In HIV-infected patients, there is a gradual loss of CD4+ T cells over time. These cells, also called T helper cells, organize the immune system's attack on disease-causing invaders, like Salmonella.
Topographic
Map is known as elevation and land features
A rain shadow is a patch of land that has been forced to become a desert because mountain ranges blocked all plant-growing, rainy weather. On one side of the mountain, wet weather systems drop rain and snow. On the other side of the mountain—the rain shadow side—all that precipitation is blocked.
