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Family Birnaviridae
Published in Paul Pumpens, Peter Pushko, Philippe Le Mercier, Virus-Like Particles, 2022
Paul Pumpens, Peter Pushko, Philippe Le Mercier
The Birnaviridae is a family of double-stranded RNA viruses forming icosahedral nonenveloped single-shelled particles with a diameter of about 65 nm (Delmas et al. 2019). According to the recent taxonomy (Delmas et al. 2019; ICTV 2020), the family Birnaviridae is not included into any order and appears as an independent member of the kingdom Orthornavirae, realm Riboviria.
The role of apoptosis in non-mammalian host-parasite relationships
Published in G. F. Wiegertjes, G. Flik, Host-Parasite Interactions, 2004
Studies on the relationship between viruses and apoptosis in ectothermic animals have mainly concentrated on fish, particularly in association with viruses of economical and/or ecological importance. Infectious pancreatic necrosis virus (IPNV) is a member of the Birnaviridae, a family of viruses that includes Drosophila X virus and infectious bursa disease virus (IBDV) of domestic fowl. IPNV is the causative agent of the disease of the same name which is endemic in most parts of Northern America, Europe and the Far East. This lethal disease is particularly important in hatchery situations in the culture of both salmonids and some species of non-salmonid fish. The virus induces a pathological response and damage in the intestine and pancreas of the affected fish, and carrier fish release the virus into the water body via various secretions. Recent studies have suggested that apoptosis may play an important role within the virus-host interaction. Hong et al. (1999a) utilized green fluorescent protein from the Cnidarian, Aequorea victoria, to visualize cellular changes in Chinook salmon embryo cells (CHSE-214) infected with IPNV. The initial response of these cells, up to 6 hours post-infection, was to produce cellular changes similar to those associated with apoptosis (Hong et al., 1998). However, in later stages of the infection (greater than 6 hours), non-typical apoptotic changes were noted. For example, formation of membrane blebs which were released from the cell membrane and holes, 0.39–0.78 μm in diameter occurred in the cell membrane. The apoptosis process was confirmed using electrophoretic analysis of DNA fragmentation. The authors suggested that apoptosis was eventually replaced by necrosis. Such cellular disruption may have assisted in viral dissemination. Subsequent studies by Hong et al. (1999b) revealed that the virus may mediate its effect by altering apoptotic gene expression. Mcl-1, a member of the Bcl2 family of genes, which was first identified in human myeloid leukaemia cells, is thought to inhibit apoptosis induced by the overexpression of c-myc. The authors noted that mcl-1 expression was reduced in cells infected with IPN during the first 8 hours of infection. These results contrast to studies in mammals where Epstein-Barr virus-transforming protein LMP1 induces a rapid but transient stimulation of mcl-1 in B cells (Wang et al., 1996). Recently Hong and Wu (2002) have extended these studies to other apoptotic genes and have revealed that expression of bad, a bcl2-related family member, which promotes apoptosis, is up-regulated in IPNV-infected cells. The use of tyrosine kinase inhibitors, e.g. genistein suggested that the viral effects may be mediated via a viral receptor which triggered bad expression via a tyrosine kinase pathway.
Role of Mushroom as Dietary Supplement on Performance of Poultry
Published in Journal of Dietary Supplements, 2019
Sohail Hassan Khan, Nasir Mukhtar, Javid Iqbal
Infectious bursal disease (IBD) is caused by a virus that is a member of the genus Avibirnavirus of the family Birnaviridae. According to the virus virulence and pathogenicity, IBD causes more severe or less severe lesions on the bursa of Fabricius and other organs such as spleen, thymus, and kidneys and may induce immunosuppression and mortality in birds. Ogbe, Mgbojikwe, Owoade, Atawodi, & Abdu, (2008) supplemented chick diets with wild Ganoderma mushroom (Ganoderma lucidum) at the rate of 0.05%, 0.1%, or 0.2%. Chicks were vaccinated against IBD at 2 and 5 weeks of age. Each feed treatment lasted for 7 days each time before and after vaccinations. The results showed that in both qualitative and quantitative agar gel precipitation tests, there was positive response in all the vaccinated groups at 6 weeks of age, in which chicks fed 0.2% mushroom diet showed the highest positive response (2.5 log2), followed by 0.1% (2.3 log2) and 0.05% (2.0 log2). There was significant increase in the positive response at 8 to 10 weeks of age in all the groups: 3.8 log2, 3.5 log2, and 3.0 log2, respectively. Selegean et al. (2009) investigated the synergistic relations between extracts (the polysaccharide-containing extracellular fractions [EFs] of the edible mushroom Pleurotus ostreatus) and BIAVAC and BIAROMVAC vaccines. In the first experiment, by administrating EFs to unvaccinated broilers, they noticed slow stimulation of maternal antibodies against IBD starting from four weeks post hatching. For the broilers vaccinated with BIAVAC and BIAROMVAC vaccines, a low to almost complete lack of IBD maternal antibodies was recorded. By adding 5% and 15% EFs in the water intake, as compared to the reaction of the immune system in the previous experiment, the level of IBD antibodies was increased. Thus the workers believed that by using this combination of BIAVAC and BIAROMVAC vaccine and EFs, good results may be obtained in stimulating the production of IBD antibodies in the period of the chicken's first days of life, which are critical to broilers' survival.