jarun011 via Getty Images
川崎市に住む10代の男性が2月25日、ジカ熱に発症していたことが分かった。男性はブラジルから帰国し、発熱や発疹などの症状を訴えていたという。2015年に中南米で感染が拡大して以降、国内で感染者が発見されたのは初めて。NHKニュースなどが報じた。
共同通信によると、国立感染症研究所のウイルス検査で感染が判明した。冬場の現在は、ウイルスを媒介する蚊が活動していないため国内で感染が広がる状況ではないという。
国内でジカ熱の感染者が確認されるのは4人目で、2013年以降、フランス領ポリネシアとタイから帰国した日本人3人が、現地で蚊にさされ帰国後に発症していた。
■ジカ熱とは？
ジカ熱は、ジカウイルスを持つ蚊に刺されることで発症する感染症だ。2015年5月のブラジルを皮切りに、中南米を中心に25の国と地域に拡大。感染者は感染者は今後400万人に上る恐れがあるとみられている。
妊婦が感染すると新生児に脳の成長に障害が出て小頭症を引き起こす恐れがあり、世界保健機関（WHO）は1日、「国際的に懸念される公衆の保健上の緊急事態」を宣言している。
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Colombia Zika(01 of30)
A gynecologist examines a rash on the arm of six-weeks pregnant Daniela Rodriguez, 19, who was diagnosed with the Zika virus at the Erasmo Meoz Hospital in Cucuta, Colombia, Thursday, Feb. 11, 2016. The most common symptoms of Zika are fever, rash, joint pain, or conjunctivitis. (AP Photo/Ricardo Mazalan) (credit:ASSOCIATED PRESS)
Pictures Of The Week Photo Gallery(02 of30)
Enclosed in a mosquito net, Nadia Gonzalez recovers from a bout of dengue fever at a hospital in Luque, Paraguay Friday, Feb. 5, 2016. Dengue, like the Zika virus, is transmitted by the same vector, the Aedes aegypti mosquito. Zika was discovered in a Ugandan forest in 1947 and until last year, the virus had never caused serious disease, but has now spread to more than 20 countries. (AP Photo/Jorge Saenz) (credit:ASSOCIATED PRESS)
Brazil Zika Mosquito Eradication(03 of30)
In this Feb. 1, 2016 photo, a technician from the British biotec company Oxitec holds a container of Aedes aegypti mosquitoes that were genetically modified to produce offspring that don\'t live, in Campinas, Brazil, before releasing them into the wild as part of an effort to kill the local Aedes population, a vector for the Zika virus. The concern is not the disease itself, Zikaâs immediate effects are mild, consisting mostly of a moderate fever and a rash, and only a fifth of those afflicted notice any symptoms. But Brazilian authorities say also they have detected a spike in cases of microcephaly, which leaves infants with unusually small heads and can result in brain damage and a host of developmental and health problems. The link between Zika and microcephaly is as yet unproven. (AP Photo/Andre Penner) (credit:ASSOCIATED PRESS)
El Salvador Zika Virus Rich and Poor(04 of30)
In this Jan. 28, 2016 photo, a city worker fumigates a classroom in a mosquito eradication effort to battle the insect blamed for spreading a virus suspected of causing birth defects, in Santa Tecla, El Salvador. While anyone can be bitten by the Aedes aegypti mosquito that transmits Zika, dengue, chikungunya and yellow fever, public health experts agree that the poor are more vulnerable because they often lack amenities that help diminish the risk, such as air conditioning and window screens. (AP Photo/Salvador Melendez) (credit:ASSOCIATED PRESS)
El Salvador Zika(05 of30)
In this Jan. 28, 2016 photo, a city worker fumigates a parking lot in an eradication effort to battle the mosquito blamed for spreading a virus suspected of causing birth defects, in Santa Tecla, El Salvador. While anyone can be bitten by the Aedes aegypti mosquito that transmits Zika, dengue, chikungunya and yellow fever, public health experts agree that the poor are more vulnerable because they often lack amenities that help diminish the risk, such as air conditioning and window screens. (AP Photo/Salvador Melendez) (credit:ASSOCIATED PRESS)
Argentina Zika(06 of30)
A fumigation brigade spray an area of Chacabuco Park in a Aedes mosquito control effort, in Buenos Aires, Argentina, Wednesday, Jan. 27, 2016. Zika virus is spread by the same Aedes mosquito as dengue fever and chikunguya. The U.S. Centers for Disease Control says researchers have found strong evidence of a possible link between Zika and a surge of birth defects in Brazil. (AP Photo/Natacha Pisarenko) (credit:ASSOCIATED PRESS)
CUBA-HEALTH-ZIKA-FUMIGATION(07 of30)
A member of the Cuban army fumigates against the Aedes aegypti mosquito to prevent the spread of zika, chikungunya and dengue, in Havana, on February 23, 2016. Cuban President Raul Castro announced Monday that 9,200 troops and police have been mobilized in a campaign to eliminate mosquitoes and protect the country against the Zika virus. Cuba has not officially recorded any cases of the mosquito-borne virus, which is strongly suspected of causing serious birth defects in babies born to infected mothers. But 28 countries and territories in the Americas and the Caribbean have reported cases of active Zika transmission, with 1.5 million in Brazil, the hardest-hit country. AFP PHOTO / YAMIL LAGE / AFP / YAMIL LAGE (Photo credit should read YAMIL LAGE/AFP/Getty Images) (credit:YAMIL LAGE via Getty Images)
CUBA-HEALTH-ZIKA-FUMIGATION(08 of30)
A member of the Cuban army fumigates against the Aedes aegypti mosquito to prevent the spread of zika, chikungunya and dengue, in Havana, on February 23, 2016. Cuban President Raul Castro announced Monday that 9,200 troops and police have been mobilized in a campaign to eliminate mosquitoes and protect the country against the Zika virus. Cuba has not officially recorded any cases of the mosquito-borne virus, which is strongly suspected of causing serious birth defects in babies born to infected mothers. But 28 countries and territories in the Americas and the Caribbean have reported cases of active Zika transmission, with 1.5 million in Brazil, the hardest-hit country. AFP PHOTO / YAMIL LAGE / AFP / YAMIL LAGE (Photo credit should read YAMIL LAGE/AFP/Getty Images) (credit:YAMIL LAGE via Getty Images)
CUBA-HEALTH-ZIKA-FUMIGATION(09 of30)
A member of the Cuban army takes part in the fumigation campaign against the Aedes aegypti mosquito to prevent the spread of zika, chikungunya and dengue, in Havana, on February 23, 2016. Cuban President Raul Castro announced Monday that 9,200 troops and police have been mobilized in a campaign to eliminate mosquitoes and protect the country against the Zika virus. Cuba has not officially recorded any cases of the mosquito-borne virus, which is strongly suspected of causing serious birth defects in babies born to infected mothers. But 28 countries and territories in the Americas and the Caribbean have reported cases of active Zika transmission, with 1.5 million in Brazil, the hardest-hit country. AFP PHOTO / YAMIL LAGE / AFP / YAMIL LAGE (Photo credit should read YAMIL LAGE/AFP/Getty Images) (credit:YAMIL LAGE via Getty Images)
CUBA-HEALTH-ZIKA-FUMIGATION(10 of30)
A member of the Cuban army takes part in the fumigation campaign against the Aedes aegypti mosquito to prevent the spread of zika, chikungunya and dengue, in Havana, on February 23, 2016. Cuban President Raul Castro announced Monday that 9,200 troops and police have been mobilized in a campaign to eliminate mosquitoes and protect the country against the Zika virus. Cuba has not officially recorded any cases of the mosquito-borne virus, which is strongly suspected of causing serious birth defects in babies born to infected mothers. But 28 countries and territories in the Americas and the Caribbean have reported cases of active Zika transmission, with 1.5 million in Brazil, the hardest-hit country. AFP PHOTO / YAMIL LAGE / AFP / YAMIL LAGE (Photo credit should read YAMIL LAGE/AFP/Getty Images) (credit:YAMIL LAGE via Getty Images)
CUBA-HEALTH-ZIKA-FUMIGATION(11 of30)
A member of the Cuban army fumigates against the Aedes aegypti mosquito to prevent the spread of zika, chikungunya and dengue, in Havana, on February 23, 2016. Cuban President Raul Castro announced Monday that 9,200 troops and police have been mobilized in a campaign to eliminate mosquitoes and protect the country against the Zika virus. Cuba has not officially recorded any cases of the mosquito-borne virus, which is strongly suspected of causing serious birth defects in babies born to infected mothers. But 28 countries and territories in the Americas and the Caribbean have reported cases of active Zika transmission, with 1.5 million in Brazil, the hardest-hit country. AFP PHOTO / YAMIL LAGE / AFP / YAMIL LAGE (Photo credit should read YAMIL LAGE/AFP/Getty Images) (credit:YAMIL LAGE via Getty Images)
TOPSHOT-CUBA-HEALTH-ZIKA-FUMIGATION(12 of30)
TOPSHOT - Health authorities with the help of the Cuban army fumigate against the Aedes aegypti mosquito to prevent the spread of zika, chikungunya and dengue in a street of Havana, on February 23, 2016. Cuban President Raul Castro announced Monday that 9,200 troops and police have been mobilized in a campaign to eliminate mosquitoes and protect the country against the Zika virus. Cuba has not officially recorded any cases of the mosquito-borne virus, which is strongly suspected of causing serious birth defects in babies born to infected mothers. But 28 countries and territories in the Americas and the Caribbean have reported cases of active Zika transmission, with 1.5 million in Brazil, the hardest-hit country. AFP PHOTO / YAMIL LAGE / AFP / YAMIL LAGE (Photo credit should read YAMIL LAGE/AFP/Getty Images) (credit:YAMIL LAGE via Getty Images)
ARGENTINA-LA PLATA-HEALTH-ZIKA-FEATURES(13 of30)
LA PLATA, Feb. 18, 2016 -- Image taken on Feb. 17, 2016 shows Dr. Juan Garcia, Director of the Center for Parasitological Studies and Vectors of the Faculty of Natural Sciences of La Plata National University, looking at a sample of Aedes aegypti mosquitoes sheltered for study at one of the Centre laboratories, in La Plata city, Argentina. CEPAVE scientists are working on a biological incecticide to fight the moquito that tramsmits the zika, dengue and chikungunya fever. (Xinhua/Martin Zabala via Getty Images) (credit:Xinhua News Agency via Getty Images)
BRAZIL-HEALTH-ZIKA-VIRUS-SCHOOL(14 of30)
A member of the Brazilian armed forces looks for larvae of the Aedes aegypti mosquito, which transmits dengue and Chikungunya fever and Zika virus, at a school in Brasilia, on February 19, 2016. On Friday, the government held a national day of mobilization against the Zika virus to raise awareness among teachers, students and school officials about the need to eliminate breeding grounds of the mosquito. AFP PHOTO/ EVARISTO SA / AFP / EVARISTO SA (Photo credit should read EVARISTO SA/AFP/Getty Images) (credit:EVARISTO SA via Getty Images)
BRAZIL-HEALTH-ZIKA-MOBILIZATION(15 of30)
A member of the National Health Foundation fumigates against the Aedes aegypti mosquito, vector of the dengue, chikungunya fever and zika viruses, in Gama, 45 km south of Brasilia, on February 17, 2016. Members of the armed forces and technicians from the Ministry of Health have been deployed for two days as part of an awareness campaign against the insect throughout Brazil. AFP PHOTO / EVARISTO SA / AFP / EVARISTO SA (Photo credit should read EVARISTO SA/AFP/Getty Images) (credit:EVARISTO SA via Getty Images)
BRAZIL-HEALTH-ZIKA-MOBILIZATION(16 of30)
A member of the National Health Foundation fumigates against the Aedes aegypti mosquito, vector of the dengue, chikungunya fever and zika viruses, in Gama, 45 km south of Brasilia, on February 17, 2016. Members of the armed forces and technicians from the Ministry of Health have been deployed for two days as part of an awareness campaign against the insect throughout Brazil. AFP PHOTO / EVARISTO SA / AFP / EVARISTO SA (Photo credit should read EVARISTO SA/AFP/Getty Images) (credit:EVARISTO SA via Getty Images)
Fernando Haddad at Zika and Dengue Awareness Campaign(17 of30)
SAO PAULO, BRAZIL - FEBRUARY 13: Mayor of Sao Paulo Fernando Haddad is seen during a combat awareness campaign against Aedes Aegypti mosquito on February 13, 2016 in Sao Paulo, Brazil. (Photo by William Volcov/LatinContent/Getty Images) (credit:Brazil Photo Press/CON via Getty Images)
Fernando Haddad at Zika and Dengue Awareness Campaign(18 of30)
SAO PAULO, BRAZIL - FEBRUARY 13: Mayor of Sao Paulo Fernando Haddad is seen during a combat awareness campaign against Aedes Aegypti mosquito on February 13, 2016 in Sao Paulo, Brazil. (Photo by William Volcov/LatinContent/Getty Images) (credit:Brazil Photo Press/CON via Getty Images)
BRAZIL-HEALTH-ZIKA-CAMPAIGN(19 of30)
Armed forces personnel hand out flyers during an awareness campaign on the day of national mobilization against the Aedes aegypti mosquito that transmits dengue and chikungunya fever and zika virus, in Sao Paulo, Brazil on February 13, 2016. Some 220,000 members of the armed forces have been deployed to visit 3 million homes throughout Brazil during the day. AFP PHOTO / Nelson ALMEIDA / AFP / NELSON ALMEIDA (Photo credit should read NELSON ALMEIDA/AFP/Getty Images) (credit:NELSON ALMEIDA via Getty Images)
BRAZIL-HEALTH-ZIKA-CAMPAIGN(20 of30)
Armed forces personnel hand out flyers during an awareness campaign on the day of national mobilization against the Aedes aegypti mosquito that transmits dengue and chikungunya fever and zika virus, in Sao Paulo, Brazil on February 13, 2016. Some 220,000 members of the armed forces have been deployed to visit 3 million homes throughout Brazil during the day. AFP PHOTO / Nelson ALMEIDA / AFP / NELSON ALMEIDA (Photo credit should read NELSON ALMEIDA/AFP/Getty Images) (credit:NELSON ALMEIDA via Getty Images)
As the zika virus makes news, Cuba intensifies its(21 of30)
SANTA CLARA, VILLA CLARA, CUBA - 2016/02/08: As the zika virus makes news, Cuba intensifies its fumigation campains to erradicate the Aedes aegypti mosquito main source of transmission of the disease. (Photo by Roberto Machado Noa/LightRocket via Getty Images) (credit:Roberto Machado Noa via Getty Images)
MEXICO-HEALTH-ZIKA(22 of30)
Municipality workers help clean the city to prevent Aedes aegypti mosquitos and the spread of Zika, Chikungunya and Dengue in Acapulco, Guerrero State, Mexico on February 8, 2016. AFP PHOTO/ Pedro PARDO / AFP / Pedro PARDO (Photo credit should read PEDRO PARDO/AFP/Getty Images) (credit:PEDRO PARDO via Getty Images)
HONDURAS-HEALTH-ZIKA-PREVENTION(23 of30)
A fireman opens an abandoned house to fumigate against Aedes Aegypti mosquito that transmits Zika virus, as well as viral diseases such as dengue and chikungunya, in Tegucigalpa on February 6, 2016. Honduras on Mondayy declared a state of emergency after officials said the number of Zika infections was rising at an \'alarming\' rate in the Central American country. Since December 16, when the first case of the mosquito-borne virus was detected, there have been more that 4,000 cases of people infected with the virus in Honduras. AFP PHOTO / ORLANDO SIERRA / AFP / ORLANDO SIERRA (Photo credit should read ORLANDO SIERRA/AFP/Getty Images) (credit:ORLANDO SIERRA via Getty Images)
HONDURAS-HEALTH-ZIKA-PREVENTION(24 of30)
People help soldiers fumigate in the fight against Aedes Aegypti mosquito that transmits Zika virus, as well as viral diseases such as dengue and chikungunya, in Tegucigalpa on February 6, 2016. Honduras on Mondayy declared a state of emergency after officials said the number of Zika infections was rising at an \'alarming\' rate in the Central American country. Since December 16, when the first case of the mosquito-borne virus was detected, there have been more that 4,000 cases of people infected with the virus in Honduras. AFP PHOTO / ORLANDO SIERRA / AFP / ORLANDO SIERRA (Photo credit should read ORLANDO SIERRA/AFP/Getty Images) (credit:ORLANDO SIERRA via Getty Images)
MEXICO-HEALTH-ZIKA(25 of30)
A woman covers her mouth and nose as an employee (out of frame) of the Health Secretariat fumigates her home against the Aedes aegypti mosquito to prevent the spread of the Zika, Chikungunya and Dengue in Acapulco, Guerrero State, Mexico on February 2, 2016. AFP PHOTO/ Pedro PARDO / AFP / Pedro PARDO (Photo credit should read PEDRO PARDO/AFP/Getty Images) (credit:PEDRO PARDO via Getty Images)
TOPSHOT-MEXICO-HEALTH-ZIKA(26 of30)
TOPSHOT - An employee of the Health Secretariat fumigates a home against the Aedes aegypti mosquito to prevent the spread of the Zika, Chikungunya and Dengue in Acapulco, Guerrero State, Mexico on February 2, 2016. AFP PHOTO/ Pedro PARDO / AFP / Pedro PARDO (Photo credit should read PEDRO PARDO/AFP/Getty Images) (credit:PEDRO PARDO via Getty Images)
GUATEMALA-HEALTH-ZIKA-VIRUS-ALERT(27 of30)
A woman takes her duck outside while a Health ministry worker fumigates her home against the Aedes aegypti mosquito, vector of the dengue, Zika and Chikungunya viruses in the Bethania neighborhood in Guatemala City on February 2, 2016. World health officials mobilized with emergency response plans and funding pleas Tuesday as fears grow that the Zika virus, blamed for a surge in the number of brain-damaged babies, could spread globally and threaten the Summer Olympics. / AFP / JOHAN ORDONEZ (Photo credit should read JOHAN ORDONEZ/AFP/Getty Images) (credit:JOHAN ORDONEZ via Getty Images)
HONDURAS-HEALTH-ZIKA-ALERT(28 of30)
Health ministry personnel fumigate against the Aedes aegypti mosquito, vector of the dengue, Chikungunya and Zika viruses in Tegucigalpa, , on February 1, 2016. Honduran President Juan Orlando Hernandez on Friday declared the country on a preventive state of alert due to the Zika virus which in the last 44 days killed a person and infected some 1000. AFP PHOTO/Orlando SIERRA. / AFP / ORLANDO SIERRA (Photo credit should read ORLANDO SIERRA/AFP/Getty Images) (credit:ORLANDO SIERRA via Getty Images)
CORRECTION-HONDURAS-HEALTH-DENGUE(29 of30)
A dengue fever patient is treated at \'Hospital Escuela Universitario\' in Tegucigalpa on January 29, 2016. The mosquitoes which carry dengue usually proliferate in times of heavy rain with the illness affecting between 50 and 100 million people in the tropics and subtropics each year, resulting in fever, muscle and joint ache. The disease, which is caused by four strains of virus that are spread by the mosquito Aedes aegypti and for which there is no vaccine, can be fatal, developing into hemorrhagic fever which can lead to shock and internal bleeding. Health authorities have issued a national alert against the Aedes aegypti mosquito, vector of the Dengue, Zika and Chikungunya. AFP PHOTO/Orlando SIERRA / AFP / ORLANDO SIERRA (Photo credit should read ORLANDO SIERRA/AFP/Getty Images) (credit:ORLANDO SIERRA via Getty Images)
CORRECTION-HONDURAS-HEALTH-DENGUE(30 of30)
Dengue fever patient are treated at \'Hospital Escuela Universitario\' in Tegucigalpa on January 29, 2016. The mosquitoes which carry dengue usually proliferate in times of heavy rain with the illness affecting between 50 and 100 million people in the tropics and subtropics each year, resulting in fever, muscle and joint ache. The disease, which is caused by four strains of virus that are spread by the mosquito Aedes aegypti and for which there is no vaccine, can be fatal, developing into hemorrhagic fever which can lead to shock and internal bleeding. Health authorities have issued a national alert against the Aedes aegypti mosquito, vector of the Dengue, Zika and Chikungunya. AFP PHOTO/Orlando SIERRA / AFP / ORLANDO SIERRA (Photo credit should read ORLANDO SIERRA/AFP/Getty Images) (credit:ORLANDO SIERRA via Getty Images)
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