Neospora

What is it?

Neospora is a parasite-type organism that has been found world-wide in cattle and many other species.

Infection while pregnant can result in abortion in cattle but much less commonly in sheep. Dogs are the definitive host in the lifecycle of the parasite, ie one in which the parasite can produce eggs, known as oocysts.

Cattle may become infected by the ingestion of oocysts shed by infected dogs (horizontal transmission) or through parasite migration during pregnancy to the foetus from dams infected before their own birth (vertical transmission). Cattle infected with the parasite are 3-7 times more likely to abort than uninfected cattle. Vertical transmission of the parasite is very efficient and infected animals may pass the parasite to their offspring over several generations and in successive pregnancies.

Clinical Signs
  • Abortion, between 3 and 9 months of pregnancy (particularly 5 to 7 months)
  • Stillbirth or premature calves (occasionally with brain disease at birth)
  • No other signs are seen in the mother and repeat abortions are possible in the same cow.
Treatment

There are no licensed drugs for the treatment of Neospora infection in cattle. Nor are there any vaccines available in the UK.


Prevalence in UK

The parasite occurs worldwide where there are cattle, dogs or other suitable hosts. Bulk milk testing of around 500 GB dairy herds in 2012 has suggested infection levels of 51% – much higher than previously thought.

Impact

The economic effect of Neospora infection is associated with the cost of abortion, either directly as the loss of a calf but, just as importantly in the dairy industry, failing to get a cow back into milk, which may result in her experiencing prolonged dry periods. Financial modelling predicts the cost of Neospora in an average 121-cow dairy herd to be in the order of £3,000 per year.


Prevention/Control

Keep a closed herd and do not buy in any replacement stock; this will reduce the risk of introducing Neospora onto the farm. However, current diagnostic tests are not able to detect all infected animals.

Dispose of cattle tissues left over from a calving, or aborted foetuses, in a safe and timely manner. If infected with Neospora these pose a high risk of transmitting the parasite to dogs and other hosts, such as rodents or wildlife.

Prevent dogs from having access to calving areas or parts of the farm where pregnant cattle are kept in order to stop them becoming infected from eating placenta or abortion material.

Deny dogs access to areas where cattle feed is kept or fields that are used for grazing to prevent dog faeces, which could be contaminated with Neospora oocysts, being ingested by cattle.

If public footpaths cross the farm or fields used by cattle, then it is advisable to put up notices reminding dog walkers to pick up their dog’s faeces, to avoid passing on any infection to livestock


Sources
  • Neospora Report 2013 Commissioned by Wm Morrison Supermarkets plc and Arla Foods UK plc from
  • The Moredun Research Institute
  • The Moredun Research Institute website
  • NADIS
  • DairyCo