There are a number of serious and life threatening infectious diseases of dogs. You can protect your dog by using vaccines to stimulate the body’s immune system.
Your dog’s immune system – a simple introduction
The immune system is a complex defence mechanism developed against specific foreign material or agents. In its simplest form it requires the body to recognise this foreign material, and then mount a reaction against it. The specific markers (flags) on the surface of the cell, bacteria or virus that identify it are called antigens. It may be possible to alter or kill the virus / organism without altering the “flag” antigen.
In this way modified, less pathogenic viruses may be used in vaccine production. In some viruses, there may be a number of different strains making it more difficult for the body to recognise them. It is important to stress that the immune reaction is aimed at a specific antigen rather than a disease entity – so it is possible to vaccinate against Parvovirus for example, but not against diarrhoea.
When first exposed to an antigen, the body recognises the “flag” and reacts by producing specific protective antibodies. This takes a little time and so the rise in antibody levels at the time of first exposure is relatively slow. However, once the body is programmed to recognise the antigen, any subsequent reaction to challenge is rapid. It is for this reason that most initial vaccine programmes require at least 2 injections a set time apart. The exception is when live vaccines are used since the altered virus remains in the system for longer stimulating a greater immunity.
There are a number of different types of antibodies. Some are active in the circulating blood and some on mucus membranes and tissues. This is important since the stimulation of immunity to some diseases requires stimulation of the immunity at these surfaces (eg Bordetella vaccination in dogs by nasal spray)
Immunity can be broadly classified as active (by the stimulation of the body’s own immune system) or passive (by the supply of pre-formed antibodies). Each of these can be further be subdivided into natural and artificial types.
Can my dog survive infections naturally?
This depends to some extent on the number of organisms attacking your dog. If the number is too large, the body’s defences are overwhelmed and death occurs before the immune system can react. However, a smaller challenge (helped by supportive treatment) will allow the body to develop an active natural immunity and recovery may occur. The body’s immune system is now primed for any future challenges and so will react more quickly.
In cases of endemic or common diseases, this immunity is constantly being strengthened by new natural challenges of the virus and so the immunity may remain strong. If the dog fails to meet the virus naturally, the specific immunity may be reduced over time.
Immunity and vaccination
To avoid the real risk of your dog dying from these serious infectious diseases, the immune system can be stimulated by the use of vaccines. A vaccine is manufactured from modified live virus / bacteria or dead viral / bacterial particles. The body recognises these antigens and produces antibodies.
More importantly the immune system becomes primed to recognise this antigen in the future, either as a booster vaccination or the real naturally occurring virus.
Is immunity passed from the bitch to her puppies?
Yes – antibodies pass from the blood of the mother to the blood of the offspring via the placenta or in the colostrum. This protects the puppies from the diseases to which the mother is immune for a limited period of time. The amount of immunity transferred depends on the level of maternal immunity and the amount of colostrum taken. It is important to check the vaccination status of the bitch when acquiring a new puppy.
The maternal antibodies will be gradually cleared from the body, the time taken depending on the original level achieved. Usually most will have gone by 8 - 12 weeks of age by which time the young animal’s own immune system would have matured. The length of activity of maternally derived antibodies is very important in deciding on the primary vaccine protocols for puppies. When hand rearing puppies, try to ensure that colostrum is given. Where this is not possible, recognise that the natural passive immunity may be low, and vaccination may need to be commenced earlier.
From what diseases can my dog be protected?
There is a wide range of disease antigens that can be incorporated into a vaccine protocol. The WSAVA (World Small Animal Veterinary Association) has published guidelines for core vaccines which are recommended to provide immunity against infectious diseases of global significance. In addition, there are non-core vaccines that are optional, but may be of particular significance in certain geographic locations. Your veterinarian will advise on the most appropriate protocol for your area.
Within Europe, the standard vaccine protocols include protection against Canine Distemper Virus, Canine Parvovirus, Canine Adenovirus and Leptospirosis. Canine Parainfluenza virus is also commonly included. Rabies vaccination may be a legal requirement in many countries, or an optional extra in rabies-free countries such as the UK when travelling under the Pet Passport scheme.
Vaccination against Borrelia (Lyme disease) and the intra-nasal vaccination against Bordetella bronchiseptica may be recommended in higher risk situations. A Canine Herpes Vaccine may be recommended for breeding bitches if they are thought to be at special risk.
When should puppy vaccinations be given?
The vaccine protocols can be adapted to suit the individual situation, but the timing of the primary course takes account of the following conflicting requirements:
- Vaccination is designed to prevent disease, therefore the sooner the better. However, high levels of maternally derived antibodies will inactivate the vaccine antigen if given early.
- Exposure to natural infection should be delayed until the development of full immunity, in some cases requiring a further booster at 14 – 16 weeks of age (WSAVA Recommendations). However, socialisation is best achieved by exposing puppies to novel experiences (including other dogs) between 7 – 13 weeks of age.
- The compromise is often to give the primary vaccinations at 8 weeks and 10 weeks of age and then allowing the pup restricted exposure to controlled areas and only to other puppies that are healthy and vaccinated. Some veterinary clinics organise puppy parties to facilitate this. However, the incidence of infection in the area, and so the relative risk of disease should be considered – your veterinarian can advise.
- If the immunity of the bitch was known to be low, or if the puppies had failed to get much colostrum, your veterinarian may suggest giving the first vaccination at 6 weeks of age.
How often should my dog be vaccinated?
The vaccination given is generally a mixture of antigens, and the duration of immunity following primary vaccination depends on the particular disease and the type of vaccine. Generally the immunity to “killed” vaccines and those containing bacterial antigens (Leptospira, Bordetella and Borrelia) is shorter requiring more frequent boosters for reliable protection.
Annual vaccination is recommended, but the components in the mix may vary – generally the complete range being given every three years.
Should my dog still be vaccinated annually when he is old?
Yes – like old people, a dog’s immune system will be compromised with age so regular boosters are important to maintain adequate protection.
Could my dog suffer any adverse reactions to a vaccine?
Adverse reactions to vaccines are rare and should be taken in the context of the protection given, and the risk of disease if not given. However, they can occur. Generally these are transient fevers that may last 24 hours. In the case of “dead” vaccines, other chemicals (adjuvants) may be added to enhance the stimulus to the immune system. These may cause local swellings and reactions at the injection site and may be more painful on administration. Your veterinarian will be able to advise on the relative risks.
Are vaccines 100% effective?
Modern vaccines are excellent and to be licensed undergo tests to prove quality, safety and efficacy. However, none can guarantee 100% protection in all circumstances. Only fit and healthy dogs should be vaccinated and diseases or drugs that depress the immune system will reduce the effect of any vaccine given.
Are “Homeopathic vaccines” vaccines effective?
No! Commercially produced vaccines have been developed to stimulate the immune system in a specifically understood way and are then tested for quality, efficacy and safety.
So-called “homeopathic vaccines” lack the specific antigens to stimulate the immune system. Puppies given such products should be considered as not vaccinated and therefore fully susceptible to disease.