Lecture 2 Tully

Determining the Seroprevalence of West Nile Virus in an Exposed Psittacine Population

Presenting Author: Thomas N. Tully, Jr., DVM, Dipl ABVP (Avian), Dipl ECAMS

Department of Veterinary Clinical Sciences, Louisiana State University School of Veterinary Medicine, Baton Rouge, LA

Interpretive Review and comments by Dr. Nemetz:

West Nile Virus (WNV) has been a large concern in the United States since its first recorded deaths of bird species in 1999. Over 150 avian species have been reported to the Centers for Disease Control and Prevention's West Nile Virus avian mortality database. Humans can contract WNV, but must be infected by the feeding of an infected mosquito. We cannot get WNV from bird species or other end hosts. How prevalent is it in our Psittacine species? Dr. Tully presented a case that could demonstrate an answer.

Dr. Tully found there were only two confirmed deaths of psittacine birds in the State of Louisiana for the entire year of 2002 and both birds were from the same facility. The other exotic psittacine birds at the facility were tested for antibody reaction to West Nile Virus and shown to be not infected.

Conclusion:

The good news is that Psittacine birds appear to be less susceptible than many other species of birds. Clients have asked if there is a vaccine. The answer is yes, but the vaccine is only approved for horses. It is NOT approved for pet birds and Dr. Nemetz would not recommend the risk knowing the results of Dr. Tully's work.

2004 Update from the AAV Conference:

WNV is an arthropod-associated viral disease transmitted predominately by the Culex species mosquitos. It was first introduced into New York Ciy in 1999 and gradually has spread west across the United States, with new reported cases, summer 2004, occurring in states West of the Rocky Mountains. Dr. Redig from the Raptor Center, College of Veterinary Medicine, University of Minnesota reconfirmed past information and presented new information regarding WNV.

  1. Grey-horned Owls are most susceptible to WNV fatal outcome
  2. Red-tailed Hawks and Crows are highly susceptible
  3. Exotic psittacine avian species still seem resistant to mortality caused by WNV
  4. Mosquitos are the ONLY carriers of WNV
  5. Humans CANNOT contract WNV from their pet birds, wild birds, or any end host species
  6. A vaccine produced for Red-tailed hawks shows promise for an avian-specific vaccine in the future
  7.  A serologic test for WNV is available. The BIRD Clinic can now test suspected carriers or cases with neurologic symptoms. Please call the clinic for more details
  8. Safeguarding your environment against mosquito breeding (standing water) is your best prevention against WNV exposure.
  9. Not all individuals that contract WNV die of the disease and over time more and more species are becoming more resistant to mortality from infections.

Upon returning from the AAV conference, Dr. Nemetz confirmed the first case of WNV in a jenday conure. A cockatoo and rosella have also been infected. Like Dr. Tully's findings in 2002, some Psittacines will be afflicted by WNV, but the case number will be few compared to the other species previously mentioned.