Books on English usage suggest that “etc” can be used with one item or more than one. The rule is when you use “etc” after a single item, you don’t put a comma before it. When you use it with more than one item, a comma is used. Some people however argue that one item lists should be avoided whenever possible.
Here are a few examples.*Venu doesn’t like cats etc. *Rahul is an expert on diet etc. *Sheba has interest in many things — music, dance, tennis, etc.
The important thing to remember is that the word “etc” cannot be preceded by “and” because “et” in “et cetera” means “and”. It is therefore incorrect to say, “Rowdy Raji likes idli, wada, dosa, and etc.” Some people argue that the word should be used with things, and not with people. They maintain that sentences like the following should be avoided: “Sarita, Ganesh, Sameer, Nisha, etc had dinner with us.” They find such usage offensive.