A 17-year-old male was diagnosed with Japanese encephalitis (JE) earlier this month, making it the nation’s second confirmed case of the viral disease this year, the Centers for Disease Control (CDC) said yesterday.
The teen exhibited symptoms, including fever, headaches and vomiting on May 31, and later experienced reduced consciousness and a stiff neck, the agency said, adding that his illness was confirmed to be Japanese encephalitis after he was hospitalized on June 1.
The young man has recovered and the three people living with him have not developed any suspicious symptoms, the CDC said.
“The patient was exposed to risk factors by living close to pig farms and paddy fields, as pigs act as amplifiers of the virus, infecting mosquitoes that take blood from them while remaining healthy, and wading birds carry the virus,” CDC physician Philip Yi-chun Lo (羅一鈞) said.
According to the CDC’s disease surveillance data, the transmission season of the virus ranges from May to October and reach its peak in June and July.
A mass vaccination program that started in 1968 has significantly reduced the number of infections, leaving about 20 to 30 cases with zero to two deaths a year in recent years, which is a big improvement from the 273 cases of infection and 206 deaths a year before the vaccination program, the CDC said.
“The 17-year-old patient actually completed the four-dose JE vaccine in 2003,” Lo said, adding that “the vaccine was not 100 percent effective.”
“Still, since most of those who were immunized are protected from the virus, it is still highly recommended that people be vaccinated,” Lo said.
In other news, the CDC said a second case of a human hard-bodied tick bite from Dermacentor taiwanesis has been reported, adding that the first case in recorded history was only confirmed two years ago.
A woman and her daughter from New Taipei City’s (新北市) Shuangsi District (雙溪) found small bug bites along the hairlines and on the insides of their arms and thighs early last month, the agency said.
“The bite marks grew bigger and became itchy and red, and the woman found a bug moving at the site of a bite. She used tweezers to pull the bug out and sought medical attention in early June,” CDC researcher Wang Hsi-chieh (王錫杰) said.
“The size of the bug brought to health authorities by the woman was about 0.14cm. The CDC has preliminarily confirmed the bug to be a nymph tick of Dermacentor taiwanesis, at the third stage of the tick’s four-stage life cycle,” he said.
This species of hard ticks mainly live in forests, which correspond with the woman’s living environment, Wang said.
Adult ticks mainly feed on large animals such as wild boars and Formosan black bears, while rodents or other small mammals are the common feeding hosts of nymph ticks, Wang said.
The agency said the blood sample from the woman has tested negative for Lyme disease, which can be caused by tick bites and can leave the infected with chronic neurological problems if untreated. It said it would conduct further tests to see whether the tick is pathogenic.