First report of Equine Parvovirus-Hepatitis (EqPV-H) in Argentina.

Overview

• This study reports the first detection of Equine Parvovirus-Hepatitis (EqPV-H) in horses and commercial horse sera in Argentina.
• The research analyzes the presence of EqPV-H DNA in various serum samples and provides genetic insights into the circulating viral strains.

Background and Significance

• EqPV-H is a recently identified virus linked to Theiler’s disease, a form of equine serum hepatitis that can cause fatal liver damage in horses.
• Theiler’s disease had previously been observed without a clearly established causative agent, but accumulating evidence suggests EqPV-H as the primary etiological virus.
• Before this study, EqPV-H infections were only reported in Brazil within South America, with no documented cases from Argentina.
• Understanding the presence of EqPV-H is critical for controlling equine health and ensuring the safety of blood-derived biological products used in veterinary medicine.

Sample Collection and Testing

• A total of 51 serum pools, 5 commercial horse serum batches, and 175 individual serum samples from donor horses across Argentina were collected and analyzed.
• Screening was performed using quantitative polymerase chain reaction (qPCR), a sensitive test that quantifies viral DNA, focusing on identifying EqPV-H DNA presence.
• Samples yielding positive or indeterminate results by qPCR underwent further confirmation and phylogenetic analysis using NS1 nested-PCR, which targets a specific viral gene for increased detection accuracy and genetic characterization.

Key Results

• No serum pools were decisively positive via qPCR; however, 9 out of 51 (approximately 17.6%) pools had indeterminate qPCR results, indicating viral DNA close to the detection limit.
• NS1 nested-PCR confirmed EqPV-H DNA in 8 of these indeterminate serum pools, representing about 15.7% positivity among the pools.
• Among the commercially available horse serum batches, 3 out of 5 (60%) tested positive for EqPV-H DNA using either qPCR or nested PCR, highlighting the virus’s presence in blood products for veterinary use.
• In individual horse serum samples, 3 out of 175 (approximately 1.71%) tested positive for the virus by both assays.

Genetic and Phylogenetic Analysis

• Partial NS1 gene sequences (12 sequences) were analyzed to determine the genetic relationship of the virus isolated in Argentina to strains reported internationally.
• The Argentine isolates displayed genetic similarity to strains previously identified in Germany and China, indicating potential global spread or shared viral ancestry.
• This genetic data was uploaded to the NCBI nucleotide database with accession numbers PP408676-PP408687, providing resources for further research and epidemiologic surveillance.

Implications and Recommendations

• This study confirms that EqPV-H is present in Argentina’s equine population and commercial equine serum products, raising concerns about virus transmission through biological materials.
• The significant detection of EqPV-H in commercial sera implies that blood-derived equine biological products may represent a pathway for virus dissemination.
• Results underscore the need for strict biosecurity measures and screening protocols to prevent iatrogenic infections in horses receiving serum-based treatments.
• Further surveillance and research are recommended to monitor EqPV-H prevalence and to develop strategies to mitigate the risk of Theiler’s disease in Argentina and beyond.