Researchers Develop Possible New RNA Therapy for West Nile Virus

Yale University

A research group at Yale University and from Hanyang University, South Korea, developed a new RNA therapy for West Nile Virus. The findings, which were studied in mice, was published in Cell Host & Microbe.

The study, titled, “Small Interfering RNA-Mediated Control of Virus Replication in the CNS Is Therapeutic and Enables Natural Immunity to West Nile Virus,” describes an intranasal therapeutic for the disease. West Nile Virus (WNV) is transmitted by mosquitoes and was tested in mice. The researchers used a rabies virus-derived neuron-targeting peptide (RVG9R) to deliver the therapeutic to the central nervous system.

The leader author, Priti Kumar, an associate professor of infectious disease at Yale School of Medicine, believes the study may lead the way for treating WNV. There are currently no approved vaccines or therapies for WNV.

ScienceDaily notes, “To investigate a possible new therapy to treat West Nile Virus disease, Kumar and her colleagues focused on a small ‘interfering’ RNA molecule developed in her lab. The RNA acts against multiple mosquito-borne flaviviruses. To direct the RNA to infected cells, they packaged it in a peptide derived from the rabies virus, which is able to enter nerve cells. The final step was to deliver the therapy through the nose where it could bypass natural barriers protecting the brain.”

The results of the study in mice found that it reduced the WNV in the brain and prevented damage to nerve cells. Mice receiving the treatment had a 90 percent survival rate after infection compared to placebo. And in the surviving mice, the immune system cleared the virus, giving long-term protection from future exposure.

The work was partially funded by grants from the National Institutes of Health. Kumar and Yanyang University’s San Kyung Lee are co-founders of Signet Biotech.

Although noting that the mouse nose is different from that of human beings, the researchers hope further study will have broad applications in people. “In translation, it should be an effective strategy for people,” Kumar said in a statement.

According to the U.S. Centers for Disease Control and Prevention (CDC), about one in five people who are infected by WNV develop a fever and other symptoms. The rest show no symptoms. About 1 out of 150 infected individuals develop a serious, sometimes deadly, disease. Most who develop the disease have fever, headache, body aches, joint pain, vomiting, diarrhea or rash. Most affected individuals recover completely, but fatigue and weakness often lasts for several weeks to several months.

In the rare cases where the disease is fatal, they develop central nervous system disorders such as encephalitis or meningitis. Symptoms of severe disease include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis. Although individuals over 60 years of age are at greatest risk, it can occur in people of any age. Individuals who are immunocompromised, or have cancer, diabetes, high blood pressure, kidney disease or have received organ transplants are at higher risk.

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