Severe fever with thrombocytopenia syndrome virus (SFTSV) is an emerging tick-borne bunyavirus that causes severe disease in humans with case fatality rates of approximately 30%. There are few treatment options for SFTSV infection. SFTSV RNA synthesis is conducted using a virus-encoded complex with RNA-dependent RNA polymerase activity that is required for viral propagation. This complex and its activities are, therefore, potential antiviral targets. A library of small molecule compounds was screened using a high-throughput screening (HTS) based on an SFTSV minigenome assay (MGA) in a 96-well microplate format to identify potential lead inhibitors of SFTSV RNA synthesis. The assay confirmed inhibitory activities of previously reported SFTSV inhibitors, favipiravir, and ribavirin. A small-scale screening using MGA identified four candidate inhibitors that inhibited SFTSV minigenome activity by more than 80% while exhibiting less than 20% cell cytotoxicity with selectivity index (SI) values of more than 100. These included mycophenolate mofetil, methotrexate, clofarabine, and bleomycin. Overall, these data demonstrate that the SFTSV MGA is useful for anti-SFTSV drug development research.

Respiratory syncytial virus (RSV) is associated with adverse outcomes among immunocompromised patients. Inhaled ribavirin has been shown to improve mortality rates. The Small-Particle Aerosol Generator delivery system (SPAG-2) is the only FDA-cleared device to deliver inhaled ribavirin. However, it is difficult to set up and maintain. We developed a method for delivery of this medication using the vibrating mesh nebulizer (Aerogen®). We did not observe any adverse events with this method.

The prevalence and case fatality rates of Pediatric Lassa fever disease (LFD) are not well documented. This study was aimed at determining the prevalence, pattern and outcome of Pediatric LFD. It was a prospective observational study. A total of 183 subjects that met the criteria for LFD suspects were recruited consecutively and subjected to Lassa virus PCR test. Structured questionnaire was used to collect information. Of the 183 children recruited, 24 tested positive to Lassa virus PCR, giving a positivity rate of 13.1%. Mean duration of illness at presentation was 8.54 ± 3.83 days. Fever, abdominal pain and vomiting were the three highest presenting complaints. Seven out of 24 children died giving a case fatality rate (CFR) of 29.2%. Subjects with bleeding, poor urine output, convulsions and unconsciousness were more likely to die of LFD. Positivity and CFR of LFD are high. Improved case finding and prompt treatment is advocated.

The emergence of new SARSCoV-2 variants can affect vaccine efficacy, laboratory diagnosis and therapies already available, triggering interest in the search for antiviral agents for SARSCoV-2 infections. Ribavirin (RBV) is a broad-spectrum antiviral with demonstrated in vitro activity against multiple viruses, including SARSCoV-2. Methods. This retrospective study evaluated the dynamic and viral clearance of SARSCoV-2 in hospitalized adult participants (PTs) with COVID-19 pneumonia who received RBV aerosol within a compassionate use study. Was also assessed the impact of RBV on the clinical outcome and the mutational profile of SARSCoV-2. Results. The median RNA values measured in nine PTs included in the study de-creased from baseline to discharge (at BL, threshold cycle (Ct)=22.4, IQR 19.84-5.07; at discharge, Ct=27.92, IQR 26.43-36.11). Seven/9 PTs experienced a clinical improvement, while two PTs deceased during hos-pitalization. In PTs with a favorable outcome the virus clearance rate at discharge was 28.6%. The cumulative clearance rate was 71.4% within day 14th from discharge. A mutational pattern after RBV was detected in 3/5 PTs in whom was available whole genome sequencing. Conclusions. RBV may limit SARSCOV-2 replication resulting in a favorable clinical outcome. Ribavirin may also contribute to the mutational spectrum of SARSCoV-2.

Combining antiviral drugs with different mechanisms of action can help prevent the development of resistance by attacking the infectious agent through multiple pathways. Additionally, by using faster and more economical screening methods, effective synergistic drug candidates can be rapidly identified, facilitating faster paths to clinical testing. In this work, a rapid method was standardized to identify possible synergisms from drug combinations. We analyzed the possible reduction of antiviral effective concentration of drugs already approved by the FDA, such as ivermectin  (IVM), ribavirin (RIBA) and acyclovir (ACV) against Zika virus (ZIKV), Chikungunya virus (CHIKV) and herpes virus type 2 (HHV-2). Essential oils (EOs) were also included in the study since they have been reported for more than a couple of decades to have broad-spectrum antiviral activity. We also continued studying the antiviral properties of one of our patented molecule with broad-spectrum antiviral activity, the ferruginol analogue 18-(phthalimid-2-yl)ferruginol (phthFGL). In general, the combination of IVM, phthFGL and Oregano EO showed the greatest synergism potential against CHIKV, ZIKV and HHV-2, obtaining a reduction in the EC99 value of up to ~8, and ~27, and ~12-fold for CHIKV, in example, respectively. The ternary combination RIBA, phthFGL, Oregano EO was slightly more efficient than the binary combination RIBA/phthFGL but much less efficient than IVM, phthFGL, Oregano EO which indicates that IVM could contribute more to the differentiations of cell targets (for example by inhibition of host heterodimeric importin IMP α/β1 complex) than ribavirin. PhthFGL showed a good pharmacokinetic profile.