Why Was Only Miriam Afflicted with Leprosy?

Question: 

It says in Beha'aloscha, that both Miriam and Aaron spoke against Moshe regarding the Cushite woman he had married (12.1). Then later it says that Miriam was afflicted with tzaraas (12.10).

 

From what I understand, if a person speaks loshen hara, three people are affected: the speaker, the listener, and the person being spoken about. If both Miriam and Aaron spoke loshon hara, why wasn't Aaron also afflicted?

Answer:

According Rabbi Akiva[i] and others[ii], Aharon, too, was smitten with leprosy as a result of his participating in the discussion about Moshe.

Also, as a woman, Miriam felt more passionately about the plight of Moshe’s wife, and therefore initiated the conversation[iii]. The Torah therefore focuses primarily on the consequences that Miriam had to contend with while only alluding to those experienced by Ahraon.

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[i]) Yalkut Shimoni, Shelach 749.

[ii]) Talmud, Shabbos 97a

[iii]) See Rabbeinu Bachaye and Alshich (Bamidbar 12:1).