United States Department of the Interior
U.S. GEOLOGICAL SURVEY
National Wildlife Health Center
6006 Schroeder Rd.
Madison, WI 53711
April 29, 2014
Mr. Richard Hatcher
Director
Oklahoma Department of Wildlife Conservation
P.O. Box 53465
Oklahoma City, OK 73152
Reference Case Number:
23042, Cave bat (Myotis velifer), Woodward County, Oklahoma
Dear Mr. Hatcher:
In early May 2010, a cave bat (Myotis velifer) with clinical signs suggestive of white-nose
syndrome (WNS) was observed in the James Selman Cave System in Woodward County,
Oklahoma. The bat was euthanized and submitted to the US Geological Survey – National
Wildlife Health Center (NWHC). Upon receipt, the carcass was noted to be desiccated, and a
star-burst like dermal scar was observed on the left wing. Laboratory analyses were conducted,
and a PCR product1 consistent with presence of nucleic acid from Pseudogymnoascus (formerly
Geomyces) destructans (Pd) was amplified from wing skin but not from muzzle tissue from the
carcass; DNA sequence of the PCR product matched 100% to the type isolate of Pd.
Additionally, fungal hyphae without definitive morphological characteristics of Pd were
observed superficially on wing-skin and infiltrating epidermis of the muzzle. Based upon this
collective evidence, the case was characterized by NWHC as “presumptive WNS”, and on 19
May 2010, Woodward County, Oklahoma was identified as “WNS likely” (later revised to
“suspect”) on the map distributed by the Pennsylvania Game Commission.
Numerous inquiries have since prompted an internal review of this case. The original bat carcass
from Oklahoma was reexamined by histopathology, fungal culture, and PCR (using a new and
more specific procedure),2 and upon review was negative for characteristic WNS lesions and Pd.
The disparity of these results with those of previous tests now leads us to classify the bat as
negative for WNS and equivocal for the presence of Pd. Attempts to determine the possible
cause of the clinical signs observed in the field using additional molecular tests were
unsuccessful.
In contrast, for similar cases during winter 2009/2010 from other at-risk states (i.e., Tennessee
and Missouri), PCR-based detections of nucleic acid from Pd on bats were confirmed by
independent laboratory techniques (i.e., culture or histopathology analyses), through diagnostic
re-testing of the original samples, and/or by testing of additional samples from the same sites.
This has not, however, been the case for the Oklahoma samples. Specifically, tissues from five
additional M. velifer collected at the James Selman Cave System during winter 2010/2011 were
submitted to NWHC, and all were negative for Pd and WNS by all analyses. Additionally, 81
combination wing/muzzle swabs from hibernating bats in Oklahoma, including 40 swabs from
hibernacula in Woodward County, were submitted to NWHC during winter 2013/2014, and all
were negative for nucleic acid from Pd by PCR.2
Thus, following a review of our laboratory’s original PCR and histology results, lack of
confirmation by follow-up analyses conducted using tissues from the original carcass, and
inability to detect Pd on bats from Oklahoma during follow-up surveillance efforts, we (NWHC)
propose that until ongoing surveillance and diagnostic testing indicate otherwise, Oklahoma
should be reclassified as negative for Pd and WNS, and M. velifer should be removed from the
list of Pd-positive species.
As we have developed more specific diagnostic assays we have been able to retrospectively
review cases such as this and provide more accurate results to our submitters and partners. I
believe it is vital that we do so to ensure accuracy and transparency in our diagnostic results and
provide our submitters with the best service possible. Diagnosing novel, emerging diseases is a
challenge and I commend our scientists for constantly striving to improve.
Please accept my apologies for any confusion the change in diagnostic status of this case may
cause, and please do not hesitate to contact me if you have any questions or concerns.
Sincerely,
Jonathan Sleeman, MA, VetMB, Dipl. ACZM, Dipl. ECZM, MRCVS
Director, National Wildlife Health Center
cc:
Melynda Hickman, OK Dept of Wildlife Conservation
Josh Richardson, OK Dept of Wildlife Conservation
Jeremy Coleman, WNS Coordinator, US Fish and Wildlife Service
References Cited:
1) Lorch, JM, A Gargas, CU Meteyer, BM Berlowski-Zier, DE Green, V Shearn-Bochsler, NJ Thomas and DS Blehert. 2010. Rapid polymerase
chain reaction diagnosis of white-nose syndrome in bats. J Vet Diag Invest 22: 224-230.
2) Muller, LK, JM Lorch, DL Linder, M O’Connor, A Gargas, DS Blehert. 2013. Bat white-nose syndrome: a real-time TaqMan polymerase
chain reaction test targeting the intergenic spacer region of Geomyces destructans. Mycologia 105(2): 253-259. On-line pub: 6Sep2012.