A Dead Cert : Experiment 8
8. Pregnant mares deliberately infected with abortion-causing virus
Animal Health Trust (Newmarket)
A team of researchers based at the Animal Health Trust studied the immune responses of Welsh Mountain ponies – some of whom were known to be in advanced pregnancy – to infection with equine herpes virus (EHV-1). This virus is know to cause respiratory disease, affect the nervous system and may also lead to abortion.
Eleven foals and ten pregnant mares were used. Six of the foals, and five of the pregnant mares, were deliberately infected with the virus. A further 14 adult ponies were also infected. Some of these ponies had been previously experimentally infected once or even twice with EHV-1.
Blood samples were taken from all the ponies at regular intervals over a period of four months. The authors describe their results only in terms of the data revealed in the blood tests. There is no description of the clinical symptoms experienced by the ponies and no mention of whether any of the animals aborted during the study.
Comment: EHV-1 is easily spread between horses and, once infected, an animal may shed the virus during periods of stress.
Paillot R, Daly JM, Luce R, Montesso F, Davis-Poynter N, Hannant D, Kydd JH. Developmental & Comparative Immunology,2007; 31:202-214. Frequency and phenotype of EHV-1 specific, IFN synthesising lymphocytes in ponies: the effects of age, pregnancy and infection.