Surveillance by the Unexplained Deaths and Critical Illnesses Project (UNEX
) uncovered a novel presentation of adenovirus type 3 infection that satisf
ied the criteria for toxic shock-like syndrome in a 28-year-old immunocompe
tent man. Adenovirus may be a cause of toxic shock syndrome; surveillance s
ystems such as UNEX may uncover additional causes of this and other clinica
lly defined infectious syndromes.