You can Google to get a hotel, find a flight and buy a book. Now you may be able to use Google Inc. (GOOG) to avoid the flu.

One month into flu season, Google on Tuesday opened a free Web service that the Internet company says can show if the number of influenza cases is increasing in areas around the U.S., earlier than many existing methods.

The service, called Flu Trends (www.google.org/flutrends), uses computers to crunch millions of Internet searches people make for keywords that might be related to the flu-for instance 'cough,' or 'fever.' It displays the results on a map of the U.S. and shows a chart of changes in flu activity around the country.

The data is meaningful because the Google arm that created Flu Trends found a strong correlation between the number of Internet searches related to the flu and the number of people reporting flu symptoms.

Google built the service with the guidance of the Centers for Disease Control and Prevention, the U.S. government's public health watchdog that runs a range of flu surveillance systems. Flu Trends can be a complement to those tools, health officials say. Flu Trends 'maps very closely to the influenza-like trends that we see in the U.S.,' says Lyn Finelli, lead of the influenza surveillance team at CDC's headquarters in Atlanta.

The service adds Google to a growing number of Web sites that are trolling, culling and crunching Internet data in ways to better pinpoint and predict where diseases are hitting around the world. The sites use varying degrees of human and computer methods for detecting outbreaks and many have historically been aimed at doctors and health care professionals. Google executives say their service could also appeal to consumers.

In any given year, between 5% and 20% of Americans can catch the flu, depending upon the strength of a particular flu virus and other factors, the CDC says. Around 145 million doses of flu vaccines will be available this flu season, which generally runs from October to May and typically peaks in February.

Finding a new tool to stave off infection is important to Maureen Rinehart, a 28-year-old kindergarten teacher in San Francisco. Ms. Rinehart says daily contact with her kids means she gets sick about once a month. She got a flu shot about two weeks ago and is armed with hand sanitizer in the classroom.

'They're really snotty and they want to hold hands with you; you know how it is with the little guys,' says Ms. Rinehart. So if the Google service shows flu cases are rising, she says, 'you could bulk up on vitamins and wash your hands more - all the necessary things you should do.'

The Google service is the brainchild of Google.org, a three-year-old group at the Mountain View, Calif., company that works on areas for the public good-such as renewable energy-that may or may not have a direct financial benefit to Google. The company won't use advertising on the Flu Trends site.

The Google group examined flu-related keywords over five years, noting times when searches of those terms surged. It then compared those times to CDC records and found a strong correlation between when people searched flu keywords and when people have had flu-like symptoms. It spent the past year testing new search results against data from the CDC, tweaking its software to make its results more accurate, Google executives said.

The Flu Trends site displays results of its analysis in a five-tier scale of flu activity ranging from 'minimal' to 'intense,' with a middle point of 'moderate.' The site includes CDC flu prevention messages, a flu vaccination locator and links to flu-related news items. 'It's still quite experimental,' says Jeremy Ginsberg, Google's lead engineer on Flu Trends. 'We feel it's an interesting, unique way to track disease outbreaks.'

Robert A. Guth

可以通过谷歌(Google)网站来预定旅馆、查找航班或买书。现在，你或许还能利用谷歌来避开流感。

在进入流感季节一个月后，谷歌周二推出了一个免费的网络服务，这家互联网公司表示，这项服务能早于现有的任何手段显示出全美各地流感病例是否在增加。

这项名为Flu Trends（流感趋势, www.google.org/flutrends）的服务利用电脑对数百万次含有流感相关字段（如咳嗽、发烧等）的网络搜索进行处理，然后把结果显示在一张美国地图上，并附上全美流感变化的图表。

这些数据是具有实际意义，因为研发Flu Trends的谷歌团队发现进行流感相关搜索的次数和汇报流感症状的人数具有极强的关联性。

谷歌是根据美国公共卫生监管机构疾病控制预防中心(Centers for Disease Control and Prevention)的指导原则开发上述服务的。美国疾病控制预防中心有一系列流感监测系统。卫生官员表示，Flu Trends可能会成为这些检测系统的有益补充。疾病控制预防中心亚特兰大总部流感监测团队负责人费南利(Lyn Finelli)说，Flu Trends地图显示的美国流感发展趋势和我们监测到的情况非常接近。

这项服务也让谷歌加入了一个新的网站行列，眼下越来越多的网站通过综合、筛选及处理互联网数据来更好地发现和预测全球各地的疾病发展状况。这些网站综合使用人力和电脑来监测疾病爆发情况，其中很多是面向医生和医疗保险专业人士服务的。谷歌的高级管理人员表示，他们的服务也会吸引普通用户。

疾病控制预防中心称，每年大约有5%-20%的美国人会患上流感，具体比例取决于流感病毒的种类及其他因素。在这个流感季，大约有1.45亿只流感疫苗供美国人使用。流感季一般从10月持续至次年5月，通常2月是发病高峰。

对28岁的旧金山幼儿园老师林哈特(Maureen Rinehart)来说，找到避免感染流感的新工具非常重要。林哈特说，每天和儿童接触意味着她每个月都要病一次。她大约在两周前打了流感疫苗，并在教室里使用手部消毒杀菌剂。

林哈特说，有些孩子流着鼻涕，而且他们总是想和老师拉手。而且，你也知道这些小孩子的表现。她说，如果谷歌服务显示她所在地区的流感案例不断上升，她就会服用更多维生素，更加频繁地洗手──总之，采取一切必要的预防措施。

Flu Trends是Google.org的新创意。这个成立仅三年的团体所开发的产品主要服务于公共利益，如可再生能源，而且可能不会为谷歌带来直接的财务收益。谷歌不会在Flu Trends网站上投放广告。

Google.org在过去五年研究了和流感相关的关键词，而且找出了这些关键词搜索量飙升的时间段。然后，他们把这些数据和疾病控制预防中心的记录进行对比，发现人们搜索流感相关关键词的时间和出现流感症状的时间具有很强的关联性。谷歌管理人员表示，他们用过去一年的时间来测试和疾病控制预防中心数据相左的新搜索结果，并对软件进行了调整，以使Flu Trends的结果更加准确。

Flu Trends网站会显示出分析结果，并用从"微弱"(minimal)、"中等"(moderate)到"剧烈"(intense)等五个等级来衡量流感活动。该网站还提供疾病控制预防中心关于预防流感的信息、流感疫苗注射地定位软件以及流感相关新闻等。谷歌Flu Trends首席工程师吉恩博格(Jeremy Ginsberg)说，这个网站还是试验性的，我们认为它是一种跟踪疾病爆发的独特、有趣的途径。

Robert A. Guth