Introduction
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 or COVID-2019) spread in Wuhan city of Hubei province in China is family of Corona viruses (CoVs) that cause respiratory and intestinal illnesses in humans and animals ( poultry infectious bronchitis disease (IBD)) . They usually cause mild colds in human .The outbreaks of severe acute respiratory syndrome (SARS) 2002–2003 in China and Middle East Respiratory Syndrome (MERS) in the Arabian Peninsula in 2012 showed that corona viruses can also cause severe disease.(9)
Outbreak of novel coronavirus infectious disease was happened in December 2019. Until now , no treatments or drugs have been reported for COVID-19 infection. There is currently no vaccine or specific antiviral drug available for the infection of the COVID-19 virus. It is very important to find a safe and effective therapeutic agent for patients infected with the COVID-19 virus.(16,33,34)
Newcastle Disease (ND) and Poultry Infectious Bronchitis(IB) are two diseases that cause irreparable damage in industrial and domestic poultry flocks. These two diseases are prevented by effective live & inactivated vaccines.
The causative agent of Newcastle disease (ND) is a single-stranded negative-sense RNA virus belonging to avian paramyxovirus type 1 (APMV-1) of the family Paramyxovirida and subgenus Avulavirus . NDV can be divided into three groups according to their virulence in poultry: velogenic, mesogenic, and lentogenic . (10) ND vaccines are mainly prepared from strains of the lentogenic group (like I2 strain) which one of the most important advantages is grown to a high titer in embryonated eggs, and they can be administered via the nasal route .(23) Vaccinologists has interested in NDV (APMV-1) which has simple RNA genome, efficient replication, host restriction, and non pathogenicity in most mammals for its oncolytic activity and its use as animal and human vaccines vector against lethal emerging human diseases recently.(3,5,8,10,12,14)
In addition NDV has no similar pathogenicity in humanity and it has been shown in prior studies that NDV does not pose a threat to human health, and the majority of the human population does not have pre-existing immunity.(3,18,20)
IBV, the chicken coronavirus , is one of the important causes of economic loss within the poultry industry. The IB virus like COVID-19 virus replicates in epithelium of respiratory tract tissue.(7)
The phenomenon of viral interference between ND and IB in live vaccines has been reported since the 50’s and in many articles have be reported its prejudicial effects on avian immunization. (6,13,26,30,32)
Viral interference take place when two viruses infect a single cell and one of them put a problem with the growth or replication of the other virus. (19,29) Interference of IB virus with ND has been established in poultry ,(15) embryonated chicken eggs (27) and chicken embryo kidney cells .(2)
Currently, there are different opinions about the antiviral function of ND virus interferon, but if they do not consider it to be the only factor, they consider it to be an effective antiviral action in interference.(4,22,29)
Cardoso WM et al. proved that if a bivalent vaccine (IB-ND) is used instead of inoculating Newcastle and Infectious Bronchitis that were combined just before vaccination, the interference between the two viruses would be reduced.(6)
Moghaddam Pour et al. in the development research bivalent IB/ND vaccine of RAZI , the interference between viruses was reduced by using different ratios of viruses. In that research, chickens were inoculated with bivalent live vaccines with different titers of ND virus and IB virus. No antibody against infectious bronchitis was observed in the group of chickens inoculated with the bivalent live vaccine that contained more ND virus than IB virus. That is, with the superiority of ND virus particles over IB virus, no antibodies against IB virus were secreted in the bird and vice versa. In previous researches, it has been reported that the interference is observed in the superiority of IB to ND virus, but the phenomenon of interference can also happen with the superiority of ND to IB, and in this case, the lack of growth of IB virus can be predicted. ( 24)