When to Call Your State Diagnostic Lab

By Erin Luley, VMD, MPH, DACVP

When the vets at Millerstown Veterinary Associates saw something unusual on a beef herd, they knew exactly who to call. The case was a 7-year-old Hereford cow that had developed ulcerative lesions on her muzzle and udder. Dr. Jim Osborne initially saw the case, and after conferring with colleague Dr. Jim Lawhead, they elected to call up the Animal Diagnostic Lab at Penn State.

Pennsylvania is home to the Pennsylvania Animal Diagnostic Laboratory System (PADLS), a tripartite lab with locations strategically distributed across the state. Each lab offers the same core services, including necropsy and histopathology for both mammalian and avian cases, bacteriology, and molecular diagnostics, while also individually having areas of specialization. The Pennsylvania Veterinary Laboratory, located in Harrisburg, does a large percentage of the regulatory tests such as PCR testing for Johne’s disease and serology for brucellosis. The diagnostic lab at the New Bolton Center, the Kennett Square campus of the University of Pennsylvania School of Veterinary Medicine, is the home to all toxicology testing for the three labs as well as the Wildlife Futures Program. The Animal Diagnostic Laboratory at Penn State offers a vast array of molecular diagnostics, especially for bovine and poultry pathogens, and whole genome sequencing. One common purpose across all three labs is the shared mission to provide unparalleled diagnostic expertise to veterinarians and livestock producers throughout the state.

Millerstown Veterinary Associates has a long-standing relationship with PADLS. As their practice is located mid-way between Harrisburg and State College, some of their clients may prefer one lab over the other based on proximity. Dr. Osborne initially collected samples from the affected tissues on the cow’s muzzle and shipped them to ADL. Based on the initial presentation, a viral dermatitis caused by infectious bovine rhinotracheitis (bovine herpesvirus 1) or a related virus was considered a differential diagnosis.

Dr. Lawhead forwarded results of a blood chemistry panel as well as pictures of the lesions on the muzzle and udder. This helped to differentiate the lesions from vesicles, which would have prompted a different set of differentials, and raised the possibility of photosensitization as the underlying cause of the skin lesions as several liver enzymes were slightly elevated. Initial testing on the submitted tissue was negative for infectious bovine rhinotracheitis by PCR and bovine mammallitis (bovine herpesvirus-2) by virus isolation. Unfortunately, the animal’s condition continued to decline, and she was euthanized about two weeks after the initial submission. At that point the producer transported the animal to the Animal Diagnostic Lab for a complete necropsy.

At necropsy, the liver was found to be small, firm, and pale. The skin lesions had significantly worsened since the initial pictures were taken and were confined to non-pigmented areas with little hair coverage. Histopathology confirmed that there was extensive acute hepatic degeneration and necrosis. All of this information was incorporated to achieve a final diagnosis of hepatogenic photosensitization. The underlying cause of liver disease was speculated to be a hepatotoxic substance, potentially a plant, though was not definitively identified. This case represented an excellent example of collaboration between the referring veterinarians and resources at the diagnostic lab to achieve a diagnosis for the producer.

Situations that warrant a call to the diagnostic lab include high morbidity or mortality on a farm, an unusual presentation of a disease or more rapid progression of signs, or cases where a more definitive answer is needed. Cases where a transboundary disease is suspected necessitate a prompt call to a state animal health official prior to moving any samples from a premise.

So, what do you need to do if you have a case that you would like to submit? First, reach out to the lab closest to you or your client to ensure that the lab is able to accommodate your submission. You will have the opportunity to speak with the on-call pathologist at the lab to discuss the case history and any specific testing requests that you might have. Submission forms for all the labs can be found on their respective websites. The main PADLS website contains information about available testing and fees. Ensuring that the specimen arrives at the lab with the correct paperwork is extremely helpful in providing the most information to you and your client. The great thing

UNDERSTANDING GFI #256

® Do You Know What’s In A Compound? New FDA Guidance Says You Should.

The FDA recently finalized GFI #256, regulatory guidance for compounded animal medications from bulk drug substances for use in nonfood producing animals. This new guidance impacts both office stock in veterinary practices and individual animal-patient prescriptions. It’s important your daily practice operations are compliant!

Use our free resources to learn more about GFI #256 and how to minimize risk in your practice!

888.508.5032 | EPICURPHARMA.COM about submitting to one lab is that you get the offerings and expertise of all three. In the case of the Hereford cow, a sample of liver tissue was forwarded to the NBC lab for toxicology testing to rule out any heavy metal intoxications as a cause of liver damage.

Our goal is to work with you and your client to provide comprehensive testing to improve animal and human health. So, the next time you have a case that you need help getting to the bottom of, please call your state diagnostic lab!

Contact information:

New Bolton Center Diagnostic Lab – 610-444-5800, https://www.vet.upenn.edu/veterinary-hospitals/NBChospital/diagnostic-laboratories/new-bolton-center-padls Penn State Animal Diagnostic Lab – 814-863-0837, https://vbs.psu.edu/adl

Pennsylvania Veterinary Lab – 717-787-8808, http://padls.agriculture.pa.gov

About the Author: Erin Luley, VMD, MPH, DACVP, is a pathologist at the Penn State Animal Diagnostic Lab. A graduate of Penn Vet, she returned to her undergraduate alma mater in 2017 to complete a residency in pathology after spending several years in practice in central PA. She can be reached at ehl5008@psu.edu or 814-865-9981.