Antibodies to snowshoe hare virus of the California group in the horse population in Nova Scotia.

The study investigated the presence of antibodies to the California group of viruses (particularly, the snowshoe hare virus) in horses in Nova Scotia, Canada, indicating the wildlife-to-domestic animal transmission of this virus group in the region.

Overview of the Research

The researchers aimed to detect the presence of antibodies to the California group of arboviruses (CAL), particularly to the snowshoe hare virus, in the equine population of Nova Scotia, North America. The presence of these antibodies would indicate exposure of the horses to these viruses, suggesting that this group of viruses is active in the region’s fauna.

Methodology and Testing Approach

• The researchers obtained a significant number of equine samples from North America to test for antibodies to the CAL group of viruses.
• They conducted hemagglutination inhibition tests using the snowshoe hare virus as the antigen on 861 equine sera.
• Hemagglutination inhibition tests are a common serological testing method to detect antibodies in a sample. The presence of hemagglutination, or the clumping of red blood cells, indicates the presence of corresponding antibodies in the serum.
• The snowshoe hare virus was used as an antigen in this test to specifically detect antibodies against this virus in the serum samples.

Results and Findings

• Out of 861 equine sera tested, 106 samples (or 12.3%) tested positive for the presence of antibodies to the snowshoe hare virus.
• These positive results indicate that these horses had been exposed to the snowshoe hare virus, suggesting this virus’s activity in the domestic animal population of Nova Scotia.
• To confirm these results, further neutralization tests were performed on the positives sera, which confirmed the presence of antibodies to the snowshoe hare virus in 72 of the samples.

Implications of the Research

• This research study provides evidence of the California group of viruses’ activity, particularly the snowshoe hare virus, in the domestic animal (equine) population of Nova Scotia, North America.
• The results report one of the few documented instances of wildlife-to-domestic animal transmission of this group of viruses in this area. The CAL group of viruses typically cycle between mosquito vectors and avian or small mammal hosts in their natural sylvatic cycle, and infection in horses hints at the virus’s ability to spill over to domestic animals.

The study thereby contributes to our understanding of the geographical spread and host range of the CAL group of viruses and helps in informing public health policies and preventive measures.