The Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) reported Sept. 23 that a recent slew of positive West Nile virus (WNV) tests have increased the total number of equine cases in that state to 19.

As of Sept. 18, the TVMDL confirmed that a horse in each of the following counties has tested positive for WNV:

  1. Houston County
  2. Atascosa County
  3. Jefferson County (two cases)
  4. Roberts County
  5. Sterling County
  6. Parker County
  7. Randall County
  8. Liberty County
  9. Scurry County
  10. Hutchinson County
  11. Taylor County
  12. Nolan County
  13. Trinity County
  14. Robertson County
  15. Midland County
  16. Orange County
  17. Harris County
  18. Victoria County

The affected horses range in age from a yearling to more than 10 years old. As with earlier reported positive cases, the majority of the affected horses were not previously vaccinated against WNV.

[brightcove videoid="3151235477001" title="Health Alert: West Nile Virus"]

West Nile is transmitted to horses via bites from infected mosquitoes. Clinical signs for WNV include flulike signs, where the horse seems mildly anorexic and depressed; fine and coarse muscle and skin fasciculations; hyperesthesia (hypersensitivity to touch and sound); changes in mentation (mentality), when horses look like they are daydreaming or "just not with it"; occasional somnolence (drowsiness); propulsive walking (driving or pushing forward, often without control); and "spinal" signs, including asymmetri