Leptospirosis in the UK is not a reportable disease. The vaccines do not and never have prevented your dog from catching Lepto. If you choose to not to vaccinate your dog has the very small risk of catching lepto which if caught early enough is treatable with appropriate antibiotics.

However, If you choose to vaccinate because of your dogs lifestyle you feel warrants it, be aware your dog then has two risks one of still catching lepto the second the risk of an adverse reaction. There are several hundred dogs on this site who have had an adverse reaction after vaccination. The number of strains in the vaccine title is irrelevant.

Leptospirosis is an infectious disease that causes serious illness in dogs, other animals, and people. The disease is caused by spiral-shaped bacteria called leptospires that live in water or warm, wet soil, puddles, ponds, lakes, reservoirs, canals and another infected dog. The bacteria mainly comes from the urine of rats, pigs and cattle, which makes farms the most likely place for the disease to be transmitted.

Symptoms: High temperature, loss of appetite, vomiting, lethargy, depression, muscle pain, diarrhoea and blood in the urine. Leptospirosis affects the liver and the kidneys so watch out for excessive drinking and urinating, yellow eyes and persistent vomiting.


Leptospirosis can pass to humans cause serious illness. Lepto in people is also known as Weil’s disease. If you have concerns that you or someone you know may have Leptospirosis, it is best to contact your doctor or the NHS for advice.

If your dog has a mild case of Lepto, your vet may be able to use antibiotics, a fluid drip and other medicines to help fight the disease.

Dogs with lepto must be treated in isolation to prevent them spreading it to other pets or hospital staff. Even after they’ve recovered, dogs with Lepto can keep spreading the bacteria in their urine and remain a risk to other pets and people for some time.

If you suspect that your dog has contracted leptospirosis, contact your vet immediately. There are a few different types of leptospirosis bacteria and each one is slightly different. Fortunately, we can vaccinate against the types of lepto bacteria commonly found in the UK.

Leptospirosis know the risks

Leptospirosis (lepto) is a bacterial infection with some 200 different variants (serovars). The vaccine contains 2 or 4 strains. The risk of your pet contracting lepto is dependent on three factors: climate, geographic area and lifestyle.

A lepto vaccine is usually given to your dog at the same time as either a DHP or DHPPi vaccine, commonly called a “booster” or annual vaccination. The lepto part of the vaccine is a liquid and is given this way to act as a dilutant for the powder form of DHP/DHPPi. Saline solution can be used instead.

Because of this combination it is impossible to isolate which part of the vaccine has caused an adverse reaction should your pet suffer one. This allows manufacturers to evade their responsibilities. The vaccine needs to given at a separate time and in isolation. Any adverse reaction should be reported to the VMD and if your vet won’t do it, then do it yourself. https://www.vmd.defra.gov.uk/adversereactionreporting/

The vaccine does not prevent your pet from catching leptospirosis. The vaccine is designed to reduce shedding of the bacteria in an infected animal, because the disease is zoonotic and can be transferred to humans. Read the Summary of Product Characteristics leaflets. However, it is not a notifiable disease. Sewer workers in the UK aren’t given this vaccine due to the side effects so why should we give it to our pets? It’s perfectly treatable with antibiotics (doxycycline).

The incidence of leptospirosis in the UK is very rare, with most human cases in the UK being contracted in foreign climates. See Gideon’s Year Book – it records bacterial infection worldwide.

A peer reviewed research paper by Christopher Ball at the Liverpool University Veterinary School sponsored by MSD manufacturer of Nobivac/Canigen to show how prevalent leptospirosis was in the rodent population in the UK was published. Do google and read it: it failed.

Leptospirosis is difficult to isolate. It does not survive on dry land and your dog would have to swim in a pond or drink water just after a rodent excreted it. It is also difficult to test for, with two tests available:

1) MAT test. Once vaccinated, the patient’s serum can no longer be a useful record for diagnostic tests, as the serum antibody titre from the vaccine cannot be distinguished from antibody caused by natural infection.

2) PCR test. Effective testing is now done via the PCR DNA test ; the actual organism is retrieved from either blood or urine.
If your vet tells you that there have been recently diagnosed cases in your area be sure to ask which serovar was confirmed – it may not even be one included in the vaccine.

Adverse reactions to the L4 vaccine including bad reactions / ailments / disease / premature death from leptospirosis vaccines are quite diverse. Some documented reactions include *:
• Lymphadenopathy [enlarged lymph nodes]
• Infections with flesh-eating bacteria
• Urinary tract infections
• Uncontrollable pruritis
• Chronic weight loss
• Mast cell disease
• Enlarged spleen
• Kidney failure
• Dehydration
• Polyarthritis
• Anaphylaxis
• Pancreatitis
• Liver failure
• Screaming
• Dermatitis
• Lameness
• Anorexia
• Vomiting
• Diarrhea
• Lethargy
• Cancer
• Fever
*Source: Leptospirosis Vaccination: A False Sense of Security https://bit.ly/30YvLAI; Dr. Patricia Jordan, DVM, CVA, CTCVH & Herbology, holistic veterinarian, world-renown vaccine researcher and author of “Vaccinosis: The Mark of the Beast” and “Emotions and “Biological Harmony in Humans and Pets

This information is not meant to be a substitute for veterinary care. Always follow the advice provided by your veterinarian.