Can bird flu cause encephalitis?

The H5N1 bird flu virus may have spread to the brain of the Indonesian woman who contracted bird flu and died yesterday. Bloomberg.com reports that the woman’s condition deteriorated when she developed encephalitis (acute inflammation of the brain) and doctors are trying to determine if H5N1 has caused this infection.

H5N1 typically targets the respiratory system. Flu-like symptoms may include fever, cough, sore throat and muscle aches, but the symptoms may worsen to include pneumonia, severe respiratory diseases (such as acute respiratory distress), and other severe and life-threatening complications.

Neurological symptoms occur rarely with human H5N1 cases. The first report of the H5N1 infecting the brain was in February 2005 from the Feb. 17 issue of the New England Journal of Medicine. Two Vietnamese siblings died of died of encephalitis and were later found to be infected with the virus. The children had severe diarrhea and worsened to seizures, coma and later death. Laboratory tests found the virus in the cerebrospinal fluid, blood, throat and feces of both children.

Human influenza virus is known to cause encephalitis in some cases, said Dr. James D. Campbell, an influenza expert and an assistant professor of pediatrics at the University of Maryland School of Medicine. But encephalitis usually occurs as an aftermath to respiratory disease, he said. “What is unusual is that these cases of encephalitis occurred without respiratory symptoms,” he explained.

Tags: Asia, avian flu, avian influenza, H5N1, Indonesia, encephalitis, flu symptoms