Dog owners are being urged to clean up after their pets to help stop the spread of a virulent parasite.
Cattle must be kept away from dog waste to avoid infection
The parasite, Neospora, is found in dogs’ faeces and, if they foul grazing land and pregnant cattle ingest the parasite, it will cause them to abort or give birth to calves infected for life.
Farming organisations and landowners, including the Yorkshire Dales National Park Authority, are trying to raise awareness of the Neospora parasite.
Alan Hulme, the Yorkshire Dales National Park Authority Ranger Services Manager, said: “We are urging all dog owners to make sure they clean up after their pets when they are walking in the National Park.
Alan Hulme YDNPA
Just one incident of a cow eating some of these parasite eggs can have a huge impact on a whole herd – and a farmer’s future livelihood.”
Cattle and dogs could die
Farmers are becoming concerned at the increasing number of cattle infected by this parasite and the resultant abortions in herds.
NFU Scotland Vice-President and qualified vet, Nigel Miller said in a recent article: “Dogs, whether working animals like the farm collie or pets whose owners are taking access on grazing land, are presenting a growing threat to the well-being of farm animals.
For those walking or working with dogs in the country, there is a need to recognise the danger that their animal may pose to the health of farm animals and ask them in particular to collect and deposit all faeces.
Link to raw meat
Research seems to indicate that problems observed in cattle may only be part of the story, as the life cycle of the Neospora Caninum parasite also involves other canids and raw meat.
NFU Scotland Vice-President, Nigel Miller
Initial infection can be acquired by ingesting food and water contaminated with oocysts excreted in the feces of dogs, or by ingesting infected tissues, or trans-placentally.
Transmission may therefore occur from dogs to cattle and vice versa.
Clinically the dog, or other canid, is what is called the definitive host and cattle are the intermediate host.
There are no effective control measures against the parasite so it is essential that dogs are not allowed to foul farm land which could be grazed by cattle.
Dogs should also not eat raw meat as this could complete the circle of infection and contamination.
Working dogs at high risk
Dogs, especially hunting dogs, can also die as a result of infection as can goats, deer and horses.
Puppies and young dogs seem especially susceptible to fatal infection.
Farmers should also ensure that they clean up after their own dogs to avoid spreading the parasite. High risk areas include feed and bedding stores and water troughs.
Neosporosis is often misdiagnosed as Toxoplasma Gondii.
Infected dogs often display muscle weakness, paralysis and other neurological symptoms within a few days of infection.
No danger to humans from Neospora Caninum
Skipton vet Andy Barrett, from the Kingsway Veterinary Group, stressed that there was no danger to humans from eating meat from an infected cow or drinking its milk.
Andy Barrett, Kingsway Veterinary Group
But he said: “Just one infected cow can have dire consequences on the profitability of a farm.
If cattle are infected during pregnancy, the result can be abortion, birth of a weak calf or birth of a normal-looking calf that is infected for life. These calves then transmit the parasite across the placenta to all their offspring for the rest of their lives and these offspring are themselves up to seven times more likely to abort.”
Abortions are very costly and they deprive beef farmers of a calf from the affected cow and in the case of dairy cows, lead to the loss of milk and a calf.
An abortion in a dairy cow has been estimated to lead to a financial loss of £1,200.
In addition, infected cattle can only be identified by expensive blood tests and there is no treatment for the infection.
Once introduced into a herd, the parasite is spread very efficiently to calves and the involvement of dogs is no longer necessary.
Dogs should not be fed raw meat
Some studies indicate one possible transmission route to dogs and other animals is via infected raw meat.
Cooking or freezing raw meat can kill off the spores.
Humans can not be affected due to the acid and other agents in the human stomach killing off the nasty bug. However, medical laboratories are constantly vigilant to the possibility of human infection.
Neospora discovery
Parasitologist Jitender P. Dubey is credited with the identification and naming of Neospora caninum in 1988.
He showed it could induce a severe toxoplasmosis-like disease in dogs and that the two diseases are often confused.
Research suggests that around 4% of dogs are hosts for the neospora parasite.
The first recognized outbreak of neosporosis abortion occurred in a New Mexico dairy and was reported in 1989.
Neospora warning signs
Infection in dogs is often via the placenta causing foetus death or infected pups. Older dogs can also become infected and exhibit symptoms which once observed can quickly prove fatal.
Some dogs may however just be carriers exhibiting few if no signs of infection.
Dog owners should seek immediate professional advice if their dog becomes lethargic, confused, unusually stiff or paralysed. Further details are available on the Helium website.
Further information
- Merck Veterinary Manual – Neosporosis
- University of Liverpool – Test for infection
- Neosporosis in Beagle dogs – Clinical signs, diagnosis and treatment
- Neospora caninum Sequencing – The Neospora caninum genome project at The Wellcome Trust Sanger Institute
- Lack of Serologic Evidence of Neospora caninum in Humans, England – Report
- NFU opens debate on dog threat to animal health – NFU Scotland
- NFU briefing note (.pdf) on Neospora
