Heat Resistant Vaccine against Newcastle Disease: Importance and Application

The objective of vaccination is reducing the number of susceptible birds against the Newcastle disease (ND). Many Newcastle disease vaccines deteriorate after storage for one or two hours at room temperature. This makes them unsuitable for use, especially in villages where the vaccine may need to be transported for hours or in some cases days at ambient temperature. A heat resistant Newcastle disease strain is more robust and is known as a thermostable vaccine. Such a vaccine strain, is suitable not only for use in rural Chickens in tropical areas, but also to provide sufficient time for the vaccination of poultry by drinking water method. The virus identified as Avian Paramyxovirus serotype 1 (APMV-1) by molecular tests. It is proved avirulent through in vitro and in vivo conventional experiments. The stability of virus tested to ensure that is resistant to heat. Then quality control tests for master seed was achieved included safety, potency, stability, sterility (freedom from bacteria, fungi, mycoplasmas) and purity (absence of extraneous agents) tests based on pharmacopoeia. The results of pathogenicity tests and determination of pathogenicity indices (MDT, ICPI, IVPI) showed that studied virus is in the range of avirulent NDVs. Molecular tests and sequencing of F gen, confirmed the conventional tests and indicated similarity between studied virus and heat-stable vaccinal strains. Eventually the master seed passed quality control tests successfully. The avirulent, thermostable ND vaccine strains were developed by researchers at the University of Queensland in Australia (Spradbrow 1999) to provide rural poultry farmers with an effective, affordable means of controlling ND in their flocks. These vaccines have been used successfully in village chicken populations in many countries in Asia and Africa. The results obtained in this study show that our vaccine has potent to use successfully via different routes in chickens. It reduces the costs for backyard poultry in our villages especially that has also capacity for feed administration.