It is possible. Its not an airborn disease and is caught by contact of the mucous that comes from the nose or thats released from the abcess itself.
It is highly contagious and all persons should wash their hands, boots and any equipment that has come into contact with an affected horse.
Ive had strangles on my yard a few times now and its an awfull disease but once they've had it its highly unlikely they will get it again.

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