Canine Leptospirosis – to vaccinate or not to vaccinate?


  1. What is Leptospirosis? 

Leptospirosis is a bacterial infection spread through the urine of infected rats, wildlife and dogs. It causes kidney and liver disease, but can affect other organs such as the heart or eyes, and can eventually cause organ failure and death. It is also a serious zoonosis risk, which means it can be passed on to humans too. Thankfully Leptospirosis very rarely infects cats.

  1. So how could my dog catch it?

Dogs will typically come into contact with the bacteria in infected water, soil or mud, or from coming into contact with urine from an infected animal. Working dogs, dogs that live near wooded areas and dogs that live near farms are at an increased risk of acquiring leptospirosis; however any dog can be affected.

Its’s worth knowing that the organism, normally found in water, is rapidly destroyed by light and temperatures above 20ºC, so does not survive long in bright sunlight. Therefore, where possible it is advisable to keep your dog away from stagnant water in shady areas.

  1. What are the symptoms of leptospirosis?

Sadly there are no classical symptoms which are specific of Leptospirosis which means it can be difficult to recognise, especially in the early stages of the disease. We would urge owners to contact us if they see any of the following symptoms in their dogs: lethargy, reduced appetite, high temperature, vomiting, diarrhoea, increased drinking, and jaundice.

  1. How is it treated?

Leptospirosis is a life threatening disease which can progress very rapidly but can respond well to antibiotic treatment as long as it is treated promptly and as soon as the symptoms of the disease are first detected. In order to diagnose the condition, the vet will usually run a series of blood and urine tests. For dogs that are more severely affected, they will need to be hospitalised and treatment will depend on the affected organs.

  1. Can it be prevented?

Prevention through vaccination is far better than cure, not least when the disease is potentially fatal, hard to diagnose and treat. The vaccine requires two doses to be given 4 weeks apart before full protection is achieved, with annual boosters required.

Historically we always used a bivalent vaccine, L2, which provided cover for what were at that point the 2 most commonly occurring causes of Leptospirosis. Over recent years there has been increasing evidence that the threat to UK dogs now comes from 2 other forms of Leptospirosis, and so the vaccine has been updated, giving L4.

  1. I’ve heard that there are risks with the Leptospirosis vaccination, especially the ‘L4’ injection, is this true?

We are aware that there has been a lot of discussion in national newspapers and online regarding apparent adverse reactions associated with the administration of the Leptospirosis vaccine. As a result, we have had a few understandably concerned owners questioning whether to vaccinate their dogs or not against this disease. Our answer is almost always yes, and here is why:

Firstly, Leptospirosis is out there, and it is killing dogs across the UK. That is a fact. The incidence rates vary depending on where you live, and where you walk your dog, but the truth is most dogs are at some level of risk of infection.

Secondly, the risks associated with the vaccine are very low. Sadly no vaccine is risk free, nor is any medication, or surgical procedure. What is important is to look at the specific risks associated with the vaccination, and for this we take our guidance not from the drug companies who you may argue may be biased, but from the Veterinary Medicines Directorate (VMD), an organisation which independently monitors all veterinary medications and vaccines licenced in the UK, as well as any associated adverse reactions.

Their current evidence states that in the years since the vaccine was authorised, the incidence of suspected adverse animal reactions has been 0.064%. In other words, for every 10,000 doses sold, the VMD has received reports of 6 suspected adverse reactions.

The VMD also points out that where these suspected adverse reactions have occurred, it is by no means clear that the Leptospira vaccine was responsible for the symptoms. This is because the vaccine is very rarely administered in isolation, and is often combined with other routine vaccinations, as well as worming and flea treatments. Therefore, the clinical signs observed may be related to any of the products used or they may be unrelated.

The VMD also states that where reactions do occur the majority of the adverse reactions to Nobivac L4 are linked to allergic type reactions which are well-recognised potential side effects of any vaccine, so the Leptospira vaccine is not alone in this position.

So to summarise the incidence of an adverse reaction is rare, and where it does occur the most commonly reported reaction is an allergic type, which can occur with any vaccine. On the other hand Leprospirosis is a real risk factor to a high number of dogs, can be hard to diagnose, hard to treat, and potentially fatal to both dogs and humans. So we consider the risks of not vaccinating higher than any reported adverse reactions to the vaccine itself.

This view is also shared by the World Small Animal Veterinary Association, a global association, independent of any vaccine producing companies, who’s aim is to advance the health and welfare of companion animals worldwide who’s advice to veterinary surgeons is that the vaccine should be administered to dogs where there is a risk of infection, and from 8 weeks of age.

  1. Does my dog really need a booster every year?

At Lamond vets we would certainly never force anyone to vaccinate their dog against their will. Our practice protocol would be to revaccinate all dogs against Leptospirosis each year, in accordance with the vaccine manufacture guidance. However if you are concerned about over vaccination, there is an option of a blood test to measure your dog’s circulating antibody levels which can be offered instead of a vaccine to establish whether a repeat vaccination is required. For further information please contact the practice and we will be happy to discuss this matter further.

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