Comparison among three different serological methods for the detection of equine influenza virus infection

The equine influenza virus (EIV) H3N8 subtype is responsible for all EIV outbreaks worldwide while the H7N7 subtype is less pathogenic and is considered extinct as it has not been confirmed in outbreaks since 1980. Although EIV is enzootic in Brazil, few reports describe the actual EIV antibody status in the country. The aims of this study were: ­ to evaluate the efficiency of different serum treatments described by the World Organisation for Animal Health (OIE) and the World Health Organization (WHO) to remove non-specific haemagglutination inhibitors for the haemagglutination inhibition (HI) assay for EIV ­ to evaluate the presence of EIV antibodies by HI, enzyme-linked immunosorbent assay and agar gel immunodiffusion in 83 non-vaccinated equines from São Paulo State ­ to evaluate a strategy to better analyse equine sera for EIV antibodies. Although there was no statistical difference among treatments, receptor-destroying enzyme treatment followed by chicken erythrocyte adsorption showed more consistent results, which corroborate the OIE and WHO recommendation to use this treatment preferentially. The HI results suggest equine H3N8 virus circulation among the animals tested from São Paulo State. The algorithm suggested here could be used to guide antibody detection against equine influenza virus in equines, improving the test specificity by aiming to avoid false positive results.(AU) i

Identification of pathogens and virulence profile of Rhodococcus equi and Escherichia coli strains obtained from sand of parks

The identification of pathogens of viral (Rotavirus, Coronavirus), parasitic (Toxocara spp.) and bacterial (Escherichia coli, Salmonella spp., Rhodococcus equi) origin shed in feces, and the virulence profile of R. equi and E. coli isolates were investigated in 200 samples of sand obtained from 40 parks, located in central region of state of Sao Paulo, Brazil, using different diagnostic methods. From 200 samples analyzed, 23 (11.5%) strains of R. equi were isolated. None of the R. equi isolates showed a virulent (vapA gene) or intermediately virulent (vapB gene) profiles. Sixty-three (31.5%) strains of E. coli were identified. The following genes encoding virulence factors were identified in E. coli: eae, bfp, saa, iucD, papGI, sfa and hly. Phylogenetic classification showed that 63 E. coli isolates belonged to groups B1 (52.4%), A (25.4%) and B2 (22.2%). No E. coli serotype O157:H7 was identified. Eggs of Toxocara sp. were found in three parks and genetic material of bovine Coronavirus was identified in one sample of one park. No Salmonella spp. and Rotavirus isolates were identified in the samples of sand. The presence of R. equi, Toxocara sp, bovine Coronavirus and virulent E. coli isolates in the environment of parks indicates that the sanitary conditions of the sand should be improved in order to reduce the risks of fecal transmission of pathogens of zoonotic potential to humans in these places.

Detection of Genetic characterization of Porcine circovirus 2 (PCV2) in Brazilian wildlife boars

A semi-intensive wildlife boars farm presented a clinical history of high mortality in 70 - 90 days-old pigs (> 50 %). Two 90 days-old animals with weight loss and wasting were necropsied and the samples tested for PCV2 by polymerase chain reaction (PCR). The genetic material of PCV2 was sequenced and classified into the PCV2a genotype together with PCV2 sequences obtained from samples of Poland, Brazil, Slovenia and Greece wild boars.

On the interference of clinical outcome on rabies transmission an perpetuation

Rabies is a viral zoonotic infectious disease that affects mammals and is caused by genotypes/species of the Lyssavirus genus (Rhabdoviridae, Mononegavirales), with the genotype 1 (classic rabies virus - RABV) being the most prevalent. Despite continuous efforts, rabies is still an incurable disease that causes thousands of deaths amongst humans worldwide. Due to a wide range of hosts and the different evolutionary paths of RABV in each host, several host-specific variants have arisen in an ongoing process. The result of RABV replication in nervous tissues may lead to two opposite clinical outcomes, i.e., paralytic/dumb form and encephalitic/furious one. The paralytic form creates dead-end hosts mainly amongst herbivores, while the furious form of the disease allows for augmented transmission when manifested in gregarious carnivores, as their natural aggressive behavior is accentuated by the disease itself. The aim of this article is to propose a theoretical model intended to explore how the rabies virus intrinsically modulates the immune system of different host classes, the pathological changes that the virus causes in these animals and how these elements favor its own perpetuation in nature, thus providing a basis for better prediction of the patterns this disease may present.

Molecular epidemiology of rabies virus strains isolated from wild canids in Northeastern Brazil

Rabies in wild canids in Northeastern Brazil is frequent and has been reported for some time, with episodes of rabies transmission from these animals to humans also reported. In this study, we analyzed the antigenic and genetic profiles of the rabies virus nucleoprotein gene, isolated from 20 samples taken from domestic animals and wild canids located in the Northeastern region of Brazil. All viruses isolated from domestic animals (dogs and cats) belonged to the antigenic variant 2 (AgV2). Among the wild animal samples, only four were AgV2, and nine showed a divergent antigenic profile. Phylogenetic analysis revealed two Brazilian clusters. Cluster 1 (Brazilian domestic carnivore-related strains) showed two subclusters, called 1A and 1B, and cluster 2 (Brazilian wild canid-related strains) also showed two subclusters, called 2A and 2B. The majority of the samples with divergent antigenic strains segregated into subcluster 2A. The intracluster identity of cluster 1 was 95.6% and that of cluster 2, 92.4%. When clusters 1 and 2 were compared, an identity of 88.6% was found. The genetic analysis of wild canid samples performed in this study indicates that there are two distinct rabies cycles among canids in Brazil, one represented by domestic canids and the other by wild canids. This study shows that the virus samples isolated in Northeastern Brazil are region and species-specific.

Phylogeny of rabies virus identified in a cat closely related to vampire bat rabies based on the nucleoprotein gene

Rabies-infected bats are preyed upon by dogs and cats and the transmission of vírus from bats to domestic animais has been reported. It is expected that bat-related virus variants might be found with higher frequency in dogs and cats living in urban areas where the terrestrial cycle has been controlled. This article reports the genetic characterization of one sample of rabies virus from a cat that had contact with a bat on the border of São Paulo city. The sample was genetically typed as variant 3, associated with Desmodus rotundus, suggesting that bats and their rabies virus variants must from now on be considered in the epidemiology of rabies of urban domestic animais and in public health policies.

A nested polymerase chain reaction test for bovine coronavirus diagnosis bases on the RNA-dependent RNA-polymerase gene

Bovine coronavirus (BCoV) causes enteritis and respiratory iIIness in calves and dysentery in cows. Difficulties found in the production of large amounts of BCoV in cel! culture and those regarding envelope integrity pose a major problem to antigen, hyperimmune sera and monoclonal antibodies production. This study aimed at the development of a polymerase chain reaction for BCoV detection in fecal samples of calves targeted to the gene of the RNA-dependent RNApolymerase, and the comparison of this test with the hemagglutination/ hemagglutination inhibition test (HA/HI). Both tests were applied to 203 fecal samples. HA/HI resulted in an individual-levei BCoV frequency of 35.47% and a farm-Ievel frequency of 73.68%, while the proposed PCR resulted in an individual-levei BCoV frequency of 25.12% and a farm-Ievel frequency of 52.63%. Both Kappa and Youden's tests revealed a low agreement between PCR and HA/HI. Hypotheses are suggested to explain such a disagreement. The PCR proposed is a useful toei forthe detection of BCoV, for epidemiological surveys and as a screening test for studies focused on other BCoV genes, such as the spike gene.