Serum antibodies and DNA indicate a high prevalence of equine papillomavirus 2 (EcPV2) among horses in Switzerland.

This research study investigates the prevalence of equine papillomavirus type 2 (EcPV2), a virus linked to tumours in horses, within the healthy horse population in Switzerland. Using DNA and serum antibody tests, the study found both forms of EcPV2 evidence in a significant portion of the sampled population, suggesting the virus is widespread.

Objective and Methodology

• The study aimed to understand the genotypic and seroprevalence (presence of the virus’ DNA and antibodies respectively) of EcPV2 within the horse population of Switzerland.
• The researchers sampled 50 healthy horses brought to a university clinic, specifically choosing those without any signs of infection or other severe diseases.
• They collected DNA samples using cytobrushes, a tool typically used for cervical screening in humans, which they applied to the animals’ genital areas.
• For the purpose of genoprevalence, they extracted DNA from these samples and performed PCR assays (a method of amplifying DNA samples) targeting a specific region of the EcPV2 genome.
• To measure seroprevalence, they used an enzyme-linked immunosorbent assay (ELISA), a test that detects and measures antibodies in the blood, specifically looking for antibodies against the major capsid protein (L1) of EcPV2.

Results

• The study found that EcPV2-specific DNA was present in 10% of the horses (5 out of 50). However, these 5 horses did not have detectable antibodies against the virus.
• Antibodies against EcPV2, but no viral DNA, were found in 28% (14 out of 50) of the horses.
• In 8% of the horses (4 out of 50), both viral DNA and antibodies were detected. This indicates these horses had both been exposed to the virus and mounted an immune response.
• The remaining 54% of the sample (27 out of 50 horses) showed no signs of either viral DNA or antibodies.

Conclusions

• The presence of EcPV2 antibodies in a significant portion of the sampled population suggests that this virus is widespread within Switzerland’s horse population.
• The lower genoprevalence as compared to seroprevalence indicates that active infections (where the virus’s DNA is present) are less common.
• The discrepancy between geno- and seroprevalence suggests different stages of infection might exist within the tested cohort; some horses might have cleared the infection but maintained antibodies, while others could be in the early stages of infection, with viral DNA present but no significant antibody response yet.