Risk assessment for hepatitis E virus infection from domestic pigs introduced into an experimental animal facility in a medical school

Hepatitis E virus (HEV) is known to cause zoonotic infections from pigs, wild boars and deer. Domestic pigs have been used as an experimental animal model in medical research and training; however, the risks of HEV infection from pigs during animal experiments are largely unknown. Here, we retrospectively investigated the seroprevalence and detection rates of viral RNA in 73 domestic pigs (average 34.5 kg) introduced into an animal experimental facility in a medical school during 2012-2016. We detected anti-HEV immunoglobulin G antibodies in 24 of 73 plasma samples (32.9%), though none of the samples were positive for viral RNA. Plasma samples of 18 pigs were sequentially monitored and were classified into four patterns: sustained positive (5 pigs), sustained negative (5 pigs), conversion to positive (6 pigs) and conversion to negative (2 pigs). HEV genomes were detected in 2 of 4 liver samples from pigs that were transported from the same farm during 2016-2017. Two viral sequences of the overlapping open reading frame (ORF) 2/3 region (97 bp) were identical and phylogenetically fell into genotype 3. A 459-bp length of the ORF2 region of an amplified fragment from a pig transported in 2017 was clustered with the wbJYG1 isolate (subgenotype 3b) with 91.5% (420/459 bp) nucleotide identity. Based on our results, we suggest that domestic pigs introduced into animal facilities carry a potential risk of HEV infection to researchers, trainees and facility staff. Continuous surveillance and precautions are important to prevent HEV infection in animal facilities

Antiviral Effect of Ephedrine Alkaloids-Free Ephedra Herb Extract against SARS-CoV-2 In Vitro

We report for the first time that ephedrine alkaloids-free Ephedra Herb extract (EFE) directly inhibits the replication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in vitro and that the addition of EFE to the culture medium before viral infection reduces virus titers in the culture supernatant of SARS-CoV-2, including those of variant strains, by more than 99%, 24 h after infection. The addition of Ephedra Herb macromolecule condensed-tannin, which is the main active ingredient responsible for the anticancer, pain suppression, and anti-influenza effects of EFE, similarly suppressed virus production in the culture supernatant by 99% before infection and by more than 90% after infection. Since EFE does not have the side effects caused by ephedrine alkaloids, such as hypertension, palpitations, and insomnia, our results showed the potential of EFE as a safe therapeutic agent against coronavirus disease 2019

HTLV-1 Proliferation after CD8+ Cell Depletion by Monoclonal Anti-CD8 Antibody Administration in Latently HTLV-1-Infected Cynomolgus Macaques

ABSTRACT Human T-cell leukemia virus type 1 (HTLV-1) induces chronic asymptomatic latent infection with a substantial proviral load but without significant viral replication in vivo. Cumulative studies have indicated involvement of CD8-positive (CD8+) cells, including virus-specific CD8+ T cells in the control of HTLV-1 replication. However, whether HTLV-1 expression from latently infected cells in vivo occurs in the absence of CD8+ cells remains unclear. Here, we examined the impact of CD8+ cell depletion by monoclonal anti-CD8 antibody administration on proviral load in HTLV-1-infected cynomolgus macaques. Five cynomolgus macaques were infected with HTLV-1 by inoculation with HTLV-1-producing cells. Administration of monoclonal anti-CD8 antibody in the chronic phase resulted in complete depletion of peripheral CD8+ T cells for approximately 2 months. All five macaques showed an increase in proviral load following CD8+ cell depletion, which peaked just before the reappearance of peripheral CD8+ T cells. Tax-specific CD8+ T-cell responses were detected in these recovered CD8+ T cells. Importantly, anti-HTLV-1 antibodies also increased after CD8+ cell depletion, indicating HTLV-1 antigen expression. These results provide evidence indicating that HTLV-1 can proliferate from the latent phase in the absence of CD8+ cells and suggest that CD8+ cells are responsible for the control of HTLV-1 replication. IMPORTANCE HTLV-1 can cause serious diseases such as adult T-cell leukemia (ATL) in humans after chronic asymptomatic latent infection with substantial proviral load. Proviruses are detectable in peripheral lymphocytes in HTLV-1 carriers, and the association of a higher proviral load with a higher risk of disease progression has been observed. However, neither substantial viral structural protein expression nor viral replication was detectable in vivo. Cumulative studies have indicated involvement of CD8+ cells, including virus-specific CD8+ T cells in the control of HTLV-1 replication. In the present study, we showed that CD8+ cell depletion by monoclonal anti-CD8 antibody administration results in HTLV-1 expression and an increase in proviral load in HTLV-1-infected cynomolgus macaques. Our results indicate that HTLV-1 can proliferate in the absence of CD8+ cells, suggesting that CD8+ cells are responsible for the control of HTLV-1 replication. This study provides insights into the mechanism of virus-host immune interaction in latent HTLV-1 infection

Host-seeking ticks collected in Shimonoseki, Yamaguchi Prefecture.

<p>Host-seeking ticks collected in Shimonoseki, Yamaguchi Prefecture.</p