A Bovine Model of Respiratory Chlamydia psittaci Infection: Challenge Dose Titration

This study aimed to establish and evaluate a bovine respiratory model of experimentally induced acute C. psittaci infection. Calves are natural hosts and pathogenesis may resemble the situation in humans. Intrabronchial inoculation of C. psittaci strain DC15 was performed in calves aged 2–3 months via bronchoscope at four different challenge doses from 106 to 109 inclusion-forming units (ifu) per animal. Control groups received either UV-inactivated C. psittaci or cell culture medium. While 106 ifu/calf resulted in a mild respiratory infection only, the doses of 107 and 108 induced fever, tachypnea, dry cough, and tachycardia that became apparent 2–3 days post inoculation (dpi) and lasted for about one week. In calves exposed to 109 ifu C. psittaci, the respiratory disease was accompanied by severe systemic illness (apathy, tremor, markedly reduced appetite). At the time point of most pronounced clinical signs (3 dpi) the extent of lung lesions was below 10% of pulmonary tissue in calves inoculated with 106 and 107 ifu, about 15% in calves inoculated with 108 and more than 30% in calves inoculated with 109 ifu C. psittaci. Beside clinical signs and pathologic lesions, the bacterial load of lung tissue and markers of pulmonary inflammation (i.e., cell counts, concentration of proteins and eicosanoids in broncho-alveolar lavage fluid) were positively associated with ifu of viable C. psittaci. While any effect of endotoxin has been ruled out, all effects could be attributed to infection by the replicating bacteria. In conclusion, the calf represents a suitable model of respiratory chlamydial infection. Dose titration revealed that both clinically latent and clinically manifest infection can be reproduced experimentally by either 106 or 108 ifu/calf of C. psittaci DC15 while doses above 108 ifu C. psittaci cannot be recommended for further studies for ethical reasons. This defined model of different clinical expressions of chlamydial infection allows studying host-pathogen interactions

Investigation of Chlamydophila spp. in dairy cows with reproductive disorders

<p>Abstract</p> <p>Background</p> <p>Reports worldwide indicate high prevalence of <it>Chlamydophila </it>spp. infection in cattle. To assess the prevalence in Sweden, 525 cows in 70 dairy herds with reproductive disorders was investigated.</p> <p>Methods</p> <p>To detect antibodies two commercially available kits were used. Moreover, 107 specimens, including vaginal swabs, organ tissues and milk were analysed by Polymerase Chain Reaction (PCR).</p> <p>Results</p> <p>Two (0.4%) cows were seropositive in the Pourquier <it>Cp. abortus </it>ELISA. The seroprevalence with the Chekit ELISA was 28% with no difference between cases and controls. Five specimens were positive in real-time PCR and further analysed by nested PCR. <it>Cp. pecorum </it>was confirmed by partial <it>omp1 </it>DNA sequencing of the nested PCR product of vaginal swabs from control cows.</p> <p>Conclusion</p> <p>The results suggest that <it>Cp. abortus </it>infection is absent or rare in Swedish cows whereas <it>Cp. pecorum </it>is probably more spread. They also suggest that <it>Chlamydophila </it>spp. are not related to reproduction disorders in Swedish cattle.</p

Ultrasonographic examination of postpartum uterine involution in sows.

Physiological uterine involution during the puerperium period is essential for sow reproductive health. Uterine involution in sows has mainly been described using macroscopic and histological examination after slaughter. The aim of this study, therefore, was to describe the continuous regression of uterine diameter from day 2-14 after parturition and on the day before weaning using ultrasonography in sows housed in a free farrowing system and in farrowing crates. Diameter of three uterine cross-sections was measured at 24 -hs intervals in 46 sows housed in a free farrowing system in Switzerland and 49 sows housed in farrowing crates in Germany. Overall, there was continuous regression of uterine diameter during the lactation period in both groups. Median diameter of the uterus decreased from 32.4 mm (min: 18.6 mm, max: 52.3 mm) on day 2-9.0 mm (min: 7.6 mm, max: 12.7 mm) on the day before weaning (on average 30 days p.p.) in sows housed in free farrowing systems. Median diameter of the uterus of sows in farrowing crates decreased from 38.5 mm on day 2 (min: 21.6 mm, max: 56.3 mm) to 10.1 mm (min: 8.8 mm, max: 13.6 mm) the day before weaning (on average 29 days p.p.). Interestingly, parity, obstetrical intervention and administration of oxytocin was not associated with the decrease of uterine diameter during the study period. In summary, the ultrasonic examination is a suitable method to evaluate diameter of the uterus during the puerperium period in sows and to describe uterine involution in vivo

Dioxin exerts anti-estrogenic actions in a novel dioxin-responsive telomerase-immortalized epithelial cell line of the porcine oviduct (TERT-OPEC)

Oviduct epithelial cells are important for the nourishment and survival of ovulated oocytes and early embryos, and they respond to the steroid hormones estrogen and progesterone. Endocrine-disrupting polyhalogenated aromatic hydrocarbons (PHAH) are environmental toxins that act in part through the ligand-activated transcription factor arylhydrocarbon receptor (AhR; dioxin receptor), and exposure to PHAH has been shown to decrease fertility. To investigate effects of PHAHs on the oviduct epithelium as a potential target tissue of dioxin-type endocrine disruptors, we have established a novel telomerase-immortalized oviduct porcine epithelial cell line (TERT-OPEC). TERT-OPEC exhibited active telomerase and the immunoreactive epithelial marker cytokeratin but lacked the stromal marker vimentin. TERT-OPEC contained functional estrogen receptor (ER)-alpha and AhR, as determined by the detection of ER-alpha- and AhR-specific target molecules. Treatment of TERT-OPEC with the AhR ligand 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) resulted in a significant increase in the production of the cytochrome P-450 microsomal enzyme CYP1A1. Activated AhR caused a downregulation of ER nuclear protein fraction and significantly decreased ER-signaling in TERT-OPEC as determined by ERE-luciferase transient transfection assays. In summary, the TCDD-induced and AhR-mediated anti-estrogenic responses by TERT-OPEC suggest that PHAH affect the predominantly estrogen-dependent differentiation of the oviduct epithelium within the fallopian tube. This action then alters the local endocrine milieu, potentially resulting in a largely unexplored cause of impaired embryonic development and female infertility

Prolonged parturition and impaired placenta expulsion increase the risk of postpartum metritis and delay uterine involution in sows

It was hypothesized that prolonged parturition and impaired placenta expulsion increase the risk of postpartum metritis and delay uterine involution. At parturition, for 99 Yorkshire x Large White sows (parity 2–5), we determined the number of liveborn (NLP; 14.8 ± 3.4) and stillborn piglets (NSP; 1.1 ± 1.1), farrowing duration (FAR, time between first and last piglet; 333 ± 249 min), placenta expulsion duration (PLA, time between first and last placental part; 292 ± 241 min) and number of expelled placental parts (PART; 3.0 ± 1.0). FAR was categorized as ‘normal’ (300 min; n = 55/99). The relative PLA (rPLA; (PLA * 100)/FAR; 76 ± 101%) and the relative PART (rPART; (PART * 100)/(NLP + NSP); 22 ± 8%) were calculated and placenta expulsion was categorized as ‘normal’ (rPLA and rPART > 10%; n = 93/99) or ‘impaired’ (relPLA and relPART < 10%; n = 6/99). We also recorded whether manual palpation occurred (Yes/No) and/or oxytocin was used (Yes/No). After parturition, an ultrasound examination of the uterus was performed once for each sow between the 2nd and 7th day postpartum and the uterine size (mean sectional area of three to five uterine cross-sections) and intrauterine fluid accumulation (Yes/No) were recorded. Uterine size was categorized as ‘normal’ (n = 55/99) or ‘enlarged’ (n = 44/99) and used as an indicator of delayed uterine involution. Intrauterine fluid was used as an indicator of metritis. Prolonged FAR (35/54, 2.0 ± 0.5, 13.1, 7.6; n/N, β ± SE, Wald χ2, Odds; P = 0.001), manual palpation (12/17, 1.5 ± 0.7, 4.4, 4.3; P = 0.036), oxytocin administration (18/31, - 1.5 ± 0.7, 4.7, 0.2, P = 0.040) and NSP ≥ 2 (15/21, 1.4 ± 0.7, 3.8, 3.9; P = 0.052) were associated with increased uterine size (n = 44/99) and NSP ≥ 2 (7/21, 2.6 ± 0.9, 8.7, 13.7; P = 0.003), manual palpation (10/17, 1.8 ± 0.8, 5.0, 6.0; P = 0.025), prolonged FAR (13/15, 1.7 ± 0.8, 4.3, 5.7; P = 0.039) and impaired PLA (4/6, 3.3 ± 1.7, 4.0, 26.9; P = 0.044) with intrauterine fluid accumulation (n = 15/99). The results confirm the hypothesis, indicating that prolonged parturition and impaired placenta expulsion increased the risk for postpartum metritis. Stillborn piglets and manual palpation were also identified as risk factors. Postpartum metritis delays uterine involution whereas the use of exogenous oxytocin supports it