Confirmation of Japan's first Zika infection since an outbreak erupted in Latin America last year has elevated concern about the disease.
The mosquito-borne virus was detected in a male high school student from Kawasaki days after he returned from a vacation in Brazil with his family.
While Zika has made headlines worldwide for its suspected link to birth defects in Brazil, experts say its symptoms tend to be mild. They also say a massive outbreak in Japan is unlikely at the moment because the mosquitoes are dormant.