Louping Ill Virus

Louping ill is a tick-borne viral disease that occurs mainly in the British Isles where Ixodes ricinusare found. It affects sheep, red grouse, cattle, goats, horses, llamas, alpacas, pigs, dogs, deer, European elk and humans. It can also infect a number of small mammals including shrews, wood mice, voles, rats, hares and rabbits.

Louping ill can be shed in the milk of goats and sheep. Red grouse can be infected by eating ticks, and pigs have become ill after they ingested raw meat from infected lambs. It can be spread by needles and surgical instruments. Louping ill virus can also be transmitted to humans via infected tissues or cultures.

Many animals may develop neurological disease and up to 60% of the flock can die. Louping ill has been known to infect humans since 1934. Humans can develop flu-like symptoms, encephalitis and/or neurological signs after exposure.

Humans can be infected with this member of the Flaviviridae family through tick bites or by contact with the virus in tissues or laboratory cultures. Louping ill virus may be transmitted through skin wounds, and aerosol exposure has been reported in laboratories. Iowa University College of Veterinary Medicine reports it might be possible to acquire this virus by drinking unpasteurized milk (especially goat milk).

Iowa University found Louping ill has been reported in sheepherders, veterinarians and others. "In people, this disease begins 2-8 days after exposure, as a nonspecific, influenza-like illness with symptoms such as fever, headache, joint pain and malaise. In the second stage of the illness, some patients develop meningoencephalitis or paralytic neurological signs that resemble polio. Hemorrhagic fever has also been reported. Deaths are very rare, but convalescence times can be prolonged."


There is currently a commercially available ELISA test for Louping ill.


Symptoms can include a flu-like illness, fever, headache, anorexia, muscle stiffness and dizziness. This stage tends to resolve in about one week. The later state can include symptoms such as: high fever, vomiting, severe headache, neck stiffness, drowsiness, paralysis, disturbance of bowel and bladder function, coma and tremor of head and limbs. A poliomyelitis-like illness has also been described.


There is no specific treatment for Louping ill. Some patients have been treated as if they had Tick Borne Encephalitis (TBE).


Iowa University, College of Veterinary Medicine.

Louping ill in a man: a forgotten disease

Wiki- The Free Encyclopedia

J Infect. 1991 Nov;23(3):241-9.


Louping ill in man: a forgotten disease.

Davidson MM1, Williams H, Macleod JA.

Louping ill disease of sheep has been recognised in Scotland for centuries. It causes encephalitis and is transmitted by the sheep tick, Ixodes ricinus. Human infection was first reported in 1934. Thirty-one cases of human infection have now been described.

Four clinical syndromes are seen, an influenza-like illness, a bi-phase encephalitis, a poliomyelitis-like illness and a hemorrhagic fever. Certain occupational groups, e.g. laboratory personnel working with the virus and those who kill injected sheep, are at increased risk of acquiring louping ill infection.

In many instances, infection is subclinical. Eight new human cases are described. Six were in crofters or shepherds in the north and west of Scotland, one was in a general practitioner in the Western Isles and the eighth was in a butcher in Edinburgh. Louping ill disease should not be forgotten in cases of unexplained encephalitis in those whose lifestyle exposes them to the virus.


Full article here: http://www.theoneclickgroup.co.uk/documents/louping_ill/Louping%20ill%20in%20man,%20Davidson.pdf

Last Updated- April 2019

Lucy Barnes