| dc.description.abstract | Birds has an important role in daily lives of Indonesia. Poultry in Indonesia is important as the main source of protein and companion birds are bred to fulfill market demand for pets. Infectious bronchitis virus (IBV) is one of avian coronaviruses that can cause economic loss in poultry and found in various birds. The finding of IBV in birds other than poultry suggests a link between poultry and other birds, but there is limited information on IBV in other birds in Indonesia to assess the risk. Indonesia has several endemic Psittacine species often bred to be kept as pet to help in conservation effort. Research of viral diseases which affect productivity such as IBV in these species is very limited, despite its importance for conservation and disease prevention. Meanwhile in poultry, IBV prevention in Indonesia still faces trouble such as difficulty for IBV detection, ineffective vaccination, and lack of information of pathological lesion in field cases. Sufficient information from both sectors is required to assess the link between poultry and companion birds. Thus, this research aimed to find better detection method of IBV cases and its pathomorphological lesion in chicken as well as identifying avian coronavirus in several Psittacine species commonly bred for companion birds.
For poultry research, a total of 11 flock samples of suspected IBV infections were collected from cases submitted to Pathology Division, Faculty of Veterinary Medicine, IPB University, and from farms around Bogor, Sukabumi, and Padang. Organ samples were analyzed by RT PCR using two primer sets: IBVN+/IBVN- targeting partial gene N and XCE+/XCE- targeting partial gene S of IBV. RT PCR result showed one sample is positive for gene S, 5 samples are positives for gene N. All positive samples of N gene were proven positive by immunohistochemistry, showing that RT PCR targeting N gene had better sensitivity than S1 gene. Due to mutations often occurring within S1 gene, detection by RT PCR targeting S1 gene can be challenging despite pathological lesion showing IBV infection. The mutation may caused primers unable to capture new field strains, causing false negatives and requires researchers to design new primers. However, S1 gene is still important because it plays a role in immunoprotectivity, which is important for vaccination, and thus still need to be identified after N gene positive result is found. Immunohistochemistry by Ostrich IgY anti-IB Antibody showed the virus could be found on the trachea, kidney, and oviduct of positive samples which may differ in the degree of severity and or microscopic lesion depending on the phase of infection and the strain of infecting virus.
For psittacine research, cloacal swabs were taken from 41 healthy Psitaccine birds from two breeding facilities consisted of 15 sulfur-crested cockatoos (Cacatua sulphurea), 10 palm cockatoos (Probosciger aterrimus), 10 Eclectus parrot (Eclectus roratus), two blue and yellow macaws (Ara ararauna), two green winged macaws (Ara chloropterus), and two scarlet macaws (Ara macao). One batch of swab samples were inoculated to Specific Pathogen Free (SPF) embryonated egg for allantoic fluid and embryo. Swab samples and allantoic fluid samples were tested by RT PCR for avian coronavirus by avian coronavirus primer UTR41+/11- and for IBV using primer set IBVN+/IBVN- and XCE2+/XCE2-. Harvested embryos were examined for histopathological lesion by Hematoxylin Eosin staining. Three swab samples of E. roratus were found positive of IBV and from allantoic fluid, eight samples (three of C. sulphurea, one of P. aterrimus, and four of E. roratus) were positive by IBV primers. Nucleotide sequencing by S1 gene HVR3 region of one E. roratus sample showed 100% homology in HVR3 region of S1 gene with Lineage G-13 IBV vaccine strain 4/91 and infectious 4/91 strain. This indicated that IBV-like virus similar to the one found in poultry exist in captive bred Psittacine despite the route of infection being unknown. Inoculation to embryonated chicken possibly increases viral load which improves the rate of detection. No significant change was found in gross anatomy and histopathological feature on chicken embryos inoculated by the samples. Due to sampled individuals appearing to be healthy and no significant changes found on the chicken embryo fetus, it is undetermined whether the IB-like virus cause disease in both Psittacine species they were found in or in chicken. However, the findings of IBV in Eclectus parrot and IBV-like virus in Sulphur crested cockatoo and Palm cockatoo show that probably reverse spillover from poultry to the environment and other birds had occurred.
In conclusion, primers targeting N gene appeared to capture more IB cases compared to primers targeting S1 gene, reconfirmed by immunohistochemistry, and thus suitable for screening outbreak cases in poultry. IBV-like virus was found in Psittacine birds, one of which shows high nucleotides similarity with Lineage G-13 4/91 IBV virus found in chicken. Avian coronavirus finding in various species raises concern about interspecies transmission of these viruses between poultry, wild birds, and captive bred companion birds. The findings of this research highlighted the urgency of better biosecurity and disease surveillance in various bird species. | id |
