Opening the door to potential new treatments for West Nile virus infection researchers have discovered how the most severe forms of the mosquito-borne illness cause memory loss and mood disorders. Half of patients who survive the most damaging kind of West Nile infection often go on to develop memory loss learning difficulties a lack of concentration and irritability. But exactly why this happens has been a mystery until now the study said. Researchers discovered that the virus does not kill off neurons but sparks inflammation that prunes synapses the connections that carry messages between nerve cells. What we found in