newcastle disease vaccine with its advantages & disadvantages

Newcastle Disease Vaccine | Advantages | Disadvantages

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Newcastle Disease Vaccine

Newcastle disease (ND) define as a viral disease caused by Newcastle disease virus (NDV) under the family of paramyxoviridae. Its nonsegmented negative-sense RNA virus. It caused disease in poultry especially chicken, pigeon, etc.

Maternal immunity represents a particular problem in vaccination against Newcastle disease as it may prevent the effectiveness of primary vaccination.

Poultry diseases, 6th edition (pages:305-307), Diseases of poultry (page 102-103),

Types of ND vaccine



There are five types of NDV vaccine around the world given below

live lentogenic vaccine

live mesogenic vaccine

inactivated vaccine

Recombinant vaccine

Others experimental vaccine

Live vaccine



Live vaccines defined as vaccines containing live viruses that prepared from living attenuated organisms or from viruses that have been attenuated but can still replicate the cells of the host organism.

Live vaccines use a weakened (or attenuated) form of the germ that causes a disease in to the host due to these vaccines are so similar to the natural infection that they help prevent &  create a strong and long-lasting immune response.

Poultry diseases, 6th edition (pages:305-307), Diseases of poultry (page 102-103),

 That why attenuation takes an infectious agent and alters it so that it becomes harmless or less virulent.

Live NDV vaccine usually prepared from an egg-grown virus that is killed by treatment with formalin or β-propiolactone.



In many countries, where outbreaks of Newcastle disease are rare, vaccination of broiler chickens is not practised as birds are kept such a short time after protection due to maternal immunity has waned.

Poultry diseases, 6th edition (pages:305-307), Diseases of poultry (page 102-103),
Advantages
  1. Mass application of live NDV vaccines in drinking water, sprays, or aerosols is inexpensive and less labor-intensive than administering inactivated vaccines to individual birds.
  2. Easy to administer and provide mucosal immunity
  3. Ocular delivery provides the best response (93%)
  4. For day-old chickens with maternal antibodies, aerosol delivery produced a better immune response than water delivery.
  5. Some live vaccine viruses with Intracerebral pathogenicity index ( ICPI) equal to or greater than 0.7 are injected intradermally into the wing-web to decrease the severity of respiratory disease from the vaccine.



The addition of dried skim milk may increase the stability of the vaccine virus for water application

Disadvantages
  1. Difficult to produce protective antibodies in high percentages of birds in a flock
  2. While vaccine delivery in water or spray may produce protective antibodies in only 53% to 60% of the birds
  3. ND vaccine in a spray or aerosol. If the particles are too small vaccine reactions may develop in the form of respiratory disease because the virus is deposited deep in the lungs, and if the particles are too big, the immune response may not be optimal because the virus drops out of the air before the birds can become infected
  4. The inability to control the amount of water consumed per bird, inactivation of vaccine by heat, or impurities make water delivery problematic.
  5. The live vaccine virus will be shed from immunized birds to their nonvaccinated flock mates, extending the amount of time that live virus circulates on the farm. This may lead to vaccine reactions demonstrated by respiratory disease, especially if secondary infections or high ammonia levels are present.
  6. Most importantly, live vaccines are inactivated by high temperatures and require refrigeration.




Live vaccine viruses are neutralized by maternal antibodies and this is problematic for countries with stringent vaccine protocols for breeders, which subsequently produce chicks with high maternal antibody levels.

Poultry diseases, 6th edition (pages:305-307), Diseases of poultry (page 102-103),

Inactivated Vaccine

Inactivated vaccines are made from whole-cell (Killed antigene,g viruses, bacteria, others) that have been killed through physical or chemical processes. These killed organisms cannot cause disease.

Oil-emulsion inactivated vaccines have also been used successfully in 1-day-old, maternally immune chicks.

Poultry diseases, 6th edition (pages:305-307), Diseases of poultry (page 102-103), ,



General criteria of killed vaccine are inactivated killed produced under a controlled environment. Vaccine strains are killed which means to reduced infectivity (virulence) & thus prevent infection or causing disease from the vaccine strain.

Advantages

a) Immune responses induced by inactivated vaccines are less affected by maternal antibodies than by live vaccines.

Poultry diseases, 6th edition (pages:305-307), Diseases of poultry (page 102-103),

b) Inactivated vaccines produce high neutralizing antibody levels.

c) They are often formulated with other avian pathogen vaccines and delivered as a multivalent product to decrease the cost of administration



d) There is a 42-day minimum holding period between the time of injection

Disadvantages

a) Inactivated vaccines are more expensive to produce and more laborious to administer because they are given intramuscularly or subcutaneously.



b) Special attention to avoid accidental human injections is required when working with oil emulsion vaccines because they can cause severe inflammatory responses in humans.

What are the common source of Newcastle disease in developing countries?

In some countries, particularly developing countries, many chickens are reared as scavenging village chickens, which frequently act as reservoirs for NDV.



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