Who is Dangerous

Prachi now in London over 6 months found it strange to find a house fly in our house. She was not scared, but was feeling uneasy over its presence. She kept telling every 10 minutes, “Ammmma, look at this fly. It is flying around” (Well, what else can the flies do!)To pacify her I told her, “Flies are ok. Mosquitoes are dangerous.” Then I was thinking about the risks of flies and diseases it could cause and unknowingly said aloud, “Well, flies are also dangerous.” Prachi, who was playing around heard this and stared at me questioningly. I did not want to frighten my little kid and said very casually, “Baabu, they are not that dangerous. They are ok.” Prachi was satisfied and went out. Within a second she came back again and told “Amma, vyyyys is danger.”
Me: What chinno?
Prachi: I know vyyyys is danger
Me: Sorry babba…I did not understand you. What is danger?
Prachi: I know for sure vyyyys is danger. Remember, the other day dad got chicken pox because of vyyyys.
Me(Full of laughter): Yes Chinno, Virus is dangerous.