In May the US FDA approved the addition of plague to the list of indications for moxifloxacin. Plague is a very rare disease affecting only between 1000 to 2000 people annually. It is caused by the bacteria Yersinia pestis and is transmitted to humans through bites from infected fleas as well as by contact with infected animals or humans.

The three most common forms of plague are bubonic (infection of the lymph nodes), pneumonic and septicaemic. Yersinia pestis is considered a potential bioterrorism agent. As plague is such a rare disease it would not be possible to conduct adequate efficacy trials in humans, so the FDA has approved the indication based on an efficacy study in African Green monkeys.

Other treatment options for plague include streptomycin, doxycycline, tetracycline, ciprofloxacin and levofloxacin.