Since Adams birth pathogens and living creatures are to be
dagger drawn on each other. To take the bull of infection on
right its horn and pay back in the same coins is the achievement
The main purpose of all vaccines and
consequently vaccination is to administer an optimum and safe
amount of antigen to elicit immune response in the bird.
Vaccination does not give guarantee that birds are protected.
There are number of factors which may furnish the success of a
It is a worth remembering that antigens or vaccine or
vaccination itself does not produce immunity rather it is the
birds immune system in general and immune cells in particular
that provoke the immune response and present the antigen to T lymphocytes and by macrophages and from there it is expressed to
b lymphocyte where the immune response initiated in items of
These antibodies are identical to the antigen of
The successful vaccination comes up in terms of higher and
stonger immunity. On most of occasions we get proper protection
with vaccination but immunity breakdown is usually not known.
There current topic highlighted the factors which will come up
in term of good immunity.
GENERAL PRINCIPLES OF VACCINATION :
Vaccination involves the administration of antigen to stimulate
the immune system to produce specific antibodies against viral,
vacterial, and protozoal disease. Vaccination program should be
based on the following considerations.
Diseases prevalent in the urea of operation.
Risk of exposure.
Immune status of parent stocks.
Cost of acquisition and administration of vaccines
Flock placement programs.
Availability of specific vaccines.
Cost benefit ratio associated with vaccination taking into
account the risk of infection and financial loses from disease.
PRECAUTION FOR USE OF VACCINES :
1. Do not vaccinate the birds during stress period
particularly few days before or after the debeaking, transfer
shifting and grading. In these conditions negative Immuno-modulation
occur which ended with low level of active immunity.
2. It is not wise to vaccinate the birds during extreme
weather, because heat stress on one end affect the bird and on
other end effect the vaccine due to high environment
3. Avoid using metal drinkers and containers for mixing
of vaccines, as the metal ions and metals react with the
vaccines to inactivate the live vaccines offered through the
drinking water. Aluminum and brass containers are not
recommended due their maximum inactivation properties. It is
recommended to use the PVC or PET containers (Plastic).
4. Use clean equipment and drinkers and sterile syringes,
so not use any chemical to disinfect the vaccine utensils
because the residues of these chemicals inactivate the vaccines.
Rinse the utensils with fresh water to avoid the errors.
5. Always use sterile diluents preferably of the same
company for reconstitution of injectable vaccines as the
different sources are not synchronized with the optimal
requirements. Some diluents contains dyes more than optimum
levels which act as sterilizes for diluent and at the same time
inactive the vaccine .
6. Do not use waterfor vaccine dilution containing
disinfectants, particularly the Bleaching Powder (Chlorine
compounds) to avoid the possibility of these chemicals either
stop usage of these substances a day earlier the vaccine is
offered or two days earlier the vaccine is offered or two days
vaccination, enteric forms of vaccines are more sensitive to
these type of chemicals.
7. Try to use the vaccines as soon as possible the
vaccines are reconstituted, delay to offer by the farmers or
sonsumption by the birds leads to temporal decrease in the
8. In those areas where the salt concentration is too
high preferably vaccine the birds through injection or eye, nose
or mouth dropping.
9. Addition of skim milk is recommended, as the particles
of vaccines are distributed well in the water. In case milk with
fat or fresh milk is used it make aggregates on or near the
surface of the container ( due to light weight fat) where the
vaccine is mixed, leading to develop different concentration
zones in the container.
10. Lower limit of skim milk per liter is fixed but there
is no upper limit, the higher the milk concentration the best
will be the suspension of vaccine in drinking water, the
drinkers should be empty in one hour maximum taking in
consideration of temperature of house and feed time, the off
water time may be adjusted.
ROUTE OF ADMINISTRATION :
It is emphasized that appropriate control over the
reconstitution of live vaccines is required to ensure potency.
The actual administration of vaccines of should be monitored by
submission of serum samples to diagnostic laboratory for titer
assay using ELISA or acceptable technique. Various methods of
administrating vaccines are used commercially, including:
1. INTRANASAL: By instillation or dipping the beak up to
the naries. In birds nose, mouth and lachrymal duct opened in
mouth, therefore, each of the route ended up with the same
results with exception of the sensitivity and accommodation by
the eyelid epithelium otherwise routes are nearly same. In these
route please do not dip the beak for too long short time.
2. INTRAOCULAR: Eye dropping is most popular route of
vaccination. There some ereors in the eye dropping made during
the vaccination. Eye drop and intranasal routes suitable for
hatchery adminstration and during brooding of chicks. In
Pakistan the eye droppers are 30ml for 1000 birds, the
vaccinator make the vial and drop the birds until and unless the
whole of the vaccine is not spent. The too longer time holding
the vaccine. In these cases contaminated diluents or vaccines
leads to infection of eye and blocked of lachrymal duct and
drooling of water from the eye used for vaccination. This
reaction may some time normally occur after vaccination of ILT.
3. IN DRINKING WATER: This corresponds to oral and intra
nasal administration. Drinking water administration, can be
implemented at low cost but it is of limited effectiveness
against some infections.
4. INJECTION: Subcutaneous, intra muscular depending on
the type of vaccine and the direction of the manufacturer,.
Subcutaneous, injection to administer either live or inactivated
emulsion vaccines to chicks rearing stocks and breeders.
5. IN OVO VACCINATION: At 18 days of incubation using the
patented Inovoject system. Most commonly recommended in the case
of Gumboro and Mareks vaccines.
6. POST-HATCH SPRAY VACCINATION: In cabinets for mass-adminstration
of aerosol vaccines to day old chicks. This is mostly employed
for ND, IB vaccination on day one in hatchery or farm.
7. WING-WEB STAB: This method is used to administer fowl
pox vaccine or other live vaccines directly to each bird. Be
careful that eye of the needle carries vaccine each time or not.
8. AEROSOL ADMINISTRATION: Using a knapsack or electric
sprayer to deliver vaccines to flocks as a coarse spray.
FAILURE OF VACCINE :
USE OF EXPIRED VACCINE
Vaccines re expired by many ways, among the most common are the
expired in storage due to sale, expired in storage due to sale,
expired due to less shelf life ( it must be year plus when
reached in Pakistan ) expired supply by the manufacturer only
with few months in hand.
The major histocompatibility complex varies from bird to bird
and its structure dictates if a bird will respond to an antigen
at all. Due to some structural lacks in MHC it is possibility
that the birds are recognize the one of the antigens. Therefore
that strain of birds might be more susceptible to pathogen.
IMPROPER STORAGE OF VACCINES
This is the most common cause of vaccine failure in routine uses
of vaccines. This might be due to transportation from market to
farm or from manufacturer to distributor to market, failure of
electricity, failure of refrigerators, storage in deep freezers,
exposure of sunlight.
Ignoring the use of ice box, coolers or thermos and using the
translucent thin membrane shoppers permitting the sunlight
Exposure of heat, sunrays, room temperature, brooding house
temperature to diluents mixed vaccines. To avoid the damages
bottles either packed in cold bucket or use chilled diluents.
Do not open the lid of vaccine in the open environment as the
vaccines are contained in negative pressured bottles. Use
disposable syringe to constitute the vaccine or open the bottle
lid inside the water to avoid the sudden change in pressure.
Avoid to use the improper disinfected syringes and needles.
Always use wide bore needles for vaccine suction or dilution,
narrow bore needle may retained the cell culture vaccines, which
make the non uniform mixing of vaccine and lower the antigen
Exposure to viricidal disinfectants (phenols, alcohol) may be
avoided as these chemicals inactivate the vaccinal virus.
HEALTH STATUS OF THE FLOCK
The infectious agents such as Chicken Anemia Agent (Circo
virus), Gumboro Disease Virus (Birna virus), Mareks Disease
Virus (Herpes Virus ), REO Virus, Salmonella and Mycoplasma etc.
may cause varying degree negative immunomodulation which
consequently may lead to vaccinal failure or adverse reaction in
the face of these disease.
IMMUNO SUPPRESSION DUE TO DRUGS
Continuous administration of Immuno-suppressive drugs such as
chloramphenicol, furazolidone may cause cause poor immunity
Presence of mycotoxin in the feed affect the vaccinal response
very badly. Mycotoxin reduce host immunity directly by reducing
the Macrophage engulfing tendency and production of toxin,
lymphocytes which give poor out put in immunity development.
Mycotoxin indirectly affect the bird by producing steroids from
the adrenal glands which decrease the lymphocytes and increase
the neutrophils by the virtue of increased nutrophil the bird
become Immune compromised.
WATER DEPRIVATION AND HEAT STRESS
Due to water deprivation the bird is exposed to heat stress. Due
to heat stress lot of steroid production do occur which decrease
the lymphocytes produce the antibodies. This is common
observation that the dehydrated and heat exposed birds commonly
infected with coli septicemia and other diseases.
COLD AND HIGH DENSITY STRESS
These are social stress as well as stress like heat stress and
decrease the immunity by decreasing the number of lymphocyte,
which is the factory of antibodies.
Hypoprotenemia especially protein hurt the immune response as
antibodies are made up of amino acids. Poor nutrition causes
problem with metabolism, protein synthesis and immunity.
PRESENCE OF AMMONIA IN HOUSES
On the port of entry from where the pathogens are entered the
body to produce infection there are some host defense mechanism
which prevent the entry of pathogens. Hairs cilia moist
membranes are among the preventive cushions. The moist membranes
of or the mucous membranes among the gut , trachea, nostrils and
bronshi produce Immunoglobulin .a through the lymphocytes
present on the surface of these organs. This is called secretory
immune mechanism and it is watch dog on the port of entry.
If the ammonia levels are high in the house above 30PPM it has
bad effect on the birds ability to produce local immunity as the
cells on the surface of moist membranes are affected badly with
the ammonia because ammonia is water soluble gas. In the absence
of the local immunity the bird become susceptible to viral
diseases particularly those which proliferates in respiratory
tract. Ammonia condentration above 100 PPMm always associated
with the respiratory disease. As the ammonia is water soluble
gas one can easily felt the ammonia as it dissolved in lachyymal
secertion of the eyes .
ADMINISTRATION ERRORS QUALITY OF WATER
Water quality ispoor in most of the areas of Pakistan,
particularly in salinity affected areas such as Faisalabad,
Sheikhupura and Multan Division, where the salt level is half of
the sea water and EC even in Islamabad is 600-2000. Poor water
quality and high salt concentration produce ill effect on the
vaccine diluted in such kind of water.
High maternal antibodies inhibit the chicken immune response. It
has negative feed back effect on B lymphocytes. Moreover high
levels of maternal antibodies against infectious agent such as
Gumboro, also play a role in neutralizing the vaccinal antigen
thus making the vaccine less effective and designing the vaccine
program more difficult. Due to high maternal antibodies not only
the vaccinal antigen is destroyed but also the maternal
antibodies are also destroyed leaving the bird exposed to field
challenge if earlier vaccination in high titer is done.
PRESENCE OF VARIANT IN FIELD
It has been observed that with the emergence of new variants the
classical vaccines are no more effective to control the disease.
Classical vaccine of gumboro is missing the VP-2 protien
therefore it is not effective against field variant or strain.
The hot intermediate and intermediate plus do have the VP-2
protein and can penetrate up to the site of proliferation. In
the same manner classical IB is no more effective against IB
POOR ANTIGENICITY OF VACCINES
Live vaccines must be applied at a level at or above the minimum
infective dose. After the live virus has been applied the bird
serves as a virus production site. The bird is media in which
the initial dose of vaccine can multiply to a level which will
stimulate a proper immune response. For potency testing of
vaccines, always contact well facilitated Lab. Inactivated
vaccines should contain sufficient amount of antigen to
stimulate an immune response when applied the bird as there is
no multiplication of the virus of bacteria in the bird.
Do not give live respiratory vaccines (IB,ND,ILT) within 3 to 4
days if not combined by the manufacturer in licensed
combination. Reation may be too great or response to the later
vaccine may be compromised due to interference. This is also
true in case of ND and AI vaccine. Do ND vaccine earlier andthan
proceed for AI vaccine.
Means simply the geographical influence on the gentics of local
poultry ppulation. The geontical influence may affect the
ultimate response of birds to vaccine under indigenous
environments and may result in vaccine failure. The difference
pay more if they are present in MHC.
Adverse vaccine reaction, however do not serve a useful purpose
and should be prevented if at all possible. Several factors can
affect the severity of the reaction that occur. These include:
Level of maternal antibodies.
Doses of vaccine used.
Route of application.
Timing of vaccination.
Water,litter and air quality.
A normal respiratory vaccine reaction in broiler chicks begins
about four days post vaccination and lasts about five days. A
build up of dust and ammonia often occurs, and will cause
respiratory vaccine reactions to be more severe which may never
clear completely between vaccinations. A rolling vaccine
reaction is one of increased duration and/or intensity compared
to what is normally expected. The bacteria or fungus in haled
during few hours of life or present in the yolk sac, can
complicate vaccination andresult in airaculitis. These birds
will react to respiratory vaccines for several days some time
during the entire grown out.