Today the virus is expanding its geographic reach and threatens several billion people on the planet. Dr. Julie Jacobson, director of the Japanese encephalitis program at Seattle-based Program for Appropriate Technology in Health (PATH) said, "This has been a disease of the world's poor."
According to Jacobson most of those killed or maimed by the virus have gone uncounted, misdiagnosed or regarded as the tragic, inevitable victims of an "orphan disease."
Today, the government of India celebrates with PATH for having immunized 9 million children against Japanese encephalitis that was part of a campaign aimed at reaching 11 million in high-risk districts.
Japanese encephalitis infects the brain and is likely to kill or cause permanent brain damage leading to serious illness in perhaps one in 25 infected, killing 30 percent and causing brain damage in perhaps 40 percent. Because of the poor monitoring of the disease it would be reasonable to expect that the annual death toll of 10,000 is a gross underestimate.
At present there is no viable treatment for the infection. Since children are at highest risk, the children of India are the ones being targeted for immunization.
"This is so exciting," said Jacobson, "For many years, at every twist and turn, it looked impossible. But now it's happening."
Credit for this goes in part to the $27 million grant which the Gates Foundation gave to PATH in 2003 to support a vaccination campaign in Asia. But the real reason behind its recent success is because Jacobson and her colleagues were willing to listen to Indian officials and change course.
In 2000, PATH received $25 million from the Gates Foundation to launch an immunization improvement project in Andhra Pradesh to mainly introduce a vaccine against hepatitis B.
At the time local government and health officials agreed to cooperate in the devotion of resources and funding to the project provided the Seattle team would also target Japanese encephalitis.
Jacobson said, "I didn't know anything about it. I was trained in tropical medicine, but even in our specialized textbooks there were maybe two paragraphs about JE."
During the ensuing negotiations Jacobson and her colleagues at PATH found out that the Indians were so adamant about this disease threat because the seasonal arrival of migrating egrets and cranes every year also brought with it the brain fever season. The virus appeared to be spreading in Asia mainly because of these migrations, infecting birds and passed onto humans by mosquitoes feeding on infected animals.
Jacobson said, "The hospitals were just overwhelmed by all these children having seizures, going into comas." However obstacles like the nature of the vaccine itself stood in the way.
As the Andhra Pradesh PATH project gathered momentum Jacobson found that China had what looked like a better vaccine. It was grown from hamster kidney cells, could be delivered in a single dose and was a lot cheaper and easier to manufacture in large amounts.
However as Jacobson said,"India doesn't like to depend upon China for anything," she said. This only changed Uttar Pradesh suffered a massive JE outbreak.
She said,"After the outbreak, the government decided it had to act." PATH, with assistance from the World Health Organization and UNICEF, helped negotiate India's purchase of the Chinese vaccine.
"That was a huge financial risk for them," Jacobson said. But with "good faith" prevailing on all sides, children are now being vaccinated in four other high-risk states: Assam, Uttar Pradesh, Karnataka and West Bengal.
Nepal has also recently decided to launch its own Japanese encephalitis vaccination campaign, Jacobson noted. She said that the ultimate goal is to see the vaccine incorporated as one of the routine immunizations throughout all of Asia where the virus threatens.