Infection with streptococci, the bacteria that cause strep throat, had normally been easily cured with penicillin. However, for reasons that are not well understood, a more lethal strain of the bacteria, called group A streptococci, has become increasingly common. The sudden death of Muppets puppeteer Jim Henson in 1990 from fulminating pneumonia and toxic shock was caused by this new, virulent strain.


The headline-grabbing “flesh-eating bacteria” that infect wounds to the extent of necessitating amputations and even causing death are also group A streptococci. The group A strain, which produces a potent toxin, was prevalent in the early part of the 20th century, when it caused scarlet fever, frequently fatal in children, and rheumatic fever, which often caused damage to the heart. For decades, the group A strain was superseded by strains B and C, which were much milder in their pathogenic effects.


But now, for reasons that are not clear, the group A strain has become much more prevalent. Global surveillance for infectious diseases is critically important for identifying potential epidemics early enough to bring them under control. Effective control of emerging infectious diseases requires worldwide disease surveillance focusing not only on human populations, but also on domestic animals and wildlife.