North American Veterinary Licensing Examination (NAVLE) Practice Test

Which disease is suggested by swollen muzzles, mucous membrane erosions, high fevers, and lameness in sheep and deer?

1. Bluetongue

2. Peste des petits ruminants (PPR)

3. Caprine arthritis encephalitis

4. Foot-and-mouth disease (FMD)

The correct answer is: Bluetongue

The clinical signs described—swollen muzzles, mucous membrane erosions, high fevers, and lameness—are characteristic of bluetongue disease, which primarily affects ruminants such as sheep and can also impact deer. Bluetongue is transmitted by biting midges, and its symptoms align with the presentation of vesicular lesions and inflammation, particularly affecting the skin and mucous membranes of the head and oral cavities of infected animals. While peste des petits ruminants (PPR) does cause systemic illness with respiratory signs, it typically does not present with the pronounced vesicular lesions on the muzzle or erosions of the mucous membranes that are seen in bluetongue. Caprine arthritis encephalitis primarily affects goats and leads to chronic conditions rather than acute symptoms such as high fever and acute lameness. Foot-and-mouth disease (FMD) also causes vesicular lesions but is most commonly associated with cattle and has a broader range of systemic signs affecting multiple species, often including young animals more severely. Therefore, the presence of the unique clinical signs associated specifically with bluetongue makes it the most fitting disease for this scenario in sheep and deer.