If the Italian is in Brazil for Carnival then he probably transmitted the disease to scores of people.
Yup.
Check back in Rio in about 3 weeks for any further contact cases.
It's likely this man in Brazil came in contact with many people considering it was Carnaval time and that Sao Paulo is a huge densely populated city.
My understanding is that this virus is less contagious in humid conditions than in dry air. It will be interesting to see if the spread in Brazil where it is hot and humid now is lower than the spread in Italy where it is winter. Although it would appear that Brazil has identified patient zero while Italy did not. It all depends on how many people this Brazilian man came in contact with while he was contagious and before he sought treatment.