Getting help from a diagnostic laboratory

Animal Health: Diagnostic testing is geared for disease prevention and control

Veterinarians and their large animal clients find themselves in a new era. Regulatory changes regarding the use and acquisition of antimicrobials through 2018 redefined the need for veterinary-client patient relationships between livestock producers and veterinary practitioners. Increasingly sophisticated electronic communication, the universal use of computers and a changing culture of service opened the doors to a re-examination of how producers and veterinarians communicate, and how ongoing veterinary-client patient relationships become a natural part of other services like the use of diagnostic laboratories.

Dr. Anatoliy Trokhymchuk, director of applied research, surveillance and veterinary services at Prairie Diagnostic Services Inc., provided insight into how a modern full service diagnostic lab functions at the recent Western Canadian Association Bovine Practitioners’ conference in Saskatoon. Prairie Diagnostic Services, a world-class full-service regional animal health diagnostic laboratory, has served Western Canada since 1998. The American Association of Laboratory Diagnosticians and the Standards Council of Canada accredit Prairie Diagnostic Services activity. The organization’s mandate includes:

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  • Animal health diagnostics and surveillance.
  • Educational support.
  • Applied research.

A board of 13 directors governs Prairie Diagnostic Services. Laboratory services are supported through the provision of grants and in-kind contributions from the province and the university as well as fees for service paid by clients. The grant and in-kind support from the province supports the provision of diagnostic testing services to the livestock industry as well as core disease surveillance work. The grant from the university supports undergraduate and graduate teaching of veterinary students, diagnostic support for research and test development at Western College of Veterinary Medicine (WCVM). Prairie Diagnostic Services helps maintain professional diagnostic expertise among the college’s faculty. Eight professional diagnostic staff and approximately 45 laboratory technologists and administrative staff provide diagnostic service. WCVM faculty actively participates in providing diagnostic service through contract arrangements with Prairie Diagnostic Services.

Prairie Diagnostic Services, along with other university, provincial and federal laboratories across Canada, is part of the Canadian Animal Health Surveillance Network, established to increase surveillance and diagnostic testing capacity for emerging and foreign animal diseases. In support of the network’s initiative, Prairie Diagnostic Services operates a Level 2+ biosecurity testing laboratory where testing on highly pathogenic organisms can be performed including avian influenza, hog cholera, and foot and mouth disease.

The diagnosis of common bovine diseases like bovine respiratory diseases (BRD) and neonatal scours pose significant challenges to the clinician because multiple infectious organisms, operating singly or in combination, are involved. Clinical signs alone are often not diagnostic, necessitating laboratory support for the clinician. Recently, many molecular-based tests have moved from the research bench to the veterinary diagnostic lab. Advanced technology means clinicians actively consult with their diagnostic counterparts in labs to interpret test results. The rate of development and use of molecular diagnostic tests have outpaced understanding by many field veterinarians.

Tough questions facing animal owners and veterinarians with respect to disease outbreaks include:

  • Sick calves recover from illness. What caused the disease?
  • Calves die following acute illness. Why?
  • Cattle die after a prolonged illness and treatment. What initially caused the disease? Why did the treatment fail? What caused them to die?
  • Vaccination programs were sound, so what went wrong?
  • When an infectious agent is found, is it an infection looking for a disease? How do we prove the infectious agent caused disease?

Veterinarians and animal owners are faced with challenges of accurate and timely diagnosis when ill and dying cattle are involved. Intervention strategies to control or minimize disease become paramount. The clinician and those managing the animals are always the first line of defense. Observing the animals to detect clinically affected animals is important, yet clinically ill animals often do not exhibit signs or lesions characteristic for a specific etiology.

In veterinary medicine, particularly food animal production, diagnostic testing is ultimately geared for disease prevention and control. This incorporates one or more of four key areas:

1. Vaccination programs.
2. Selection of antimicrobial treatment regimes.
3. Removing the cause of disease, which might include metabolic and toxicity issues.
4. Implementation of biosecurity plans.

Veterinary medicine and the animal industry also have important roles to play formulating animal health regulations, especially as they apply to foreign animal disease and disease agents associated with animal movement.

To be effective in this day and age, diagnostic facilities like Prairie Diagnostic Services have established web-based tools for fast and efficient online submissions that provide convenient access to all reports and real-time case updates. Modern laboratories have started down the long road towards better diagnostics and managing individual animal care by finding new and cheaper ways to sequence DNA, the most powerful method to reveal genetic variations at a molecular level. Genomic fingerprinting will lead to a clearer understanding of why animals do what they do in different physiological settings, and help define pathological conditions.

Using modern technology such as nanopore sequencing, single molecules of DNA or RNA can be rapidly sequenced without older amplification processes (e.g. polymerase chain reaction). This accurately characterizes the organism from which the sample originated, guiding important control steps like treatment. Nanopore sequencing offers relatively low-cost genotyping, high mobility for testing, and rapid processing of samples with the ability to display results in real time. In short, this technology will eventually bring accurate diagnostics chute-side.

Trokhymchuck’s take-home messages were:

  • Stay connected (web page, internet).
  • Provide client and practitioner feedback to laboratories.
  • Get a Prairie Diagnostics Services web client account because online submissions are faster and more effective.
  • Collect the right samples and package them properly.
  • Do not be afraid to ask questions.

About the author

Columnist

Dr. Ron Clarke prepares this column on behalf of the Western Canadian Association of Bovine Practitioners. Suggestions for future articles can be sent to Canadian Cattlemen ([email protected]) or WCABP ([email protected]).

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