All disease, drugs, vaccines, countries, and microbes pages have a 'Download and references' section:

Click 'Prepare PDF' to generate a PDF file for download.

In a couple of seconds, a green notification will appear  - click on it or on the same button that will now say 'Download PDF' to retrieve the file: 

You can also download comparison tables, graphs, diagnosis cases, and pathogen identification results in a similar manner.