ROUTES FOR ADMINISTRATION OF VACCINES IN ANIMALS

(Part-VI)

By

Dr. ZAYTOON ZAHEER (Honorary Deputy Editor Veterinary News &

Views).

Types of vaccines, basic differences between mechanism of action of inactivated and

attenuated vaccines, handling of inactivated, attenuated vaccines and vaccine diluents,

vaccines available in market have been discussed in previous articles as far as routes of vaccine

administration are concerned, there could be multiple options for administration of vaccines.

Regardless of the route of administration, careful planning and preparation, as well as

consistent application and attention to details, are key to a successful outcome. Faults or

shortcomings in the administration of vaccines are, by far, the most common cause of poor

response to vaccinations. Different routes for vaccine administration in animals are as follows:

1. Subcutaneous

2. Intramuscular

3. Intradermal

4. Intranasal: drops, aerosol and spray.

5. Occular drops (Eye drops)

6. Oral : drops or drinking water

7. Inovo

8. Wing web puncture

9. Feather follicle

10. Spray on Feed

11. Scarification

1. Subcutaneous (S/C) Injection of vaccines:

Vaccines are introduced subcutaneously by using a hypodermic (literally – under skin) syringe to

inject a liquid vaccine through a hollow needle into the space between the skin and underlying

tissues. Typically the site of application used is the area of loose skin e.g at the back of the neck.

However, injection into the muscles must be avoided.

Needle length and direction of insertion are used to control the site of vaccine deposition. Greater

care is necessary to avoid accidental self-injection with this technique than with intramuscular

administration. The product should be deposited 5-10 mm away from the point of skin puncture

to reduce the risk of vaccine leakage and to facilitate healing of the puncture. It is important to

ensure that all equipment used is properly cleaned, sanitized and maintained to avoid

contamination of the product. If the product to be administered is a live vaccine, it is also

important to ensure that the equipment used for vaccination are not contaminated with the

residues of chemical sanitizer which might damage vaccinal agent.

Examples:

Almost all the inactivated oil based vaccines can be administered subcutaneously whereas live

vaccines can be administered through eye drops, nasal route, oral route.

Marek’s disease, Newcastle disease (ND), Infectious Bronchitis (IB), Infectious Bursal disease

(IBD), canine distemper, parvo virus, adenovirus vaccine e.t.c.

2. Intramuscular (I/M) Injection of vaccines:

Administration through I/M route means the deposition of vaccine within a mass of muscle.

Typically these injections are administered in areas having highest muscle mass e.g the thigh,

chest (in birds) and neck muscles, may be used for this purpose. This technique requires all of

the same care as for SC vaccination. The aim while using this route is to introduce the vaccines

more deeply in to the animal’s body hence there is a greater potential for damage to the bodily

structure e.g joints, tendons, blood vessels and nerves.

A range of problems can be encountered with I/ M administration:

· Partial or complete non-injection of vaccines in the muscles due to partial or complete

injection in subcutaneous tissues.

· Damage to blood vessels, tendons or joints.

· Penetrating into the body cavity or liver, liver abscesses or peritonitis ( e.g Injection in the

chest muscles of birds especially with poorly developed birds).

Examples:

Newcastle disease, Fowl Cholera, Fowl Coryza, Feline panleukopenia, rhino virus vaccine e.t.c.

3. Intradermal injection of vaccine:

Vaccines can be administered via the intradermal route, i.e. injection in the dermis, one of the layers of

the skin. This layer, underneath the epidermis, is highly vascularized and contains a large amount of

immune cells, mainly dermal dendritic cells. Intradermal (ID) inoculation has been used for

vaccinating laboratory animals, domestic farm animals, and humans. However, intradermal jet

injectors do not contain needles. Instead, these intradermal injection tools use a high pressured, fast

stream of injection liquid (or vaccine) to penetrate the skin.

Examples:

Rabbit hemorrhagic disease (RHD), Rabies vaccine e.t.c.

4. Intranasal route:

a). Nasal Drop:

This is almost identical to the preceding method – however while vaccinating through this route

the drop is placed in the nasal cavity. Where a high and early challenge is anticipated, it may be

used in conjunction with eye-drop administration.

Examples:

Bordetella, ND,IB, IBD e.t.c.

b).Coarse Spray:

Coarse Spray vaccines are mostly used for vaccinating birds at hatchery or at farm to provide

immunity against certain diseases.

i). Coarse Spray Cabinet (Hatchery)

Hatchery spray cabinets were initially developed to allow early and rapid administration of

respiratory vaccines. They may be manually operated by placing a single box of chicks in

the hatchery at a time but more commonly in broiler hatcheries they are sited over a roller

conveyor and the spray is activated when the box passes through. The later type generally

use a flat-fan type spray. Pressure of operation, and nozzle type and maintenance are the

main factors which affect performance of these systems. They may be simply monitored by

assessing the pattern of spray when a series of empty boxes with dry chick papers is put

through. The objective is to achieve a coarse spray of droplets on the down. Chicks should

remain moist for 10-15 minutes – this is usually achieved with a volume of application of

200-300mls per thousand chicks, though lower and higher rates of application are

sometimes used. Droplets of 100-300µ are appropriate for day-olds. Chicks should not be

transported until they have dried to reduce the risk of chilling.

Coarse spray systems are also being developed for the administration of coccidiosis vaccines.

Example:

ND, IB e.t.c.

ii).Coarse Spray (at Poultry Farm):

A range of sprayers is used to apply coarse spray to birds on-farm. This can involve simple

hand-held or back-pack sprayer, often to do day-old administration into the chick boxes if

not done at the hatchery. Day-old administration aims to mimic the effect of hatchery

administration – so it is best to do it before releasing chicks into the house.

Spraying can also involve more sophisticated motorised equipment, and, for caged units,

trolleys with multiple spray nozzles adjusted to cage tiers. In fact these systems actually

generate a broad range of particle sizes (typically from 50 to 1000µ). The larger particle

sizes do not travel very far from the nozzle in many systems.

However it must be appreciated that most spray systems actually generate a range of droplet

sizes, even when they are predominantly coarse.

Some equipment can result in excessive vaccinal reaction, particularly where flocks are stressed

by viral challenges, poor ventilation and infections such as Mycoplasma gallisepticum.

Furthermore spray systems may exacerbate respiratory disease.

Spray vaccination should normally be practised with purified or distilled water. If tap water

must be used then a suitable chlorine inactivator should be added before mixing the vaccine.

If tap-water is used rather than purified or distilled water, particularly in areas of hard

water, it will be more difficult to maintain the spray systems clean and functioning

consistently as clogging may occur.

The ventilation system should normally be closed down during vaccination and for a period of

at least 15 minutes afterwards, but the importance of this may vary with the type of sprayer

used. If environmental temperatures are unusually high, then it is beneficial to vaccinate early

in the morning.

It is usually helpful to turn down the lights during vaccination, although there needs to be

sufficient light to allow the operators to clearly see the area being covered. The whole flock

needs to be covered by following a consistent path.

All operators must be provided with personal protective equipment as recommended by the

manufacturers.

Example:

ND,IB, IBD e.t.c.

c). Aerosol or Controlled Droplet Administration (CDA):

Administration of vaccines through this route is widely used in poultry industry. Aerosol

generators or foggers have been used for poultry vaccination for many years. They

tend to produce a finer, and more uniform, particle size (e.g. 80-100µ). These fine particles

are readily inhaled by the birds.

In recent years there has been an increase in use of sprayers originally developed for

horticultural use which have a much more uniform particle size (Controlled Droplet

Administration – CDA). These utilize a spinning disk that throws off particles from its edge, and

a fan to disperse it over a wide area. These sprayers readily distribute the fog over an area

about one metre wide and three to four metres long allowing the operator to rapidly vaccinate

a large number of birds.

The vaccine is applied by systematically moving down the house covering the entire floor area,

but aiming the nozzle above bird height.

Example:

ND, IB, IBD e.t.c.

5. Occular drops (Eye-drop):

This is one of the most effective ways of administering vaccines and ensures that individual

animal has been vaccinated with the complete dose (difficult to be ensured when vaccines are

administered in drinking water). Each animal is restrained with its head to one side and a drop

of the vaccine is placed in the uppermost portion of eye and head is held in this position until

the animal blinks the eye to ensure complete dose administration.

Example :

Infectious Laryngo Tracheitis, Newcastle disease, Feline panleukopenia, Feline Calcivirus,

Herpes virus vaccine e.t.c.

6. Oral route:

a). Oral drops

Vaccines can be administered orally in the form of drops. For this restrain the head of animal

and open the oral cavity to administer vaccine then close the oral cavity of animal and gently

rub your hand on the underside of animal’s neck to develop swallowing reflex. This route is

used for vaccinating different animal species against particular diseases.

Examples:

Rabies and others.

b). Drinking Water

The drinking water route of administration is used mainly where the target organ is the gut. But

may also be used for respiratory system vaccines. In preparing for water based vaccination it is

important to understand the details of the plumbing system at farms, and to have water lines and

drinkers as clean as possible. Mild acidification of water ahead of vaccination may be helpful in

removing bio-film. It is usual to wash drinkers on the day of vaccination – however the water

used should not contain a disinfectant and should have neutral pH. The vaccinal viruses are

equally susceptible to disinfectants as are field viruses so it is very important to ensure that they

are not exposed to disinfectant residues.

It is normal to mix an additive in the water used for vaccination to bind with and inactivate any

residue of chlorine in the water. The traditional additive used for this is skimmed milk powder,

used at a rate of 2g per litre. However it is not suitable for dosing systems in which a concentrate

of vaccine is made up and then administered into the stream of drinking water. It also delivers

nutrients into drinker system which can contribute to the build up of bio-film . To address these

problems a range of proprietary products have been developed which contain a dye and a

rapidly-acting chlorine neutralizer. The main purpose of the dye in such products is to allow

simple verification of effective vaccine distribution by direct observation of the colour of water

sampled at different locations.

The dilution rate of vaccine depends on altered expected water intake of the flock and will be

modified by the type and weight of birds, time of day, and ambient temperature

The aim is to ensure that there is sufficient water to ensure that the vaccine remains in the

system for 1.5 to 2.5 hours and that all birds drink during this time. Various tools may be used

to encourage water intake while vaccinating – choice of time of day, controlling light and/or

presentation of feed and withdrawing water for a short period. Water deprivation can be useful

but should not be excessive to avoid stressing the flock.

There are four basic approaches for administering vaccines to birds in drinking water:

· Mixing the vaccine in a reservoir and distributing directly into drinkers with a watering can

(really only appropriate for smaller flock sizes).

· Mixing vaccine in a header tank

· Mixing vaccine in a dedicated reservoir with coupled pump to inject into or circulate

within the drinker system.

· Mixing vaccine as a concentrate and administration into the line with a proportioner

Examples:

Avian Encephalomyleitis , IBD, ND, IB e.t.c.

7. In-ovo Injection of vaccine.

In ovo vaccine is the practice of vaccinating the embronated eggs approximately at 18 th day of

incubation commercially so that the chicks hatching from vaccinated eggs have immunity against

the disease for which they were vaccinated during embryonation.

This technique was developed initially for the administration of Marek’s disease vaccine

into broiler embryos ( approximately at 18th day of incubation) . It is, in fact, a form of

mass-administration of vaccine.

The equipment used for in ovo vaccine moves a tray of incubated eggs into an injection area,

then the eggs are held in position and punched over the air cell. The injection system has

sanitizer to sanitize needle and eggs on each inoculation after injection of vaccine the injection

system seals the eggs with wax. If eggs are not sealed after vaccine injection then microrganisms

from the environment can interfere with growth and hatching of chicks.

Examples:

Mareck’s disease, IBD e.t.c.

8. Wing Web Puncture for vaccination:

Through this route vaccines are injected by puncturing wing web of birds. This methods is

sometimes called ‘transcutaneous’. They have, in the past, been used to administer live vaccines

which, if administered more invasively, are excessively pathogenic.

However they are now used almost exclusively for fowlpox vaccination.

A double-needle or two prong applicator is provided with the vaccine. The needles have

depressions near their tips which take up the vaccine when dipped in it. Dip the needles in

vaccine before vaccinating each bird then spread the wing to expose the under-side of the wing

web, and stab through it, avoiding visible blood vessels.

Example:

Fowl pox.

9. Feather Follicles.

If using the feather follicle method for vaccination, a few feathers are plucked from the thigh

and the vaccine is brushed on the exposed follicles. This is another transcutaneous method for

vaccine administration.

Example:

Fowl pox.

10. Spray on Feed

Spray on feed stuff is also a way of vaccinating animals however surprisingly the feed-based

administration of vaccines is not used more frequently. This is probably because of the difficulty

in ensuring adequate stability and distribution of the vaccine on a feed base.

It is normally applied by using a mechanical sprayer to provide a coarse spray over the total

surface area of the feed. Sprayed feed when consumed by animals will produce immunity

against particular diseases.

Example:

ND (This ND strain is not commonly available as it has to be relatively thermostable and its

efficacy and immunogenicity is also debatable in highly endemic and severe threat areas) e.t.c

11. Scarification:

During scarification vaccines are administered through a scratch on the skin. Scratches on skin

can be made by syringe needles or two pronged needle. Scarification was first used nearly two

centuries ago to administer the first smallpox vaccinations. Today sc arification is still used

to vaccinate against the viruses of family Poxviridae. Scarification in food animals can be

done on the inner side of thigh.

Example:

Orf, goat pox, sheep pox, cow pox e.t.c .

Conclusion:

Vaccine must be administered through an appropriate route ensuring immunity against the

disease for which animal is vaccinated. Selection of route for vaccination can be influenced by

animal species, disease, age, sex e.t.c. Vaccine produced under GMP(good Manufacturing

Practices ) and GLP (Good lab Practices) from a reliable, consistent source should be used to

help to immune animal against VPDs (Vaccine preventable diseases).