Confirmation of Elsey virus infection in a Queensland horse with mild neurologic signs

Abstract

Abstract. In 2011, a 2-year-old horse in northern Queensland, Australia, was reported to have developed mild neurologic signs, and a blood sample was submitted for laboratory investigation. Virus isolation was performed using the blood sample, and an orbivirus was isolated. This was confirmed to be a strain of Elsey virus (ELSV) after transmission electron microscopy and nucleotide sequencing. The nucleotide sequence was compared with those in GenBank, and had 100% identity with ELSV previously reported from the Northern Territory, Australia. ELSV is taxonomically closely related to Peruvian horse sickness virus.

Novel Hendra Virus Variant Detected by Sentinel Surveillance of Horses in Australia

“…Testing for HeV is less commonly performed on horses with similar disease manifestations farther south in Australia because of a perception that spillover infection is less likely to occur in regions without BFF ( 26 ). Among >1,000 horses with manifestations consistent with HeV disease tested annually across regions of established risk, <1% are found to be positive ( 25 , 27 ).…”

“…Additional nucleoprotein (N) gene–specific testing ( 29 ) is limited to HeV-positive samples that undergo confirmatory testing ( 30 ) or in the minority (<7% nationally) of suspected equine HeV cases submitted directly to the national reference laboratory from states where spillover is considered less likely ( 25 ) and state testing is unavailable. This distinction is notable because it means that most horse-disease cases found negative for HeV are not investigated further, despite evidence that other viruses with potential spillover risk to horses, including novel related batborne paramyxoviruses, circulate in Australia ( 27 , 31 – 35 ). Likewise, animal health surveillance worldwide prioritizes targeted testing to exclude pathogens of established importance over open-ended diagnostic approaches, which are inherently more challenging to put in place and interpret.…”

Novel Hendra virus variant detected by sentinel surveillance of Australian horses

“…Importantly, this means that most horse-disease cases found to be negative for HeV are not investigated further. This is despite evidence for other viruses circulating with potential spillover risk to Australian horses, including novel related bat-borne paramyxoviruses (27, 31–35). This is consistent with animal health surveillance globally, which often prioritizes exclusion testing targeting pathogens of established significance rather than open-ended diagnostic approaches that are inherently more challenging to implement and interpret.…”

“…Despite high rates of HeV testing in horses with consistent disease across regions of established risk (>1000 tested annually), less than 1% are found to be positive (25, 27).…”