Molecular analysis of the full-length VP2 gene of Brazilian strains of canine parvovirus 2 shows genetic and structural variability between wild and vaccine strains.

Canine parvovirus 2 (CPV-2), a highly contagious virus, affects dogs worldwide. Infected animals present severe and acute gastroenteritis which may culminate in death. CPV-2 VP2 protein is responsible for important biological functions related to virus-host interactions. Herein we obtained VP2 full-length gene sequences from Brazilian dogs with bloody diarrhea (n=15) and vaccine strains (n=7) produced by seven different laboratories and marketed in Brazil. All wild sequences and one vaccine strain were classified as CPV-2b and six vaccines were the classic CVP-2. Mutations in VP2 protein from vaccine and wild strains obtained in Brazil and worldwide were analyzed (n=906). Amino acid sequences from vaccine strains remarkably diverge from each other, even that classic CPV-2. Phylogenetic analysis based on VP2 gene and conducted with sequences displaying mutations in epitope regions previously described shows that vaccine strains are distantly related from the wide range of wild CPV-2. The impact of amino acid mutations over VP2 protein structure shows that vaccine and wild strains obtained in this study diverge in loop 3, an epitope region that plays a role in the CPV-2 host range. This is the first analysis of CPV-2 VP2 from commercial vaccine strains in Brazil and wild ones from Minas Gerais State, Brazil, and the first detailed attempt to vaccinal VP2 molecular and structural analyses.

Isolation and genetic stability of an infectious bronchitis virus strain (IBV) / Isolamento e estabilidade genética de uma cepa do vírus da bronquite infecciosa (IBV)

O vírus da bronquite infecciosa (IBV) é um importante patógeno respiratório presente na avicultura comercial e tem provocado grandes perdas econômicas em todo o mundo. A vacinação é realizada pela indústria produtora de aves, mas continuam surgindo novos sorotipos e variações antigênicas, dificultando o controle de IBV. Nós realizamos uma caracterização molecular de uma cepa de IBV obtida diretamente de tecidos e comparamos com a mesma cepa que havia sido passada três vezes em ovo embrionado. Nós mostramos uma variação significante na sequência viral depois de ter sido isolada em ovo embrionado.(AU)

The expression of NTPDase1 and -2 of Leishmania infantum chagasi in bacterial and mammalian cells: Comparative expression, refolding and nucleotidase characterization.

Visceral Leishmaniasis (VL) represents an important global health problem in several warm countries around the world. The main targets in this study are the two nucleoside triphosphate diphosphohydrolases (NTPDases) from Leishmania infantum chagasi that are the main etiologic agent of VL in the New World. These enzymes, called LicNTPDase1 and -2, are homologous to members 5 and 6 of the mammalian E-NTPDase/CD39 superfamily of enzymes. These enzymes hydrolyze nucleotides and accordingly can participate in the purine salvage pathways and in the modulation of purinergic signaling through the extracellular nucleotide-dependent host immune responses. They can therefore affect adhesion and infection of host cells and the parasite virulence. To further characterize these enzymes, in this work, we expressed LicNTPDase1 and -2 in the classical bacterial system Escherichia coli and mammalian cell system COS-7 cells. Our data demonstrate that changes in refolding after expression in bacteria can increase the activity of recombinant (r) rLicNTPDase2 up to 20 times but has no significant effect on rLicNTPDase1. Meanwhile, the expression in COS-7 led to a significant increase in activity for rLicNTPDase1.

In vitro assessment of the antiviral potential of trans-cinnamic acid, quercetin and morin against equid herpesvirus 1.

The antiviral activity of quercetin, morin and trans-cinnamic acid was evaluated in vitro against equid herpesvirus 1 (EHV-1) by determining the virucidal activity and using the time of addition assay to test inhibition of the viral replication cycle. The cytotoxicity of each substance was assessed using MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide]. Quercetin showed virucidal action and inhibition of the viral replication cycle at 0 and 1h. Morin showed potential virucidal and viral replication cycle inhibition at 0 h. Trans-cinnamic acid did not show virucidal activity but inhibited the viral replication cycle at -1 and 0 h. This study demonstrates the potential of these compounds as future antiviral candidates in relation to viruses of importance in veterinary medicine.

Porcine circovirus-2 viral load versus lesions in pigs: perspectives for post-weaning multisystemic wasting syndrome.

Porcine circovirus-2 (PCV-2) is the main agent related to post-weaning multisystemic wasting syndrome (PMWS) and it is also associated with other syndromes affecting pigs. Not all pigs infected with PCV-2 will develop PMWS and the incidence of PMWS is higher when coinfecting viral and bacterial pathogens are present. In this study, PCV-2 viral loads were evaluated in the tissues of animals with and without PMWS in order to investigate the relationship between viral load and microscopical lesions. Lymph nodes had the highest average viral load, but there was no significant difference between lesion severity and the viral load in these structures. There was no significant difference between the average viral load in inguinal lymph nodes of animals with and without PMWS. However, samples from pigs with PMWS had more severe lesions compared with samples from non-PMWS animals. These findings suggest that other infectious and non-infectious cofactors may be important in the pathogenesis of PMWS.

Classification and putative origins of Brazilian porcine circovirus 2 inferred through phylogenetic and phylogeographical approaches.

Porcine circovirus 2 (PCV2) is the major causative agent of postweaning multisystemic wasting syndrome (PMWS) and is associated with different syndromes affecting pigs. The PCV2 genome has three main open reading frames (ORFs) among which the ORF2 encodes the capsid protein. In this study, the ORF2 nucleotide sequences of 30 Brazilian isolates were analyzed. The sequences were compared to other GenBank sequences using phylogenic and phylogeographic approaches. Our results show high sequence variability in Brazil, since, in this work, the Brazilian isolates were classified into subgroup 1AB, 2D and 2, which reveals that the virus was introduced in Brazil more than once. On the other hand, most of Brazilian isolates seem to be derived from only one introduction. According to the data from the Pig Breeders' Association, the multiple introductions of the virus probably occurred through the import of animals with the asymptomatic form of the virus or through the import of contaminated semen. The results point to the necessity of implementing programs aimed at selecting sows in order to avoid the import of animals infected by Group 1 PCV2.