"Is it the cause?"--Robert Koch and viruses in the 21st century.

Confirmation that a virus is genuinely the cause of a disease is unexpectedly difficult, especially with new molecular approaches to diagnosis. This paper discusses the problems, which are closely related to the methods used to detect virus (or components of virus), and suggests that longitudinal studies are essential to confirming causation and avoiding unwarranted assumptions.

For debate: is disinfection of specimens, which may contain unknown or bio-terrorist organisms, essential before electron microscopic examination?

Severe and unexpected infections may be due to bioterrorism (BT), or the natural emergence of novel micro-organisms. Whatever the cause, there will be an urgent need to identify it for several reasons: defusing public anxiety, providing logical management and countermeasures, etc. For viruses and some bacteria, electron microscopy provides the fastest answers and identifying the cause quickly may eliminate BT. In the interests of safety, many would recommend that the specimen be disinfected at some stage before examination, but with unknown agents, however, reliable disinfection cannot be guaranteed and attempting to do so may also impair structure sufficiently to make recognition difficult or even impossible. As a basis for debate, this paper discusses the pros and cons of disinfecting such specimens.