Maedi Visna (MV) is a highly infectious viral disease affecting goats and sheep. It is mainly transmitted through the ingestion of milk from a virus infected sheep, although disease can be spread within flocks through direct contact or contamination. The virus does not affect people and therefore there is no impact on human health.

Current Situation (October 2019)

The island of Ireland is currently free of MV, but the disease is widespread amongst sheep in most industrial countries, including Great Britain (GB).  A recent case of MV was detected earlier this year when two sheep were imported from GB into Northern Ireland (NI) from a MV non accredited flock.  Both sheep tested negative prior to import. Following post import checks, one sheep tested positive for MV.  Movement restrictions were placed on the holding and the sheep were destroyed without compensation. 

What are the clinical signs?

MV is an infectious, incurable and very slow developing condition which causes wasting and failing.  The main clinical signs are progressive paralysis, wasting, arthritis and chronic mastitis. MV has a long incubation period and cannot be detected early in an animal’s life.  The signs are not normally visible until adulthood. 


Keeping NI free from MV is vital for our animal health and trading status.  As part of its surveillance programme, the Department now samples any new arrivals into NI from outside the island of Ireland, for the presence of the disease.  Animals imported from MV non accredited flocks in GB will be sampled in isolation 5 months after importation.  Animals from MV accredited free flocks and from mainland Europe will be sampled on arrival. 

The Department would urge farmers to think carefully before importing sheep from GB or mainland Europe and remember that

  • Any sheep coming into NI from GB must either be from a flock that is accredited free of disease, or
  • Have been held in isolation for 30 days and tested for MV, with negative results, prior to import. (These sheep will also have to move into a pre-approved isolation premises and undergo a test at 5 months post import.)

Animals subsequently found to be infected with MV will either be re-exported or slaughtered without compensation. Movement restrictions will also be placed on the holding.

MV is a notifiable disease.  If you suspect disease you must inform your local DAERA Direct Office immediately.  Failure to do so can be deemed an offence.

For further information specific to the import of sheep and goats, please see the following link.

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