Japanese health authorities said Friday that a Zika virus infection has been detected in a boy who returned from Pacific islands in Oceania, the fifth confirmation in the country of the infection of the mosquito-borne virus this year.
The boy in Chiba Prefecture was confirmed to have contracted the virus after he returned to Japan on Wednesday after spending 15 months in Pacific islands in Oceania, said the Ministry of Health, Labor and Welfare and the Chiba Prefectural Government. The ministry only gave the boy's age as being between 10 and 19.
"Since Japan is not in a season where mosquitoes are active, we believe the risk for the spread of the disease is extremely low," a health ministry official said.
While the Zika virus usually causes mild symptoms, such as skin rashes and headaches, it is suspected to cause abnormally small head sizes in newborn children, a condition called microcephaly, when mothers contract the virus during pregnancy. Brazil has seen a rapid increase in such cases.
Zika virus infections have also been reported in such Oceania nations as Fiji, New Caledonia and Samoa.
The boy living in the Chiba city of Shiroi is believed to have contracted the virus before returning to Japan.
The boy developed a fever and rash the day he returned to Japan, and was diagnosed with Zika virus infection the following day through an examination by the Chiba prefectural institute of health research.
The boy said he was bitten by a mosquito before returning to Japan. The fever has gone down and he is staying at home for recovery. His parents have not developed a fever.
So far eight people in Japan have been confirmed to have Zika virus infection since the first such case in the country in 2013, with all of them infected overseas.