There are 3 important viral diseases which dogs should be vaccinated against. These are DISTEMPER, HEPATITIS AND PARVOVIRUS. Vaccination is recommended because these diseases are highly infectious, have no specific treatment, and are very often fatal in dogs of all ages. Puppies are usually protected after birth by ingestion of antibodies passed on from their mother in the first milk (colostrum). Vaccination may only be effective for 12 months, thus it is recommended that dogs receive an annual booster to give them adequate protection throughout their lives.

Vaccination of Pets

Introduction:

The role of vaccination is preventing the spread of many infectious diseases should not overshadow the general concept and importance of maintaining good health in groups of animals and individual pets. Good hygiene, nutrition, and safe environmental conditions against exposure to infections is still the core for maintaining the overall health of animals. The sole reliance on vaccines to ensure health in pets is unrealistic and often unwise. Vaccination however continues to have a major impact on the control of many infectious and lethal diseases such as a canine distemper and parvovirus in dogs as well as feline panleueopenia in cats.

Immunisation:

The success of vaccination relies on the animal's own system of body defence and in particular its immune system. This system recognises foreign material such as infectious organisms including viruses and bacteria that are collectively called antigens.

The invasion of the body by these antigens stimulates the immune system to produce an immune response. These responses vary depending on the type of antigen, and the invasive activity of the antigen. The immunity so developed is called an acquired immunity and can be a result of either exposure to infectious diseases or vaccination. Within the larger population of any animal species the prevention of the spread of highly infectious diseases is controlled if the majority of the population has immunity. A level of over 80 % immunised is stated as being necessary for many infectious diseases of humans. It has been estimated that between only 30 and 40% of pets in Australia are immunised. This implies that infectious diseases,particularly in 'socially mobile' pets, have every opportunity to persist and spread in the community, causing illness or death in larger numbers of unvaccinated animals. Again in any population of animals there will he marked differences in individual response to vaccination. The majority of animals will develop a good and satisfactory protection and be well immunised, and yet a small but significant percent will fail to become adequately immunised. This phenomenon is in part associated with the genetics and breeding of animals. Secondary influences such as environmental stress, parasites, poor nutrition, and even intercurrent diseases play an equally important part in lowering their nutrition, and even intercurrent diseases play an equally important part in lowering their immune response. In other words stress -free animals in good health, in a disease free environment respond best to vaccination.Young animals rely on the immunity that is passed on to them from their mothers in the colostrum. It serves to protect them for only a limited time after birth. This is known as passive immunity. As with the variable responses to vaccination, the amount and period of passive immunity in each animal, even in a single litter, will vary within the population of newborns. Some animals will be protected for only a few weeks whereas others for about 3 months.

Vaccines:

There are two basic types of vaccines:

1. Modified live vaccines and

2. Inactive or killed vaccines.

The modified live vaccines replicate in the animal in order to stimulate the immune response. The inactive vaccines rely on providing sufficient amount of antigen in the first place aided by a specific immune cell stimulant called an adjuvant that optimises the response. Vaccination programs for your animals are developed specifically for the type of vaccine used and for the capability of the animal's immune system to respond at these early ages. Generally this will require at least two vaccinations from 6 - 8 weeks of age. Annual boosters are advocated to maintain immunity each year regardless of the type of vaccine used.

Sometimes vaccinations do not produce results anticipated and are said to fail. There are a number of reasons why this may occur.

1.The animal may already be incubating the disease.

2. The vaccine may have been 'damaged' by incorrect storage and or mixing.

3. The young animal may have had maternal (colostrum) antibodies that interfere with the initial vaccinations).

4. The animal may be a poor responder for genetic or secondary environmental reasons.

5. The vaccinated animal may be overwhelmed by a disease challenge. This may occur before the immunity has been established.

Only after 7-10 days of completing the vaccination program recommended by the manufacturer can there be any assurance that the animal will be protected. Up until this time all vaccinated 'at risk' animals should be kept isolated from likely sources of infection, i.e.: before socialisation and contact with other animals. Reducing exposure to infection is important. The proper implementation of hygiene and quarantine procedures to reduce disease organisms and to keep them out of the location is often difficult. It is most important to maintain these high standards especially where large collections of animals are held as in animal refuses , shelters or boarding facilities.

Conclusion:

There are many factors that determine the success or failure of vaccination. These involve the complex interaction of the animal, it's environment and the disease itself. Veterinarians are in the best position to advise pet owners about the value of vaccination as part of an overall health and hygiene program.

Article:

Vaccination of Pets

by M J Lindsey BV SC

Cyanamid Webster Pty Ltd