ESPECIALLY AT LAMBING TIME
RISK FOR ZOONOSES ISHIGH,
ESPECIALLY AT LAMBING TIME
Risk of infection from zoonotic
sheep diseases is especially
high at lambing time.
Hannah Velten investigates
the main diseases likely to
be transmitted to humans
and precautions to take
against infection
EFFECTIVE hygiene controls and safe working practices are the key to preventing zoonotic infections at lambing. However, controlling disease in stock reduces risk as well as making economic sense.
All employers and self-employed people are legally required to assess the risks to health involved with lambing, prevent exposure to zoonoses, introduce control measures and inform lambing staff of risks and precautions to take, says Neil Craig of the Health and Safety Executive.
The most publicised zoonoses are enzootic abortion, toxoplasmosis, campylobacter and listeriosis, which can cause abortion or flu-like illness in pregnant women. "Although infection is uncommon, the risk is well known among farmers," says Mr Craig.
Some control is possible by vaccinating at-risk ewes before tupping, checking bought-in ewes and avoiding contact between pregnant women and infected afterbirth, which includes soiled work clothes.
"To avoid spreading infection between stock, isolate aborted ewes and be scrupulous about hygiene practices especially when handling still-born lambs and afterbirth – which should be burned or buried – as they can remain infectious for several days," says Ian Davis of Veterinary Laboratories Agency, Shrewsbury.
Contact with sheep dung is also a common way of picking up infections, such as E coli and cryptosporidioses, which are carried by stock. These infections will cause diarrhoea, fever and abdominal pains in humans but stock will usually show no symptoms, says Mr Craig.
"Ensuring high standards of stock and personal hygiene at lambing will prevent infection through dung and urine.
"Try to prevent animals carrying or excreting large numbers of organisms by isolating animals with diarrhoea, keeping housing clean and drinking water free from dung. And keep animals as stress-free as possible because stress will cause them to excrete extra bugs."
Staff washing
Employers should provide washing facilities for staff at lambing – at least clean, running water and paper towels. Gloves should also be used when aiding a lambing, says Mr Craig. "Any protective clothing should be cleaned properly between use and replaced regularly, and never re-use disposable gloves."
To avoid infection some traditional practices, such as mouth-to-mouth resuscitation of new-born lambs, need to be replaced by more hygienic methods, such as massaging or clearing nostrils with straw.
Open wounds should also be covered with waterproof dressings, however, the HSE recommends preventing lesions in the first place, which would include disposing of used needles in a sharps box rather than in the bin.
Q fever can be a particularly harmful infection caught from sheep, with human symptoms ranging from mild illness to pneumonia or even liver and heart valve damage. It is transmitted by contact with animals or their products, such as raw milk or inhaling dust contaminated with birth fluids, dung or urine.
Vaccinating ewes against orf is one way of preventing this virus in humans, another is covering cuts and abrasions on hands and arms. Orf lesions occur on sheep and lambs, particularly around the mouth and on the ewes udder, warns Mr Davis.
Mr Craig also advises caution. "People think orf is a minor health problem, but it can have a systemic effect and spread throughout the body. People also need to be aware that orf virus can also live on wool, fencing and hedges."
Ringworm is occasionally seen in sheep and infected stock should be treated. However, the fungus can enter the human body through wounds. "Infections can even occur around shirt cuffs, where they rub on arms," says Mr Davis.
The majority of zoonoses produce flu-like symptoms in humans and to avoid mis-diagnosis, doctors should be told that there has been contact with sheep. Infections are more likely to occur in young children, the elderly, people without a spleen and those with transplanted organs.
When inviting the public on to a farm at lambing time, aside from controls already discussed, further precautions need to be taken, says Bob Clay, livestock lecturer at Sparsholt College, Hants.
Risk awareness
"People must be made aware of the risk of zoonoses before they come on to the unit, especially pregnant women. When advertising a lambing day, the advert could contain warnings, but be sure to maintain a balance between scare-mongering and raising awareness," he says.
Warning signs should be placed outside buildings, additional washing facilities must be set up on site – close to the lambing area – and parents or teachers should check that children do not put fingers in their mouths after touching lambs, he advises. *
ZOONOSES
• Control disease in stock.
• Safe working practices.
• Ensure personal hygiene.