"Threadworms are known to cause intense itching around your anus. In girls, vaginal itching can also occur. The itching is particularly intense at night, when the female worms are active laying their eggs. This may cause you to experience a loss of sleep and make you irritable."
it doesn;t say that worms can cause thrush, but it can cause vaginal irritation, so IMO, I reckon that it can be confused with thrush.