EQUINE RABIES
Some content Published in Equine Disease Quarterly - Submitted by Dr. Martin English

The number of horses with rabies each year is usually between 13 and 47. The number of cases in 2014 reflected 25 of the 9 million horses in the United States contracted rabies and in 2018, the CDC reported 13 cases of rabid horses and mules in the United States. These figures represent only lab confirmed cases since not every neurological horse which dies is submitted for necropsy and rabies testing.

A variety of Clinical signs occur in rabid horses, such as behavior changes ranging from aggression to depression, ataxia, paresis, hyperesthesia (hypersensitivity to stimuli), fever, colic, lameness, and recumbency. With such a variety of clinical presentations, diagnosis in the live animal is difficult. The disease usually progresses to death in four to five days, although survival to 15 days is possible. Rabies is 100% fatal in horses and most other domestic species. Diagnosis is made on lab testing of tissues taken at necropsy.

There are several reservoirs of the rabies virus in the U.S.: raccoon, skunk, fox, bat and coyote. Wild animals were the source of 7,899 (93%) of all rabies cases in 1997, with raccoon being the most frequently detected (4,300), followed by skunks (2040), bats (958), and foxes (448). Most of the rabid raccoons were found in 19 states along the eastern seaboard, east of the Ohio River in the North and east of the Appalachian Mountains in the South, where there is currently an epizootic of raccoon rabies.

In general horses are assumed to be infected with the predominant variant of rabies found in their home area, raccoons in the east; skunks in the central United States. However, in 1994 one Kentucky horse was confirmed to have been infected with bat rabies. Specialized testing of the brain tissue to determine the source of rabies is routinely done in humans, but is not commonly performed on animals.

Rapid bats were found in 46 of the 48 contiguous states and pose a threat to horses, other mammals and people. Four cases of human rabies in 1997 were the result of rabid bat exposure and 19 of 21 human cases of rabies in the US from 1990-1997 were due to the bat rabies variant. The CDC currently recommends rabies prophylaxis for people who awaken to find a bat in the room, or for unattended children, mentally disabled in incapacitated people found in rooms with bats.

Although bats are nature’s form of insect control, building and maintaining bat houses around homes and animal housing is discouraged. Rabies vaccines are licensed for use in horses, cattle, sheep, domestic cats, dogs and ferrets. Equine vaccination should start at three months of age and annually thereafter.

Contact our office to set up a vacination schedule for your equine family!