A survey of dogs in the South Island of New Zealand for prevalence of positive MAT titres to Leptospirosis and urine shedding of Leptospira organisms

Farmers are all aware of the significance of Leptospirosis in cattle, but is the hard-working farm dog also at risk from this disease?

Leptospirosis is a disease of worldwide significance, both for its effect on companion animals, farm animals and wildlife. It has the potential to infect humans through contact with animal urine, contaminated water or at the meatworks. Common features of illness caused by leptospirosis in humans and animals include fever, loss of appetite, liver disease, jaundice, and kidney failure. These symptoms resemble those of many other illnesses, and it is possible that Leptospirosis is under diagnosed in humans, livestock and dogs.

Exposure to Leptospira organisms is common in dogs in New Zealand. A survey of New Zealand dogs in 2004 showed more than 10% of dogs tested had antibodies to serovar (‘strain’) Copenhageni. This serovar is maintained in the rodent population, and is spread to other animals by contamination of water or feed with rat urine. It is somewhat different from the strains Hardjo and Pomona which are commonly associated with infection of cattle (and also pigs and sheep). The same 2004 study suggested that farm dogs may be at increased risk of infection with serovars Hardjo and Pomona.

Diagnosis of exposure to Leptospirosis is usually based on detecting antibodies to leptospirosis in a blood sample. It is possible for cattle to shed leptospires in their urine despite having negative antibody tests, and it is theoretically possible for dogs to do the same. It is not known if the urine of infected dogs poses a significant risk of infection to humans or other animals, and whether farm dogs form part of the reservoir that enables leptospirosis to persist on a property. PCR is a new technique for identifying the presence of the leptospires in urine, blood or tissue. Thus technique, along with blood antibody tests, is being use in a current survey of working farm dogs.

Currently available Leptospirosis vaccines for dogs in New Zealand will stimulate immunity against serovar Copenhageni. These vaccines do NOT provide dogs with protection against the Pomona and Hardjo strains present in livestock; so further investigation into the risk of this disease for farm dogs and provision of a suitable vaccine is imperative.

Vaccines for cattle, sheep, deer, goats and pigs contain serovars Pomona, Hardjo and in some vaccines serovar Copenhageni.

Research into leptospirosis in dogs currently being conducted at the Massey University is focussing on several areas:

  • A survey of farm working dogs and South Island dogs to investigate the prevalence of exposure to leptospirosis.
  • Urine sampling and PCR testing of the same dogs to investigate the prevalence of urinary shedding of leptospiral organisms. This will provide further information on the potential for dogs to be involved with the transmission of Leptospirosis to other species
  • Research into vaccines that may provide dogs with protection against other strains of Leptospirosis.

This research involves collaboration and support from the Massey University Veterinary Teaching Hospital, Epicentre, the Leptospirosis Research Group, the Hopkirk Research Centre, the Centre for Service and Working Dog Health and the New Zealand Veterinary Association’s Companion Animal Health Fund.

Contact Person
Name: Alison Harland
Email address: a.l.harland@massey.ac.nz