Analysis of the anti-apoptotic activity of four vaccinia virus proteins demonstrates that B13 is the most potent inhibitor in isolation and during viral infection.

Vaccinia virus (VACV) is a large dsDNA virus encoding ~200 proteins, several of which inhibit apoptosis. Here, a comparative study of anti-apoptotic proteins N1, F1, B13 and Golgi anti-apoptotic protein (GAAP) in isolation and during viral infection is presented. VACVs strains engineered to lack each gene separately still blocked apoptosis to some degree because of functional redundancy provided by the other anti-apoptotic proteins. To overcome this redundancy, we inserted each gene separately into a VACV strain (vv811) that lacked all these anti-apoptotic proteins and that induced apoptosis efficiently during infection. Each protein was also expressed in cells using lentivirus vectors. In isolation, each VACV protein showed anti-apoptotic activity in response to specific stimuli, as measured by immunoblotting for cleaved poly(ADP ribose) polymerase-1 and caspase-3 activation. Of the proteins tested, B13 was the most potent inhibitor, blocking both intrinsic and extrinsic stimuli, whilst the activity of the other proteins was largely restricted to inhibition of intrinsic stimuli. In addition, B13 and F1 were effective blockers of apoptosis induced by vv811 infection. Finally, whilst differences in induction of apoptosis were barely detectable during infection with VACV strain Western Reserve compared with derivative viruses lacking individual anti-apoptotic genes, several of these proteins reduced activation of caspase-3 during infection by vv811 strains expressing these proteins. These results illustrated that vv811 was a useful tool to determine the role of VACV proteins during infection and that whilst all of these proteins have some anti-apoptotic activity, B13 was the most potent.

Evidence of natural interspecific recombinant viruses between bovine alphaherpesviruses 1 and 5.

Closely related bovine alphaherpesviruses 1 (BoHV-1) and 5 (BoHV-5) co-circulate in certain countries, rendering cattle co-infection possible. This is a prerequisite for BoHV recombination. Here, we report the first identification of homologous recombination between field isolates of BoHV-1 and BoHV-5, two alphaherpesviruses belonging to two distinct species with an average genomic similarity of 82.3%. Three isolates of BoHV-5, previously classified as subtype "BoHV-5b", were phylogenetically studied and analyzed via eight PCR sequencing assays dispersed at regular intervals throughout the genome to discriminate between BoHV-1 and BoHV-5. In the phylogenetic analysis, differences of clustering were found in the UL27 gene which encodes the glycoprotein B (gB). We detected two recombination breakpoints in the open reading frame of the UL27 gene. We compared the amino acid sequences of the gB of BoHV-1.1 and 1.2, BoHV-5a and recombinant formerly named BoHV-5b (chimeric gB) and subsequently performed molecular modeling. All structures were alike and, simultaneously, similar to the chimeric gB. Neutralizing antibodies against BoHV-1, BoHV-5 and recombinant viruses were analyzed via serum virus neutralization test using polyclonal sera and a monoclonal antibody against gB to demonstrate an absence of viral escape for both assays. Our results show that homologous recombination between two related species of ruminant alphaherpesviruses can occur in natural field conditions. We found three recombinant field isolates, previously classified as BoHV-5b subtypes, between BoHV-1 and BoHV-5.

Human norovirus infection in Latin America.

Noroviruses are important enteric pathogens involved in non-bacterial gastroenteritis outbreaks worldwide. Noroviruses mainly occur from person to person via the fecal-oral route but also through contaminated food or water; indirect contamination is also possible due to the resistance of the virus in the environment. Latin American countries as a whole cover a vast North-to-South range, which is highly heterogeneous in terms of climate, ecosystem, human population distribution (urban areas with high human densities versus closed communities), economic development and genetic backgrounds resulting from each particular historical context. This review aims to present epidemiological and clinical patterns of human norovirus infections in Latin American countries. Divergent prevalences were observed depending on the country and the surveyed population. In particular, a shift in rotavirus/norovirus ratio in the etiologies of gastroenteritis was detected in some countries and could be attributed partly to rotavirus vaccine coverage in their infant population. While GII.4 noroviruses were seen to constitute the most common genotype, differences in genotype distribution were observed both in the environment (via sewage sampling proxy) and between genotypes circulating in healthy and diarrheic patients. Due to high climatic discrepancies, different patterns of seasonality were observed. Accordingly, this continent may condense the different particular epidemiological features encountered for HuNoV infections worldwide.