What happens if woman is breastfeeding a child and she is unware that she is HIV Positive?

Will child also be infected ?

Yes. Even though chances are low there is also a possbility. As a matter of fact there are also kids being born healthy from HIV positive moms if they are lucky.
But as soon as the mother finds out she is infected she must stop breastfeeding. As for women who find out during pregnancy if she is lucky enough to have a healthy child C.-section is recommended to avoid blood contact.

There is a chance that the baby will be infected, but it's not as high as you might think.

In a country where a clean and safe alternative to breast feeding is available then bottle feeding is definately safer.

BUT in a country where water suppies are not clean and formula is unavailable or unaffordable, then breast feeding may be safer if her viral load is under control by drugs.

The thing which seems to be most dangerous seems to be if the baby is fed by a mixture of bottle and breast, no one quite knows why.

But of course thing like cracked nipples or teething baby will vastly increase the risk because blood carries more HIV than milk.

Yes, if she does not know she is positive and breast feeds, then the child will most likely become infected.

On the other hand, if she did know and were taking the HAART treatment drugs, and had an undetectable viral load, then she probably wouldn't pass it on. However she would probably not be breast feeding especially if the child was HIV negative.

Than there is a possability that the baby may be infected as well. Also, if the mother was HIV posative while preganant than the baby may already have it.

It is possible. Women who have HIV should not breastfeed. (The virus can also be transmitted through pregnancy and delivery.)

Quite possibly. That's what is crippling Africa.
If there is any possibility that someone could be HIV positive they should do a test, especially if they are having a baby.

the child is likely to get hiv also as it is possible to transmit the disease through breast feeding a child.

There is that possibility, as HIV is transmittable through breast milk.

HIV can pass to the baby both during the pregnancy and when breastfeeding.