Meat workers may contract leptospirosis from sheep

New Zealand Veterinary Association

Media release

25 June 2008

Study shows meat workers may contract leptospirosis from sheep

New Zealand has one of the highest rates of human leptospirosis in the developed world. The disease, which is passed to humans through the urine of sheep, cattle, pigs, rodents and deer, can attack the kidneys and liver and, in some instances cause death.

But the risk of contracting the disease is just part of the job for many New Zealanders. Meat workers, inspectors, farmers and veterinarians are among the most common occupationally-exposed groups.

Following the death of a meat worker last year from the disease, and with an increase in the number of cases of leptospirosis in meat workers in the Hawke’s Bay, veterinarians at Massey University’s EpiCentre have embarked on a co-operative study with meat company Silver Fern Farms (formerly PPCS).

Findings from the research, carried out in February and March this year at the meat company’s Takapau plant, will be presented to veterinarians at the New Zealand Veterinary Association conference this week.

Massey’s Dr Jackie Benschop says the research started with a visit to the plant late last year to find volunteers.

“We were delighted with the response from the workers, and ended up testing 242 people out of about 700 – which gave us a great sample size.”

Workers at the plant had occupational exposure to sheep only.

“In the last 20 years there has been a big push to vaccinate dairy cattle and pigs against leptospirosis, but exposure from deer, beef cattle and sheep is also high.

“Our results add weight to the hypothesis that sheep are an important source of leptospiral infections to humans.”

Testing involved interviewing workers and taking blood samples. Results showed that 23 people tested positive to antibodies for Leptospira serovars pomona or hardjo-bovis and one tested positive to both.

“The Takapau study, on a group which was thought to be lowly infected, showed that about three percent of workers may get infected with Leptospira every year,” says Massey University Associate Professor Cord Heuer.

The study looked at workers from all areas of the meat works, including those in less exposed areas, like the cutting floor and boning room.

The results from detailed analysis of the data will be released at the conference this week. These should shed light on whether suspected risk factors, such as handling kidneys, are important in workers’ exposure to the bacteria.

Dr Heuer says the incidence of Leptospirosis is likely to be massively under-reported.

“Although half of the people who present with the disease go on to be hospitalised, leptospirosis commonly presents as a flu-like illness initially. Given that those most likely to be infected are working age men in a rural environment, many may not seek healthcare assistance.”

The researchers attended a meeting with the Department of Labour, ACC and other stakeholders.

“It’s been really nice to have a multi-disciplinary approach – including veterinarians and scientists interested in the human-animal interface, medical doctors, Government departments, the meat company and the meat workers union,” says Dr Benschop.

“There have been a number of different stakeholders, bringing together a diverse group of people with a common goal”

She says one of the biggest supporters of the research has been Rural Women New Zealand.

“They’ve given us tremendous support. Over the last year they’ve made leptospirosis their national fundraising cause and as a result presented us with a cheque for $87,000.”

While the donation will go a long way to funding a much-needed student to carry out further studies, funding for the research remains a huge issue.

“We haven’t had any guarantees as to where the funding will come from, but our first round of retesting needs to be completed before the end of the slaughter season in August, which means the next phase of the research really has to be done now.”

ENDS … //

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