Biology Reference
In-Depth Information
Although virus isolation was the gold standard for confirmed WNV infec-
tion, the CDC later expanded the diagnostic case definition to include positive
PCR results for the virus (CDC 2004). Of the animals tested, 1.8% were positive
for WNV by virus isolation. An additional 3.7% were positive by WNV PCR.
These combined results show that 5.5% of individual animals tested through
the system were actively infected at the time of sampling. Furthermore, 12%
of the animals tested were sero-positive, suggesting either exposure to the
virus at some previous time or a history of WNV vaccination.
5.3.5 lessons learned
There were many lessons learned from the WNV surveillance system for
zoological institutions that can be used to make future zoonotic disease sur-
veillance in zoos more efficient and successful. The majority of these lessons
revolved around data collection and entry. Each institution was instructed
to complete two forms after sampling, (a) the standard sample information
sheet for the lab, and (b) a short individual animal form, which collected
demographic and clinical information about the animal that was sampled.
Both of these were sent to the laboratory with the samples, at which point
the lab would fax or mail the individual animal form to LPZ where it would
be manually entered into an Access database. At Cornell, information about
the sample was entered into their Laboratory Information Management
System (LIMS). Once results were obtained, they would be entered into
LIMS and then faxed to LPZ where they would be added to the Access data-
base. As the program grew and system administrators no longer had the
capacity, Cornell took over all data entry. Once all the samples had been
tested, an attempt was made to join the two databases. Unfortunately, the
merge was not smooth. An extensive amount of work was required to com-
pile the information from both systems. This was a very clear lesson that
data entry should take place at one location only.
Perhaps one of the largest difficulties with the database involved the insti-
tutional ID for the animals. Each zoological institution has its own format for
assigning IDs to animals in their collection. These can range from fairly simple
(e.g., “wallaby”) to quite complex (e.g., 992201 N2002279). One issue that com-
plicated data collection was slight variations in the way IDs were recorded
across the submitted sheets and over time. For example, on the sample sub-
mission sheet, one zoo employee may write “Flaming 128” while another may
write “128 Flamingo.” Yet another may write “Flamingo_128.” The database
sees these as three separate animals. A great deal of work went into identify-
ing entries that represented the same animal. In a similar regard, if the animal
moved to a different institution, it was assigned a new ID according to the for-
mat used by the receiving zoo. Both zoos had to be contacted to get the old and
new IDs in order to link records representing the same animal. This problem
may be solved once the Zoological Information Management System (ZIMS)
