AASRP Research Summary
Seroprevalence of Cache Valley Virus in Sheep Population in the South-Central Appalachian Region
| Date/Time: |
9/12/2025
16:30
|
| Author: |
Kathryn G Hall |
| Clinic: |
Lincoln Memorial University College of Veterinary Medicine |
| City, State, ZIP: |
Morristown, TN 37813 |
P. Morris, DVM, MBA
1
;
L. Wisnieski, MS, PhD
1
;
S. Smith, DVM
1
;
K.Hall, AS
1
;
V. Morris, DVM
1
;
1College of Veterinary Medicine, Lincoln Memorial University, Harrogate, TN 37752
Introduction:
Cache Valley virus (CVV), a mosquito-borne orthobunyavirus. It is an important cause of embryonic loss and fetal malformations in sheep. While anecdotal reports suggest its presence in the Southeastern United States' ovine population, no prevalence data is currently available. The objective of this study is to determine the seroprevalence of CVV in sheep populations in the South-Central Appalachian region.
Materials and methods:
Currently sera has been collected from a total of 259 sheep across 17 farms in the Southwest Virginia and East Tennessee areas. The inclusion requirements for an animal to be entered into the study was 1) Female animals only 2) the animal must be at least a year old & 3) The animal must have been on the premises for at least 90 days prior to sampling. A total of 3ml of blood was collected using EDTA tubes and were centrifuged after collection. The samples were then stored in a -80 F freezer until shipment to the diagnostic laboratory. For this study the Ohio Department of Agriculture Animal Diagnostic Laboratory assessed the presence of CVV neutralizing antibodies using a serum neutralization assay.
Results:
Data from 259 sheep across 17 farms was collected. A total of 15.2 (sd=1.9) samples were collected per farm. The overall prevalence of CVV across all farms was 44.4% (95% CI: 38.3%-51.7%). Prevalence varied significantly between farms, ranging from 0% to 93.8%. The intraclass correlation coefficient (ICC) was 0.45 (95% CI: 0.26-0.67), suggesting substantial variation in CVV prevalence between farms.
Significance:
This study has shown that CVV has a prevalence on certain farms in the south-central Appalachian region. However, prevalence rates from one farm to another can have a large range of variation. Possible risk factors to explain this drastic difference include presence of standing water, wooded areas on the property and proximity to rivers and lakes. The above risk factors would attract a larger mosquito population therefore resulting in higher prevalence rates. Next steps would include considering the species of mosquitoes that are carriers of CVV in this region, further investigation on risk factors, and how to mitigate infections is needed.
