Introduction: A feedlot is an intensive farming system for finishing livestock. Bovine respiratory disease (BRD) is a cause of morbidity and mortality in beef cattle, especially in feedlots. Methodology: This study investigated the morbidity and mortality of BRD in a beef cattle feedlot in southeastern Brazil using: clinical diagnoses, therapy, morbidity, and mortality. Pulmonary fragments were collected from five steers, on feed from 3-32 days, with lesions of pneumonia for identification of BRD infectious agents PCR. Results: 188,862 steers were on feed and morbidity was 7.05% (13,315/188,862), mortality 0.64% (1,214/188,862). The causes of morbidity were: BRD (6.13%), lameness (0.29%), trauma (0.21%), clostridiosis (0.13%) and polioencephalomalacia, PEM (0.12%). The causes of mortality were: BRD (0.21%), trauma (0.17%), and clostridiosis (0.13%). When all sick cattle were considered (n=13,315), BRD (86.9%) was the principal cause of morbidity, followed by lameness (4.13%), trauma (3.05%), and clostridiosis (1.82%). The cost of BRD-associated cattle mortality and morbidity was estimated at $14,334.00/10,000 and $16,315.40/10,000 respectively. It was projected that the economic effects due to BRD-associated morbidity in Brazil were $6.31 million/annum, while losses due to mortality were $5.54 million, resulting in an annual loss of $11.85 million. Coinfections in cattle with pneumonia due to Mannheimia haemolytica and Pasteurella multocida were identified in 4/5 steers tested. Conclusions: This is the first longitudinal study that investigated the incidence of BRD in feedlot cattle from Brazil, and the results herein described indicate that BRD contributed significantly to the development of mortality and morbidity of cattle on feed.

We investigated the occurrence of infectious pathogens during an outbreak of bovine respiratory disease (BRD) in a beef cattle feedlot in southern Brazil that has a high risk of developing BRD. Nasopharyngeal swabs were randomly collected from steers ( n = 23) and assessed for the presence of infectious agents of BRD by PCR and/or RT-PCR assays. These included: Histophilus somni, Mannheimia haemolytica, Pasteurella multocida, Mycoplasma bovis, bovine respiratory syncytial virus (BRSV), bovine coronavirus (BCoV), bovine viral diarrhea virus (BVDV), bovine alphaherpesvirus 1 (BoHV-1), and bovine parainfluenza virus 3 (BPIV-3). Pulmonary sections of one steer that died with clinical BRD were submitted for pathology and molecular testing. The frequencies of the pathogens identified from the nasopharyngeal swabs were: H. somni 39% (9 of 23), BRSV 35% (8 of 23), BCoV 22% (5 of 23), and M. haemolytica 13% (3 of 23). PCR or RT-PCR assays did not identify P. multocida, M. bovis, BoHV-1, BVDV, or BPIV-3 from the nasopharyngeal swabs. Single and concomitant associations of infectious agents of BRD were identified. Fibrinous bronchopneumonia was diagnosed in one steer that died; samples were positive for H. somni and M. haemolytica by PCR. H. somni, BRSV, and BCoV are important disease pathogens of BRD in feedlot cattle in Brazil, but H. somni and BCoV are probably under-reported.

Proteus mirabilis is an opportunistic pathogen often associated with a variety of human infections acquired both in the community and in hospitals. In this context, the present work aimed to evaluate the genotypic and phenotypic characteristics of the virulence factors and antimicrobial resistance determinants of 32 P. mirabilis strains isolated from chicken carcasses in a poultry slaughterhouse in the north of the state of Paraná, Brazil, in order to assess a potential zoonotic risk. The isolates presented a variety of virulence genes that contribute to the development of infection in humans. The mrpA, pmfA, atfA (fimbriae), ireA (siderophores receptor), zapA, ptA (Proteases), and hpmA (hemolysin) genes were found in 32 (100%) isolates and ucaA (fimbriae) in 16 (50%). All isolates showed aggregative adherence in HEp-2 cells and formed biofilms. Of all strains, 27 (84.38%) showed cytotoxic effects in Vero cells. Antimicrobial susceptibility was tested using 20 antimicrobials, in which 25 (78.13%) strains were considered multidrug-resistant. The presence of bla ESBL and bla ampC genes conferring resistance to β-lactams and qnr to quinolones were also detected in the isolates after presumption in the phenotypic test, in which 7 (21.88%) isolates contained the CTX-M-2 group, 11 (34.38%) contained CIT group and 19 (59.38%) contained qnrD. Therefore, chicken carcasses contaminated with P. mirabilis may pose a health risk to the consumer, as these isolates have a variety of virulence and antimicrobial resistance characteristics that can be found in P. mirabilis strains isolated from human infections.

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Bovine respiratory disease (BRD) is a complex multifactorial and multi-etiological disease entity that is responsible for the morbidity and mortality particularly in feedlot cattle from North America. Information relative to the occurrence of BRD in Brazil and the associated infectious agents are lacking. This study investigated the participation of infectious agents of BRD in a beef cattle feedlot from Southeastern Brazil. Nasopharyngeal swabs of 11% (10/90) of cattle (n, 450) with clinical manifestations of respiratory distress were analyzed by targeting specific genes of the principal infectious pathogens of BRD. In addition, pulmonary fragments of one the animals that died were collected for histopathological and molecular diagnoses. The nucleic acids of Histophilus somni and bovine respiratory syncytial virus (BRSV) were identified in 20% (2/10) of the nasopharyngeal swabs of the animals with respiratory distress; another contained only BRSV RNA. Moreover, the nucleic acids of both infectious agents were amplified from the pulmonary fragments of the animal that died with histopathological evidence of bronchopneumonia and interstitial pneumonia; the nasopharyngeal swab of this animal also contained the nucleic acids of both pathogens. Additionally, all PCR and/or RT-PCR assays designed to detect the specific genes of Mannheimia haemolytica, Pasteurella multocida, Mycoplasma bovis, bovine viral diarrhea virus, bovine herpesvirus -1, bovine parainfluenza virus-3, and bovine coronavirus yielded negative results. Phylogenetic analyses suggest that the isolates of H. somni circulating in Brazil are similar to those identified elsewhere, while there seem to be diversity between the isolates of BRSV within cattle herds from different geographical locations of Brazil.

Although the effects of aflatoxin on animal performance have been well established in previous studies, there are few studies reporting on the relationship between aflatoxin and Saccharomyces cerevisiae. The ability of Saccharomyces cerevisiae to minimize aflatoxicosis was evaluated. An aflatoxin-free diet and six contaminated diets (400 lg kg -1 aflatoxin) were formulated with five diets containing the viable yeast (Y1026 or Y904). A 28-day bioassay using 21-day-old and 60-g body weight Wistar rats was conducted. The results showed that there were no significant (P [ 0.05) differences for: food consumption; daily weight gain; food conversion, and enzyme activity. Hepatic tissues from the aflatoxin control group suffered from hepatotoxicity, cellular disorganization, and hepatocyte necrosis. The inclusion of yeast or yeast and amino acids (methionine and cysteine) reduced the toxicity.

Given the need to understand the virulence profile of Proteus mirabilis isolates from cellulitis in broiler chickens and their ability to cause lesions, the present study aimed to characterize genotypically and phenotypically the virulence profiles of two strains of P. mirabilis isolated from cellulitis in broilers, as well as to evaluate their ability to experimentally reproduce the lesions in vivo. The strain with the highest virulence potential (LBUEL-A33) possessed mrpA, pmfA, ucaA, atfA (fimbriae), zapA, ptA (proteases), hpmA (hemolysin), and ireA (siderophore) genes, formed a very strong biofilm, and expressed the pattern of aggregative adhesion and cytotoxicity in Vero cells. The strain with the lowest virulence potential (LBUEL-A34) did not present the pmfA and ucaA genes, but expressed the pattern of aggregative adhesion, formed a strong biofilm, and did not show cytotoxicity. Both strains developed cellulitis in an animal model within 24 h post-inoculation (PI), and the degree of lesions was not significantly altered up to 120 h PI. The LBUEL-A33 strain was also inoculated in combination with an avian pathogenic Escherichia coli (APEC 046), and the lesions showed no significant changes from the individual inoculation of these two strains. Histological analysis showed that the LBUEL-A33 strain developed characteristic cellulitis lesions. Thus, both strains of P. mirabilis isolated in our study have several virulence factors and the ability to develop cellulitis in broilers.

The pathological and molecular findings associated with Histomonas meleagridis are described in a leucistic Indian peafowl (Pavo cristatus) from Southern Brazil. The most significant gross findings were multifocal necrotizing hepatitis and diphtheric typhlitis. Histopathologic evaluation of the liver, ceca, kidney, spleen, and small intestine revealed systemic histomoniasis (SH) associated with intralesional and intravascular accumulations of histomonad organisms consistent with H. meleagridis. PCR was used to amplify the DNA of H. meleagridis from the liver, ceca, small intestine, spleen, lungs, and kidneys. Direct sequencing and phylogenetic analyses confirmed that the isolate of the flagellated trichomonad identified from this investigation is more phylogenetically related to H. meleagridis than Tetratrichomonas gallinarum, Tritrichomonas foetus, and Dientamoeba fragilis. These results confirmed the occurrence of SH in this peafowl and add to the diagnosis of this disease in birds from Brazil. This report might represent the first complete identification of spontaneous histomoniasis in a peafowl due to pathological and molecular characteristics and one of the few documented cases of SH in non-commercial birds.