In Vitro Antiviral Activity of Nordihydroguaiaretic Acid against SARS-CoV-2.

The coronavirus infectious disease 2019 (COVID-19) is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and has been spreading rapidly worldwide, creating a pandemic. This article describes the evaluation of the antiviral activity of nordihydroguaiaretic acid (NDGA), a molecule found in Creosote bush (Larrea tridentata) leaves, against SARS-CoV-2 in vitro. A 35 µM concentration of NDGA was not toxic to Vero cells and exhibited a remarkable inhibitory effect on the SARS-CoV-2 cytopathic effect, viral plaque formation, RNA replication, and expression of the SARS-CoV-2 spike glycoprotein. The 50% effective concentration for NDGA was as low as 16.97 µM. Our results show that NDGA could be a promising therapeutic candidate against SARS-CoV-2.

In vitro inhibition of SARS-CoV-2 Infection by dry algae powders.

Chlorella spp., Spirulina spp., and fucoidan dry powders, are commercialized as food supplements and are considered safe for human consumption. Their broad-spectrum antiviral properties have been studied, however, their effect against SARS-CoV-2 remains unknown. We investigated the potential antiviral activity of three algae powders: Chlorella vulgaris, Arthrospira maxima (Spirulina) and fucoidan purified from marine brown algae Sargassum spp. against SARS-CoV-2 infection in vitro. Vero cells were incubated with 70 µg/ml of each algae powder and either 50 or 100 TCID50/ml of SARS-CoV-2, in two types of experiments (pretreatment and simultaneous) and comparing two kinds of solvents (DMEM and DMSO). Chlorella vulgaris powder, inhibited SARS-CoV-2 infection in all assays; viral RNA was significantly reduced in supernatants at 24, 48, 72, and 96 h post-infection, the highest difference in viral load (8000-fold) was observed after 96 h. Arthrospira maxima powder inhibited SARS-CoV-2 infection using 50 TCID50/ml for both experimental schemes, but protection percent was lower when viral inoculum was increase to 100 TCID50/ml; viral RNA decreased 48 h after infection, reaching a 250-fold difference at 72 h. Fucoidan powder partially inhibited SARS-CoV-2 infection since no CPE was observed in 62.5% of trated cultures in DMEM, but the antiviral activity was increased to 100% of protection when DMSO was used as solvent. All the algae samples showed high antiviral activity against SARS-CoV-2 with a SI above of 18. These results suggest that all three algae samples are potential therapeutic candidates for the treatment of COVID-19.

Possible Routes for Zika Virus Vertical Transmission in Human Placenta: A Comprehensive Review.

Zika virus (ZIKV) infections have gained notoriety due to congenital abnormalities. Pregnant women have a greater risk of ZIKV infection and consequent transmission to their progeny due to the immunological changes associated with pregnancy. ZIKV has been detected in amniotic fluid, as well as in fetal and neonatal tissues of infected pregnant women. However, the mechanism by which ZIKV reaches the fetus is not well understood. The four dengue virus serotypes have been the most widely used flaviviruses to elucidate the host-cell entry pathways. Nevertheless, it is of increasing interest to understand the specific interaction between ZIKV and the host cell, especially in the gestation period. Herein, the authors describe the mechanisms of prenatal vertical infection of ZIKV based on results from in vitro, in vivo, and ex vivo studies, including murine models and nonhuman primates. It also includes up-to-date knowledge from ex vivo and natural infections in pregnant women explaining the vertical transmission along four tracks: transplacental, paracellular, transcytosis mediated by extracellular vesicles, and paraplacental route and the antibody-dependent enhancement process. A global understanding of the diverse pathways used by ZIKV to cross the placental barrier and access the fetus, along with a better comprehension of the pathogenesis of ZIKV in pregnant females, may constitute a fundamental role in the design of antiviral drugs to reduce congenital disabilities associated with ZIKV.

Zika Virus in Salivary Glands of Five Different Species of Wild-Caught Mosquitoes from Mexico.

Zika virus (ZIKV) is a mosquito-borne pathogen, and Aedes aegypti has been identified as the main vector of the disease. Other mosquito species in the Aedes and Culex genera have been suggested to have the potential for being competent vectors based on experimental exposition of mosquitoes to an infectious blood meal containing ZIKV. Here, we report the isolation in cell culture of ZIKV obtained from different body parts of wild-caught female mosquitoes (Ae. aegypti, Ae. vexans, Cx. quinquefasciatus, Cx. coronator, and Cx. tarsalis) and whole male mosquitoes (Ae. aegypti and Cx. quinquefasciatus) in Mexico. Importantly, this is the first report that shows the presence of the virus in the salivary glands of the wild-caught female mosquitoes species, Cx. coronator, Cx. tarsalis, and Ae. vexans. Our findings strongly suggest that all the species reported herein are potential vectors for ZIKV.

Author Correction: Zika Virus in Salivary Glands of Five Different Species of Wild-Caught Mosquitoes from Mexico.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.