Question

AIDS is transmitted by infected needles but not by mosquitoe bite. Why?

Answer 1

1. The AIDS virus (HIV) on used needles is infectious when injected into a human where the virus can bind to T cells and start to replicate.

2. The human T cell is a very specific host cell for HIV. When a mosquito feeds on a person with HIV in his or her blood, the HIV enters the insect's gut, which does not contain human T cells.

3. The virus thus has no host cell in which to replicate and it is broken down by the mosquito's digestive system.