Leptospirosis in Aotearoa New Zealand: A Growing Threat with a Human Face

Leptospirosis in Aotearoa New Zealand: A Growing Threat with a Human Face

Leptospirosis, a bacterial disease once thought to primarily affect farmers and meat workers, is now emerging as a broader public health concern across New Zealand. Recent research, community initiatives, and personal stories are painting a clearer picture of how this disease is evolving—and why awareness is more important than ever.

New Research: Risk Factors Are Changing

A nationwide study led by Massey University has revealed that leptospirosis is no longer confined to traditional farming roles. The disease is now affecting people in non-traditional occupations, with environmental and behavioural factors playing a larger role in transmission.

• Uncovered cuts or scratches while working with livestock
• Not wearing gloves during on-farm slaughter
• Cleaning urine or faeces from yard surfaces
• Using untreated water from creeks, streams, or rainwater
• Rodent exposure, which is becoming a more prominent source
• Livestock carrying strains not covered by current vaccines

Climate and Flooding: A Perfect Storm

Flooding events—like those following Cyclone Gabrielle—have been linked to spikes in leptospirosis cases. The bacteria thrive in moist environments, and contaminated floodwaters can carry the disease into homes, workplaces, and recreational areas.

A Farmer’s Story: “I Thought I Had a Chill – It Was Leptospirosis”

In a recent NZ Herald Listener article, a Kiwi farmer shared his harrowing experience of being diagnosed with leptospirosis. Initially mistaking his symptoms for a common chill, he soon found himself battling a life-threatening infection. His story highlights how easily leptospirosis can be overlooked, especially in rural settings.

Why We Vaccinate Dogs Against Leptospirosis

Dogs are not only vulnerable to leptospirosis—they can also transmit it to humans. In New Zealand, the main host animal for canine leptospirosis is the rat, and dogs can become infected through contact with contaminated water, soil, or food bowls.

• Loss of appetite
• High fever and shivering
• Vomiting and collapse
• Jaundice (yellow gums or eyes)
• Kidney and liver failure

Even if treated, dogs may shed the bacteria in their urine for months, posing a risk to other animals and humans.

Vaccination is the best prevention. Dogs should receive:

• A primary course of two vaccines, given 2–4 weeks apart
• Annual boosters to maintain immunity

Understanding Leptospira Strains: NZ vs. Global Coverage

Leptospirosis is caused by Leptospira bacteria, which come in over 250 different strains (called serovars). These strains vary by region and host species.

In New Zealand, dogs are most commonly exposed to:

• Copenhageni (from rats)
• Pomona and Hardjo (from livestock)
• Tarassovi (emerging in cattle)

However, the standard dog vaccine in NZ (e.g., Nobivac Lepto 1) only protects against Copenhageni, which is derived from the serovar Icterohaemorrhagiae. This means dogs may still be vulnerable to other strains like Pomona or Hardjo, especially in rural or farming environments.

In other countries, particularly North America and Europe, dog vaccines often cover four serovars:

• Canicola
• Icterohaemorrhagiae (Copenhageni)
• Grippotyphosa
• Pomona

This broader coverage reflects different regional risks and wildlife reservoirs. However, even these vaccines don’t cover all strains, and cross-protection is limited. That’s why environmental management, rodent control, and awareness remain essential alongside vaccination.

Community Action: Rural Women NZ Steps Up

In response to the rising threat, Rural Women New Zealand has launched a national project in partnership with Massey University to raise awareness and funds for better disease control.

Their goals include:

• Mobilising rural communities to spread awareness
• Encouraging early diagnosis
• Promoting protective practices
• Funding further research into human, animal, and environmental transmission

Final Thoughts

Leptospirosis is no longer just a farmer’s disease—it’s a community issue. With changing climate patterns, evolving risk profiles, and deeply personal stories like that of the NZ farmer, it’s clear that education, prevention, and early intervention are key.

Whether you're working on a farm, enjoying the outdoors, or caring for pets, understanding the risks and taking precautions—like vaccinating your dog with the full two-dose course—can make a life-saving difference.