Infection caused by canine distemper virus (CDV) is a highly contagious disease with high incidence and lethality in the canine population. Antiviral activity of flavonoids quercetin, morin, rutin and hesperidin, and phenolic cinnamic, trans-cinnamic and ferulic acids were evaluated in vitro against the CDV using the time of addition assay to determine which step of the viral replicative cycle was affected. All flavonoids displayed great viral inhibition when they were added at the times 0 (adsorption) and 1h (penetration) of the viral replicative cycle. Both quercetin and hesperidin presented antiviral activity at the time 2h (intracellular). In the other hand, cinnamic acid showed antiviral activity at the times 0 and 2h while trans-cinnamic acid showed antiviral effect at the times -1h (pre-treatment) and 0 h. Ferulic acid inhibited CDV replicative cycle at the times 0 and 1h. Our study revealed promising candidates to be considered in the treatment of CDV. Structural differences among compounds and correlation to their antiviral activity were also explored. Our analysis suggest that these compounds could be useful in order to design new antiviral drugs against CDV as well as other viruses of great meaning in veterinary medicine.

Canine distemper is a highly contagious viral disease caused by the canine distemper virus (CDV), which is a member of the Morbillivirus genus, Paramyxoviridae family. Animals that most commonly suffer from this disease belong to the Canidae family; however, the spectrum of natural hosts for CDV also includes several other families of the order Carnivora. The infectious disease presents worldwide distribution and maintains a high incidence and high levels of lethality, despite the availability of effective vaccines, and no specific treatment. CDV infection in dogs is characterized by the presentation of systemic and/or neurological courses, and viral persistence in some organs, including the central nervous system (CNS) and lymphoid tissues. An elucidation of the pathogenic mechanisms involved in canine distemper disease will lead to a better understanding of the injuries and clinical manifestations caused by CDV. Ultimately, further insight about this disease will enable the improvement of diagnostic methods as well as therapeutic studies.

This study aimed to track Yersinia enterocolitica contamination in a pork production chain in Minas Gerais, Brazil, and to characterize the virulence and antibiotic resistance of isolates. Samples were collected from four different steps of the pork production chain (pig farm, carcass, processing environment and end product; n = 870), and tested for the presence of Y. enterocolitica. The pathogen was detected in 8 samples (palatine tonsils = 5; mesenteric lymph nodes = 2; carcass after bleeding = 1), from which 16 isolates were obtained and identified as Y. enterocolitica bioserotype 4/O:3. XbaI macrorestriction allowed the clustering of isolates in 5 pulsetypes, and the identification of identical profiles of Y. enterocolitca isolated from different samples. All isolates were positive for the virulence related genes ail, virF, myfA, ystA, tccC, ymoA, hreP and sat, and negative for ystB, ystC, fepA, fepD and fes. Considering 17 antibiotics from 11 classes, only ciprofloxacin and kanamycin were effective against all isolates, and three multidrug resistance profiles were identified among them, with simultaneous resistance to 9 of 11 classes. All isolates presented positive results for emrD, yfhD and marC, related to multidrug resistance. The results of this study demonstrated the contamination routes of Y. enterocolitica within the assessed pork production chain, and highlighted the pathogenic potential and antibiotic resistance of this foodborne pathogen.

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Listeria monocytogenes contamination was assessed in different steps of a pork production chain. Ten lots of pigs were sampled at termination barns, at slaughter (after bleeding, after buckling, after evisceration, and after final washing), at processing (knives, deboning tables, and employees' hands), and of end products (ribs, shoulder, ham, and sausage). All samples (n = 670) were subjected to L. monocytogenes detection, and the obtained isolates (n = 18, identified as Listeria spp.) were characterized by their biochemical characteristics, serogroups, virulence genes, pulsed-field gel electrophoresis profiles, antibiotic resistances (ampicillin, penicillin, gentamicin, and sulfamethoxazole-trimethoprim), and adhesion abilities. The results revealed the low occurrence of Listeria spp. in the evaluated pork production chain. However, four tested sausage samples (40%) were positive for Listeria spp., with L. monocytogenes identified in two (20%) of these samples. Ten isolates were identified as L. monocytogenes (eight from serogroup 1/2a or 3a and two from serogroup 4b, 4d, or 4e): all isolates were also positive for the virulence-related genes hlyA, iap, plcA, actA, inlA, inlB, inlC, and inlJ and susceptible to the tested antibiotics. One sausage sample was contaminated by both serogroups 1/2a or 3a and 4b, 4d, or 4e. Isolates from serogroup 1/2a or 3a obtained during visits 5 and 6 presented distinct genetic profiles by pulsed-field gel electrophoresis, indicating that contamination may come from different sources. The adhesion potential exhibited by Listeria spp. isolates (n = 18) ranged from weak (serogroup 4b, 4d, or 4e) to moderate (L. innocua and L. monocytogenes serogroup 1/2a or 3a). Despite the low occurrence of L. monocytogenes, pathogenic serogroups were detected in sausages, demanding control measures by the industry. HIGHLIGHTS