Here are a few basics about the swine flu outbreak in the U.S. and Mexico.

What is swine flu?

It's flu that occurs in pigs. In rare cases, humans contract swine flu from close contact with pigs. The strain circulating now is cause for concern because it can pass directly from person to person. Like routine human flu, cases of swine flu can range from mild to severe.

Is the disease the same in Mexico and the U.S.?

The virus appears to be the same. But the disease has caused at least 20 deaths in Mexico, while it has appeared more mild in the 20 confirmed U.S. cases, with no deaths and most patients recovering without needing to be hospitalized. It's unclear why confirmed cases have been more severe in Mexico than in the U.S. A CDC official warned on Sunday that as cases continue to emerge in the U.S., some may prove fatal.

What are the symptoms?

Symptoms are similar to those of regular flu: fever, along with problems such as cough, sore throat, body aches, headaches, chills and fatigue. Some cases have also included reports of vomiting or diarrhea.

What should I do if I feel sick?

People with ordinary flu symptoms do not need to seek emergency care, New York City officials said. But people with certain warning signs in addition to basic symptoms should seek urgent attention. In children, those signs include difficulty breathing; bluish skin color; flu symptoms that begin to improve, then return with fever and worse cough; and fever with a rash. In adults, warning signs include difficulty breathing, pain or pressure in the chest or abdomen, sudden dizziness, confusion, and severe or persistent vomiting.

Can the swine flu be treated with drugs?

Two drugs, sold under the brand names Tamiflu and Relenza, are believed to reduce the severity and the duration of the disease. But most of the patients who contracted swine flu in the U.S. have recovered without taking the drugs. Both drugs have also been approved to reduce the risk of contracting the flu. But, unlike a vaccine, they do not provide long-lasting protection. So their preventive use is typically for short-term situations, such as for family members of someone who has the flu. The drugs, which are included in the federal government's pandemic stockpile, are only available with a doctor's prescription.

Does this year's flu vaccine protect against the swine flu?

The CDC says the seasonal flu vaccine is 'unlikely to provide protection' against the swine flu. The agency has created a 'seed vaccine' specifically tailored to this swine flu. That could be used to manufacture a targeted vaccine if officials deem it necessary to do so. But manufacturing a new vaccine would take months.

Are there ways to reduce the spread of disease?

Cover your nose and mouth when you cough or sneeze. Wash your hands often. Avoid touching your eyes, nose or mouth. Avoid close contact with infected people. People who have mild symptoms should stay home from school or work until 48 hours after the symptoms have passed, to avoid spreading disease, New York health officials said. 

以下是有關在美國和墨西哥爆發的豬流感的一些基本知識。

何謂豬流感？

這是豬身上爆發的流感。在很少一些案例中，人類因與豬密切接觸而感染豬流感。目前流行的病毒毒株之所以令人擔憂，就是它能在人與人之間直接傳染。同普通的人流感一樣，豬流感病情也有從輕微到嚴重之分。

墨西哥與美國爆發的同一種豬流感嗎？

致病的病毒看來是相同的。但墨西哥的豬流感已導致至少20人死亡，而美國已確診的20例豬流感則要輕微的多，其中并沒有死亡病例，大多數患者都在康復之中，無需住院治療。目前還不清楚為何墨西哥確診的病例要比美國嚴重的多。美國疾病控制預防中心(CDC)一位官員周日警告說，隨著美國繼續發現豬流感病例，其中一些可能會有生命危險。

豬流感有何癥狀？

癥狀同普通流感相似：發熱，并伴有咳嗽、咽喉痛、肌肉痛、頭痛，發冷和疲勞。還有一些病例會有嘔吐或腹瀉的情況。

如果我感覺患病，應該怎么做？

紐約市官員說，出現普通流感癥狀的患者不需看急診。但除了基本癥狀外，還出現一些危險癥狀的患者應該看急診。對兒童來說，這些癥狀包括呼吸困難；皮膚顏色變青；流感癥狀開始改善，然后又出現發熱和咳嗽加劇；以及伴有皮疹的發熱等。對成人而言，危險的癥狀包括呼吸困難、胸腹部疼痛或有壓迫感、突然的頭暈或神志不清、以及嚴重或持續的嘔吐。

能用藥物治療豬流感嗎？

據信達菲(Tamiflu)和瑞樂沙(Relenza)這兩種藥物能夠降低豬流感的病情和發病時間。但在美國，感染豬流感的大多數患者在沒有服藥的情況下病情也出現了好轉。這兩種藥物也獲批可以用來降低感染流感的風險。但與疫苗不同，它們并不能帶來長期持續的保護作用。因此，它們一般只具有短期的預防作用，如在某位家庭成員感染流感的情況下。這兩種藥物都在美國政府的疫情儲備藥物當中，且只能憑醫生處方購買。

今年的流感疫苗能預防豬流感嗎？

美國疾病控制預防中心說，季節性的流感疫苗不太可能預防豬流感。該機構已經開發了專門針對豬流感的“種子疫苗”。如果政府部門認為有必要，這種疫苗可用于生產有針對性的疫苗。但生產一種新疫苗可能需要數月時間。

有沒有減少豬流感擴散的辦法？

紐約市衛生官員說，在咳嗽或打噴嚏時遮住你的鼻子和口。經常洗手。避免接觸你的眼睛、鼻子和嘴。不要與受感染者密切接觸。出現輕微癥狀的人在癥狀消失48小時之內應呆在家中，不要上學或上班，以避免傳染疾病。