Bovine herpesvirus type 5 (BoHV-5) is an important pathogen that causes meningoencephalitis in cattle. Few studies have used the mouse as a model for BoHV-5 infection. Despite the fact that BoHV-5 can infect mice with immune deficiencies, little is known about viral replication, immune response, and the course of infection in the central nervous system (CNS) of wild-type mice. Therefore, the aim of this study was to evaluate the response in the CNS of BALB/c mice acutely infected with BoHV-5 at different days post-inoculation (dpi). BoHV-5, when inoculated intracranially, was able to infect and replicate within the CNS of BALB/c mice. Until 15 dpi, the mice were able to survive without showing prominent neurological signs. The infection was accompanied by a Th1 immune response, with a significant expression of the cytokines IFN-γ and TNF-α and chemokine CCL-2. The expression of these cytokines and chemokines was most significant in the early course of infection (3 and 4 dpi), and it was followed by meningoencephalitis with perivascular cuffing and periventriculitis, composed mainly of macrophages and lymphocytes. After the expression of cytokines and chemokine, the mice were able to curb BoHV-5 acute infection in the brain, since there was a decrease in the number of BoHV-5 DNA copies after 3 dpi and viable viral particles were not detected after 6 dpi. Importantly, BoHV-5 was able to infect the trigeminal ganglia during acute infection, since a large number of BoHV-5 DNA copies were detected on 1 and 2 dpi.

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We investigated the infection of Bovine Leukemia Virus (BLV) related to other pathogens (Neospora caninum, Bovine Herpesvirus-1 (BoHV-1), Bovine Viral Diarrhea Virus (BVDV), and pathogenic bacteria] in 80 bovine aborted fetuses. The materials comprised whole fetuses, fetal organs, and placenta. The BLV was diagnosed by nested-PCR (env gp51 BLV gene), the identification of viral genotypes by sequencing, and the phylogenetic analysis by neighbor-joining and maximum composite likelihood methods. The other pathogens and diagnoses were, respectively: Neospora caninum (nested-PCR), BoHV-1 (nested-PCR), BVDV (PCR), Brucella spp. (isolation and identification), Leptospira spp. (PCR), aerobic bacteria (Enterobacteriaceae, Gram positive cocci, Trueperella (Arcanobacterium) pyogenes) and microaerophilic (Campylobacter spp., Histophilus somni, and Listeria monocytogenes) by isolation and identification. BLV fetal antibodies were identified by ELISA kit. Thirteen (16.25%) fetuses were positive by BLV nested-PCR. Phylogenetic analysis revealed BLV genotypes 1, 5, and 6, which are frequently found in cattle in Brazil, Argentina, and Uruguay. No fetuses were positive for BLV antibodies by ELISA. A single case of coinfection with BLV was found for each of the pathogens Trueperella (Arcanobacterium) pyogenes, Klebsiella spp., and Streptococcus spp. were isolated as a pure or representing the preponderance of bacteria in a pooled culture. In the 67 BLV-negative fetuses, pathogens identified were single cases of Trueperella (Arcanobacterium) pyogenes, Staphylococcus aureus, and Brucella abortus; 2 of Escherichia coli; 3 of bovine viral diarrhea virus; and 4 of Neospora caninum. No pathogens were found in 55 fetuses. The low number of BLV positive samples infected or no by other pathogens didn´t allow performing statistical analysis, in order to understand if there were significative differences among not infected and infected BLV fetuses. Because BLV is an immunosuppressive agent and predisposes the cow to other pathogens, its connection with Leukemia or abortions need additional studies with bigger sampling, for elucidating pathogenesis in the pregnant cow and in the fetus. The rates of BLV transplacental transmission show the necessity of prophylactic measures in Brazilian cattle herds, in order to avoid infection in-utero.