It’s not exactly a misspelling because “fervo” is a valid Portuguese word, but it’s not what the author probably means. “Fervo” is the singular first person, present tense, of the verb “ferver” (to boil), as in “eu fervo a água” (“I boil the water”). The cultural element, which is probably what the author intended to say, is spelled “frevo”.

Edit: there’s another misspelling I found, “Janiero”. It’s actually “Janeiro”, “Rio de Janeiro”.