Altweb is a subsite of the Johns Hopkins Bloomberg School of Public Health's Center for Alternatives to Animal Testing (CAAT) website (http://caat.jhsph.edu/). The two sites are closely intertwined, and the Altweb site links back and forth to the CAAT website.

CAAT's communications manager Michael Hughes says, “Altweb has been the number one online resource on humane science since its inception in 1997.” There is information for everyone, from researchers to elementary school students. There are links to online courses, FAQs, a glossary of terms and even web pages in Spanish.

The heart of the site, however, is for researchers. The homepage opens to up-to-date news reports. Among the news items on the day Lab Animal's reviewer visited was a call for proposals for the CAAT Science-based Refinement Awards (deadline 30 September 2013), which sends the reader back to the CAAT website for details. The UK-based National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs) 3Rs Prizewinner, lung on a chip, was featured, as was an interview with CAAT Director Thomas Hartung that was published in Nature. Some of the news items give readers things to do: nominate someone as a technical expert for the US Environmental Protection Agency (deadline 1 April 2013—sorry, the due date has passed); reply to a European survey on the monocyte-activation test (again, deadline has passed) or even attend the LATINFARMA 2013 conference: 3Rs Alternatives in Pharmacology, Toxicology and Teaching Workshop, to be held 21–25 October 2013 in Havana, Cuba. Hughes says that the news items are updated regularly, so they will be different by the time this review is published. The news is also available by RSS feed.

The left-hand side of the homepage holds a banner that leads to various areas of the site, 'About Us,' 'Resources,' 'Altex,' 'Featured Items,' 'Publications,' 'Newsletter,' 'Calendar,' 'Espanol' and 'CAAT Home.' The right-hand side banner includes a direct link to the latest issue of Altex, which is the journal of CAAT, the European Society for Alternatives to Animal Testing, t4 (Transatlantic Think Tank for Toxicology) and the research chairs funded by the Doerenkamp-Zbinden Foundation in Germany, India, The Netherlands, Switzerland and the US. The January 2013 issue of Altex contains an editorial, commentary, original research in the 3Rs and a report on the workshop, “Evidence-Based Toxicology for the 21st Century: Opportunities and Challenges,” held 24–25 January 2013 in Research Triangle Park, NC. The archived issues extend back to 2005. The right-hand banner also includes a link to an online course, also linked to information for students and teachers, and a list of recent and upcoming meetings.

The page this reviewer found most informative was the 'Featured Items' page. The top part of the page refers to articles in past issues of Altex and some older articles about REACH, the European Community regulation on chemical sales and use (Registration, Evaluation, Authorisation and Restriction of Chemical substances), in various publications. Hartung and others posit that REACH unnecessarily increases use of animals. Scrolling down the page leads to the best part: two links under 'For Scientists and Researchers,' which are essential: 'Search for Alternatives: a step-by-step approach to an alternatives search' and 'IACUCs and Animal Ethics Committees Resources.' The 'Search for Alternatives' page has an exhaustive list of databases, links to international policies and regulations, links to other sources and links to Cefic's The Long-Range Initiative and to the UC Davis Center for Animal Alternatives Information, among many others. The resources for IACUCs link leads to sites throughout the world and includes additional links specifically on pain and distress. Under the heading 'For Students' are the FAQs, as well as the complete text of Russell and Burch's classic, The Principles of Humane Experimental Technique.

The 'Publications' page leads to links to journals, books, reports, articles, newsletters and proceedings. These are from all over the world, some newer, some 20 years old, but all fascinating.

Visitors can also subscribe to Altweb News at the 'Newsletter' tab.

The 'Calendar' tab leads to a calendar that, at the time of Lab Animal's visit, extended to October 2013, with conferences and workshops worldwide listed.

This site is worth visiting time and again.

http://altweb.jhsph.edu/