The Horses of Follyfoot — Monica Dickens

Dora is invited out to America to help set up a home of rest for horses. When she leaves and is given a horse to take back to Follyfoot, she can't believe her luck. But once they're home things start to go badly wrong. One of the horses falls ill. And it looks like the same epidemic that is sweeping America . . . Has Dora's horse brought the disease to England?