ABSTRACT
BACKGROUND AND AIM: Aspergillus fumigatus is a ubiquitous pathogen causing aspergillosis in poultry. This research aimed to evaluate the clinical and pathological features of aspergillosis infection in broilers. MATERIALS AND METHODS: A. fumigatus infection was induced experimentally by intra-air sac inoculation of a 1.7×108 spore suspension into broilers. Infected and non-infected birds were closely observed for the development of clinical signs of infection twice daily. Pathological samples were collected 5, 14, and 30 days post-infection (dpi) and examined by hematoxylin-eosin staining. RESULTS: A total of 160 birds were included in this study. Clinical signs emerged at 3 dpi and became consistent at 5 dpi. A considerable decrease in severity and number of birds showing infection symptoms followed. The clinical signs of aspergillosis included anorexia (n=40; 50%), lethargy (n=32; 40%), dyspnea (n=38; 48%), and gasping (n=29; 36%). Macroscopic changes in the air sacs at 3 dpi included the development of minor lesions showing cloudiness, slight membrane thickening, and local exudates. Histopathological examination of the air sacs collected at 3 dpi indicated local inflammation surrounded by hyphae and spores. At 5 dpi, infected birds developed nodules, necrosis, and parenchymal consolidation of the lungs. Pulmonary changes, such as bronchopneumonia, spores, septate hyphae, and mild granulomatous inflammation, were also observed. At 14 dpi, multiple caseous nodules and plaques were found in the air sacs; plaque and necrosis in large areas of the lungs and severe multifocal granulomatous inflammation were noted. CONCLUSION: The clinical symptoms of aspergillosis emerged at 3 dpi and gradually decreased beginning at 7 dpi. Similar pathological changes were observed in the air sacs and lungs. The results of this work provide additional information on the pathogenesis of aspergillosis.
ABSTRACT
AIM: Infectious coryza is caused by Avibacterium paragallinarum. In Indonesia, this infection results in a 10%-40% decrease in egg production by laying hens. This study was conducted to determine the effectiveness of tetravalent coryza vaccine contained A. paragallinarum bacterin serovars A, B, C2, and C3; strain A-221, B-Spross, C2-Modesto, and C-3-Akko in layers based on antibody titer and clinical signs using a post-challenge test. MATERIALS AND METHODS: Forty four-week-old Lohmanns strain chickens were used in this study. Forty chickens were divided into four groups for serological and challenge test: Group 1 (unvaccinated and challenged by A. paragallinarum serovar A), Group 2 (unvaccinated and challenged by A. paragallinarum serovar B), Group 3 (vaccinated and challenged by A. paragallinarum serovar A), and Group 4 (vaccinated and challenged by A. paragallinarum serovar B). Vaccination was done using the tetravalent vaccine in oil-emulsion adjuvant contained A. paragallinarum bacterin serovars A, B, C2, and C3; strain A-221, B-Spross, C2-Modesto, and C-3-Akko. Vaccination was performed at day 1 and booster was done at day 14. Blood serum was collected on days 0, 14, and 28 for the hemagglutination-hemagglutination inhibition (HI) test. The challenge test was given at day 29 through intranasal administration using A. paragallinarum serovars A-L2447 and B-L1710 approximately 6×108 CFU/mL. Clinical signs were observed for 14 days post-infection. At the end of the study, chickens were euthanized, and pathological features of the infraorbital sinus, facial skin, and trachea were recorded. RESULTS: Data analysis of antibody titers and pathological changes was performed descriptively, while clinical symptom scores were analyzed non-parametrically with the Mann-Whitney U-test using SPSS version 21. At days 14 and 28 post-vaccination, the antibody titer in Group 3 was 5 HI and 20 HI, respectively. However, the antibody titers in Group 4 at 28 days post-vaccination were 0 HI. Clinical observations, the vaccinated groups that were challenged with A. paragallinarum serovars A and B showed clinical symptoms on days 4 and 6 post-infection, namely mild unilateral facial edema and severe bilateral facial edema, respectively. Clinical signs in Groups 3 and 4 were less severe than in Groups 1 and 2 (p<0.05). Pathological examination findings supported clinical observations and serological testing. CONCLUSION: Tetravalent coryza vaccine in chickens has efficacy to protect against the challenge test of A. paragallinarum serovars A and B isolated from Indonesia.
