Antiviral treatments targeting the coronavirus disease 2019 are urgently required. We screened a panel of already-approved drugs in a cell culture model of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and identified two new agents having higher antiviral potentials than the drug candidates such as Remdesivir and Chroloquine in VeroE6/TMPRSS2 cells: the anti-inflammatory drug Cepharanthine and HIV protease inhibitor Nelfinavir. Cepharanthine inhibited SARS-CoV-2 entry through the blocking of viral binding to target cells, whilst Nelfinavir suppressed viral replication partly by protease inhibition. Consistent with their different modes of action, synergistic effect of this combined treatment to limit SARS-CoV-2 proliferation was highlighted. Mathematical modeling in vitro antiviral activity coupled with the calculated total drug concentrations in the lung predicts that Nelfinavir will shorten the period until viral clearance by 4.9-days and the combining Cepharanthine/Nelfinavir enhanced their predicted efficacy. These results warrant further evaluation of the potential anti-SARS-CoV-2 activity of Cepharanthine and Nelfinavir.

Rickettsiae belongs to the order Rickettsiales, whose members were described as obligate intracellular gramnegative microorganisms. Several species cause diseases in humans and other vertebrate or invertebrate hosts, and have a worldwide distribution. For the last 15 years, nine new rickettsiosis have been reported, that is, Japanese spotted fever caused by Rickettsia japonica (19,39), Flinders Island spotted fever caused by R. honei (33,34), Astrakhan tick bite fever caused by Astrakhan fever rickettsia (5), African tick bite fever caused by R. africae (15), California flea typhus caused by R. felis (the ELB agent) (35), and four other unnamed spotted fevers caused by R. mongolotimonae (30,44), R. slovaca (18, 31, 36), R. helvetica (11, 25), and "R. heilongjiangii," (17, 45) respectively. In Japan, 63 tick-associated rickettsiae strains, belonging to at least three serotypes, have been isolated over the last several years (8-10), including R. japonica isolated from the Dermacentor taiwanensis and Haemaphysalis frava ticks, respectively; R. helvetica (strains IP-1 and IM-1), strains Abstract: In order to understand the natural situation of rickettsiae in the ticks in Japan, the rickettsial genes, gltA gene, rOmpA gene, and 17-kDa gene, were amplified from the ticks by nested PCR. The prevalences of rickettsial gltA genes among Haemaphysalis formosensis, H. longicornis, H. megaspinosa, Ixodes ovatus, H. flava, H. kitaokai, and I. persulcatus were 62, 57, 24, 24, 19, 13, and 10%, respectively; 26% (186/722) being the average. The gltA genes amplified from the ticks were classified into 9 genotypes (I to IX) by the difference in nucleotide sequences. Genotype I was detected from 7 species of ticks. Genotype II mainly was detected from H. longicornis and H. formosensis. Genotypes III and VII mainly were detected from H. flava and I. ovatus. The polarization in the distribution of genotypes among regions where the ticks were collected was not clear. Based on the phylogenetic analysis of the three genes presented here, genotypes I, III, and IV (detected from H. formosensis, H. hystricia, and I. ovatus) are genetically close with each other, but rickettsiae of the same property still have not been isolated from ticks anywhere in the world. These genotypes should be considered as new species among SFG rickettsiae. Genotype II was identical with strain FUJ-98, genetically close to R. japonica which has been isolated from ticks in China. Genotype V was identical with R. felis and strain California 2 isolated from the cat flea. This is the first report on the detection of R. felis from ticks. Genotype VI detected from Ixodes sp. did not seem to belong to genus Rickettsia. Based on the previous antigenic data and the phylogenetic analysis presented here, Genotype VII should be considered a variant of R. helvetica and genotype VIII detected from I. ovatus and I. persulcatus were identical with R. helvetica. Genotype IX detected from I. nipponensis was genetically close to the strains IRS3, IRS4, and IrR/Munich isolated from...

SummaryAntiviral treatments targeting the emerging coronavirus disease 2019 (COVID-19) are urgently required. We screened a panel of already-approved drugs in a cell culture model of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and identified two new antiviral agents: the HIV protease inhibitor Nelfinavir and the anti-inflammatory drug Cepharanthine. In silico modeling shows Nelfinavir binds the SARS-CoV-2 main protease consistent with its inhibition of viral replication, whilst Cepharanthine inhibits viral attachment and entry into cells. Consistent with their different modes of action, in vitro assays highlight a synergistic effect of this combined treatment to limit SARS-CoV-2 proliferation. Mathematical modeling in vitro antiviral activity coupled with the known pharmacokinetics for these drugs predicts that Nelfinavir will facilitate viral clearance. Combining Nelfinavir/Cepharanthine enhanced their predicted efficacy to control viral proliferation, to ameliorate both the progression of disease and risk of transmission. In summary, this study identifies a new multidrug combination treatment for COVID-19.

A highly pathogenic simian/human immunodeficiency virus (SHIV), designated C2/1, was obtained by serum passages in cynomolgus monkeys of p-SHIV, an SHIV strain that contains the env gene of pathogenic human immunodeficiency virus type 1 89.6. CD4+ lymphocyte depletion was induced within 1 week of the SHIV-C2/1 infection in peripheral blood as well as in various lymphoid organs in all the animals tested, with symptoms of diarrhoea and no increase in body weight, followed by intense viraemia. Serum antibody against Env protein was detected from 4 weeks after the virus infection, while the anti-Gag antibody response was absent in the SHIV-C2/1-infected animals. In contrast, both anti-Gag and anti-Env antibody responses were present in animals infected with p-SHIV or the non-pathogenic SHIV-MN. Sequencing of the env gene of isolates of SHIV-C strains showed conserved amino acid changes in the Env C2 and V3 regions that included changes to negatively charged amino acids, in the cytoplasmic region of gp41 that included a 42 amino acid deletion, and in the Nef protein. The pathogenic SHIV-C2/1-monkey model suggests that virus-specific pathogenicity in SHIV infection may be associated with the absence of anti-Gag antibody responses in animals and may be caused by genetic changes during serum passage in vivo.

A descriptive study on rickettsiosis was conducted at the largest referral hospital in Hanoi, Vietnam, to identify epidemiological and clinical characteristics of specific rickettsiosis. Between March 2001 and February 2003, we enrolled 579 patients with acute undifferentiated fever (AUF), excluding patients with malaria, dengue fever, and typhoid fever, and serologically tested for Orientia tsutsugamushi and Rickettsia typhi. Of the patients, 237 (40.9%) and 193 (33.3%) had scrub and murine typhus, respectively, and 149 (25.7%) had neither of them (non–scrub and murine typhus [non-ST/MT]). The proportion of murine typhus was highest among patients living in Hanoi whereas that of scrub typhus was highest in national or regional border areas. The presence of an eschar, dyspnea, hypotension, and lymphadenopathy was significantly associated with a diagnosis of scrub typhus (OR = 46.56, 10.90, 9.01, and 7.92, respectively). Patients with murine typhus were less likely to have these findings but more likely to have myalgia, rash, and relative bradycardia (OR = 1.60, 1.56, and 1.45, respectively). Scrub typhus and murine typhus were shown to be common causes of AUF in northern Vietnam although the occurrence of spotted fever group rickettsiae was not determined. Clinical and epidemiological information may help local clinicians make clinical diagnosis of specific rickettsioses in a resource-limited setting.