Endotoxin and b-(1 / 3)-glucan exposure in poultry and ruminant clinics

Background: Exposure to organic dust is a well-known hazard for farm animal workers leading to respiratory diseases. Organic dust exposure has not been adequately evaluated in environmental settings in relation to veterinarians. Objective: To investigate inhalable dust, endotoxin, and β-(1 → 3)-glucan exposure among caretakers, veterinarians, and veterinary students. Task-based determinants of exposure were studied. Methods: This study investigated the exposure during veterinary education in the ruminant and poultry clinics. Dust measurements were performed using the conical inhalable samplers (CIS). Endotoxin and β-(1 → 3)-glucan were determined by the kinetic limulus amebocyte lysate (LAL) assay and inhibition enzyme immunoassay (EIA), respectively. Determinants of exposure were identified by multiple linear regression analysis. Results: Personal exposure levels of dust, endotoxin, and β-(1 → 3)-glucan were higher for poultry [geometric mean (GM): dust, 1.32 mg m(-3) (below the lower limit of detection

Identification of Brachyspira hyodysenteriae and other pathogenic Brachyspira species in chickens from laying flocks with diarrhea or reduced production or both

Cecal samples from laying chickens from 25 farms with a history of decreased egg production, diarrhea, and/or increased feed conversion ratios were examined for anaerobic intestinal spirochetes of the genus Brachyspira. Seventy-three samples positive in an immunofluorescence assay for Brachyspira species were further examined using selective anaerobic culture, followed by phenotypic analysis, species-specific PCRs (for Brachyspira hyodysenteriae, B. intermedia, and B. pilosicoli), and a Brachyspira genus-specific PCR with sequencing of the partial 16S rRNA gene products. Brachyspira cultures were obtained from all samples. Less than half of the isolates could be identified to the species level on the basis of their biochemical phenotypes, while all but four isolates (5.2%) were speciated by using PCR and sequencing of DNA extracted from the bacteria. Different Brachyspira spp. were found within a single flock and also in cultures from single chickens, emphasizing the need to obtain multiple samples when investigating outbreaks of avian intestinal spirochetosis. The most commonly detected spirochetes were the pathogenic species B. intermedia and B. pilosicoli. The presumed nonpathogenic species B. innocens, B. murdochii, and the proposed “B. pulli” also were identified. Pathogenic B. alvinipulli was present in two flocks, and this is the first confirmed report of B. alvinipulli in chickens outside the United States. Brachyspira hyodysenteriae, the agent of swine dysentery, also was identified in samples from three flocks. This is the first confirmed report of natural infection of chickens with B. hyodysenteriae. Experimental infection studies are required to assess the pathogenic potential of these B. hyodysenteriae isolates

Selective breeding for high natural antibody level increases resistance to avian pathogenic Escherichia coli (APEC) in chickens

Keyhole limpet hemocyanin (KLH)-binding natural antibody (NAb) titers in chickens are heritable, and higher levels have previously been associated with a higher survival. This suggests that selective breeding for higher NAb levels might increase survival by means of improved general disease resistance. Chickens were divergently selected and bred for total NAb levels binding KLH at 16 weeks of age for six generations, resulting in a High NAb selection line and a Low NAb selection line. To for test differences in disease resistance, chickens were challenged with avian pathogenic Escherichia coli (APEC) in two separate experiments. Chickens at 8 days of age received one of four intratracheal inoculations of 0.2 mL phosphate buffered saline (PBS): 1) mock inoculate, 2) with 0.2 mL PBS containing 108.20 colony-forming units (CFU)/mL APEC, 3) with 0.2 mL PBS containing 106.64 CFU/mL APEC, and 4) with 0.2 mL PBS containing 107.55 CFU/mL APEC. Mortality was recorded during 7 days post inoculation. Overall, 50–60% reduced mortality was observed in the High line compared to the Low line for all APEC doses. In addition, morbidity was determined of the surviving chickens at 15 days of age. The High line had lower morbidity scores compared to the Low line. We conclude that selective breeding for high KLH-binding NAb levels at 16 weeks of age increase APEC resistance in early life. This study and previous studies support the hypothesis that KLH-binding NAb might be used as an indicator trait for to selective breed for general disease resistance in an antigen non-specific fashion.</p

Enterococcus hirae-associated endocarditis outbreaks in broiler flocks: clinical and pathological characteristics and molecular epidemiology.

Background: Enterococcus hirae-associated endocarditis, characterized by a peak in mortality during the second week of the grow-out, and occasionally lameness, was diagnosed at Dutch broiler farms. Objectives: Field cases were studied to increase knowledge on clinical and pathological characteristics, pathogenesis and epidemiology of these infections. Animals and methods. In total, 1266 birds of 25 flocks from 12 farms were examined. Post-mortem examinations, bacteriology, histopathology, PCR and DNA fingerprinting was carried out. Six flocks were followed longitudinally (n¿=¿1017 birds). Results: Average mortality was 4.1% for the entire grow-out, of which 36% was attributed to endocarditis. Fibrinous thromboendocarditis of the right atrioventricular (AV) valve was found in 24% of hearts, compared to 7% and 4% with lesions of left and both AV valves, respectively. Thrombotic lesions were found in 24% (n¿=¿432) of lungs, but only in larger branches of the Arteria pulmonalis. Occasionally, thrombi were found in the Arteria ischiadica externa and in liver and brain vessels. Enterococcus was cultured from 54% (n¿=¿176) of heart and in 75% (n¿=¿28), 62% (n¿=¿106) and 31% (n¿=¿16) of liver, bone marrow and lung samples, respectively. Further identification, using the Rapid ID Strep 32 API system and a PCR targeting mur-2 and mur-2(ed) genes was carried out on a subset of Enterococcus positive isolates (n¿=¿65): both techniques identified the isolates as Enterococcus hirae. Pulsed-field gel electrophoresis did not indicate evidence of clonality between farms and flocks. Conclusions: The relevance of these findings for pathogenesis and epidemiology of E. hirae infections is discussed. Clinical importance. This study may facilitate diagnosis of field cases and may contribute to the design of further research and development of control measure