Newcastle disease defined as an infection of poultry caused by the groups of virus of avian paramyxovirus serotype 1 (AVMP-1) that should covers one criteria for virulence:
- Newcastle disease virus has an intracerebral pathogenicity index (ICPI) (Gallus gallus) of 0.7 or greater in day-old chicks (according to OIE) & 1.2 in two weeks older birds ( according to EU)
- Virus showing multiple basic amino acid either directly or by deduction.
Types Of Vaccine
Vaccination refers to procedure of application vaccine of a specific antigen of specific pathogen to stimulate immune system to produce homologous antibodies against Virus, Bacteria & protozoa. Several types of vaccine are below
Others experimental vaccine
1. live lentogenic Vaccine
Live lentogenic vaccines are usually derived from field viruses that have been shown to have low pathogenicity for poultry but produce an adequate immunity in poultry.
Single live lentogenic vaccine produce titer 23-25 which not reached to desirable levels.Diseases of poultry. 13 th edition page 104-107
Typical Lentogenic vaccine strains are
Hitchner B1 and La Sota :
There are mainly two starin are available Live B1 and LaSota, developed in the 1940s & continue to be used worldwide.
Ulster 2C, QV4 & VG/GA
More recent strains, Ulster, QV4 and VG/GA are also commonly used. QV4 (also called V4) and the I-2 strains have some ability to withstand heat and are often used in areas where a “cold-chain” is not reliable.
2. Mesogenic vaccines
Typical vaccine strains are Roakin, Mukteswar,Komarov and H have usually been derived in the laboratory from fully virulent strains.
Inactivated and live NDV vaccines formulated with NDV strains of are the most commonly administered vaccines
Usually prepared from egg-grown virus that is killed by treatment with formalin or β-propiolactone. Aqueous inactivated vaccines have been used but in recent years these have been superseded by those based on oil.
The immunogenicity of such vaccines may vary considerably with the type and ratios of the components of the vaccine.
Both low virulence, such as B1 and LaSota virulent and avirulent viruses have been used as a source of antigen for inactivated vaccines.
From a safety aspect, viruses of low virulence would seem the most sensible source of antigen and have the added advantage of usually growing to higher titres in eggs.
Inactivated vaccines were first adjuvanted with aluminum hydroxide, but oil emulsions have proved to be more effective
Formalin, beta-Propiolactone (BPL), and binary ethylenimine (BEI) are used to inactivate NDV
Whereas binary ethylenimine (BEI) is not known to affect the HA potential of the virus after inactivation, formalin and BPL both decrease the HA titers after inactivation (The same strains used as live vaccine are also used in inactivated vaccinesDiseases of poultry. 13 th edition page 104-107
4. Recombinent Vaccine
A recombinant vaccine is a vaccineproduced through recombinant DNA technology.
Recombinant technology has allowed for the commercial production of recombinant fowl pox or Marek’s disease virus serotype-3, also designated as herpes virus of turkeys (HVT), as live-vector vaccines to express the glycoprotein of NDV.
These vaccines may be delivered in ovo, produce no respiratory vaccination reactions, and can be administered to chicks with maternal antibody. They must be reconstituted as directed by the manufacturers, and require more time, typically 3–4 weeks, before immunity is reached in chickens
5. Other experimental vaccines
virosomes, virus-like particles, immune stimulating complexes [ISCOMS]
NDV antigen expression in transgenic plants) also have been shown to provide effective immunity
Cytokine genes inserted into recombinant NDV strains to act as adjuvants to modulate the immune response also are being characterized for use to enhance protection against ND.