Prevalence of Linda Virus Neutralizing Antibodies in the Austrian Pig Population

Abstract

A novel pestivirus species, termed Lateral-shaking Inducing Neuro-Degenerative Agent virus (LindaV), was discovered in a piglet-producing farm in Austria in 2015 related to severe congenital tremor cases. Since the initial outbreak LindaV has not been found anywhere else. In this study, we determined the seroprevalence of LindaV infections in the domestic pig population of Austria. A fluorophore labeled infectious cDNA clone of LindaV (mCherry-LindaV) was generated and used in serum virus neutralization (SVN) assays for the detection of LindaV specific neutralizing antibodies in porcine serum samples. In total, 637 sera from sows and gilts from five federal states of Austria, collected between the years 2015 and 2020, were analyzed. We identified a single serum showing a high neutralizing antibody titer, that originated from a farm (Farm S2) in the proximity of the initially affected farm. The analysis of 57 additional sera from Farm S2 revealed a wider spread of LindaV in this pig herd. Furthermore, a second LindaV strain originating from this farm could be isolated in cell culture and was further characterized at the genetic level. Possible transmission routes and virus reservoir hosts of this emerging porcine virus need to be addressed in future studies.

New Emergence of the Novel Pestivirus Linda Virus in a Pig Farm in Carinthia, Austria

“…However, the virus persisted in lymphoid tissues and was still detectable after 21 days. To date, LindaV has been detected in the index case as well as in a farm 10 km away as a consequence of a nationwide screening for LindaV neutralizing antibodies [16]. This study revealed a very low seroprevalence of 0.15% (based on the number of sera screened) and 0.7% (at farm level) in Austria [16].…”

“…This study revealed a very low seroprevalence of 0.15% (based on the number of sera screened) and 0.7% (at farm level) in Austria [16]. A novel, genetically closely related LindaV strain (LindaV strain Austria2) could be isolated from a serum sample in 2016 [16]. Interestingly, clinical signs of CT had never occurred in pigs of that farm, according to the farmer and responsible veterinarian.…”

“…The SVN assay was performed as previously described [16]. Briefly, sera were heat inactivated at 56 • C for 30 min and a five-fold serial dilution (1/5 starting dilution, 1/390,625 final dilution) was prepared in DMEM (Biowest) in a 96-well cell culture plate (STARLAB).…”

“…To date, LindaV has been detected in the index case as well as in a farm 10 km away as a consequence of a nationwide screening for LindaV neutralizing antibodies [16]. This study revealed a very low seroprevalence of 0.15% (based on the number of sera screened) and 0.7% (at farm level) in Austria [16]. A novel, genetically closely related LindaV strain (LindaV strain Austria2) could be isolated from a serum sample in 2016 [16].…”

Characterization of a Cytopathogenic Reporter CSFV

“…E2 fusion protein reporter viruses showed stronger reporter activity because the E2 is stable and accumulates in infected cells. Such an E2 reporter pestivirus was recently used in serological assays to determine LINDA pestivirus seroprevalence [ 48 ]. Considering that cp pestiviruses have much stronger protein expression than ncp pestiviruses, we hypothesized that reporter activity for E2 reporter genes would be further increased in the context of cp viruses.…”