Investigations of Enterococcus faecalis-induced bacteraemia in brown layer pullets through different inoculation routes in relation to the production of arthritis

In the present aerosol experiment, assessment of the respiratory tract of 1-day-old birds as a natural route of infection for induction of Enterococcus faecalis bacteraemia and arthritis was performed. Second, the severity and type of arthritis produced through intramuscular infection in two different inoculation sites (musculus pectoralis versus musculus gastrocnemius) was studied. Third, the resulting bacteraemia was assessed qualitatively and quantitatively in relation to the occurrence of arthritis. Exposure of 1-day-old brown layer pullets to aerosolized E. faecalis with an estimated uptake of 104 to 105 colony forming units per chick resulted in bacteraemia; however, joint lesions were not induced. In contrast, 3/10 birds inoculated intratracheally with 108 colony forming units developed both bacteraemia and arthritis. This suggests the occurrence of a dose effect and a role for the respiratory tract as a natural infection route in young chickens. In both intramuscularly inoculated groups the incidence of arthritis was 10/10 birds and 9/10 birds, respectively. Birds inoculated in the m. pectoralis developed symmetric polyarthritis, which harmonizes with haematogenous colonization of joints. In contrast, m. gastrocnemius-inoculated chicks mostly had asymmetric (poly)arthritis of the injected leg and varus deformation of the contralateral leg, suggesting predominantly local spread. The qualitative and quantitative results of bacteriology of blood samples show that arthritis develops in those groups with the highest number of bacteraemic birds and the highest median bacterial colony forming units per millilitre of blood during the first 24 to 36 h after treatment

Transmissibility of Infectious Bronchitis Virus H120 Vaccine Strain Among Broilers under Experimental Conditions

The aim of this study was to quantify transmission of infectious bronchitis virus (IBV) H120 vaccine strain among broilers, and to assess whether birds that have been exposed to vaccine strain-shedding birds were protected against clinical signs after infection with a virulent strain of the same serotype. A transmission experiment and a replicate were carried out, each with six groups of commercial broilers. At day of hatch (n 5 30) or at 15 days of age (n 5 20), half of each group was inoculated with either IBV H120 vaccine (H120 group), virulent IBV M41 (M41 group), or were mock-infected, thereby contact-exposing the other half of each group. Nasal discharge was recorded, and antibody response and virus shedding were measured. To measure clinical protection, four weeks after inoculation all birds, in all groups, were challenged with IBV M41. The reproduction ratio (R; the average number of contact infections caused by one infectious bird) was determined to quantify virus transmission. All contactexposed birds, except for one in an H120 group, became infected with either IBV H120 or IBV M41. Almost all birds contactinfected with IBV H120 or IBV M41 were subsequently protected against clinical signs after challenge with IBV M41. The lower limits of the 95% confidence interval (CI) of the R of IBV H120 vaccine, and of IBV M41, were significantly ,1. For both IBV H120 and IBV M41, the 95% CI was [2.1–‘] following inoculation at day of hatch and [1.8–‘] after inoculation at 15 days of age. This finding demonstrates that IBV H120 vaccine is able to spread extensively among broilers. This implies that this vaccine strain might be able to become endemically present in the poultry population. It also implies that, even if not all birds received vaccine during spray application, due to the ability of the vaccine to spread in the flock, they will most likely be protected against clinical signs after a subsequent field virus infection

Transmissibility of Infectious Bronchitis Virus H120 Vaccine Strain Among Broilers under Experimental Conditions

The aim of this study was to quantify transmission of infectious bronchitis virus (IBV) H120 vaccine strain among broilers, and to assess whether birds that have been exposed to vaccine strain-shedding birds were protected against clinical signs after infection with a virulent strain of the same serotype. A transmission experiment and a replicate were carried out, each with six groups of commercial broilers. At day of hatch (n 5 30) or at 15 days of age (n 5 20), half of each group was inoculated with either IBV H120 vaccine (H120 group), virulent IBV M41 (M41 group), or were mock-infected, thereby contact-exposing the other half of each group. Nasal discharge was recorded, and antibody response and virus shedding were measured. To measure clinical protection, four weeks after inoculation all birds, in all groups, were challenged with IBV M41. The reproduction ratio (R; the average number of contact infections caused by one infectious bird) was determined to quantify virus transmission. All contactexposed birds, except for one in an H120 group, became infected with either IBV H120 or IBV M41. Almost all birds contactinfected with IBV H120 or IBV M41 were subsequently protected against clinical signs after challenge with IBV M41. The lower limits of the 95% confidence interval (CI) of the R of IBV H120 vaccine, and of IBV M41, were significantly ,1. For both IBV H120 and IBV M41, the 95% CI was [2.1–‘] following inoculation at day of hatch and [1.8–‘] after inoculation at 15 days of age. This finding demonstrates that IBV H120 vaccine is able to spread extensively among broilers. This implies that this vaccine strain might be able to become endemically present in the poultry population. It also implies that, even if not all birds received vaccine during spray application, due to the ability of the vaccine to spread in the flock, they will most likely be protected against clinical signs after a subsequent field virus infection

Pathological features in dead on arrival broilers with special reference to heart disorders

A gross postmortem investigation was done on 302 broilers that died between catching and slaughter to establish predisposing factors for dying in this period. Special attention was paid to heart disorders, which were established by determining the ratio of the right ventricle mass to the total ventricle mass (RV:TV) and to postmortem changes in hearts and lungs of broilers that were dead on arrival (DOA). Macroscopic pathologic lesions were found in 89.4% of DOA broilers. Signs of infectious diseases appeared to be most frequent (64.9%), followed by heart and circulation disorders (42.4%), and trauma (29.5%). The RV:TV was significantly higher for DOA broilers in comparison with slaughtered broilers. The prevalence of hearts with an abnormal RV:TV in DOA broilers was 34.4 vs. 4.1% in slaughtered broilers. The DOA broilers with an abnormal heart ratio more frequently showed ascites and hydropericardium. Postmortem changes in lungs depend on the position of the carcass the first several hours after death. Broilers, which remain in dorsal recumbency for several hours after death, develop engorged lungs. A good health status as well as more attention for the catching and crating process is crucial in decreasing the percentage of DOA broilers. Prevention of an increased heart ratio and of ascites will improve the livability in the broiler house and also decrease the DOA rate enormousl

Tetratrichomonas gallinarum granuloma disease in a flock of free range layers

International audienceGranuloma disease in a flock of free range productive layers in the Netherlands in 2017 is described. The disease resembled granuloma outbreaks in layers caused by Tetratrichomonas gallinarum in 2013 and occurred in the same area in which the rearing farm considered as the source of the 2013 outbreaks was located. Between 55 and 84 weeks of age mortality was 20.3% (breeder's norm 3.9%). All dead hens examined (n ¼ 20) showed granulomas especially in liver and ceca. Nine hens with or without liver and/or ceca granulomas were examined for trichomonads in mentioned organs by in situ hybridization (ISH), nested PCR, and cloning and sequencing. Ceca were also examined by culture. T. gallinarum ISH was positive in all livers and ceca with granulomas and negative in case granulomas were absent. T. gallinarum strain 13/16632, which caused the 2013 outbreaks was found in 4/8 hens with granulomas. Moreover, other trichomonads were detected: a T. gallinarum strain GPO-like and a Simplicimonas sp. strain GABC1-like. Mixed infections also occurred. Infectious causes of granuloma disease other than the afore-mentioned trichomonads could be excluded. Trichomonad DNA was not detected in environmental samples and wild ducks originating from the farm of concern, except for one duck in which the same Simplicimonas sp. as in hens was detected, leaving the source of the T. gallinarum infection in hens unknown. It is concluded that the herein described granuloma disease likely was caused by T. gallinarum strain 13/16632. However, the pathogenicity of the other trichomonads found remains to be clarifie