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Nineteen Brazilian isolates of bovine viral diarrhea virus (BVDV) were characterized antigenically with a panel of 19 monoclonal antibodies (mAbs) (Corapi WV, Donis RO and Dubovi EJ (1990) American Journal of Veterinary Research, 55: 1388-1394. Eight isolates were further characterized by cross-neutralization using sheep monospecific antisera. Analysis of mAb binding to viral antigens by indirect immunofluorescence revealed distinct patterns of reactivity among the native viruses. Local isolates differed from the prototype Singer strain in recognition by up to 14 mAbs. Only two mAbs -one to the non-structural protein NS23/p125 and another to the envelope glycoprotein E0/gp48 -recognized 100% of the isolates. No isolate was recognized by more than 14 mAbs and twelve viruses reacted with 10 or less mAbs. mAbs to the major envelope glycoprotein E2/gp53 revealed a particularly high degree of antigenic variability in this glycoprotein. Nine isolates (47.3%) reacted with three or less of 10 E2/ gp53 mAbs, and one isolate was not recognized by any of these mAbs. Virus-specific antisera to eight isolates plus three standard BVDV strains raised in lambs had virus-neutralizing titers ranging from 400 to 3200 against the homologous virus. Nonetheless, many antisera showed significantly reduced neutralizing activity when tested against heterologous viruses. Up to 128-fold differences in cross-neutralization titers were observed for some pairs of viruses. When the coefficient of antigenic similarity (R) was calculated, 49 of 66 comparisons (74.24%) between viruses resulted in R values that antigenically distinguish strains. Moreover, one isolate had R values suggesting that it belongs to a distinct serologic group. The marked antigenic diversity observed among Brazilian BVDV isolates should be considered when planning diagnostic and immunization strategies.

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Nontyphoidal Salmonella are one of the leading causes of foodborne diseases in the world. As poultry products are recognized as main sources of human salmonellosis, nontyphoidal Salmonella control has become a global issue for the poultry industry. The increasing antimicrobial resistance in poultry-related nontyphoidal Salmonella serovars is a global matter of concern. By monitoring the evolution of antimicrobial resistance, alternative treatments can be identified and possible restrictions in the treatment of systemic human salmonellosis foreseen. A meta-analysis was conducted to assess the profile and temporal evolution of the antimicrobial resistance of nontyphoidal Salmonella of poultry and human origin in Brazil, isolated in the period from 1995 to 2014. Four databases were researched; twenty-nine articles met the eligibility criteria and were included in the meta-analysis. In the nontyphoidal isolates of poultry origin, the highest levels of antimicrobial resistance were verified for sulfonamides (44.3%), nalidixic acid (42.5%), and tetracycline (35.5%). In the human-origin isolates, the resistance occurred mainly for sulfonamides (46.4%), tetracycline (36.9%), and ampicillin (23.6%). Twenty-two articles described results of antimicrobial resistance specifically for Salmonella Enteritidis, also enabling the individual meta-analysis of this serovar. For most antimicrobials, the resistance levels of Salmonella Enteritidis were lower than those found when considering all the nontyphoidal serovars. In the poultry-origin isolates, a quadratic temporal distribution was observed, with reduced resistance to streptomycin in Salmonella Enteritidis and in all nontyphoidal serovars, and a linear increase of resistance to nalidixic acid in Salmonella Enteritidis. In the human-origin isolates, a linear increase was identified in the resistance to nalidixic acid in Salmonella Enteritidis and in all the nontyphoidal isolates, and to gentamicin in Salmonella Enteritidis. Continuous monitoring of the development and spread of antimicrobial resistance could support the measurement of the consequences on poultry and human health.

Pythium insidiosum is a fungus-like organism present in subtropical and tropical areas, such as Brazil, known to infect humans and various animal species. P. insidiosum is the etiological agent of pythiosis, an emerging and granulomatous disease characterized mainly by cutaneous and subcutaneous lesions in horses, the principal species affected. Accurate diagnosis of pythiosis and identification of its causal agent by microbiological and serological tests can be often difficult and inconclusive principally for horses and humans. The aim of this study was to evaluate the application of the previously described P. insidiosum-specific nested polymerase chain reaction (PCR) assay to directly detect P. insidiosum DNA in clinical and experimental lesions. Universal fungal primers (ITS1 and ITS4) were used during the first-round of PCR to amplify ITS1, 5.8s, and ITS2. A second-round of PCR was conducted with P. insidiosum-specific primers (PI1 and PI2) to amplify a variable region within this ITS1. In this study, a total of 21 equine clinical samples (kunkers) and 28 specimens from experimentally infected rabbits were analyzed by nested PCR. The first-round of PCR generated 800-base pair products, and the second-round produced 105-base pair amplicons for each P. insidiosum-specific sample; no amplicons were generated in negative control samples. Our results suggest that nested PCR is an important and efficient tool for diagnosis of both endemic (horse samples) and experimental (rabbit samples) pythiosis.

Gil, L. H. G. V.; Botton, S. A.; Weiblen, R.; Ridpath, J. F.; Kreutz, L. C.; Pilati, C.; Driemeyer, D.; Moojen, V.; and Wendelstein, A. C., "Clinical, pathological and antigenic aspects of bovine viral diarrhea virus (BVDV) type 2 isolates identified in Brazil" (2000). AbstractNucleotide sequencing and phylogenetic analysis of Brazilian bovine viral diarrhea virus (BVDV) ®eld isolates identi®ed four viruses belonging to the genotype 2. Comparison of 5 H UTR sequences from these isolates to those of North American BVDV type 2 revealed genomic variations that correlated with the geographic origins of the isolates. Two of the Brazilian type 2 viruses were isolated from clinical cases of gastroenteric/respiratory disease and two were isolated from healthy bovine fetuses. The clinical cases affected young animals (8-and 18-months-old) and were characterized by diarrhea, respiratory signs, extensive oral and digestive tract erosions, conjunctival and vulvar congestion, occasional digestive bleeding and vulvar and heart petechial hemorrhage. Antigenic analysis of these isolates with a panel of 10 monoclonal antibodies revealed marked antigenic differences in the major envelope glycoprotein, gp53/E2, compared to standard laboratory and vaccine BVDV strains. In addition, virus-speci®c antisera raised to Brazilian BVDV type 2 viruses displayed very low serological cross-reactivity with standard BVDV type 1 strains. Differences up to 64-fold in cross-neutralization titers were observed between BVDV type 1 and Brazilian BVDV type 2 isolates. The identi®cation of BVDV type 2 among Brazilian cattle may have important implications for epidemiological studies, diagnostic and immunization strategies. Furthermore, the low neutralizing activity of BVDV type 1 antisera against the recently identi®ed Brazilian BVDV type 2 isolates raises the question about the degree of protection conferred by BVDV vaccines, most of them based on a single type 1 strain. #

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Foot-and-mouth disease virus (FMDV) is one of the most contagious agents of animals. Recent disease outbreaks in FMD-free countries have prompted the development of new control strategies that could improve the levels of protection against this virus. We have delivered a plasmid expressing a short hairpin RNA (shRNA) directed against a highly conserved sequence in the 2B nonstructural protein coding region of FMDV RNA to porcine cells. After virus infection, these cells showed a significant reduction in the synthesis of viral RNA and proteins, as well as a decrease in virus yield when compared to control cells. The antiviral effect was sequence specific and not attributable to induction of the interferon pathway. Since FMDV is an antigenically variable virus, we examined the effectiveness of this strategy against multiple serotypes and found that expressed 2B shRNA resulted in efficient silencing of at least 4 FMDV serotypes. Thus, RNA interference may be a potential alternative control strategy to limit the spread of this highly contagious virus in livestock.