The tobacco in cigarettes hosts a bacterial bonanza — literally hundreds of different germs, including those responsible for many human illnesses, a new study finds.

“Nearly every paper that you pick up discussing the health effects of cigarettes starts out with something to the effect that smokers and people exposed to secondhand smoke experience high rates of respiratory infections,” notes Amy Sapkota of the University of Maryland, College Park. The presumption has been that smoking renders people vulnerable to disease by impairing lung function or immunity. And it may well do both.

“But nobody talks about cigarettes as a source of those infections,” she says. Her new data now suggest that’s distinctly possible.

If these germs are alive, something she has not yet confirmed, just handling cigarettes or putting an unlit one to the mouth could be enough to cause an infection.

Read More: Science News