The Centers for Disease Control and Prevention (CDC) has created this uniformly excellent site to help the general public learn about the H1N1 flu. The homepage is well-organized, and it contains helpful social networking buttons, along with direct links to email updates, and their RSS feed. Here, visitors can also read the "Situation Update" section, which includes a map of the United States...

Emerging viruses are those "whose incidence in humans has increased in the past 2 decades or threatens to increase in the near future." This week's Topic in Depth focuses on sites related to viruses, particularly those that are considered "emerging." The first site (1) is an essay by Alison Jacobson of the University of Capetown that discusses some emerging and potentially emerging viruses,...

These Web sites provide detailed and timely information about SARS. The Centers for Disease Control Web site on SARS (1) is a great place to begin an online exploration of the disease and the current epidemic. Visitors will find general information about SARS, the latest CDC developments on the issue, SARS-related news, and much more. The next site is the World Health Organization's main Web page...

When winter rolls around and we begin to spend more time indoors, the common cold becomes an unfortunate reality for many of us. But for something as common as the cold, misconceptions about it are remarkably common as well. The following collection of Web sites provides an in-depth look at the cold and the cold virus. The first site (1) comes from the Common Cold Care Center of Cardiff...

The West Nile Virus, a mosquito-borne virus that causes encephalitis in vertebrates, was only found in the Eastern Hemisphere until 1999, when it was isolated in the northeastern United States. Seven deaths and several cases of severe illness caused by the virus have raised concern for public safety in the region. Recently, a special West Nile virus surveillance program has been funded in...