Llywelyn Roberts noted "a great similarity between the two diseases." It was accompanied by a rash, which was not described as a feature of the English disease. Similar to the English sweating sickness, there was also intense sweating and fever noticed with the Picardy sweat. However, Henry Tidy argued that John Caius's report applies to fulminant cases fatal within a few hours, in which type no eruption may develop. A 1906 outbreak of Picardy sweat struck 6,000 people; bacteriologist André Chantemesse led a commission which studied it, and they attributed infection to the fleas of field mice. Henry Tidy found "no substantial reason to doubt the identity of "sudor anglicus" and Picardy sweat." Furthermore, it was speculated that the English sweating sickness and the Picardy Sweat may both be caused by a species of hantavirus.