Veterinary advice: Zoonotic disease goes from cats to sheep... to humans

Recently, I was talking here about zoonotic diseases. Today I have another important zoonotic disease for you, toxoplasmosis in sheep.
Veterinary advice: Zoonotic disease goes from cats to sheep... to humans

I read an interesting article lately, written by Dr Susan Rodgers, BVMS (Hons), MRCVS, who has researched this disease at the famous Moredun Institute in England.

As we all know, this is one of the major causes of abortion in sheep.

It also causes stillbirths, mummified lambs and the birth of weak lambs, depending on the time of pregnancy that the ewe becomes infected.

Unfortunately, it also causes abortion in pregnant women who come into contact with it, either by handling infected material or by being around sheep especially at lambing time.

Toxoplasmosis does not spread from one ewe to the next, but needs an intermediate host.

Cats, and more often kittens, are a very common intermediate host.

The cat may eat some persistently infected small animal, like a mouse, and the Toxoplasma reproduces in the gut of the cat, and develops into the infective stage, before passing out in the faeces onto the food (concentrates, hay, grass) or water that the sheep eats or drinks.

Cuts and scratches are also an avenue for the infection to enter either the human or the sheep.

A funny thing about toxoplasmosis is if a ewe has twins, then only one lamb is affected.

Weakly lambs may survive for a few weeks before dying and often have a weak suck.

Ewes that have had an abortion due to toxoplasmosis develop immunity to toxoplasma, and will not abort again due to this disease.

Apart from the obvious clinical signs, diagnosis can be confirmed by getting your vet to blood sample ewes that have abortedm,

and also by sending the aborted lambs and afterbirths to the laboratory for post mortem examination.

You must book this through your local vet.

So how do you prevent this serious disease from affecting your flock?

Biocontainment (if you already have toxoplasmosis) and bio-exclusion (if you do not have it) are the buzz words.

If you already have toxoplasmosis on your farm, then you must remove all infected material (aborted foetus, afterbirths, etc), and vaccinate all breeding ewes, at least three weeks before breeding.

Like all medications and vaccines, the accompanying information leaflet should be read and carefully adhered to, as it is a serious risk to human health if not used properly.

The manufacturer advises the use of gloves and even goggles when using this product.

Pregnant women should have nothing at all to do with this vaccine, as it is a live vaccine, and can cause abortion in humans.

Once the ewe is vaccinated, she does not need a booster for two years, which is a great help, economically.

This booster shot should again be given at least three weeks before breeding.

On farms that have cats, vaccination of the cats might be a good idea.

Controlling the numbers of cats on your farm might also be considered prudent, so having them neutered, to prevent a load of unwanted kittens, could be considered.

If you do not have Toxoplasmosis on your farm, then you must keep it out by not buying in infected hoggets or ewes.

Buy from a known source that you can trust, a source that you know does not have Toxoplasmosis, and lastly, vaccinate your flock.

If you have not vaccinated your ewes, and you find yourself in the midst of an abortion storm caused by toxoplasma, then certain antibiotics have been shown to have an effect on the disease.

If you find yourself in this situation, then talk to your vet about what you can do to control the outbreak.

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