal antibody (mAb) selection pressure in quasispecies populations of HPAI A/crested eagle/Belgium/01/2004 (H5N1). Mutation-specific RT-PCRs were developed for two mutations (one in HA1 and one in HA2) and validated using plasmids representing either the wildtype sequence or the mutation. The approach achieves a precise and accurate estimation of mutation frequencies on mixed populations in the range of 1% to 99% and does not require standard curves or calibrators. For the HA1 mutations, a directional increase of % G over the passages towards fixation of the G mutation could be observed. On the contrary, as expected from the inaccessibility of the HA2 region to antibodies, the HA2 mutation increased in frequency by factors unrelated to mAb-driven selection. This approach allows in-depth analysis of quasispecies dynamics using large sample sizes. It may also be applied to the dynamics of hot spots of mutations in several genes, such as HA or PB2, and to the early detection of critical changes in the field situation.

Identification of a dominant epitope in the hemagglutinin of an Asian highly pathogenic avian influenza H5N1 clade 1 virus by selection of escape mutants

H5N1 avian influenza virus has caused widespread infection in poultry and wild birds, and has the potential to emerge as a pandemic threat to humans. The hemagglutinin (HA) is a glycoprotein on the surface of the virus envelope. Understanding its antigenic structure is essential for designing novel vaccines that can inhibit virus infection. The aim of this study was to map the amino acid substitutions that resulted in resistance to neutralization by monoclonal antibodies (MAbs) of the highly pathogenic A/crested eagle/Belgium/01/2004 (H5N1), a clade 1 virus. Two hybridomas specific to H5N1 clade 1 viruses were selected by enzyme-linked immunosorbent assay, virus neutralization test, and immunofluorescence assay. Escape mutant populations resisting neutralization by those MAbs (8C5 and 5A1) were then selected, and sequencing of these mutants allowed the prediction of the HA protein structure by molecular homology. We could detect an amino acid change in our escape mutants at position K189E corresponding to antigenic site 2 of H5 HA1 and site B of H3 HA1. Interestingly, 336 out of 350 available HA sequences from H5N1 clade 1 and clade 2.3 viruses had Lys (K) at position 189 in the HA1, whereas HA sequences analyzed from dade 2.1 and 2.2 viruses had Arg (R). This residue also interacts with the receptor-binding site, and it is thus important for the evolution of H5N1 viruses. An additional substitution K29E in HA2 subunit was also observed and identified with the use of NetChop software as a loss of a proteasomal cleavage site, which seems to be an advantage for H5N1 viruses.

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.

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.

Inhibition of avian metapneumovirus (AMPV) replication by RNA interference targeting nucleoprotein gene (N) in cultured cells

Avian metapneumovirus (AMPV) is the primary causative agent of severe rhinotracheitis in turkeys. It is associated with swollen head syndrome in chickens and is the source of significant economic losses to animal food production. In this study, we designed specific short interfering RNA (siRNA) targeting the AMPV nucleoprotein (N) and fusion (F) genes. Three days post-virus infection, virus titration, real time RT-PCR, and RT-PCR assays were performed to verify the effect of siRNA in AMPV replication. A marked decrease in virus titers from transfected CER cells treated with siRNA/N was observed. Also, the production of N, F, and G mRNAs in AMPV was decreased. Results indicate that N-specific siRNA can inhibit virus replication. In future studies, a combination of siRNAs targeting the RNA polymerase complex may be used as a tool to study AMPV replication and/or antiviral therapy.

Effects of experimental inoculation of bovine respiratory syncytial virus in different inbred mice lineages: Establishment of a murine model for BRSV infection

Bovine respiratory syncytial virus (BRSV), a member of the subfamily Pneumovirinae, family Paramyxoviridae, is a major cause of respiratory disorders in young cattle. A number of studies were conducted to validate a reliable animal model for the infection, since BRSV inoculation on the natural host is costly and often unsuccessful. Unfortunately, after inoculation of BRSV in Balb/C mice, viral replication may be detected; however, evident pathological alterations are absent on the experimentally infected animals. In order to establish a mice model that could be used further for preliminary studies of pathological and immunological aspects of BRSV infection, three mice inbred lineages (Balb/C, A/J and C57BL6), possessing different genetic backgrounds, were tested about its susceptibility to the inoculation with BRSV. Animals were inoculated through the nasal and ocular routes and were observed after inoculation. At 7 days post-inoculation (dpi) animals were necropsied and virological (virus isolation and viral nucleic acid amplification) as well as histopathological examinations were performed. A/J and C57BL6 showed interstitial pneumonia, when compared to the Balb/C group. These findings shows that mice may constitute a suitable model for the study of BRSV infections, depending on the mice strain used for experimental inoculations.

Phylogenetic relationships of Brazilian bovine respiratory syncytial virus isolates and molecular homology modeling of attachment glycoprotein

Bovine respiratory syncytial virus (BRSV) causes lower respiratory tract disease in young cattle. Recently, it was possible to determine the sequence of the G protein gene, which plays a role in the attachment of BRSV particles to the cells, from three distinct Brazilian isolates. The phylogenetic analysis conducted here using those sequences compared to other worldwide distributed isolates of BRSV allow us to allocate Brazilian strains within the subgroup B, which was no longer found in the world since the 1970s. One of the Brazilian strains has a major mutation between amino acid residues 173 and 178, within the central hydrophobic conserved region, exactly on the site of two of the four cysteine-noose forming cysteine residues. Homology modeling with the previously determined NMR structure of this protein domain was made to check whether these mutations altered the three-dimensional conformation of this immunodominant region. Possible consequences on the biological effects induced by such mutation on the G protein are discussed.

Rabies neutralizing antibody detection by indirect immunperoxidase serum neutralization assay performed on chicken embryo related cell line

The aim of this study was to evaluate the indirect immunoperoxidase virus neutralization (IPVN) and mouse neutralization test (MNT) to detect antibodies against rabies virus from vaccinated dogs and cattle. The IPVN was set up for the ability to measure 0.5 International Units/ml (IU) of antibody required by the World Health Organization and the Office International des Epizooties as the minimum response for proof of rabies immunization. IPVN was developed and standardized in chicken embryo related (CER) cell line when 141 dog and 110 cattle sera were applied by serial five-fold dilutions (1:5, 1:25, 1:125) as well as the positive and negative reference controls, all added in four adjacent wells, of 96-well microplates. A 50 microl amount of CVS32 strain dilution containing 50-200 TCID50/ml was mixed to each serum dilution, and after 90 min 50 microl of 3 x 10(5) cells/mlcell suspension added to each well. After five days of incubation, the monolayers were fixed and the IPVN test performed. The correlation coefficient between the MNT and IPVN performed in CER cells was r = 0.9949 for dog sera (n = 100) and r = 0.9307 for cattle sera (n = 99), as well as good specificity (94.7%), sensitivity (87.5%), and agreement (96.6%) were also obtained. IPVN technique can adequately identify vaccinated and unvaccinated animals, even from low-responding vaccinated animals, with the advantage of low cost and faster then MNT standard test.

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.