Enterotoxigenic Escherichia coli (ETEC) is the major cause of diarrhea in newborn and weaned pigs. Bacteria adhesion to the host cell is considered a specific phenomenon among fimbrial and non-fimbrial adhesins with their respective RESUMO Escherichia coli (E. coli) enterotoxigênica (ETEC) é considerada importante causa de diarreia em suínos neonatos e desmamados. A adesão da bactéria à célula do hospedeiro é considerada um fenômeno específico entre as adesinas fimbriais e não fimbriais com seus respectivos receptores nos enterócitos. Os distúrbios entéricos estão relacionados com as fímbrias F4 (K88), F5 (K99), F6 (987P),

Congenital tremor in pigs involves several etiologies, including pestivirus, which may cause neurological injuries in different animal species. To evaluate whether bovine viral diarrhea virus (BVDV), an important pestivirus, is one of the etiological agents of congenital tremor in swine, gilts and the fetuses were challenged at 45 days of gestation with BVDV-2. Four pregnant gilts were inoculated oronasally, four gilts underwent fetal intrauterine inoculation, and two gilts constituted the control group. Antibody titers were determined by virus neutralization (VN), and viral RNA was detected by RT-PCR. Blood samples were collected from all gilts and piglets born to obtain whole blood and serum for analysis. One third of the neonates were euthanized at three days old, and samples of the encephalon, brain stem and spinal cord were collected for anatomopathological evaluation and viral RNA detection. The piglets that remained alive were clinically evaluated every day, and blood sampling was performed regularly for 35 days. The piglets from gilts in both inoculation treatment groups showed no clinical neurological signs and were born with no viral RNA in their blood and organs. Piglets born from oronasally inoculated gilts did not present antibodies against BVDV-2 at birth, although they were acquired by passive maternal transfer. In contrast, intrauterine-inoculated piglets were born with high antibody titers (80 to 640) against the agent, which remained high until the end of the experimental period. Microscopically, no noticeable changes were observed. Macroscopically, 29.5% of the total piglets euthanized, from both inoculation groups, were born with a low cerebellar:brain ratio. Nevertheless, some piglets had a high cerebellar:brain ratio, indicating the need for standardizing this value. Thus, it was concluded that BVDV is not an etiological agent for congenital swine tremor.

This study determined the distribution of stx1 and stx2 genes in Escherichia coli isolated from dairy herds with regard to animal age, season, and farm production-scale, and analyzed the phylogenetic distribution of the groups A, B1, B2, and D of 276 isolates of bovine feces Shiga toxin-producing E. coli (STEC). The stx1 profile was the most common, detected in 20.4% (202/990) of the isolates, followed by stx2 (4.54%, 45/990) and stx1+stx2 (2.92%, 29/990). The stx1 gene was detected more frequently in calves than in adult animals. In the dry season (winter), the presence of stx1+stx2 profile in cattle feces was higher than in the rainy season (summer), while no significant changes were observed between seasons for the stx1 and stx2 profiles. The most predominant phylogenetic groups in adult animals were B1, A, and D, while groups A and B1 prevailed in calves. Our data highlight the importance of identifying STEC reservoirs, since 7.5% of the tested isolates were positive for stx2, the main profile responsible for the hemolytic-uremic syndrome (HUS). Moreover, these microorganisms are adapted to survive even in hostile environments and can contaminate the food production chain, posing a significant risk to consumers of animal products.

Swine can be infected by bovine viral diarrhea virus (BVDV). However, transmission routes among pigs are still unknown. The objective of the present study was to induce experimental infection of BVDV-1 in weaned piglets and to assess the potential transmission through pen back pond water, used to facilitate heat exchange of the pigs housed in barns. Two repetitions (BP1 and BP 2) were performed using 12 piglets proven to be free BVDV (n=6 per repetition) allocated into three groups: control, sentinels and infected with two piglets each. The piglets were placed in stainless steel isolators. The infected group received an inoculum containing BVDV-1, Singer strain. The piglets remained in the cabinets for 25 days, during which samples of nasal swab were collected daily and blood sampled weekly. At the end, the piglets were euthanized, necropsied and organ fragments were collected for histopathology, immunohistochemistry and RT-PCR. In the first experiment (BP1) the infected animals shed the virus between days 6 and 21 post-infection. Regarding the sentinel group, shedding occurred in only one piglet, on the 20th day after infection, and seroconversion was observed on the 25th day post-infection. In BP2, infected piglets I3 and I4 shed the virus on days 4 and 21 post-infection, respectively. Only one sentinel piglet (S3) she the virus on day 13 post-infection. Therefore, it was concluded that pigs can become infected with BVDV-1 and shed potentially infectious viral particles consequently, being able to transmit the virus to other pigs through back pond water.