Yellow Fever Virus Maintained by Sabethes Mosquitoes during the Dry Season in Cerrado, a Semiarid Region of Brazil, in 2021

In recent decades, waves of yellow fever virus (YFV) from the Amazon Rainforest have spread and caused outbreaks in other regions of Brazil, including the Cerrado, a savannah-like biome through which YFV usually moves before arriving at the Atlantic Forest. To identify the vectors involved in the maintenance of the virus in semiarid environments, an entomological survey was conducted after confirmation of yellow fever (YF) epizootics at the peak of the dry season in the Cerrado areas of the state of Minas Gerais. In total, 917 mosquitoes from 13 taxa were collected and tested for the presence of YFV. Interestingly, mosquitoes of the Sabethes genus represented 95% of the diurnal captured specimens, displaying a peak of biting activity never previously recorded, between 4:30 and 5:30 p.m. Molecular analysis identified three YFV-positive pools, two from Sabethes chloropterus-from which near-complete genomes were generated-and one from Sa. albiprivus, whose low viral load prevented sequencing. Sa. chloropterus was considered the primary vector due to the high number of copies of YFV RNA and the high relative abundance detected. Its bionomic characteristics allow its survival in dry places and dry time periods. For the first time in Brazil, Sa. albiprivus was found to be naturally infected with YFV and may have played a role as a secondary vector. Despite its high relative abundance, fewer copies of viral RNA were found, as well as a lower Minimum Infection Rate (MIR). Genomic and phylogeographic analysis showed that the virus clustered in the sub-lineage YFVPA-MG, which circulated in Pará in 2017 and then spread into other regions of the country. The results reported here contribute to the understanding of the epidemiology and mechanisms of YFV dispersion and maintenance, especially in adverse weather conditions. The intense viral circulation, even outside the seasonal period, increases the importance of surveillance and YFV vaccination to protect human populations in affected areas.

Differential proteomics of Zika virus (ZIKV) infection reveals molecular changes potentially involved in immune system evasion by a Brazilian strain of ZIKV

Zika virus (ZIKV) is an arbovirus that was responsible for multiple outbreaks from 2007 to 2015. It has been linked to cases of microcephaly in Brazil in 2015, among other neurological disorders. Differences among strains might be the reason for different clinical outcomes of infection. To evaluate this hypothesis, we performed a comparative proteomic analysis of Vero cells infected with the African strain MR766 (ZIKVAFR) and the Brazilian strain 17 SM (ZIKVBR). A total of 550 proteins were identified as differentially expressed in ZIKVAFR- or ZIKVBR-infected cells compared to the control. The main findings included upregulation of immune system pathways (neutrophil degranulation and adaptive/innate immune system) and potential activation of immune-system-related pathways by ZIKVAFR (mTOR, JAK-STAT, NF-κB, and others) compared with the ZIKVBR/control. In addition, phagocytosis by macrophages and engulfment of leukocytes were activated in ZIKVAFR infection. An in vivo analysis using an immunocompetent C57BL/6N mouse model identified interstitial pneumonia with neutrophil infiltration in the lungs only in mice infected with ZIKVBR at 48 hours postinfection, with a significant amount of virus detected. Likewise, only animals infected with ZIKVBR had viral material in the cytoplasm of lung macrophages. These results suggest that activation of the immune system by ZIKVAFR infection may lead to faster viral clearance by immune cells.

Real-Time Genomic Surveillance during the 2021 Re-Emergence of the Yellow Fever Virus in Rio Grande do Sul State, Brazil

The 2021 re-emergence of yellow fever in non-human primates in the state of Rio Grande do Sul (RS), southernmost Brazil, resulted in the death of many howler monkeys (genus Alouatta) and led the state to declare a Public Health Emergency of State Importance, despite no human cases reported. In this study, near-complete genomes of yellow fever virus (YFV) recovered from the outbreak were sequenced and examined aiming at a better understanding of the phylogenetic relationships and the spatio-temporal dynamics of the virus distribution. Our results suggest that the most likely sequence of events involved the reintroduction of YFV from the state of São Paulo to RS through the states of Paraná and Santa Catarina, by the end of 2020. These findings reinforce the role of genomic surveillance in determining the pathways of distribution of the virus and in providing references for the implementation of preventive measures for populations in high risk areas.

Novel Gyrovirus genomes recovered from free-living pigeons in Southern Brazil

Wild birds carry a number of infectious agents, some of which may have pathogenic potential for the host and others species, including humans. Domestic pigeons (Columba livia) are important targets of study since these increasingly cohabit urban spaces, being possible spillover sources of pathogens to humans. In the present study, two genomes (PiGyV_Tq/RS/Br and PiGyV_RG/RS/Br), representative of Gyrovirus genus, family Anelloviridae, were detected in sera of free-living pigeons collected in Southern Brazil. The genomes exhibit less than 50% identity to previously described members of Gyrovirus genus, suggesting that they constitute a new viral species circulating in pigeons, to which the name "pigeon gyrovirus (PiGyV)" is proposed. The current study characterizes these two PiGyV genomes which, to date, are the first gyrovirus species identified in domestic pigeons.

Molecular evidence of bovine herpesvirus 1 and 5 in cattle with suspected rabies in Rio Grande do Sul state, Brazil

Rabies and herpetic encephalitis are the main viral infections in bovines with neurological symptoms. Bovine rabies has a high prevalence in Central and South America, while bovine encephalitis associated with herpesvirus is especially important in South America. Viral isolation is the classical way to confirm herpesvirus infection, but molecular evidence of the presence of the virus in affected animals is gaining importance in the diagnosis of the disease in the laboratory. This study investigated the presence of herpesvirus type 1 and 5 (BoHV-1 and BoHV-5) in 182 encephalon of rabies-suspected cattle in Rio Grande do Sul state (RS), Brazil using multiplex real-time polymerase chain reaction (mRT-PCR). The rabies virus was investigated by direct fluorescent antibody assay and intracerebral suckling mouse inoculation. The genomes of BoHV-1 and BoHV-5 were detected in 17% of samples. BoHV-5 and BoHV-1 were detected in 100% and 19% of BoHV positive samples, respectively, indicating the circulation of the pathogens in cattle herds in RS. The high Ct values and the absence of isolation suggest viral latency. Coinfection of herpesvirus and the rabies virus was detected in 28% of samples, although no significant association between pathogens was observed. Rabies was detected in 57.7% of suspected samples, confirming the importance of the disease in the state. Concerning the method by which samples were conserved, no significant difference was observed between the number of positive results in frozen and refrigerated samples.

Phylogenetic analysis of rabies viruses isolated from cattle in southern Brazil

Bats and dogs are the main reservoirs of rabies virus (RABV) in Latin America and are responsible for the maintenance of different cycles of infection. In the two neighbour and most southern Brazilian states of Rio Grande do Sul (RS) and Santa Catarina (SC), rabies in dogs has been successfully controlled for more than 30 years. However, rabies associated to the rural cycle remains endemic, with a significant, though oscillating-annual incidence of rabies in cattle. Despite the plethora of studies on genetic analyses of Brazilian RABV, isolates from southern Brazil have only scarcely been investigated. This work was performed to identify the genetic lineages of RABVs circulating in states of RS and SC. Fifty-nine RABV cattle isolates from RS and SC were selected and submitted to reverse transcription/polymerase chain reaction (RT-PCR) followed by sequencing of the nucleoprotein gene. In RS, the circulation of two sublineages (1A and 1B) of RABV was detected, both with characteristics of lineages usually detected in vampire bats (Desmodus rotundus). In SC, only one sublineage of RABV (1B) was detected. Nevertheless, the findings reported here are expected to contribute to the understanding of the biology of the virus in the region and its interactions with the natural host D. rotundus.

The intestinal virome of malabsorption syndrome-affected and unaffected broilers through shotgun metagenomics

Malabsorption syndrome (MAS) is an economically important disease of young, commercially reared broilers, characterized by growth retardation, defective feather development and diarrheic faeces. Several viruses have been tentatively associated to such syndrome. Here, in order to examine potential associations between enteric viruses and MAS, the faecal viromes of 70 stool samples collected from diseased (n = 35) and healthy (n = 35) chickens from seven flocks were characterized and compared. Following high-throughput sequencing, a total of 8,347,319 paired end reads, with an average of 231 nt, were generated. Through analysis of de novo assembled contigs, 144 contigs > 1000 nt were identified with hits to eukaryotic viral sequences, as determined by GenBank database. A number of known and unknown representatives of Adenoviridae, Anelloviridae, Astroviridae, Caliciviridae, Circoviridae, Parvoviridae, Picobirnaviridae, Picornaviridae and Reoviridae, as well as novel uncharacterized CRESS-DNA viruses, were identified. However, the distribution of sequence reads of viral genomes identified in diseased or healthy birds revealed no statistically significant differences. These findings indicate no association between the occurrence of MAS and enteric viruses. The viral genomes reported in the present study, including a variety of novel viruses, seem part of the normal intestinal microbiota of chickens.

Columbid circoviruses detected in free ranging pigeons from Southern Brazil: insights on PiCV evolution

Pigeon circovirus (PiCV) is taxonomically classified as a member of the Circovirus genus, family Circoviridae. The virus contains a single stranded DNA genome of approximately 2 kb, with minor length variations among different isolates. The occurrence of PiCV infections in pigeons (Columba livia) has been documented worldwide over the past 20 years; however, in Brazil there were still no reports on PiCV detection. This study identifies seven PiCV genomes recovered from domestic pigeons of South Brazil through high-throughput sequencing and shows a high frequency of PiCV infection, through quantitative real-time PCR. Phylogenetic classification was performed by maximum likelihood analysis of the full genomes, ORF V1 (Rep) and ORF C1 (Cap). The results show that either full genome or Cap based analysis allowed PiCV classification into five major clades (groups A to E), where Brazilian sequences were classified as A, C or D. Recombination analyses were carried out with Simplot and RDP4 and the results show that both Rep and Cap ORFs contain several recombination hotspots, pointing to an important role for such events in PiCV evolution.

Full-Genome Sequence of Porcine Circovirus type 3 recovered from serum of sows with stillbirths in Brazil

Two full-genome sequences of porcine circovirus type 3 (PCV3) are reported. The genomes were recovered from pooled serum samples from sows who had just delivered litters with variable numbers of stillbirths. The two circular genomes (PCV3-BR/RS/6 and PCV3-BR/RS/8) are 2,000 nucleotides long and contain two open reading frames (ORFs) oriented in opposite directions that encode the putative capsid (Cap) and replicase (Rep) proteins. The intergenic region contains a stem-loop motif, as reported for other circoviruses. Rolling circle replication motifs and putative helicase domains were identified in the Rep coding region. The degree of overall nucleotide similarity between the genomes reported here and those available at GenBank was higher than 97%. No PCV3 sequence was detected in pooled serum samples from sows which had no stillbirths on the same farms. However, further studies are necessary to confirm the association between PCV3 and the occurrence of stillbirths.

Genomic and antigenic relationships between two 'HoBi'-like strains and other members of the Pestivirus genus

'HoBi'-like viruses comprise a putative new species within the genus Pestivirus of the family Flaviviridae. 'HoBi'-like viruses have been detected worldwide in batches of fetal calf serum, in surveillance programs for bovine pestiviruses and from animals presenting clinical signs resembling bovine viral diarrhea virus (BVDV)-associated diseases. To date, few complete genome sequences of 'HoBi'-like viruses are available in public databases. Moreover, detailed analyses of such genomes are still scarce. In an attempt to expand data on the genetic diversity and biology of pestiviruses, two genomes of 'HoBi'-like viruses recovered from Brazilian cattle were described and characterized in this study. Analysis of the whole genome and antigenic properties of these two new 'HoBi'-like isolates suggest that these viruses are genetically close to recognized pestiviruses. The present data provide evidence that 'HoBi'-like viruses are members of the genus Pestivirus and should be formally recognized as a novel species.

Faecal virome of healthy chickens reveals a large diversity of the eukaryote viral community, including novel circular ssDNA viruses

This study is focused on the identification of the faecal virome of healthy chickens raised in high-density, export-driven poultry farms in Brazil. Following high-throughput sequencing, a total of 7743 de novo-assembled contigs were constructed and compared with known nucleotide/amino acid sequences from the GenBank database. Analyses with blastx revealed that 279 contigs (4 %) were related to sequences of eukaryotic viruses. Viral genome sequences (total or partial) indicative of members of recognized viral families, including Adenoviridae, Caliciviridae, Circoviridae, Parvoviridae, Picobirnaviridae, Picornaviridae and Reoviridae, were identified, some of those representing novel genotypes. In addition, a range of circular replication-associated protein encoding DNA viruses were also identified. The characterization of the faecal virome of healthy chickens described here not only provides a description of the viruses encountered in such niche but should also represent a baseline for future studies comparing viral populations in healthy and diseased chicken flocks. Moreover, it may also be relevant for human health, since chickens represent a significant proportion of the animal protein consumed worldwide.

Complete genome sequence of Deltapapillomavirus 4 (bovine papillomavirus 2) from a bovine papillomavirus lesion in Amazon Region, Brazil

The complete genome sequence of bovine papillomavirus 2 (BPV2) from Brazilian Amazon Region was determined using multiple-primed rolling circle amplification followed by Illumina sequencing. The genome is 7,947 bp long, with 45.9% GC content. It encodes seven early (E1, E2,E4, E5, E6,E7, and E8) and two late (L1 and L2) genes. The complete genome of a BPV2 can help in future studies since this BPV type is highly reported worldwide although the lack of complete genome sequences available.

Genome characterization of a bovine papillomavirus type 5 from cattle in the Amazon region, Brazil

Papillomaviruses are small and complex viruses with circular DNA genome that belongs to the Papillomavirus family, which comprises at least 39 genera. The bovine papillomavirus (BPV) causes an infectious disease that is characterized by chronic and proliferative benign tumors that affect cattle worldwide. In the present work, the full genome sequence of BPV type 5, an Epsilonpapillomavirus, is reported. The genome was recovered from papillomatous lesions excised from cattle raised in the Amazon region, Northern Brazil. The genome comprises 7836 base pairs and exhibits the archetypal organization of the Papillomaviridae. This is of significance for the study of BPV biology, since currently available full BPV genome sequences are scarce. The availability of genomic information of BPVs can provide better understanding of the differences in genetics and biology of papillomaviruses.

Novel Bovine Papillomavirus Type Discovered by Rolling-Circle Amplification Coupled with Next-Generation Sequencing

Currently, fifteen bovine papillomavirus (BPV) types have been identified and classified into four genera: Deltapapillomavirus, Epsilonpapillomavirus, Dyoxipapillomavirus, and Xipapillomavirus. Here, the complete genome sequence of a new BPV type (BPV 04AC14) recovered from a papillomatous lesion is reported. The genome is 7,282 bp in length and exhibits the classic genetic organization and motifs of the members of Papillomaviridae. Maximum likelihood phylogenetic analyses revealed that BPV 04AC14 clusters with members of the Xipapillomavirus genus. The nucleotide sequence of the L1 capsid protein of the novel BPV is closely related to its counterpart, BPV3, with which it shares 79% similarity. These findings suggest that this virus is a new BPV type of the Xipapillomavirus genus.

Development of an Indirect ELISA for Serological Diagnosis of Bovine herpesvirus 5

Bovine herpesviruses 1 and 5 (BoHV-1 and BoHV-5) are economically important pathogens, associated with a variety of clinical syndromes, including respiratory and genital disease, reproductive failure and meningoencephalitis. The standard serological assay to diagnose BoHV-1 and BoHV-5 infections is the virus neutralization test (VNT), a time consuming procedure that requires manipulation of infectious virus. In the present study a highly sensitive and specific single dilution indirect ELISA was developed using recombinant glycoprotein D from BoHV-5 as antigen (rgD5ELISA). Bovine serum samples (n = 450) were screened by VNT against BoHV-5a and by rgD5ELISA. Compared with the VNT, the rgD5ELISA demonstrated accuracy of 99.8%, with 100% sensitivity, 96.7% specificity and coefficient of agreement between the tests of 0.954. The rgD5ELISA described here shows excellent agreement with the VNT and is shown to be a simple, convenient, specific and highly sensitive virus-free assay for detection of serum antibodies to BoHV-5.

Swine Influenza Virus and Association with the Porcine Respiratory Disease Complex in Pig Farms in Southern Brazil

Despite the putative endemic status of swine influenza A virus (swIAV) infections, data on the occurrence of swine influenza outbreaks are scarce in Brazil. The aim of this study was to detect and subtype swIAVs from six outbreaks of porcine respiratory disease complex (PRDC) in southern Brazil. Nasal swabs were collected from 66 piglets with signs of respiratory disease in six herds. Lung tissue samples were collected from six necropsied animals. Virus detection was performed by PCR screening and confirmed by virus isolation and hemagglutination (HA). Influenza A subtyping was performed by a real-time reverse transcriptase PCR (rRT-PCR) to detect the A(H1N1)pdm09; other swIAV subtypes were determined by multiplex RT-PCR. In lung tissues, the major bacterial and viral pathogens associated with PRDC (Pasteurella multocida, Mycoplasma hyopneumoniae, Actinobacillus pleuropneumoniae, Haemophilus parasuis and PCV2) were investigated. In some affected pigs, clinico-pathological evaluations were conducted. Influenza A was detected by screening PCR in 46 of 66 swab samples and from five of six lungs. Virus was recovered from pigs of all six herds. Subtype A(H1N1)pdm09 was detected in four of six herds and H1N2 in the other two herds. In lung tissues, further agents involved in PRDC were detected in all cases; Pasteurella multocida was identified in five of six samples and Mycoplasma hyopneumoniae in three of six. Actinobacillus pleuropneumoniae (1/6), Haemophilus parasuis (1/6) and PCV2 (1/6) were also detected. These findings indicate that subtypes A(H1N1)pdm09 and H1N2 were present in pigs in southern Brazil and were associated with PRDC outbreaks.

Chemical analysis and in vitro antiviral and antifungal activities of essential oils from Glechon spathulata and Glechon marifolia

CONTEXT

Glechon spathulata Benth. and Glechon marifolia Benth. (Lamiaceae, Mentheae) are aromatic plants used in traditional medicine for the treatment of viral infections.

OBJECTIVE

The chemical composition and antiviral and antifungal activities of Glechon spathulata and Glechon marifolia essential oils were investigated.

MATERIALS AND METHODS

The oils were obtained by hydrodistillation and analyzed by GC-FID and GC-MS. Anti-herpes virus (HSV-1) activity was examined in Vero cells by yield reduction assay, in doses of 0.0095% v/v and 0.039% v/v, for G. spathulata and G. marifolia oil, respectively. Antifungal activity was carried by the broth microdilution method, in oil concentrations that ranged from 5.2 to 500 µg/mL.

RESULTS

β-Caryophyllene (14.2% and 32.2% for G. spathulata and G. marifolia, respectively) and bicyclogermacrene (17.1% and 16.5%, respectively) were the major components of both oils. At noncytotoxic concentrations of the essential oils, the viral titer was reduced by up to 2 log10 for KOS and VR-733 strains. The antifungal activity was observed against Trichophyton rubrum (MIC 10-83 µg/mL) and Epidermophyton floccosum (MIC 83-500 µg/mL). The oil of G. spathulata exhibited activity against the three strains tested (KOS, VR733, and 29-R), whereas G. marifolia oil was active against two strains, KOS and VR733.

DISCUSSION AND CONCLUSION

The chemical composition for G. spathulata and G. marifolia essential oils is very similar. The oil of G. spathulata can be promising as a new antifungal agent against dermatophytes. The findings add important information to the biological activity of Glechon species essential oils, specifically its antiviral and antidermatophytic properties.

Detection of bovine herpesvirus 2 and bovine herpesvirus 4 DNA in trigeminal ganglia of naturally infected cattle by polymerase chain reaction

Establishment of latent infection within specific tissues in the host is a common biological feature of the herpesviruses. In the case of bovine herpesvirus 2 (BoHV-2), latency is established in neuronal tissues, while bovine herpesvirus 4 (BoHV-4) and ovine herpesvirus 2 (OvHV-2) latent virus targets on cells of the monocytic lineage. This study was conducted in quest of BoHV-2, BoHV-4 and OvHV-2 DNA in two hundred trigeminal ganglia (TG) specimens, derived from one hundred clinically healthy cattle, majority of them naturally infected with bovine herpesvirus 1 (BoHV-1) and bovine herpesvirus 5 (BoHV-5). Total DNA extracted from ganglia was analyzed by polymerase chain reaction (PCR) designed to amplify part of the genes coding for BoHV-2, and BoHV-4 glycoprotein B and, for OvHV-2, the gene coding for phosphoribosylformylglycinamidine synthase-like protein. BoHV-2 DNA was detected in TG samples of two (2%) and BoHV-4 DNA in nine (9%) of the animals, whereas OvHV-2 DNA could not be detected in any of the TG DNA. The two animals in which BoHV-2 DNA was identified were also co-infected with BoHV-1 and BoHV-5. Within the nine animals in which BoHV-4 DNA was detected, six were also co-infected with BoHV-1 and BoHV-5. This report provides for the first time evidence that viral DNA from BoHV-2 and BoHV-4 can be occasionally detected in TG of naturally infected cattle. Likewise, in this report we provided for the first time evidence that the co-infection of cattle with three distinct bovine herpesviruses might be a naturally occurring phenomenon.

Presence of Torque teno virus (TTV) in tap water in public schools from Southern Brazil

Torque teno virus (TTV) was surveyed in tap water collected in schools from three municipalities located in the south of Brazil. TTV genomes were found in 11.7 % (4/34) of the samples. TTV DNA was detected in 10.5 % (2/19) of the samples collected at the city of Caxias do Sul and in 25 % (2/8) of the samples from Pelotas. Those cities have a low rate of sewage treatment. All samples from Santa Cruz do Sul, which has nearly 92 % of its sewage treated, were negative. These results suggest that the amount of sewage treated may have an effect on the detection rates of TTV DNA in drinking water in a given urban area, showing a mild negative correlation (r = -0.76), when comparing the percentage of sewage treatment to the detection of TTV genomes. The detection rate of TTV was also compared with Escherichia coli, showing a strong correlation (r = 0.97), indicating that TTV may be a suitable marker of fecal contamination.

Bovine herpesvirus-5 infection in a rabbit experimental model: immunohistochemical study of the cellular response in the CNS

Since little information is available regarding cellular antigen mapping and the involvement of non-neuronal cells in the pathogenesis of bovine herpesvirus type 5 (BHV-5) infection, it were determined the BHV-5 distribution, the astrocytic reactivity, the involvement of lymphocytes and the presence of matrix metalloproteinase (MMP)-9 in the brain of rabbits experimentally infected with BHV-5. Twelve New Zealand rabbits that were seronegative for BHV-5 were used for virus inoculation, and five rabbits were used as mock-infected controls. The rabbits were kept in separate areas and were inoculated intranasally with 500 μl of virus suspension (EVI 88 Brazilian isolate) into each nostril (virus titer, 10(7.5) TCID50). Control rabbits were inoculated with the same volume of minimum essential medium. Five days before virus inoculation, the rabbits were submitted to daily administration of dexamethasone. After virus inoculation, the rabbits were monitored clinically on a daily basis. Seven rabbits showed respiratory symptoms and four animals exhibited neurological symptoms. Tissue sections were collected for histological examination and immunohistochemistry to examine BHV-5 antigens, astrocytes, T and B lymphocytes and MMP-9. By means of immunohistochemical and PCR methods, BHV-5 was detected in the entire brain of the animals which presented with neurological symptoms, especially in the trigeminal ganglion and cerebral cortices. Furthermore, BHV-5 antigens were detected in neurons and/or other non-neural cells. In addition to the neurons, most infiltrating CD3 T lymphocytes observed in these areas were positive for MMP-9 and also for BHV-5 antigen. These infected cells might contribute to the spread of the virus to the rabbit brain along the trigeminal ganglia and olfactory nerve pathways.

First description of Adenovirus, Enterovirus, Rotavirus and Torque teno virus in water samples collected from the Arroio Dilúvio, Porto Alegre, Brazil

Adenovirus (AdV), enterovirus (EV), genogroup A rotaviruses (GARV) and Torque teno virus (TTV) are non-enveloped viral agents excreted in feces and so may contaminate water bodies. In the present study, the molecular detection of these viruses was performed in samples of surface water collected from the Arroio Dilúvio, a waterstream that crosses the city of Porto Alegre, RS, Brazil, receiving great volumes of non-treated sewage from a large urban area. Sampling was performed during 2009, in three different occasions (January, April and September). The highest detection rate was observed for EV (64.28%), followed by TTV (28.57%) and AdV (21.43%). Rotaviruses were not detected. More than on kind of tested virus was detected in five (35. 71%) of 14 samples. January was the month with the highest viral detection rate, being all samples, collected in this month, positive for at least one group of tested virus. The correlation between the detection of these different viral agents and environmental factors is discussed. To the knowledge of the authors, this is the first description of viral genomes in water samples taken from the Arroio Dilúvio, Porto Alegre (Brazil).

Immunoadjuvant activity, toxicity assays, and determination by UPLC/Q-TOF-MS of triterpenic saponins from Chenopodium quinoa seeds

The adjuvant activity of Chenopodium quinoa (quinoa) saponins on the humoral and cellular immune responses of mice subcutaneously immunized with ovalbumin (OVA) was evaluated. Two quinoa saponin fractions were obtained, FQ70 and FQ90, and 10 saponins were determined by UPLC/Q-TOF-MS. Mice were immunized subcutaneously with OVA alone or adjuvanted with Quil A (adjuvant control), FQ70, or FQ90. FQ70 and FQ90 significantly enhanced the amount of anti-OVA-specific antibodies in serum (IgG, IgG1, and IgG2b) in immunized mice. The adjuvant effect of FQ70 was significantly greater than that of FQ90. However, delayed type hypersensitivity responses were higher in mice immunized with OVA adjuvanted with FQ90 than mice treated with FQ70. Concanavalin A (Con A)-, lipopolysaccharide-, and OVA-stimulated splenocyte proliferation were measured, and FQ90 significantly enhanced the Con A-induced splenocyte proliferation. The results suggested that the two quinoa saponin fractions enhanced significantly the production of humoral and cellular immune responses to OVA in mice.

Comparative evaluation of a competitive polymerase chain reaction (PCR) and a SYBR Green-based real-time PCR to quantify Porcine circovirus-2 DNA in swine tissue samples

Porcine circovirus-2 (PCV-2) is considered the major etiological agent of post-weaning multisystemic wasting syndrome (PMWS) in pigs. The clinical manifestations of the disease are correlated with moderate to high amounts of PCV-2 DNA in biological samples of affected pigs. A threshold of 10(7) DNA copies/ml is suggested as the trigger factor for symptoms. A comparative study was conducted to determine which quantitative method would be more suitable to estimate the PCV-2 DNA load. Two polymerase chain reaction (PCR) assays were developed: a competitive PCR (cPCR) and a SYBR Green-based real-time PCR. The assays were compared for their capacity to detect PCV-2 in DNA samples extracted from liver, lung, spleen, mesenteric lymph nodes, and kidney of PMWS-affected (n = 23) or non-PMWS-affected pigs (n = 9). Both assays could successfully quantify PCV-2 DNA in all tissue samples and were able to detect significant differences between the numbers of PCV-2 DNA copies found in tissues of PMWS-affected and non-PMWS-affected pigs (≥ 10(2.5)). The highest mean viral loads were detected by the SYBR Green real-time PCR, up to 10(7.0 ± 1.5) copies/100 ng of total DNA sample, while the cPCR detected up to 10(4.8 ± 1.5). A mean difference of 10(1.8) was found between the amounts of PCV-2 DNA detected, using the SYBR Green real-time PCR and the cPCR, suggesting that the viral load threshold for PMWS should be determined for each particular assay.

Green propolis phenolic compounds act as vaccine adjuvants, improving humoral and cellular responses in mice inoculated with inactivated vaccines

Adjuvants play an important role in vaccine formulations by increasing their immunogenicity. In this study, the phenolic compound-rich J fraction (JFR) of a Brazilian green propolis methanolic extract stimulated cellular and humoral immune responses when co-administered with an inactivated vaccine against swine herpesvirus type 1 (SuHV-1). When compared to control vaccines that used aluminium hydroxide as an adjuvant, the use of 10 mg/dose of JFR significantly increased (p < 0.05) neutralizing antibody titres against SuHV-1, as well as the percentage of protected animals following SuHV-1 challenge (p < 0.01). Furthermore, addition of phenolic compounds potentiated the performance of the control vaccine, leading to increased cellular and humoral immune responses and enhanced protection of animals after SuHV-1 challenge (p < 0.05). Prenylated compounds such as Artepillin C that are found in large quantities in JFR are likely to be the substances that are responsible for the adjuvant activity.

Efficacy of an inactivated, recombinant bovine herpesvirus type 5 (BoHV-5) vaccine

Bovine herpesvirus type 5 (BoHV-5) is the causative agent of bovine herpetic encephalitis. In countries where BoHV-5 is prevalent, attempts to vaccinate cattle to prevent clinical signs from BoHV-5-induced disease have relied essentially on vaccination with BoHV-1 vaccines. However, such practice has been shown not to confer full protection to BoHV-5 challenge. In the present study, an inactivated, oil adjuvanted vaccine prepared with a recombinant BoHV-5 from which the genes coding for glycoprotein I (gI), glycoprotein E (gE) and membrane protein US9 were deleted (BoHV-5 gI/gE/US9(-)), was evaluated in cattle in a vaccination/challenge experiment. The vaccine was prepared from a virus suspension containing a pre-inactivation antigenic mass equivalent to 10(7.69) TCID(50)/dose. Three mL of the inactivated vaccine were administered subcutaneously to eight calves serologically negative for BoHV-5 (vaccinated group). Four other calves were mock-vaccinated with an equivalent preparation without viral antigens (control group). Both groups were boostered 28 days later. Neither clinical signs of disease nor adverse effects were observed during or after vaccination. A specific serological response, revealed by the development of neutralizing antibodies, was detected in all vaccinated animals after the first dose of vaccine, whereas control animals remained seronegative. Calves were subsequently challenged on day 77 post-vaccination (pv) with 10(9.25) TCID(50) of the wild-type BoHV-5 (parental strain EVI 88/95). After challenge, vaccinated cattle displayed mild signs of respiratory disease, whereas the control group developed respiratory disease and severe encephalitis, which led to culling of 2/4 calves. Searches for viral DNA in the central nervous system (CNS) of vaccinated calves indicated that wild-type BoHV-5 did not replicate, whereas in CNS tissues of calves on the control group, viral DNA was widely distributed. BoHV-5 shedding in nasal secretions was significantly lower in vaccinated calves than in the control group on days 2, 3, 4 and 6 post-challenge (pc). In addition, the duration of virus shedding was significantly shorter in the vaccinated (7 days) than in controls (12 days). Attempts to reactivate latent infection by administration of dexamethasone at 147 days pv led to recrudescence of mild signs of respiratory disease in both vaccinated and control groups. Infectious virus shedding in nasal secretions was detected at reactivation and was significantly lower in vaccinated cattle than in controls on days 11-13 post-reactivation (pr). It is concluded that the inactivated vaccine prepared with the BoHV-5 gI/gE/US9(-) recombinant was capable of conferring protection to encephalitis when vaccinated cattle were challenged with a large infectious dose of the parental wild type BoHV-5. However, it did not avoid the establishment of latency nor impeded dexamethasone-induced reactivation of the virus, despite a significant reduction in virus shedding after challenge and at reactivation on vaccinated calves.

Multiply-primed rolling-circle amplification (MPRCA) of PCV2 genomes: applications on detection, sequencing and virus isolation

Multiply-primed rolling-circle amplification (MPRCA) was used to amplify porcine circovirus type 2 (PCV2) genomes isolated from tissues of pigs with signs of post-weaning multisystemic wasting syndrome (PMWS). Two of the amplified PCV2 genomes were cloned in prokaryotic plasmids and sequenced. Both were nearly identical (1767 nt) except for one silent substitution in the region coding for the capsid protein (ORF2). In addition, they showed high nucleotide sequence similarity with PCV2 isolates from others countries (93-99%). To investigate whether the MPRCA amplified PCV2 genomes could be used to produce infectious virus, the cloned genomes were isolated from the plasmids, recircularized and used for transfection in PK-15 cells. This procedure led to the production of infectious virus to titres up to 10(5.55) TCID(50)/mL. It was concluded that MPRCA is a useful tool to amplify PCV2 genomes aiming at sequencing and virus isolation strategies, where particularly useful is the fact that it allows straightforward construction of PCV2 infectious clones from amplified genomes. However, it was less sensitive than PCR for diagnostic purposes.

Neutralizing antibodies to bovine herpesvirus types 1 (BoHV-1) and 5 (BoHV-5) and its subtypes

This study was carried out to determine whether the sensitivity of serum neutralization (SN) tests would be affected by the use of distinct subtypes of bovine herpesvirus 1 (BoHV-1) and 5 (BoHV-5) as test challenge viruses. Bovine sera collected from a randomized sample (n=287) were tested in a 24h incubation SN against three type 1 viruses (BoHV-1.1 strains "Los Angeles" (LA) and "EVI 123"; BoHV-1.2a strain "SV 265") and three type 5 viruses (BoHV-5a strain "EVI 88"; BoHV-5b strain "A 663" and BoHV-5c "ISO 97"). SN sensitivity varied greatly depending on the test challenge virus used in the test, particularly when results against each virus were considered individually, where it ranged from 77% (detecting 80 out of 104 antibody-positive sera) with ISO 97 to 91% (95/104) with BoHV-1.1 strain LA. All tests to single viruses revealed a significantly low sensitivity (McNemar's; p<0.05). Maximum sensitivity (104/104) was achieved when positive results to a particular combination of four of the challenge viruses (LA+EVI 123+SV 265+A 663) or some combinations of five viruses (or all six viruses) were added cumulatively. These results provide evidence for no association between any particular virus type/subtype and higher SN sensitivity. In addition, it was clearly shown that when SN is performed with single test challenge viruses, sensitivity can vary so significantly that might compromise control or eradication efforts. Performing SN against a number of different viruses demonstrated to improve significantly the test's sensitivity.

Soroprevalência de herpesvírus bovinos tipos 1 e/ou 5 no Estado do Rio Grande do Sul

Este estudo objetivou estimar a prevalência de anticorpos contra os herpesvírus bovinos tipos 1 e 5 (BoHV-1 e BoHV-5) no Estado do Rio Grande do Sul (RS), Brasil, frente a diferentes cepas de BoHV-1 e BoHV-5. As amostras de soro utilizadas foram extraídas de uma amostragem mais ampla, desenhada para estimar a prevalência de brucelose bovina no Estado. Todos os soros foram coletados de vacas com idade igual ou superior a 24 meses de idade, não vacinadas contra herpesvírus bovinos, de rebanhos de corte e leite. O cálculo amostral foi baseado em uma expectativa de prevalência média de infecção de 33%, considerando-se um erro padrão não superior a 1% e um intervalo de confiança de 95%. Com base nesse cálculo foram examinados 2.200 soros, provenientes de 390 propriedades e 158 municípios. Os soros foram analisados na busca de anticorpos contra BoHV-1 e BoHV-5 pela técnica de soroneutralização (SN), executada frente a quatro cepas de vírus distintas: EVI123/98 e Los Angeles (BoHV-1.1); EVI88/95 (BoHV-5a) e A663 (BoHV-5b). A prevalência média de anticorpos contra o BoHV-1 e BoHV-5 nos animais amostrados foi de 29,2% (642/2200); animais soropositivos foram identificados em 57,7% (225/390) dos rebanhos. As estimativas de prevalência variaram de acordo com a cepa e/ou vírus utilizado para o desafio nos testes de SN. A prevalência e a sensibilidade mais altas foram obtidas quando os resultados positivos à SN frente aos quatro vírus distintos foram somados. O uso de somente um vírus de desafio na SN levaria a redução de sensibilidade de 20,4% a 34,6% quando comparada com os resultados positivos combinados. Estes achados evidenciam que anticorpos contra BoHV-1 e BoHV-5 estão amplamente difundidos nos rebanhos do RS, embora a prevalência em distintas regiões geográficas seja bastante variada. Os resultados obtidos nas estimativas de prevalência foram fortemente afetados pelas diferentes amostras de vírus usadas nos testes de SN. Esse fato deve ser levado em consideração quando estudos sorológicos para BoHV-1 e BoHV-5 forem realizados. Como a SN não é capaz de discriminar as respostas de anticorpos para BoHV-1 e BoHV-5, a prevalência tipo-específica permanece desconhecida.

Efficacy of a gE-deleted, bovine herpesvirus 1 (BoHV-1) inactivated vaccine

Bovine herpesvirus type 1 (BoHV-1) is recognized as a major cause of economic losses in cattle. Vaccination has been widely applied to minimize losses induced by BoHV-1 infections. We have previously reported the development of a differential BoHV-1 vaccine, based on a recombinant glycoprotein E (gE)-deleted virus (265gE-). In present paper the efficacy of such recombinant was evaluated as an inactivated vaccine. Five BoHV-1 seronegative calves were vaccinated intramuscularly on day 0 and boostered 30 days later with an inactivated, oil adjuvanted vaccine containing an antigenic mass equivalent to 10(7.0) fifty per cent cell culture infectious doses (CCID50) of 265gE-. Three calves were kept as non vaccinated controls. On day 60 post vaccination both vaccinated and controls were challenged with the virulent parental strain. No clinical signs or adverse effects were seen after or during vaccination. After challenge, 2/5 vaccinated calves showed mild clinical signs of infection, whereas all non vaccinated controls displayed intense rhinotracheitis and shed virus for longer and to higher titres than vaccinated calves. Serological responses were detected in all vaccinated animals after the second dose of vaccine, but not on control calves. Following corticosteroid administration in attempting to induce reactivation of the latent infection, no clinical signs were observed in vaccinated calves, whereas non vaccinated controls showed clinical signs of respiratory disease. In view of its immunogenicity and protective effect upon challenge with a virulent BoHV-1, the oil adjuvanted preparation with the inactivated 265gE- recombinant was shown to be suitable for use as a vaccine.

Diagnóstico de raiva no Rio Grande do Sul, Brasil, de 1985 a 2007

São apresentados os resultados de 23 anos de diagnósticos de raiva realizados no Instituto de Pesquisas Veterinárias Desidério Finamor, no Estado do Rio Grande do Sul, Brasil. Entre os anos de 1985 e 2007, um total de 23.460 amostras foram diagnosticadas no laboratório, compreendendo cerca de 95% do número total de amostras submetidas ao diagnóstico laboratorial de raiva no Estado. A metodologia utilizada seguiu técnicas padrões como a imunofluorescência direta (IFD) e inoculação em camundongos (IC). Não ocorreram casos de raiva humana no período. O vírus rábico (VR) foi detectado em 739 (3,1%) amostras, sendo 656 (88,7%) de origem bovina. O vírus foi também identificado em 23 caninos (3,1%), 21 eqüinos (2,9%), 29 quirópteros (4,0%), 4 felinos (0,5%), 3 ovinos (0,4%), 2 suínos (0,27%) e em um animal selvagem de espécie indeterminada (0,13%). O último caso de raiva em cães associado com variantes do vírus endêmicas nessa espécie foi diagnosticado em 1988. Dois episódios de contaminação incidental registrados em um felino em 2001 e em um canino em 2007, associados com variantes do vírus prevalentes em morcegos. Em relação à raiva bovina, os dados aqui apresentados revelam uma marcante diminuição no número de casos de raiva nessa espécie, em comparação com registros prévios. Por outro lado, um aumento no número de casos de raiva em morcegos hematófagos e não hematófagos vem sendo observado; no entanto, não é possível associar este aumento com modificações nas relações vírus/hospedeiro, pois o número de morcegos submetidos para diagnóstico tem igualmente aumentado. Isto provavelmente reflete o aumento do conhecimento sobre o papel de morcegos no ciclo de transmissão, e não necessariamente alterações no vírus e/ou nos hospedeiros.

Phylogenetic comparison of the carboxy-terminal region of glycoprotein C (gC) of bovine herpesviruses (BoHV) 1.1, 1.2 and 5 from South America (SA)

Different types and subtypes of bovine herpesvirus 1 and 5 (BoHV-1 and BoHV-5) have been associated to different clinical conditions of cattle, in such a way that type/subtype differentiation has become an essential tool for understanding the pathogenesis and epidemiology of BoHV infections. In search for a genomic region that would allow a clear distinction between BoHV-1 and BoHV-5, the carboxy-terminal portion of glycoprotein C (gC), corresponding to residues 321-450 (BoHV-1) and 301-429 (BoHV-5) of 23 South American (SA) isolates (Brazil mostly) was amplified and sequenced. The nucleotide sequence alignments revealed levels of genomic similarity ranging from 98.7 to 99.8% among BoHV-1 isolates, 88.3 to 92% between BoHV-1/BoHV-5 and 96 to 99.7% among BoHV-5 isolates. At the amino acid level, sequence similarity varied ranging from 97.5 to 99.5% among BoHV-1, 77.5 to 84.4% between BoHV-1/BoHV-5 and 92.1 to 99.5% (BoHV-5/BoHV-5). The isolates could be clearly separated into BoHV-1.1, BoHV-1.2 and BoHV-5 after phylogenetic analysis. The results suggest that the phylogenetic analysis performed here can be used as a potential molecular epidemiological tool for herpesviruses.

Adjuvant activity of Quillaja brasiliensis saponins on the immune responses to bovine herpesvirus type 1 in mice

The chemical characterization of aqueous extracts (AE) of barks, leaves and branches and the saponin fraction denominated QB-90 obtained from Quillaja brasiliensis, a native species from Southern Brazil, show remarkable similarities to Quillaja saponaria saponins which are known as adjuvants in vaccine formulations. In vivo toxicity assays of AE and QB-90 showed not to be lethal for mice in doses ranging from 50 to 1600 microg and 50-400 microg, respectively. Experimental vaccines prepared with bovine herpesvirus type 1 (BHV-1) antigen and either AE (barks 100 microg, leaves 400 microg, branches 400 microg) or QB-90 (100 microg) were able to enhance the immune responses of mice in a comparable manner to saponins from Q. saponaria (QuilA, 100 microg). BHV-1 specific IgG, IgG1 and IgG2a antibody levels in serum were also significantly enhanced by AE, QB-90 and QuilA compared to control group (p<0.05). These results showed that AE and QB-90 from Q. brasiliensis are potential candidates as adjuvants in vaccines.

Vaccination with a gE-negative bovine herpesvirus type 1 vaccine confers insufficient protection to a bovine herpesvirus type 5 challenge

In the present study, cross-protection to bovine herpesvirus type 5 (BHV-5) induced by bovine herpesvirus type 1 (BHV-1) vaccination was examined following inoculation of rabbits and calves with a glycoprotein E (gE)-negative BHV-1 vaccine and subsequent challenge with BHV-5. Rabbits (n=5) and calves (n=8) were vaccinated [five rabbits intranasally (IN), four calves IN and four intramuscularly (IM)] with 7.1 log(10)median tissue culture infective dose (TCID(50)) of the BHV-1 vaccine. Rabbits and calves were challenged IN [rabbits 2 weeks post-vaccination (pv); calves 5 weeks pv] with 9.1log(10)TCID(50) of BHV-5. Two out of five vaccinated rabbits died after challenge with typical BHV-5 disease, as did 3/5 non-vaccinated controls. In calves, 4/8 vaccinated animals displayed mild signs of disease, whereas 6/6 non-vaccinated controls developed signs of disease, so severe that 2/6 had to be killed. Besides, nasal virus shedding post-challenge was not reduced by vaccination. At necropsy, on day 21 post-challenge, typical BHV-5 lesions were evident in brain tissues of both vaccinated and non-vaccinated calves. Dexametasone administration at 180 days post-infection did not reactivate clinical signs despite BHV-5 shedding in nasal secretions of both vaccinated and non-vaccinated calves. These results show that the BHV-1 vaccine evaluated here did not confer protection to BHV-5 in rabbits. In calves, BHV-1 vaccination did confer some protection to BHV-5 induced clinical disease, but it did not prevent infection and had no effect on nasal virus shedding or on the development of encephalitic lesions.

A infecção pelo vírus da diarréia viral bovina (BVDV) no Brasil: histórico, situação atual e perspectivas

O vírus da Diarréia Viral Bovina (BVDV) possui distribuição mundial e é considerado um dos principais patógenos de bovinos. A infecção e as enfermidades associadas ao BVDV têm sido descritas no Brasil desde os anos 60. Diversos relatos sorológicos, clínico-patológicos e de isolamento do agente demonstram a ampla disseminação da infecção no rebanho bovino brasileiro. Além de sorologia positiva em níveis variáveis em bovinos de corte e leite, anticorpos contra o BVDV têm sido ocasionalmente detectados em suínos, javalis, caprinos, cervos e bubalinos. O BVDV tem sido freqüentemente detectado em fetos abortados, na capa flogística de animais persistentemente infectados (PI) oriundos de rebanhos com problemas reprodutivos, em amostras clínicas e/ou material de necropsia de animais com as mais diversas manifestações clínicas, em sêmen de touros de centrais de inseminação artificial, em fetos saudáveis coletados em matadouros e em soro bovino comercial e/ou cultivos celulares. Aproximadamente 50 isolados do vírus já foram caracterizados genética e/ou antigenicamente, enquanto um número semelhante de amostras aguarda caracterização. A maioria dos isolados caracterizados pertence ao genótipo BVDV-1, biotipo não-citopático (NCP), embora vários isolados de BVDV-2 (e alguns BVDV citopáticos CP) já tenham sido identificados. Os isolados brasileiros apresentam grande variabilidade antigênica, além de diferenças antigênicas marcantes quando comparados a cepas vacinais norte-americanas. Algumas vacinas polivalentes (BHV-1, PI-3, BRSV), contendo o BVDV inativado, têm sido utilizadas no rebanho brasileiro. No entanto, o uso de vacinação ainda é incipiente na maioria das regiões; apenas 2,5 milhões de doses foram comercializadas em 2003. A baixa reatividade sorológica cruzada entre os isolados brasileiros e as cepas vacinais tem estimulado laboratórios nacionais a desenvolver vacinas com isolados autóctones de BVDV-1 e 2. O conhecimento sobre a infecção pelo BVDV no Brasil tem aumentado consideravelmente nos últimos anos, à medida em que cresce o número de laboratórios envolvidos em diagnóstico e pesquisa sobre esse vírus. Diagnóstico sorológico, virológico ou molecular; estudos sobre epidemiologia sorológica e molecular, patogenia e produção de reagentes para diagnósitco têm contribuído para o aumento no conhecimento sobre a infecção pelo BVDV no país.

Studies on antigenic and genomic properties of Brazilian rabies virus isolates

Despite the recognized stability of rabies virus, differences among isolates from different species have been found. This work was carried out with the aim to identify antigenic and genomic differences in Brazilian rabies virus isolates and to verify whether such alterations would bear any relationship with the different hosts for the virus in nature. For that, 79 Brazilian rabies viruses isolated from different host species and from distinct regions within Brazil were submitted to antigenic characterization with a panel of 11 monoclonal antibodies (Mabs) directed to lyssavirus antigens and to genomic analyses by the reverse transcriptase-polymerase chain reaction (RT-PCR) amplification of the N gene followed by restriction endonuclease analysis (REA). In addition, the nucleotide sequences of part of the N gene (225 bp) of seven isolates, taken as representative of the majority of the viruses under study, were determined. The analyses with the Mabs and RT-PCR/REA allowed the identification of two major groups of variants, the first formed by most isolates of cattle and bats and the second formed by viruses of dog origin. Partial sequencing of the N gene confirmed the similarity among isolates from cattle origin and those of vampire bats. However, viruses from non-haematophagous bats exhibited consistent differences from those of vampire bat isolates. Such findings suggest that the variants have evolved fairly stable modifications, which are not altered after passage in a dead-end host of a distinct species. No association could be established between antigenic or genomic alterations and geographic distribution of the isolates, which suggests that evolution of the virus has been directed to adaptation to the host species.

Experimental infection of calves with a gI, gE, US9 negative bovine herpesvirus type 5

In this work, a role for the genes encoding glycoproteins I (gI) and E (gE) and the US9 protein of bovine herpesvirus type 5 (BHV-5) in neuropathogenicity and reactivation of latent infections was examined. Calves infected intranasally with a gI/gE/US9 deleted recombinant shed up to 10(2.85) TCID50/ml infectious virus in nasal secretions. Calves infected with the wild type BHV-5 parental virus shed up to 10(5) TCID50/ml virus. No signs of disease were observed in calves infected with the recombinant virus, whereas those infected with wild type virus displayed respiratory and neurological signs. The recombinant was only able to reach the basal portions of the central nervous system. In contrast, wild type virus was found widespread within the brain. Reactivation with dexamethasone 60 days post-infection resulted in reactivation of wild type virus, whereas the recombinant virus could not be reactivated. These studies demonstrate that genes gI, gE and US9 of BHV-5 are important for its neuropathogenicity and its ability to reactive from latency.

Caracterização antigênica e molecular de oito amostras do vírus da doença de Aujeszky isoladas no estado do Rio Grande do Sul em 2003

A doença de Aujeszky ou pseudoraiva (DA), causada pelo vírus da pseudoraiva (PRV) é a maior preocupação na produção de suínos. No estado do Rio Grande do Sul, Brasil, a DA foi somente detectada em 1954, em bovino. Em 2003, ocorreram dois surtos de encefalite em granjas na região norte do estado, fronteira com o estado de Santa Catarina. O vírus da doença de Aujeszky (VDA) foi isolado a partir de animais coletados em oito granjas distintas da região e submetido a análises antigênicas e moleculares. As amostras de VDA isoladas foram comparadas com as amostras padrão NIA-3 e NP. A caracterização antigênica dos mesmos foi realizada com testes de imunoperoxidase frente a um painel de anticorpos mono-clonais (Mabs) preparado contra epitopos de glicoproteinas virais (gB, gC, gD e gE). A caracterização genômica foi realizada através da análise restrição enzimática (REA) sobre o genoma total das amostras, com a enzima de restrição (REA) Bam HI. O perfil antigênico das oito amostras isoladas no Rio Grande do Sul, bem como os apresentados pelas amostras padrão NIA-3 e NP, foram similares. A REA revelou que todos as oito amostras do Rio Grande do Sul apresentaram um arranjo genômico do tipo II, genótipo frequentemente encontrado em surtos prévios de DA em outros estados do Brasil. Os resultados aqui obtidos indicam que as oito amostras isoladas no Rio Grande do Sul são similares.

Detection of Brazilian bovine respiratory syncytial virus strain by a reverse transcriptase-nested-polymerase chain reaction in experimentally infected calves

A reverse transcriptase (RT)-nested-polymerase chain reaction (PCR) was standardised to detect bovine respiratory syncytial virus (BRSV), using a Brazilian isolate, in three experimentally infected calves. This followed initial tests in infected chicken embryo related (CER) cells. One animal had lesions, characterized by interstitial multifocal pneumonia, severe interstitial and subpleural emphysema, and lung consolidated areas. Lung and tracheal tissues collected 6 days after infection were analysed by RT-nested-PCR. Primers, specific for the BRSV G and F glycoproteins genes, yielded amplification fragments of 371 and 481 bp, respectively, from the RNA of the cell-propagated virus. Using RNA extracted from organs of infected calves, RT-nested-PCR amplified the fragment of the G gene in all tracheal samples, but in only two of three lung samples analysed. These results suggest that RT-nested-PCR could be a promising assay for diagnosis and epidemiological analysis of BRSV in Brazil.

Partial Protection Induced by a BHV-1 Recombinant Vaccine against Challenge with BHV-5

Bovine herpesvirus type 5 (BHV-5) is the causative agent of bovine herpetic encephalitis, a major concern for cattle farming in Brazil and Argentina. We recently developed a differential, gE-negative vaccine (265 gE-), based on a Brazilian BHV-1 strain. The present study was carried out to examine whether such a vaccine would confer protection to BHV-5 infections. It was concluded that the recombinant BHV-1 vaccine tested here is not capable of conferring full protection to BHV-5 challenge.

Bovine herpesvirus type 5 (BHV-5) in a calf with rabies

The brain of an one year old male calf which died with signs of neurological disease was submitted to the laboratory for rabies diagnosis. Microscopical findings included moderate mielitis, mild meningoencephalitis with perivascular cell cuffing and Negri inclusion bodies in Purkinje cells of the cerebellum. Rabies virus infection was further confirmed by the direct fluorescent antibody test as well as by mouse inoculation. In addition, a herpesvirus was isolated from brain tissues. The isolate was antigenic and genetically characterized as bovine herpesvirus type 5 (BHV-5). It was not possible to determine whether BHV-5 played an active role in the outcome of the infection, since, the virus might have been present in a latent form in neural tissues. This is the first report of a mixed rabies/ BHV-5 infection in calves.

Restriction endonuclease and monoclonal antibody analysis of Brazilian isolates of bovine herpesviruses types 1 and 5

Twelve Brazilian isolates and three reference strains of bovine herpesviruses (BHVs) were subjected to restriction endonuclease analysis (REA) and monoclonal antibody (MAb) analysis. Viral DNA was cleaved with BamHI, BstEII, EcoRI, HindIII and PstI. The monoclonal antibody panel allowed the differentiation between types 1 and 5 viruses, while REA with BstEII and HindIII showed the distinction between BHV-1 and -5 subtypes. Typical 1.1 and 1.2a patterns were observed with two isolates from respiratory disease. An isolate from semen of a clinically healthy bull displayed 1.2b profile, whereas another displayed a clear 5a pattern, which was never reported before. Seven out of nine Brazilian type 5 (BHV-5) isolates displayed REA patterns similar to the Australian BHV-5 strain N569 (BHV-5a), and differing from the Argentinean A663 strain (BHV-5b) virus. Another two BHV-5 isolates, which displayed an unusual MAb pattern of reactivity, showed a BstEII profile different from both reference strains of BHV-5. These two viruses were considered BHV-5 "non-a/non-b" subtype.