茲卡病毒傳播範圍擴大 速度加快

Travel warnings about the Zika virus, especially for pregnant women, are very much in the news now, but the germ was discovered more than a half century ago, and you may have already visited places where it flourishes.

目前關於茲卡病毒的旅行警告，尤其是對孕婦的警告，受到了新聞媒體的廣泛報道。但這種病毒早在半個世紀之前就已被發現，你可能已經去過茲卡流行的地方了。

As of December 2015, the Centers for Disease Control and Prevention in Atlanta reported evidence of transmission of the virus in at least 45 countries in Africa, Asia, the Americas and the Pacific islands. There were cases reported in Mexico and El Salvador in November 2015, and one in Puerto Rico in December. Travelers should be concerned, but there is no need for panic.

截至2015年12月，亞特蘭大的美國疾病控制與預防中心（Centers for Disease Control and Prevention，簡稱CDC）收集到了茲卡病毒在非洲、亞洲、美洲和太平洋島嶼上至少45個國家傳播的證據。2015年11月，墨西哥和薩爾瓦多出現過這種病例，12月波多黎各也出現了一例。旅行者應該加以重視，但也沒有必要恐慌。

“There are two things that make people pay attention,” said one expert, Dr. Kamran Khan, an infectious disease doctor and scientist at St. Michael’s Hospital in Toronto. “It showed up where it has never been before, and it is rapidly spreading. That’s because Aedes mosquitoes are widespread throughout most of Latin America and parts of the U.S.”

“有兩件事情引起了人們的關注，”這方面的專家卡姆蘭·汗博士(Kamran Khan)表示。“它出現在了以前沒有到過的地方，而且還在迅速蔓延。這是因爲伊蚊廣泛分佈在拉丁美洲大部分地區，以及美國的部分地區。”卡姆蘭·汗是多倫多聖邁克爾醫院(St. Michael’s Hospital)的傳染病醫生和科學家。

Mosquitoes of the Aedes species (the name derives from a Greek word for “unpleasant”) seem to be the main vector. These mosquitoes also spread dengue and chikungunya, two other, more severe, viral infections.

伊蚊似乎是茲卡病毒的主要傳播媒介。這種蚊子還傳播登革熱和基孔肯雅熱，這兩種病毒感染更加嚴重。伊蚊(Aedes)一詞來源於希臘語，意爲“令人不快的”。

The virus was isolated in 1947 in the Zika Forest in Uganda. Researchers were studying the transmission of yellow fever, when they found the new virus in a rhesus monkey. Its first appearance in humans was in 1952 in Uganda and Tanzania, and the first large outbreak of disease was in 2007 on Yap Island in Micronesia.

茲卡病毒是1947年在烏干達茲卡森林(Zika Forest)被發現的。研究人員當時正在研究黃熱病的傳播，結果在一種恆河猴身上發現了這種新病毒。1952年，在烏干達和坦桑尼亞，它第一次出現在人類身上。2007年，密克羅尼西亞的雅浦島出現了第一次茲卡大爆發。

There was an even larger outbreak in French Polynesia in October 2013, when about 10,000 cases were reported. In 2014, there were cases in New Caledonia and the Cook Islands in the South Pacific.

2013年10月，法屬波利尼西亞爆發了一次較大的茲卡疫情，大約報告了1萬個病例。2014年，南太平洋的新喀里多尼亞和庫克羣島也出現了一些病例。

For most people, the Zika infection is not particularly serious. According to the C.D.C., only about 20 percent of infected people have any symptoms at all, and the few who become sick usually have a mild fever, sometimes diarrhea or a rash, headache or muscle pain. The illness goes away within a week, and rarely requires hospitalization. Rest, pain medication and hydration are the only treatments, and there is no cure or vaccine. There has never been a death attributed to the Zika virus, according to the C.D.C.

對於大多數人來說，茲卡感染並不是特別嚴重。CDC表示，只有約20%感染者會出現症狀，少數人會有輕微的發燒，有時會出現腹瀉或皮疹、頭痛、肌肉疼痛。症狀會在一週之內消失，極少有人需要住院治療。茲卡沒有特效藥或疫苗，只能通過休息、補水、服用止痛藥來緩解病情。從CDC的資料來看，以前從未有過茲卡致人死亡的病例。

Still, there are significant dangers for pregnant women because the virus has been linked to congenital microcephaly, a serious and often fatal birth defect in which the fetal brain fails to develop properly.

不過，對於孕婦來說，茲卡非常危險，因爲研究已經證明，該病毒與先天性小頭症有關。這是一種很嚴重的先天缺陷，指胎兒大腦不能正常發育，往往會導致死亡。

The large outbreak in Brazil, which began in May 2015, is particularly worrisome because the number of cases of congenital microcephaly in newborns and stillborns has abruptly increased. It is possible that there is some other reason for this, but there is general agreement that until another association is found, the Zika virus should be assumed to be the cause.

2015年5月起在巴西爆發的茲卡疫情尤其令人擔憂，因爲這裏的先天性小頭症新生兒和死胎病例急劇增加。可能也有其他因素在起作用，但人們普遍認爲，在沒有發現其他原因之前，我們應該假定茲卡病毒是罪魁禍首。

No one knows how many people in Brazil are infected, but C.D.C. estimates range from 500,000 to 1.5 million. There have been about 3,500 cases of congenital microcephaly, according to Brazilian health authorities. On Jan. 15, the Hawaii State Health Department reported that a microcephalic baby infected with the virus had been born in Oahu, the first such case in the United States. The mother had lived in Brazil during part of her pregnancy.

沒人知道巴西有多少人已被感染，但CDC估計感染人數在50萬到150萬之間。據巴西衛生部門透露，目前已有3500例先天性小頭症病例。1月15日，美國夏威夷州衛生署(Hawaii State Health Department)報告稱，一名感染茲卡病毒的小頭症新生兒在瓦胡島出生，這是美國的首例此類病例。嬰兒的母親懷孕期間曾在巴西居住。

Knowledge is evolving, but as of Jan. 15, the C.D.C . had issued Alert Level 2 Warnings (“Increased risk in defined settings or associated with specific risk factors”) for Brazil, Colombia, El Salvador, French Guiana, Guatemala, Haiti, Honduras, Martinique, Mexico, Panama, Paraguay, Suriname, Venezuela and Puerto Rico. The agency did not mention Africa or Asia in connection with the Zika virus, but warnings about the dangers of other mosquito-borne illnesses are already in effect in those regions.

研究人員的瞭解也在日益完善，但到1月15日，CDC發佈了二級警告（“某些情境下風險有所提升或與特定風險因素有關聯”），針對巴西、哥倫比亞、薩爾瓦多、法屬圭亞那、危地馬拉、海地、洪都拉斯、馬提尼克、墨西哥、巴拿馬、巴拉圭、蘇里南、委內瑞拉和波多黎各。該機構沒有提到非洲或亞洲的茲卡病毒情況，但有關其他蚊媒疾病的警告已經在這些地區生效。

Pregnant women, in no matter which trimester, should talk to their doctors if they must travel to countries where Zika infections have been found, and if the trip is not essential, they should consider postponing it. Women who are trying to become pregnant are also at risk, and should discuss their travel plans and the risks of the Zika infection with their health care providers. All travelers should strictly follow the routines that will prevent mosquito bites.

孕婦如果必須前往發現茲卡病毒感染病例的國家，無論處於哪個階段，她們都應該與醫生進行溝通。如果不是必需的，那就應該推遲出行。準備懷孕的女性也面臨風險，她們應該與醫務人員討論自己的旅行計劃及感染茲卡病毒的風險。所有旅行者都應該嚴格遵循防止蚊蟲叮咬的常規操作。

Aedes mosquitoes flourish seasonally in large areas in the United States, and year-round in most of Florida and parts of Texas and California, so travelers who are infected abroad and return to these areas could spread the illness.

伊蚊在美國大部分地區只是季節性活動，在佛羅里達州大部分地區及德克薩斯州和加利福尼亞州的部分地區是全年活動，因此在國外感染病毒然後回到這些地方的旅行者，可能會傳播這種疾病。

Sexual transmission of the virus may also be possible. In 2011, researchers found that a scientist who had contracted the Zika virus while working in Senegal transmitted it to his wife after his return home to Colorado, almost certainly through sexual intercourse. And in 2015 the virus was found in the sperm of a 44-year-old man in Tahiti. There is also at least a theoretical risk of transmission through blood transfusions.

這種病毒或許也可以通過性行爲傳播。2011年，研究人員發現，一名在塞內加爾工作時感染茲卡病毒的科學家回到科羅拉多州後將病毒傳給了妻子，幾乎可以肯定是通過性行爲傳播的。2015年，塔希提島一名44歲男子被發現精液中含有該病毒。該病毒可能也可以通過輸血傳播，至少理論上有這種風險。