It is suggested that bovine enteroviruses (BEV) are involved in the aetiology of enteric infections, respiratory disease, reproductive disorders and infertility. In this study, bovine faecal samples collected in different Brazilian states were subjected to RNA extraction, reverse transcription-polymerase chain reaction analysis and partial sequencing of the 5′-terminal portion of BEV. One hundred and three samples were tested with an overall positivity of 14.5%. Phylogenetic analysis clustered these BEV Brazilian samples into the Enterovirus F clade. Our results bring an important update of the virus presence in Brazil and contribute to a better understanding of the distribution and characterisation of BEV in cattle.

Nebovirus is a new genus of viruses belonging to the Caliciviridae family recently characterized in cattle, and is associated with gastrointestinal disorders, such as diarrhoea, anorexia and intestinal lesions particularly in calves. The aim of this study was to investigate the prevalence of neboviruses in Brazilian cattle and analyse phylogenetically the virus strains detected. A prevalence of 4·8% of neboviruses in faecal samples from 62 head of cattle from different Brazilian states was detected. All positive animals were aged <20 days and had diarrhoea. Phylogenetic analysis clustered the virus sequences into the Newbury1 clade. There was >96·0% nt (100% aa) sequence identity between the virus sequences in this study and >88·8% nt (>94·4% aa) identity with Newbury1/UK. Our results indicate, for the first time, the occurrence of neboviruses in Brazil as well as in South America, and the first Newbury1-like nebovirus found outside the UK.

In vivo and ex vivo studies of the immune system in relation to infectious disease that are carried out in the natural target species provide data that are relevant to understanding the biology of the immune cells and immunity to infection. This is particularly the case for diseases that show host specificity. Ex vivo studies that exploit the surgical cannulation of lymphatic ducts have allowed access to natural dendritic cells. Investigations of these cells have revealed the presence of subpopulations that differ in their ability to stimulate T cells and differ in the range of cytokines synthesized. These differences would be forecast to have major effects on the bias and type of immune response that are induced. Studies in vivo of the effect of depleting T-cell populations with monoclonal antibodies (mAbs) have shown how different T-cell populations have differing critical roles for different infectious diseases, and how they may contribute to the immune response and pathology after infection. Here the case is made for how studies in cattle have aided our understanding of immunity to several infections that can be exploited for the rational design of effective vaccination and control strategies.