Atovaquone and Berberine Chloride Reduce SARS-CoV-2 Replication In Vitro.

Epidemic RNA viruses seem to arise year after year leading to countless infections and devastating disease. SARS-CoV-2 is the most recent of these viruses, but there will undoubtedly be more to come. While effective SARS-CoV-2 vaccines are being deployed, one approach that is still missing is effective antivirals that can be used at the onset of infections and therefore prevent pandemics. Here, we screened FDA-approved compounds against SARS-CoV-2. We found that atovaquone, a pyrimidine biosynthesis inhibitor, is able to reduce SARS-CoV-2 infection in human lung cells. In addition, we found that berberine chloride, a plant-based compound used in holistic medicine, was able to inhibit SARS-CoV-2 infection in cells through direct interaction with the virion. Taken together, these studies highlight potential avenues of antiviral development to block emerging viruses. Such proactive approaches, conducted well before the next pandemic, will be essential to have drugs ready for when the next emerging virus hits.

Atovaquone Inhibits Arbovirus Replication through the Depletion of Intracellular Nucleotides.

Arthropod-borne viruses represent a significant public health threat worldwide, yet there are few antiviral therapies or prophylaxes targeting these pathogens. In particular, the development of novel antivirals for high-risk populations such as pregnant women is essential to prevent devastating disease such as that which was experienced with the recent outbreak of Zika virus (ZIKV) in the Americas. One potential avenue to identify new and pregnancy-acceptable antiviral compounds is to repurpose well-known and widely used FDA-approved drugs. In this study, we addressed the antiviral role of atovaquone, an FDA Pregnancy Category C drug and pyrimidine biosynthesis inhibitor used for the prevention and treatment of parasitic infections. We found that atovaquone was able to inhibit ZIKV and chikungunya virus virion production in human cells and that this antiviral effect occurred early during infection at the initial steps of viral RNA replication. Moreover, we were able to complement viral replication and virion production with the addition of exogenous pyrimidine nucleosides, indicating that atovaquone functions through the inhibition of the pyrimidine biosynthesis pathway to inhibit viral replication. Finally, using an ex vivo human placental tissue model, we found that atovaquone could limit ZIKV infection in a dose-dependent manner, providing evidence that atovaquone may function as an antiviral in humans. Taken together, these studies suggest that atovaquone could be a broad-spectrum antiviral drug and a potential attractive candidate for the prophylaxis or treatment of arbovirus infection in vulnerable populations, such as pregnant women and children.IMPORTANCE The ability to protect vulnerable populations such as pregnant women and children from Zika virus and other arbovirus infections is essential to preventing the devastating complications induced by these viruses. One class of antiviral therapies may lie in known pregnancy-acceptable drugs that have the potential to mitigate arbovirus infections and disease, yet this has not been explored in detail. In this study, we show that the common antiparasitic drug atovaquone inhibits arbovirus replication through intracellular nucleotide depletion and can impair ZIKV infection in an ex vivo human placental explant model. Our study provides a novel function for atovaquone and highlights that the rediscovery of pregnancy-acceptable drugs with potential antiviral effects can be the key to better addressing the immediate need for treating viral infections and preventing potential birth complications and future disease.

A Rare Presentation of Cryptococcal Meningitis and Cerebellitis in an Asplenic Patient, Seronegative for Human Immunodeficiency Virus (HIV).

BACKGROUND Cryptococcal meningitis in patients who are seronegative for the human immunodeficiency virus (HIV) and in patients who are splenectomized is rare. This report is an unusual case of meningeal and cerebellar infection due to the encapsulated yeast, Cryptococcus neoformans, which has not previously been associated with asplenia. CASE REPORT A 65-year-old HIV-negative patient with a previous splenectomy, presented with a three-day history of fever, vomiting, and headache. His symptoms progressed to generalized body aches, persistent fever, and neck stiffness. A lumbar puncture was performed, and cerebrospinal fluid (CSF) culture grew Cryptococcus neoformans. Treatment commenced with intravenous amphotericin B and flucytosine. The patient required serial lumbar punctures due to persistent raised intracranial pressure (ICP). Magnetic resonance imaging (MRI) of the brain showed acute meningitis and cerebellitis. Antimicrobial therapy and CSF drainage resulted in clinical improvement.  CONCLUSIONS The occurrence of meningeal and cerebellar cryptococcosis in an asplenic patient is rare, and few cases have been previously reported. This case report highlights the possibility of invasive cryptococcal infection, or cryptococcosis, in asplenic individuals in the absence of HIV infection.