Aquatic species: Diagnostic testing

Person working in lab
Andrew Vo, a microbiologist, works with bacteria samples in the Aquatic Health section of the Washington Animal Disease Diagnostic Laboratory on Nov. 9, 2022, in the College of Veterinary Medicine at Washington State University Pullman. (College of Veterinary Medicine/Ted S. Warren)

Why use WADDL for diagnostic testing for aquatic species?

Clients not only receive high-quality test results tailored to aquatic species when they test with WADDL, they also are able to consult WADDL’s team of veterinarians and veterinary pathologists who have production, clinical, and diagnostic experience working with aquatic species. WADDL is accredited by the American Association of Veterinary Laboratory Diagnosticians, which means clients can have the highest confidence in the accuracy and interpretability of testing performed at WADDL. In addition, veterinarians at WADDL assist clients with choosing the most appropriate diagnostic specimens and tests to improve the clinical value of test results.

What aquatic species can I submit to WADDL?

WADDL accepts submissions from any aquatic species, including fish, amphibians, and aquatic invertebrates. We have seen everything from larval fish to endangered frogs and salamanders to shellfish and sea pens. Visit our Sample Submission webpage for more information about the sample submission process.

What is a “diagnostic” case?

Cases are classified as diagnostic when a client is submitting sick animals. Specimens from these cases often go through a different testing process than samples from healthy fish submitted for health certification testing.

What types of samples does WADDL accept for diagnostic cases from aquatic species?

The best samples for diagnostic cases are derived from clinically ill animals. Clients can submit fresh, frozen, or fixed carcasses and tissues; for live animal submissions, please contact us in advance so we can be prepared to receive them. We can also accept samples such as cell culture supernatants and formalin-fixed paraffin-embedded (FFPE) tissues for PCR and sequencing. Each test listed on our website has information about what specimens are accepted for that test.

What diagnostic tests does WADDL offer for aquatic species?

  • Aquatic Necropsy: Clients can submit whole carcasses for necropsy; for live animal submissions, please contact us in advance so we can be prepared to receive them. This includes an examination of the animal by veterinarians at WADDL and recommendations about further diagnostic testing if necessary.
  • Aquatic Histopathology, Standard and Urgent: WADDL has several veterinary pathologists who have extensive experience with aquatic species. Clients can submit specimens and tissues fixed in neutral buffered formalin or Davidson solution from necropsies they performed; contact us to order formalin jars for sample collection. WADDL staff can also collect samples for this test while performing the Aquatic Necropsy. The fee for the Aquatic Histopathology test is per animal and includes evaluation of all tissues submitted; for more information about choosing Standard versus Urgent Aquatic Histopathology, see this announcement. WADDL has a wide array of special stains available to identify Mycobacterium spp. and other aquatic pathogens. Clients receive a detailed report describing histologic lesions as well as comments contextualizing the histologic findings and can consult with WADDL’s veterinary pathologists for further recommendations.
  • Testing for bacteria: WADDL offers a suite of diagnostic testing including bacterial culture specifically tailored to isolate and identify aquatic pathogens (aerobic and anaerobic), MALDI-TOF bacterial identification for isolates from aquatic species, antimicrobial susceptibility testing with custom plates with drugs widely used in aquatic species, and PCR testing and sequencing for many bacteria of interest in aquatic species.
  • Testing for viruses: Many of our PCR tests for aquatic viruses can test fresh tissues directly for fast results on diagnostic cases or formalin fixed paraffin embedded tissues used to produce histopathology slides linking the presence of virus to histological lesions. In addition, we maintain a number of cell lines from aquatic species for isolation of known and unknown viruses.
  • Testing for parasites: Clients can freshly-euthanized fish for evaluation for external parasites by either light microscopy or histopathology; for live animal submissions, please contact us in advance so we can be prepared to receive them. Other methods to test for microscopic parasites include several PCR assays and Aquatic Histopathology.
  • Testing for fungi: WADDL offers fungal identification and sequencing to detect and speciate fungi present in fresh, frozen, or FFPE tissues. Fungi can also be evaluated for as part of the Aquatic Necropsy and Aquatic Histopathology.

How can I get more information about diagnostic testing for aquatic species?

For more information about testing aquatic species at WADDL, please call us at 509-335-9696.