title: Inflammation-induced haemostatic response in layer chickens infected with Streptococcus equi subsp. zooepidemicus as evaluated by fibrinogen, prothrombin time and thromboelastography.
abstract: Streptococcus zooepidemicus has recently been shown to be a severe pathogen in layer chickens, where it is able to cause serious lesions in the vascular system. To evaluate the haemostatic response, 10 layer chickens were inoculated intravenously with S. zooepidemicus. Four hypotheses were tested: that the infection-induced inflammation would increase the plasma fibrinogen (Fbg) concentration, would prolong the prothrombin time (PT) and would prompt hypercoagulability or hypocoagulability as assessed by whole-blood thromboelastography (TEG), and that a possible correlation would exist between one of the TEG values and Fbg/PT. Each parameter was measured at days 1, 3 and 6 post inoculation (p.i.), and compared with the values at day 0 from each individual bird and with values obtained from non-infected control chickens (n = 10). In the infected chickens, the mean (± standard error) of Fbg was higher at day 3 p.i. (9.4 ± 1.4 g/l) and day 6 p.i. (8.0 ± 0.7 g/l) and the PT was prolonged at day 6 p.i. (168.1 ± 21.0 sec) compared with the day 0 standards (2.6 ± 0.2 g/l and 104.6 ± 2.0 sec, respectively) (P < 0.05). The majority of infected chickens demonstrated a hypercoagulable TEG result with increased mean values of the clot formation rate (α-angle) and maximal amplitude (MA) of TEG tracing at day 3 p.i. (83.1 ± 0.7°, 83.8 ± 1.4 mm) and day 6 p.i. (84.0 ± 0.4°, 89.8 ± 1.0 mm) compared with the day 0 values (75.8 ± 2.2° and 66.9 ± 1.4 mm, respectively) (P < 0.05). In control birds, the means of Fbg (1.5 ± 0.1 g/l), PT (79.4 ± 6.4 sec), TEG-α (76.7 ± 1.5°) and TEG-MA (64.0 ± 2.3 mm) were lower at day 6 compared with values observed for the infected chickens (P < 0.05). A negative correlation coefficient (-0.71) was found between the clot formation time (TEG-K) and Fbg at day 1 in the control group (P = 0.02). In conclusion, infection with S. zooepidemicus following intravenous injection in layer chickens induced haemostatic alterations including hyperfibrinogenaemia, prolonged PT, and hypercoagulability as measured by increased TEG-α and TEG-MA.
authors.affiliation: a Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences , University of Copenhagen , Frederiksberg C, Copenhagen , Denmark.
authors.forename: Krisna
authors.initials: K
authors.lastname: Roy
authors.forename: Mads Frost
authors.initials: MF
authors.lastname: Bertelsen
authors.forename: Susanne Elisabeth
authors.initials: SE
authors.lastname: Pors
authors.forename: Kasper Werner
authors.initials: KW
authors.lastname: Johansen
authors.forename: Annemarie Thuri
authors.initials: AT
authors.lastname: Kristensen
authors.forename: Mads
authors.initials: M
authors.lastname: Kjelgaard-Hansen
authors.forename: Eva Bartholin
authors.initials: EB
authors.lastname: Andreasen
authors.forename: Jens Peter
authors.initials: JP
authors.lastname: Christensen
authors.forename: Paritosh Kumar
authors.initials: PK
authors.lastname: Biswas
authors.forename: Anders Miki
authors.initials: AM
authors.lastname: Bojesen
mesh_terms: D000818:Animals; D001777:Blood Coagulation; D002645:Chickens; D005260:Female; D005340:Fibrinogen / Q000032:analysis*; D006487:Hemostasis; D006490:Hemostatics; D007249:Inflammation; D011201:Poultry Diseases / Q000097:blood* / Q000382:microbiology; D011517:Prothrombin Time / Q000662:veterinary; D013290:Streptococcal Infections / Q000097:blood / Q000382:microbiology / Q000662:veterinary*; D018502:Streptococcus equi / Q000502:physiology*; D013916:Thrombelastography / Q000662:veterinary
chemical_list: D006490:Hemostatics; D005340:Fibrinogen