Leptospirosis, or lepto as it is commonly called, is a zoonosis – i.e. a disease of animals that can be transferred to humans
The disease in cattle
Cattle and other livestock can be carriers of their own lepto serovar without showing any symptoms but all serovars can cause disease in humans. In dairy cattle lepto infection may cause abortion storms, redwater, a drop in production, rarely mastitis and in calves it can be fatal.
The disease in humans
There are a wide range of symptoms of lepto in humans ranging from mild flu-like symptoms through to meningitis and death. Other symptoms include severe headaches, fever, muscle pain, jaundice (from liver damage), photosensitivity, nausea and vomiting. Lepto can damage the kidneys and liver and patients often require hospitalisation. There have been some deaths.
Apart from the long-term health implications for the individual, the farm owner/employer may also face prosecution if they have failed to take all reasonable measures to protect their staff.
The epidemiology of lepto
Lepto is a bacterium. It can survive in water and soil for long periods in the right conditions (moist and out of sunlight). Animals infected with lepto will shed it in their urine. Humans can become infected through the membranes in their mouth, nose and eyes and through cuts in the skin. A vaccination programme is a really important part of preventing human and stock infection but staff education on the disease and the hygiene measures they can take to protect themselves is also vital.
All classes of stock need to be included in the vaccination programme.
Many years ago, Massey did a study where 30 herds in the Manawatu, who were vaccinating for lepto, had samples collected from multiple cows and those samples were checked for lepto. They found one or more cows shedding lepto in 10 of the 30 herds. That means in 10 of those herds that they felt were fully protected their staff were exposed to lepto when they came to work. Does this mean that lepto vaccination is a waste of time? No, because without it, we’d have the equivalent of the pre-vaccination days – probably closer to 25 or 30 out of 30 herds infected. A properly planned and executed lepto vaccination program will take the risk down but it never goes away fully.
And that’s why lepto vaccination, whilst an important part, is never the whole part of a lepto risk management program. We need to lay down multiple barriers to people becoming infected. We need to think of every cow as infected and stop her urine from getting onto our bodies and those of susceptible animals. This involves training staff, management of effluent and making sure they have the tools, like PPE and first aid kits, to protect themselves.
Vets spend hours crafting lepto management plans with our clients each year. They could take the form of a Leptosure consult, as a program devised by the clinic, or as a bespoke plan made for an individual farm. One drawback is that you won’t have any way to gauge whether your plan is working – until it’s too late – because our only feedback that it is not working is that someone has got sick (and even then, there’s the chance you tried your best). The good thing is that most of the facts about transmission of the disease are old, so the vet can use their knowledge and wisdom to advise what is appropriate – and sign to say they said so. That should cover you in the case of Worksafe coming knocking.
In a world where there is a lot of paperwork it would be easy to discount a lepto management plan as just another red tape exercise. But it’s also a world where staff are in short supply, so we have got to prioritise keeping them healthy and safe. If you’ve got any concerns talk to your vet now about lepto management on your farm.