With the public’s reliance on the internet for information and the huge influence of social media on our lives, clients in veterinary practice are generally far better informed than in previous years about issues relating to their pet. One of the important topics discussed in the media is vaccination. More than ever before, I find clients asking me whether their pet still needs its annual vaccinations.
Vaccinations in cats and dogs cover a wide range of infectious diseases caused by viruses and bacteria, which either cause life threatening illness or long term morbidity.
Puppies and kittens usually receive their primary course of two vaccinations from about 8 weeks, and this level of immunity is “booster-ed” or “reinforced” by annual vaccinations thereafter.
In dogs, the “core” components of the vaccine are distemper, parvo virus, infectious canine hepatitis virus (a liver virus) and leptospirosis (a bacterium that can also cause disease in humans). In cats, the “core” components are feline herpes virus and calicivirus (which make up cat flu), and feline panleucopaenia virus (also known as feline infectious enteritis virus and feline parvo virus).
The vaccines used in veterinary medicine are either weakened versions of the actual virus (or bacteria) or killed versions. The introduction of these viral or bacterial proteins into the body stimulates the immune system to mount a defensive response which clears the vaccine and leads to the production of an immune “memory”. Should a vaccinated animal come into contact with the same or a similar version of the virus in the future, the immune system “remembers” the previous challenge and is able to defend itself and clear the infectious agent far more quickly. This means that the symptoms of the disease are often mild, not prolonged, and the animal recovers far more quickly.
The frequency at which we need to re-vaccinate animals and reactivate or “booster” this “memory”, has become the subject of heated debate. Unfortunately, the arguments against vaccination are sometimes open to misinterpretation by the general public, whilst the benefits are underplayed.
There is much discussion about the risks associated with repeat vaccination. There are anecdotal reports of vaccination increasing the chance of some auto immune diseases in some dogs, and a more widely published association between vaccination and soft tissue cancers in older cats. However, in both cases the risks are very low. In the latter case it is accepted that any cat that is regularly injected with any drug is at a higher risk of developing a cancer in this area.
Vaccination not only protects the individual animal but also reduces the incidence of the disease in the general population of domestic animals at large. The effects of outbreaks of these infectious diseases are often seen in populations of unvaccinated, stray animals that enter re-homing centres. Vets regularly see cat colonies that are affected by cat flu and more recently (in Swansea) kittens that have to be euthanased on welfare grounds after being infected by feline panleucopaenia virus. Vets also see local seasonal increases in kennel cough in dogs which can be prevented through vaccination.
The success stories of vaccination, in particular in dogs, are often overlooked. The virtual eradication of distemper virus from the UK and the reduction in prevalence of parvovirus in the UK population of dogs are two key examples. Parvovirus is a debilitating, severe, life threatening disease of younger dogs (older dogs are more likely to have built up immunity). Treatment is often unrewarding and this adds to the frustration given that the disease is easily preventable through vaccination. Occasional cases of parvovirus are still seen and diagnosed in areas with poor vaccine compliance.
Historically, the veterinary profession has been guided by the clinical trials and data provided by vaccine companies, which some may argue have an invested interest in the sale of vaccine.
However, in recent years’, data released by vaccine companies suggests that some of the components of the core vaccine in dogs convey immunity that actually lasts longer than previously thought.
If the primary course received as puppy is “boostered” at one year, then the immunity to core components such as parvovirus, canine infectious hepatitis virus, and distemper can last on average nearer three years.
Vaccines currently used by most vets have followed this trend, allowing greater versatility in what is being vaccinated against, to avoid “over vaccination”.
There is currently less information on the duration of action of the core components in cats, and the recommendation is still to have annual vaccinations.
What is clear is that there is still a need to vaccinate annually against leptospirosis in dogs. Leptospirosis can cause a number of different symptoms ranging from end stage liver and kidney disease to vomiting and diarrhoea in dogs. The bacterium is transmitted in water infected by the urine of rodents and other wildlife carrying the disease. It is also infectious to humans (known as “Weil’s disease”). A recent study has indicated a change in the prevalence and strains of this bacterium in the UK. More cases of leptospirosis are being diagnosed in dogs due to the availability of DNA testing, and it’s prevalence is likely to be more widespread than initially thought. Alarmingly, there was also a recent outbreak in Bristol, in which 50 or so dogs were affected.
As a pet owner, whether or not you subscribe to the science behind protecting your pet, the other undisputed positive effect of vaccination is the opportunity for pets to be thoroughly examined by a vet on an annual basis. During this examination, the general health of the pet can be discussed and conditions such as anaemias, heart murmurs, dental disease or cancers can be detected earlier, undoubtedly increasing the longevity of the animal.
If you require any more information about vaccination of your pet, please contact your vet, or phone St James Vet Group on 01792 205000 for some advice and we will be happy to help.