Generation and Evaluation of Recombinant Thermostable Newcastle Disease Virus Expressing the HA of H9N2 Avian Influenza Virus

H9N2 avian influenza virus (AIV) has become endemic in many countries, causing great economic losses when co-infected with other pathogens. So far, several live vaccines based on Newcastle disease virus (NDV) vectors expressing influenza hemagglutinin (HA) have been developed. However, the thermostable recombinant NDV is rarely reported. In this study, using a thermostable NDV rAHR09 strain as the vector, three recombinant NDVs expressing native HA, chimeric HA ectodomain with transmembrane domain/C-terminal cytoplasmic tail domain from fusion protein of NDV, and HA ectodomain were generated, designated rAHR09-HA, rAHR09-HAF, and rAHR09-HAE. The MDT value of three recombinant NDVs was above 120 h, their ICPI value was about 0.03, and the recombinant NDVs were still infectious when treated for 100 min under 56 °C, which demonstrated that the recombinant NDVs kept the lentogenic and thermostable nature of rAHR09. The immunization data showed that rAHR09-HA and rAHR09-HAF induced a higher HI antibody titer against H9N2 AIV and NDV. After being challenged with H9N2 AIV, the rAHR09-HA and rAHR09-HAF could significantly reduce the virus shedding in cloacal and tracheal swab samples. Our results suggest that rAHR09-HA and rAHR09-HAF might be vaccine candidates against H9N2 AIV.

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Prevalence of Newcastle Disease Virus and Avian Influenza Virus (H7N3) in Poultry at Karachi

RADS Journal of Biological Research & Applied Sciences ◽

10.37962/jbas.v11i1.260 ◽

2020 ◽

Vol 11 (1) ◽

pp. 1-6

Author(s):

Amjad Ali Channa ◽

Nazeer Hussain Kalhoro ◽

Zaheer Ahmed Nizamani ◽

Ayaz Hussain Mangi ◽

Jamila Soomro

Keyword(s):

Influenza Virus ◽

Avian Influenza ◽

Newcastle Disease Virus ◽

Avian Influenza Virus ◽

Disease Virus ◽

Newcastle Disease ◽

Virus Isolation ◽

Economic Losses ◽

Rt Pcr ◽

Agar Gel

Background: Poultry is largest and rapidly growing sector of livestock in Pakistan. It is mainly influenced by viral pathogens such as Newcastle Disease Virus (NDV) and Avian Influenza Virus (H7N3). These viruses cause severe disease in poultry and leads to heavy economic losses throughout the world. The outbreaks of these pathogens have been increased in last few decades. Therefore, the study about antigenic prevalence is needed to know about the emergence of these pathogenic viruses, and to get rid of severe ailments associated with reduced poultry production. Objectives: To determine the prevalence of Newcastle Disease Virus (NDV), Avian Influenza Virus (H7N3) and co-infections in poultry flocks at Karachi. Methodology: For detection of NDV and H7N3, a total of 200 tracheal swabs were collected and tested through virus isolation (V.I); the sample with positive virus isolation were tested through agar gel precipitation (AGP) and then the RNA was isolated through TRI Reagent, which was further tested through reverse transcription polymerase chain reaction (RT-PCR). Results: The virus isolation showed that 58% of samples were positive for various viruses. Agar gel precipitation (AGP) revealed that the occurrence of NDV, H7N3 and ND+H7 were 50%, 8% and 38%, respectively. RT-PCR for F and HA gene of NDV and H7N3 confirmed the presence of NDV and H7N3 in the poultry. Conclusion: It is concluded that NDV and H7N3 are circulating in the flocks causing co-infections, therefore it is important to know the field challenge of viruses and to prepare vaccine of circulating serotype of virus to mitigate the rate of infection.

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