Beneatha was describing how her whole family has this bug she calls Ghetto-it is, which explains the actions of all the main characters in the first act. When Beneatha said this she was just welcoming Asagi into her home. He asked her what was wrong and she responded with the acute ghetto-it is term.
Ruth, to me, is acting the most on this use of speech. I would believe she suffers the most from this. Earlier in the first scene she was yelling at Walter for giving Travis so much money to bring to school. Ruth is always preaching about how the rich white people have it and complaining about her life. And every time Travis asked when the paycheck was coming she would just respond with dont worry about it.
Walter is Ruths husband and a father of one to Travis. Unlike Ruth Walter takes money not as seriously, while Ruth thinks they need to save every penny so they wont end up in the gutter. Walter handles the income of money in their family and you could say Beneatha handles the out flow.
Next in the line of Ghetto-itis would be Mama. Mama lives with the family and does house chores to help out Ruth. Mama doesnt spend much and she doesnt eat much. Mama clearly marked her position in the household. When Beneatha was questioning the existence of God Mama got up and slapped her across the face. She is a serious character.
The one person that makes the best of what they have would probably be Travis. Travis is the kind of person that makes the best of a bad situation. When Beneatha was spraying under the couch for roaches, Travis was telling her not to worry about it because they werent harming them. Even though he seems to always be happy he has no idea of what money really means.
Beneatha was the one who said the family suffers from acute Ghetto-itis. She was meaning to say that the family acts like they live in the ghetto and are horribly poor, but when in real life they are actually making a lot of money. So Beneatha does the one thing she is good at which is spending money. She has paid for horseback riding lessons and is about to take guitar lessons. Everybody questions her spending in her family. Beneatha may think that she is better than her own family.
I think Beneatha does think she is better than her own flesh and blood and that is why she is making statements like the ones she made in Act 1.
A Raisin in the Sun by Lorraine Hansberry