Writing in Nature, Arturo Casadevall and Liise-Anne Pirofski urge microbiologists to retire the pathogen paradigm, arguing that “the focus on microbes is hindering research into treatments”:
The term pathogen started to be used in the late 1880s to mean a microbe that can cause disease. Ever since, scientists have been searching for properties in bacteria, fungi, viruses and parasites that account for their ability to make us ill. Some seminal discoveries have resulted — such as the roles of various bacterial and fungal toxins in disease. Indeed, our oldest and most reliable vaccines, such as those for diphtheria and tetanus, work by prompting the body to produce antibodies that neutralize bacterial toxins.
Yet a microbe cannot cause disease without a host.
What actually kills people with diphtheria, for example, is the strong inflammatory response that the diphtheria toxin triggers, including a thick grey coating on the throat that can obstruct breathing. Likewise, it is the massive activation of white blood cells triggered by certain strains of Staphylococcus and Streptococcus bacteria that can lead to toxic-shock syndrome. Disease is one of several possible outcomes of an interaction between a host and a microbe.
It sounds obvious spelled out in this way. But the issue here is more than just semantics: the use of the term pathogen sustains an unhelpful focus among researchers and clinicians on microbes that could be hindering the discovery of treatments. In the current Ebola epidemic in West Africa, for instance, much attention has been focused on the ill and the dead, even though crucial clues to curbing the outbreak may be found in those who remain healthy despite being exposed to the virus.
The Dish 