Showing posts with label herpes. Show all posts
Showing posts with label herpes. Show all posts

Thursday, February 12, 2009

Should we vaccinate our animals?


This is a controversial topic amongst vets. There are so many conflicting opinions and vested interests involved. One of the biggest problems is that we live in a commercial world, where profit and greed, dictate a lot of the advice given to both ourselves and our pets.

The industry of giving vaccinations to our pets is a multi-million pound business. If the sole argument is to make money, then the pharmaceutical companies and veterinary clinics should be giving as many vaccines and as frequently as possible.

The pharmaceutical companies have a lot to answer for - a lot of new drug trials and university lectures/studies are sponsored by drug companies. They regularly wine and dine vets and doctors, in addition to giving free gifts to promote selling their products (which pretty much tantamounts to a form of bribery). In addition to this, a lot of new drug trials aren't always so reliable and the papers published have to be read and interpreted carefully. Since, the drug companies are paying for the trials and to publish them in popular journals - they always try and manipulate the drugs to look as favourable as possible.

A lot of new drugs aren't much different from an older version of the drug. The main reason for introducing a new drug, is often because the patent (licence) giving the company sole rights to produce the drug is expiring. When a company has a patent, it can sell the drug at high prices as there is no competition. Once the patent expires, any company can manufacture the drug and so it becomes cheap to buy (as companies compete for business). Pharmaceutical companies therefore try to sell as many vaccines as possible by recommending regular injections although over the recent years, a lot of pressure has forced us to rethink our advice of giving vaccines.

First and foremost - I think that vaccines are very important for preventing disease. Before the use of vaccines, certain diseases such as parvovirus (causing severe gastroenteritis) and distemper virus (affecting multiple body systems) were fairly commonly seen and unfortunately, claimed the lives of many pets.

So vaccines are important and we are lucky that they have played an important part in preventing disease. So where has the controversy arisen? Well, the important questions need to be addressed?

What are vaccines?
"Any preparation used as a preventive inoculation to confer immunity against a specific disease, usually employing an innocuous form of the disease agent, as killed or weakened bacteria or viruses, to stimulate antibody production".

Which vaccines should we use for which pets?
The most commonly used vaccines for dogs are against parvovirus, distemper virus, parainfluenza virus, adenovirus 2 (against hepatitis), leptospirosis (bacteria) and kennel cough (Bordetella). Other vaccines are also used in other countries such as prevention for rabies, heartworm or Lyme disease.

In cats, the most commonly used vaccinations are against herpes virus, calicivirus, panleucopaenia virus, chlamydia (bacteria) and feline leukaemia virus (FeLV). There are other vaccines such as FIV virus vaccines and coronavirus vaccines (against FIP virus) but benefits of these are debatable.

Which vaccines to use should be based on the individual animal. For example, if it is an solitary indoor cat, a FeLV vaccine is un-necessary. Likewise, if the dog rarely comes into contact with other dogs, Bordetella is probably not needed.

What are the risks involved in using vaccines?
Vaccines are relatively safe. One of the risks involved is an allergic reaction (like itchy skin or swollen face) or more seriously anaphylaxis (severe reaction which may be fatal). The reaction of the pet's immune system can be directed to any component of the vaccination (such as the infectious organism, stabiliser or preservative). Fortunately, reactions are relatively uncommon with studies showing the occurrence at 13 doses out of every 10000 given.

Other possible problems are auto-immune disorders (like haemolytic anaemia when the body destroys its own red blood cells), transient infections and a possible risk of cancer where a vaccine has been injected (mainly cats - but link still unclear as variety of injections may cause a tumour called a sarcoma).

How regularly should we vaccinate our pets?
Everyone seems to vary on their advice! The following intervals for vaccinating are commonly used guidelines:

Dogs:
Bordetella: Intranasally one dose (at 16 weeks of age) and then repeated every year (depends on dog's lifestyle - if in contact with many other dogs)

Distemper, Parvovirus, Parainfluenza and adenovirus: 3 initial vaccines (at 9,12 and 16 weeks) and then one annual booster every 3 years although initial immunity may last for 7-8 years and possibly longer (need further research).
Leptospirosis: 2 vaccines 2-4 weeks apart (at 12 and 16 weeks) and then annually (depends on whether high risk area).

Rabies: 1 dose at at around (16 weeks or more) and then every 3 years depending on vaccine type (mainly for exporting pets).

Cats:
Feline Herpes, calicivirus and panleucopaenia viruses: 3 initial vaccines at 9,12 and 16 weeks and then one annual booster then every 3 years in low risk environments (although immunity may last longer).

Rabies: As for dogs

Feline leukaemia virus: 2 doses given at 12 and 16 weeks and then booster every year (only use if high risk e.g. outdoor cat).

Bordetella vaccine: As for dogs in high risk environments.

FIV,FIP and other vaccines: Not recommended as benefit in preventing disease controversial.

Should blood samples be taken to measure antibody levels?
This is debatable. Low levels of antibodies do not necessarily indicate a lack of protection (although initially they could be used for assessing a response to a vaccine - mainly for research purposes). Since, the level of antibodies doesn't reliably indicate protection, I do not routinely recommend blood sampling titres.

Cat flu


Cat flu is one of the most common diseases in cats and can be extremely frustrating for both owners and vets. It is normally caused by several pathogens which include both viruses and bacteria.

The common pathogens that cause cat flu are:

Herpes Virus (FHV)
: this causes recurrent eye and airway problems (rhinitis). Once a cat has caught the disease, it can return during stressful periods such as boarding in a cattery. It is similar to cold sores recurring in infected people.

Calicivirus (FCV)
: This can also affect the nasal passage but less seriously than FHV. It can cause mouth ulceration and sometimes chronic mouth inflammation (gingivostomatitis) throught a cat's life .

Bordetella Bronchiseptica
: This is a bacteria which both dogs and cats can catch. It normally causes respiratory signs (tracheobronchitis) and is very infectious spreading from one animal to another. It is related to the bacteria that causes whooping cough in humans.

Other bacteria include Chlamydophila felis, Mycoplasma felis and Bartonella henselae.

Often, infected cats that recover aren't able to completely eliminate the pathogens/organisms from the body and so remain as "carriers" spreading the disease to other cats in the future.
Cat flu pathogens can survive in the environment for several days. The disease is spread by being in contact with infected cats, carrier cats and a contaminated environment.

Common symptoms of cat flu include sneezing, nasal discharge, conjunctivitis (irritated and weepy eyes), inappetance and a fever.

Treatment is frustrating and often symptomatic. Often an oral antibiotic, like doxycycline, is used for the bacterial component of the disease. Eye drops can help with the conjunctivitis e.g. chloramphenicol. Other commonly used drugs may include appetite stimulants (e.g. cyproheptadine) and mucolytics (e.g. bromhexine) to decrease the nasal secretions.

Antiviral drugs, such as interferon and acyclovir, given in a variety of ways (e.g. eye drops, injectable and oral) are used to varying degrees of success but are quite expensive to use.

Lysine can be used long term to stop the replication of the herpes virus which is useful for stopping recurrences.

There are effective vaccines against Bordetella, FHV and FCV. Cats still may develop disease though if they caught a pathogen before vaccination and/or there are many pathogens involved.
 
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