Next to dengue, Japanese encephalitis or JE is perhaps one of the diseases that Filipino families should watch out for. Similar to dengue, the disease is spread by mosquitoes—Culex species—infected with the JE virus.
JE can be difficult to diagnose because in most individuals it causes nonspecific initial symptoms. While it begins like a flu (head and body aches, fever and tiredness), JE progresses to neck stiffness and convulsions, and ends by killing up to 30 percent of its victims and leaving thousands more with neurological impairment.
Because the disease is difficult to diagnose and awareness of it is low, the global incidence of JE is unknown. Nevertheless, the World Health Organization estimates that JE claims 10,000 to 15,000 lives a year. Moreover, the international health organization PATH estimates that three billion people live in areas at risk for JE and up to 60,000 cases are reported annually.
Vaccine introduced
Dr. Ruby Dizon, medical director of Sanofi Pasteur, said: “Over half of people who survive a case of Japanese encephalitis experience longer-term psychosocial, behavioral or motor deficits. This can lead to complications such as learning difficulties, behavioral problems and more subtle neurological signs.” Sanofi Pasteur recently introduced a vaccine that confers rapid, high-level protection against JE with just one primary dose.
Considering that there is no treatment for JE, prevention by getting immunized with a JE vaccine may be regarded as the only viable solution. This is the first time a single-dose vaccine against JE is available in the Philippines.
“With a single primary vaccination, the vaccine could protect one from JE,” explained Dizon. He added that tourists and business travelers, medical and military personnel as well as those living or staying in areas where cases have been detected would benefit from the immunization.
Dizon said one should realize the lifelong toll that JE takes on its survivors. Up to half of them suffer permanent neurological damage, such as paralysis, recurrent seizures, or the inability to speak.
Since late 1800s
JE was first recognized in Japan in the late 1800s. Since then, the disease has increasingly been recognized throughout most countries of East and Southeast Asia, where it is the leading cause of childhood viral encephalitis.
Interestingly, while the incidence of JE varies by country and is usually seasonal, the disease occurs all year round in Malaysia, Indonesia and the Philippines, where rain falls throughout the year.
The JE virus is hosted by wading birds like herons and egrets, which flock to rice paddy fields and by the pigs raised in farms. Thus, transmission principally occurs in areas within or near ricefields, flood irrigation, swamps and marshes.
The JE vaccine was introduced during the 14th Philippine national immunization conference on Nov. 7 at Summit Ridge, Tagaytay City. The event was attended by vaccine advocates from both private and public sectors aiming to sustain the reduction of vaccine preventable diseases.