Heparin inhibited hemagglutination (HA) by pseudorabies virus (PRV), but not HA by Akabane virus, bovine adenovirus type 7, Fukuoka virus, Getah virus, Japanese encephalitis virus, and parainfluenza virus type 3 belonging to the families Bunyaviridae, Adenoviridae, Rhabdoviridae, Togaviridae, Flaviviidae, and Paramyxoviridae, respectively. The minimal inhibitory concentration of heparin required to inhibit 8 HA U of PRV ranged from 0.005 to 0.01 U/ml. Mouse erythrocytes failed to combine with the HA inhibitory factor of heparin. On the other hand, mouse erythrocytes treated with heparinase had greatly reduced agglutinability by PRV. Virus-heparin complex formation could be observed by sedimenting heparin with the virus particles.

Getah virus (GETV) infection causes sporadic outbreaks of mild febrile illness in horses and reproductive failure in pigs. In this study, we established a reverse transcription polymerase chain reaction (RT-PCR) method to detect GETV from suspected virus-infected samples. The reaction conditions were optimized and validated by using RNA extracted from GETV propagated in cell culture. A GETV-specific GED4 primer set was designed and used to amplify a 177 bp DNA fragment from a highly conserved region of the E1 glycoprotein gene in the GETV genome. RT-PCR performed with this primer set revealed high sensitivity and specificity. In the sensitivity test, the GED4 primer set detected GETV RNA at the level of 102.0 TCID50/mL. In the specificity test, the GED4 primer set amplified only a single band of PCR product on the GETV RNA template, without non-specific amplification, and exhibited no crossreactivity with other viral RNAs. These results suggest that this newly established RT-PCR method is useful for accurate identification of GETV infection in animals.

Several outbreaks of Getah virus (GETV) have been reported in horses and pigs, causing large economic losses. However, there have been no reports describing serological survey for GETV in South Korea pigs. The present study conducted serological survey of GETV in South Korean pigs. A total of 670 whole blood samples were collected from domestic pigs. The overall seropositive rate was 26.4%, higher than the rates observed in racehorses in 2013–2014. Preparations for epidemics of novel diseases caused by climate change should include regular serological survey for these diseases, including GETV, and the development of vaccines against novel pathogens.