Forget the hooves, horns and teeth – the diseases livestock can transmit to humans can be debilitating and the effects ongoing.
Associate Professor Jackie Benschop from Massey University is an epidemiologist and veterinarian with an interest in the diseases at the human/animal interface. She says of the 15 most frequent notifiable diseases in this country, half are zoonoses which means they are transmitted directly to humans from animals – with many also being contracted from contaminated food and water.
Leptospirosis (lepto) is common, especially amongst farmers and rural people and the numbers notified are increasing with 141 cases notified last year, nearly three times the number of cases in previous years.
Jackie suspects there are between five and 10 times more cases of leptospirosis in NZ than what is being reported. Of those cases that are notified, 60 per cent will be hospitalised and one in three will go on to have persistent and often life-changing symptoms, including depression.
Any mammal can be infected by lepto and then infect humans. However, some animals are reservoir hosts. In New Zealand these animals are cattle, sheep, deer, rodents, pigs, possums and hedgehogs and while they can carry the lepto bacteria, it won’t necessarily make them sick.
Lepto sits in the kidneys and genital tract of an infected animal so people who come into contact with that animal’s urine are at risk of contracting the disease. But the bacteria can also live in the soil and water contaminated with animal urine.
Jackie says healthy, well-grown animals are at the greatest risk to people as they will continue spreading the disease through their urine, posing a risk to people working with those animals -particularly those milking, calving, lambing, shearing or slaughtering and processing stock.
The symptoms of leptospirosis include headache, flu-like signs such as muscle and gut pain –usually without respiratory symptoms, but lepto can present in many ways.
As leptospirosis lives in water, Jackie says spikes of the disease are often seen after flood events. The water-borne bacteria can enter the body through scrapes and wounds and through the mucous membranes.
Free-standing water or puddles can be a source of leptospirosis on any farm – this can include puddles around water troughs where animals may have urinated.
Jackie says the good news is there is plenty of management practices farmers can adopt to minimise the risk of contracting these diseases.
Protecting yourself against Leptospirosis
- Be aware of this disease and if you have flu-like symptoms tell your health practitioner that you have been exposed to livestock and say “could this be lepto?”
- Vaccinate. Jackie says farmers should vaccinate their animals to stop people getting sick. Over 95 per cent of dairy cattle are vaccinated but only between 12-15 per cent of beef cattle and 8-10 per cent of deer are vaccinated. Very few sheep are vaccinated, typically only those that are being milked. It is mandatory to have commercial pig herds under a lepto programme – usually this means pigs will be vaccinated. Protection against leptospirosis does require a full and on-going herd/flock vaccination programme. Even though not all lepto strains are covered by the vaccine the vaccine works well against those that are.
- Control rodents and possums and hedgehogs. They all carry strains of leptospirosis. Be cautious when emptying rodent traps, plucking possums or handling animal feed that may be contaminated by rodent urine.
- Protect yourself from animal urine. Wear protective clothing, cover wounds and wash thoroughly after handling animals.
- Be aware that water- flood or free-standing – is a potential source of leptospirosis.
Next week we will look at campylobacter and salmonella and other diseases that impact on the health of farming families and their staff.
Find out more
For more resources about Leptospirosis visit: