North American Veterinary Licensing Examination (NAVLE) Practice Test

What disease does sudden onset of profuse, watery diarrhea and marked depression indicate in a mare?

1. Colitis X

2. Equine viral gastroenteritis

3. Equine botulism

4. Salmonellosis

The correct answer is: Colitis X

The symptoms described—sudden onset of profuse, watery diarrhea and marked depression in a mare—are characteristic of Colitis X. This condition is a severe form of colitis that can present acutely and is often associated with a high mortality rate. The sudden onset of diarrhea indicates a significant inflammatory process occurring in the colon, often leading to rapid fluid loss and systemic effects such as depression. Colitis X can result from various etiologies, including certain bacterial infections, adverse reactions to drugs, or stresses, but it is important to note that it does not always have a clear infectious cause. The clinical signs displayed are typically severe, and the rapid onset requires swift veterinary intervention. Due to the severe nature of the diarrhea and systemic involvement, the presence of marked depression supports a diagnosis of this condition rather than other potential gastrointestinal diseases. While other options can also lead to diarrhea in equines, the dramatic presentation of both diarrhea and depression aligns most closely with the acute and severe nature of Colitis X. Other diseases may also involve similar symptoms, but they usually present with additional signs or milder symptoms that differentiate them from Colitis X.