Hiv risks?

just a curious question and i hope i get a some good replies =P

i know that sharing needles is one of the highest risk for hiv transmission because the blood from the infected is directly introduced to the bloodstream of the user.

i also know that getting cut by a foreign object that just cut someone who is infected is considered a lower risk .

but why is it so ? i mean if this blade or something else just cut a hiv victim , and then if someone else used it and get cut too , doesnt the hiv blood get introduced to their blood stream too ?

considering if the foreign object was something like the edge of a heavy box etc , whereby any blood on the edge isnt that obvious , how risky is the transmission if someone who is infected get cut by the edge just before you get cut by the edge too.

seriously i am curious , i hope someone can help me with this .

When people inject drugs intravenously, they draw back on the plunger of the syringe to check if they are in a vein. A fountain of blood, the "flash", flows into the syringe barrel, indicating the needle is in the right spot.

Syringes all have a "dead space": not all of the contents are injected when you push the plunger. When the next person draws up their drug, it mixes with the fluid left in the dead space - which includes the flash from the previous user. This is then injected directly into the bloodstream.

It's a very efficient way of passing on blood borne viruses such as HIV and hepatitis C and B.

A cut from a contaminated blade could introduce HIV into the bloodstream, but not as efficently as a syringe pushing contaminated fluid directly into a vein

It all depends on the volume of blood that has got injected.... Hiv virus is active only when it is present in body fluids.... and incidence of hiv via needles is comparatively less.... only when the person is gonna share the needle regularly which the infected person uses is there a chance of getting HIV. but obviously a person cannot get cut with the same object used by the infected person regularly isn't?

yes very possible