Leptospirosis is the disease caused by infection with the bacterial Leptospira interrogans. This is a type of bacteria known as a spirochete; this means they are long cells which coil into a spiral shape.
Although all one species, Leptospira interrogans is divided into several sub-types or serovars. Different serovars may be responsible for disease in different animals. Some animals, most notably rats and some farm species such as pigs, can carry one type of Leptospira without becoming unwell. These species are known as ‘maintenance hosts’.
The most important source of L. interrogans in the environment is the urine of infected animals. However, the bacteria survive very well in cool, damp environments; standing or stagnant water that has been contaminated is a common source.
The bacteria are able to enter via a break in the skin, such as a cut or a graze, or across intact mucous membranes. This means infection may be by ingestion, but also by splashes of urine or contaminated water into the mouth, nose or eyes.
Infection with L. interrogans may cause acute kidney injury, acute liver disease, or often both. The signs of leptospirosis are generally related to disease of these organ systems and may include:
Affected dogs may also be jaundiced, with a yellow tinge to their gums or the whites of their eyes.
Treatment of leptospirosis focuses on helping to support kidney function with the use of intravenous fluid therapy, as well as intravenous antibiotics and intensive nursing and medical support to manage the adverse effects of kidney and liver injury (vomiting, nausea, abdominal pain).
How serious is leptospirosis?
Leptospirosis is a serious illness. Mortality rates of up to 50% have been recorded, even with intensive medical treatment. However, this depends on how severe the infection is, and how much kidney damage is caused. Kidney tissue is not able to regenerate, so if the kidneys are damaged to the point of being unable to produce urine, the prognosis is generally hopeless. After the acute phase of disease, dogs may be left with residual kidney damage to a variable extent. This cannot be reversed, but may be managed to maintain good health.
Leptospirosis infection is also a risk to human health. Depending on the infecting serovar, you may know of the condition as ‘Weil’s disease’. Dogs that have been infected can be a risk to human health, as they shed the bacteria in their urine. A long course of a particular type of antibiotic is given to dogs that are recovering from leptospirosis infection, to ensure that they do not develop a persistent kidney infection and continue shedding bacteria in their urine.
Much of the UK, with our cool, damp climate, is a high risk for leptospirosis. Vaccination against leptospirosis is recommended as part of a preventative vaccination schedule. The protection is not long lasting, so annual re-vaccination is required.
There are, broadly speaking, two types of leptospirosis vaccination availabe – a 2 serovar vaccine that protects against Canicola and Icterohaemorrhagiae and a four-serovar vaccine that protects against the serovars Canicola, Icterohaemorrhagiae (Copenhageni), Australis (Bratislava) and Grippotyphosa.
In 2014, several cases of Leptospirosis were recorded in the Bath and Bristol region in dogs that had received the commercial 2-serovar vaccine. These were thought to be due to the serovar Australis (Bratislava) which was not included in the vaccine. For that reason, we feel the 4-serovar vaccine is most appropriate in this region. WSAVA vaccination guidelines are that vaccinations covering as many strains known to cause disease locally as possible are used.
There has been a lot of media focus on Lepto 4 vaccination in the past few years. Most notably, an article in the national newspaper the Telegraph provoked an unusually strong response from veterinary organisations including the WSAVA, for some false statements that were made. The rate of suspected adverse reactions to Lepto 4 is 6 in every 10,000 doses (0.064%). This is in line with other vaccine products available in the UK, where the rate of suspected adverse reactions varies from 0.002% to 0.3%.
A definite cause of many of these reactions often remains unconfirmed. Often other products may have been administered over a similar time frame. This can make it difficult to ascertain which, if any, may have been responsible for symptoms. The most commonly recorded reactions to the Lepto 4 vaccine are allergic reactions which can occur with any vaccination, and are usually mild and self-limiting. If you are ever concerned your pet may be showing signs of an adverse reaction after a vaccination or medication, our vet and nursing team are available for advice and support to ensure the health of your pet.
We have been very satisfied with the safety of the Lepto 4 vaccine since we started using it. At Orchard Vets, your pet’s wellbeing is always our foremost concern, and we would never use a product if we were not satisfied with both it’s safety and it’s necessity. Our vets and nurses are always happy to discuss the recommended vaccine protocol for your pet based on their lifestyle and requirements, and come to a decision with you about what is right for your pet.
MSD Veterinary Manual – Leptospirosis in dogs.
2010 ACVIM small animal consensus statement on leptospirosis: diagnosis, epidemiology, treatment and prevention. Sykes et al, Journal of Veterinary Internal Medicine 25 (1) 1-13, 2011.
WSAVA Vaccination Guidelines 2015