Summary:
The February 2025 issue of Prairie Diagnostic Perspective showcases new diagnostic findings, research collaborations, and client resources from Prairie Diagnostic Services (PDS).
Cache Valley Virus (CVV) – A Growing Concern in Prairie Sheep Flocks
Author: Dr. Michael Zabrodski, Anatomic Pathologist (PDS)
Beginning in late 2024, PDS observed a marked increase in ovine abortion submissions featuring severe musculoskeletal and neurological malformations. Through collaboration with the Disease Investigation Unit (DIU) at the Western College of Veterinary Medicine (WCVM), Cache Valley Virus (CVV) was confirmed as the cause.
A special investigation program, funded and coordinated between PDS and WCVM, was launched to analyze malformed fetus submissions between November 2024 and January 2025. This effort yielded valuable diagnostic data and positive case material, helping PDS develop in-house PCR testing for CVV and supporting ongoing genomic research projects.
Key Insights:
- CVV is a mosquito-borne virus endemic across North America, with high seroprevalence in Saskatchewan livestock and wildlife.
- Infection of naïve ewes between 28–48 days of gestation results in congenital deformities such as arthrogryposis, maxillary prognathism, and spinal deviations (scoliosis, kyphosis, lordosis).
- Neurological lesions can include cerebellar hypoplasia, hydrocephalus, porencephaly, and hydranencephaly.
- Diagnosis relies on recognizing compatible malformations, histological confirmation of skeletal muscle hypoplasia, and laboratory testing via PCR or virus neutralization assays.
While in-house CVV PCR testing is in development, samples can currently be referred to the Animal Health Laboratory (Guelph) or Texas A&M Veterinary Diagnostic Lab for confirmatory testing.
PDS emphasizes the importance of submitting whole fetuses and placentas whenever possible to ensure thorough investigation of reproductive loss and rule out other causes such as border disease virus, BVDV, or teratogenic plants.
Trypanosomes in Beavers – A Rare and Notable Finding
Author: Dr. Lilani Munasinghe, Clinical Pathologist (PDS)**
In a rare discovery, trypanosomes were identified in the blood smear of a beaver rescued from a dam and admitted to the WCVM Veterinary Medical Centre. Trypanosomes are vector-borne protozoa capable of infecting many vertebrates, including humans, but little is known about their prevalence in Canadian wildlife.
The species identification is ongoing, and findings will contribute to a forthcoming publication aimed at increasing awareness among veterinarians and One Health professionals.
Client Resource Highlight: PDS Web Client Portal
The PDS Web Client Portal, available at pdsinc.ca, continues to streamline case submissions and result access. Key features include:
- Results: View completed case reports.
- Fee Guide: Download current or customized Tests & Services Guides (now digital-only).
- Test Search: Browse available tests and sample requirements.
- Shipping Integration: Book shipments with Canada Post, Loomis Express, or Purolator.
A User Guide is available online, and assistance with portal access can be obtained by emailing dso@usask.ca.