North American Veterinary Licensing Examination (NAVLE) Practice Test

The scenario describes a situation where a commercial pig farm is facing high mortality due to a respiratory disease affecting young pigs, which aligns with the characteristics of Actinobacillus pleuropneumoniae. This bacterium is known to cause pleuropneumonia, particularly in pigs that are less than six months old. The disease is often associated with acute outbreaks leading to high mortality rates, especially in nursing or weaned pigs, as their immune systems may not be fully developed to combat the infection effectively.

Actinobacillus pleuropneumoniae is an important pathogen in swine that can lead to severe pneumonia, characterized by sudden deaths, especially in young animals. The clinical signs commonly seen include high fever, respiratory distress, coughing, and, in severe cases, death can occur within hours of the onset of disease.

In contrast, while the other conditions listed may also affect pigs, they are less likely to cause the specific pattern of high mortality observed in young pigs under commercial farming conditions. For instance, Fusobacterium necrophorum is more commonly associated with necrotic laryngeal laryngitis or foot rot, rather than a widespread respiratory outbreak. Mycoplasma hyopneumoniae typically causes