Isolation of Saffold Virus Type 2 from Children with Acute Respiratory Infections by Using the RD-18S-Niigata Cell Line

Longitudinal Epidemiology of Viral Infectious Diseases Combining Virus Isolation, Antigenic Analysis, and Phylogenetic Analysis as Well as Seroepidemiology in Yamagata, Japan, between 1999 and 2018

“…2A); First, we screen the virus genome directly from the nasopharyngeal specimens using genome amplification methods such as RT-PCR and real-time RT-PCR, and then, we inoculate only the genome-positive specimens onto the appropriate cell lines and perform 3-5 passages. For example, after screening, we inoculate the genomepositive specimens onto the LLC-MK2-Niigata (LLC-MK2-N) cell line for the isolation of parechoviruses (PeVs) (23,24), the RD-18S-Niigata (RD-18S-N) cell line for the isolation of Saffold viruses (SAFVs) (25,26), the RD-A cell line for the isolation of EV-D68 and CV-A6, and the HeLa-ACE2-TMPRSS2 cell line for the isolation of human coronavirus 229E (HCoV-229E) ( Table 2) (27). The LLC-MK2-N and RD-18S-N cell lines have better sensitivities for PeVs and SAFVs, respectively, than the LLC-MK2 and RD-18S cell lines that we have used in our laboratory.…”

“…However, we succeeded in isolating SAFV2 using the RD-18S-N cell line with a 2-step virus isolation method (Fig. 2B, Table 2) (25). Combining molecular detection and virus isolation as well as phylogenetic analysis, we carried out a longitudinal epidemiological study of SAFVs between 2008 and 2015, with the results of this study suggesting that SAFV3 is another possible causative agent of ARIs among children as well as SAFV2 and that their infections occur mainly in the autumn season in Japan (84).…”

“…We also thank all our collaborators, who supported our research activities. We are grateful to Dr. H. Nishimura, ( (20,23,25,27,69…”

Saffold virus, an emerging human cardiovirus

“…The SAFV has been detected in patients globally (see Table for summary). Although infection rates appear low (<10%) in symptomatic patients via polymerase chain reaction methods, neutralizing antibodies from respiratory tract samples have been found at a high percentage of asymptomatic populations (55‐100%) .…”

First Isolation of Human Parechovirus Type 4 in Yamagata, Japan

“…Virus isolation in cells is important for further studies, such as virological and seroepidemiological analyses, for the control of viral infectious diseases. Based on our experience, molecular screening and virus isolation can be useful for Saffold viruses as they also grow slowly (14).…”