# Presentation: 053476

## A National Surveillance System for West Nile Virus in Zoological Institutions 

- Dominic Travis, Lincoln Park Zoo Tracey McNamara, Wildlife Conservation SocietyAmy Glaser, Animal Health Diagnostic Lab, Cornell UniversityRoy Campbell, DVBID, CDCDuane Gubler, DVBID, CDC

## Background

- June 2001 meeting
- The National West Nile virus Zoological Surveillance system working group
- Guidelines: *Surveillance for West Nile Virus in Zoological Institutions*
- One-year pilot study for national zoological surveillance (Aug ’01 – Aug ’02)
- Objectives
- Affordable/reliable testing for zoos
- Novel data source for national surveillance
- Increase relationships btw PH and Zoos/Vet Med

## Sampling Scheme

- Phase I:
- Begun August 2001 – current
- Solicited tissue/blood samples from **ill/dead** at-risk animals found on zoo grounds (captive/local wildlife)
- At-risk animals = any animal (any taxa) housed outdoors and at risk of mosquito exposure

## Sampling Scheme (cont.)

- Phase II:
**Serosurvey** of at-risk animals
- Entire country w/emphasis on emerging region
- Archived serum/plasma 6 months prior to first known positive in each state
- Opportunistically collected blood samples from **healthy** animals
- Seropositive follow-up to evaluate long term sequelae of WNV exposure
- Data on varying susceptibilities and rates of WNV seroconversion in zoo species and indigenous wildlife.

## Diagnostics

- Animal Health Diagnostic Laboratory at Cornell University, College of Veterinary Medicine performs all tests required for the project.
- Tissues are tested by RT-PCR and virus isolation
- Serum and plasma tested for virus and/or antibody, depending on history

## Looking for Virus

- RT-PCR for WNV
- Positives confirmed with virus isolation or second independent RT-PCR
- All tissues processed for virus isolation
- Identification of all viruses observed
- Avian reovirus

## Looking for Antibody

- Screen serum or plasma at 1:40 by PRNT
- Positives are titrated to a dilution of 1:640 against WNV and SLE

## Results Aug 1, 2001 – Feb 28, 2002

- Over 1,450 animals tested
- 967 birds (195 species)
- 40 equids (8 species)
- 436 other mammals (110 species)
- 20 reptiles (6 species)
- 64 participating institutions ( 20 more will submit in spring ’02)
- 30 states including the District of Colombia

## Sample Distribution

- Sample Distribution

## Slide 10

## Confirmed Results

- 30 WNV antibody-positive birds (1 wild, 29 captive)
- 29 WNV virus-positive birds (16 wild, 13 captive)
- 1 WNV antibody-positive reptile (captive crocodile monitor)
- 1 captive bird was antibody-positive for St. Louis encephalitis virus (SLE) in GA
- 13 animals (10 avian, 2 mammal, 1 reptile) screened antibody-positive and are currently undergoing confirmatory testing.

## Distribution of WNV Positives

- Antibody positive animals - zoos from 9 states
- FL, GA, LA, MA, MD/DC, NY, PA, TN, WI
- Virus-positive animals - zoos from 4 states
- MD/DC, GA, NY, PA
- All (antibody and virus) were from known WNV-endemic areas in the United States
- No positive zoo sample has predated the first positive predated the first event in any area

## Confirmed Positive Distribution

## Slide 14

## Slide 15

## Clinical Illness

- 6 (21%) WNV virus-positive captive animals exhibited clinical signs of illness
- 23 (79%) were found dead in exhibits or on zoo grounds.
- 6 (20%) WNV antibody-positive animals presented with neurologic clinical signs (including one wild crow and the crocodile monitor)
- 24 (80%) were found through serosurvey.

## Inconclusive Results

- 7 captive animals (6 birds, 1 African wild dog) were WNV antibody-positive upon screening but could not be conclusively classified as WNV or SLE upon end-point titration
- 4 captive birds WNV virus-positive by PCR were not confirmed by virus isolation
- 1 captive bird that was WNV antibody-negative but WNV virus-positive

## Other Interesting Findings

- 6 wild crows found culture-positive for an unidentified virus of the family Reoviridae
- 6 birds were shipped to one institution from Africa with weakly positive antibody titers to WNV found in serum samples archived during quarantine.

## Reporting Structure

- Results reported to submitting institution and central zoo database
- Submitting institutions required to report to local PH
- Local PH code and incorporate data into national system
- Validation survey in progress
- 30 institutions validated

## Conclusions

- Phase I and II have:
- Created/strengthened relationships between zoos and local/state health officials for the detection/reporting of a zoonotic disease threat.
- Provided data to the public health system
- Given zoos an avenue for testing endangered species
- Future Directions:
- This project created a framework that may be applied to other biologic threats of concern.
- Regional diagnostic centers** **
- Vaccination* *

## Working Group Members

**Bruce Akey**, VA Dept. Agriculture
**Wilbur Amand**, American Association of Zoo Veterinarians
**Robyn Barbiers**, Lincoln Park Zoo
**Bobby Brown**, CDC
**Grant Campbell**, CDC, DVBID
**Pamela Diaz**, Chicago Department of Public Health
**Cindy Driscoll**, MD Dept. Nat. Res.
**Ed DuBovi**, Cornell College of Veterinary Medicine
**Millicent Eidson**, NY State Dept. of Health
**Amy Glaser**, Cornell College of Veterinary Medicine

**Thomas Gomez**, USDA, APHIS, VS
**Duane Gubler**, CDC, DVBID
**Nicholas Komar**, CDC, DVBID
**Laura Kramer**, NY State Dept. of Health
**Bob McLean**, USGS, National Wildlife Health Center
**Rita McManamon**, Zoo Atlanta
**Tracey McNamara**, Wildlife Conservation Society
**Hayley Murphy**, Zoo New England
**Eileen Ostlund**, USDA, NVSL
**Mary Grace Stobierski**, MI Dept. of Community Health
**Scott Terrell**, Disney's Animal Kingdom
**Kristin Vehrs**, American Zoo and Aquarium Association