Warning issued against mosquito-borne viral infection

Health authorities issued a nationwide warning for Japanese encephalitis — brain swelling caused by a mosquito-borne viral infection — after they confirmed the presence of a mosquito vector here. The Korea Centers for Disease Control and Prevention (KCDC) said Tuesday, culex pipiens mosquitoes were found in Busan April 1, more than 20 days earlier than in previous years.

Almost all, or 99 percent, of people infected with the vaccine-preventable disease show either no symptoms or experience a mild fever or headache. But the remaining 1 percent can quickly develop a high fever, headache, disorientation, neck stiffness, coma, seizures, spastic paralysis and death.

Of 185 patients infected between 2007 and last year, 27 died due to the disease with a fatality rate as high as 30 percent.

More than 90 percent of the infected were aged over 40, the KCDC said, advising people to take particular caution against bites from mosquitoes.

It added that they should wear long sleeves during outdoor activities, especially in rural or agricultural areas associated with rice farming.