Malcolm-CasadabanMalcolm Casadaban, 60, died Sept. 13, 2009 of plague. Casadaban, a renowned molecular geneticist with a passion for new research, had been working to develop an even stronger vaccine for the plague. The medical center says the plague bacteria he worked with was a weakened strain that isn’t known to cause illness in healthy adults. The strain was approved by the Centers for Disease Control and Prevention for laboratory studies.