Structure of West Nile Virus

West Nile virus causes no symptoms in most people, but in a small number of cases infection develops into serious illness. Credit: Science Picture Co./SPL

Virology

RNA nasal spray subdues brain infection

Potential therapy slashes virus levels and mortality rates in mice.

Designer RNA molecules delivered through the nose show early promise for treating West Nile fever, trials in mice show.

No effective therapies exist for the illness caused by a mosquito-borne virus, which can invade the brain. Priti Kumar at Yale University School of Medicine in New Haven, Connecticut; Sang Kyung Lee at Hanyang University in Seoul; and their colleagues developed a small RNA molecule that stymies reproduction of the virus. The researchers then attached the RNA to a molecule known to shuttle cargo into neurons.

The team administered the experimental therapy to mice using a nasal spray. In animals with late-stage brain disease, treatment greatly lowered viral concentrations in the brain and increased survival rates compared with untreated animals. Survivors also developed long-term protection against future infection.