Lyme disease cycle. Tick eggs become larvae and feed on small mammals or birds infected with the Lyme disease bacterium, Borrelia burgdorferi. Infected tick larvae then molt into nymphs, emerging aggressively in spring to infect new hosts, including humans. The nymphs molt to become adult ticks, which seek new hosts, mate, and produce eggs.

Lyme disease cycle. Tick eggs become larvae and feed on small mammals or birds infected with the Lyme disease bacterium, Borrelia burgdorferi. Infected tick larvae then molt into nymphs, emerging aggressively in spring to infect new hosts, including humans. The nymphs molt to become adult ticks, which seek new hosts, mate, and produce eggs.

Lyme disease cycle. Tick eggs become larvae and feed on small mammals or birds infected with the Lyme disease bacterium, Borrelia burgdorferi. Infected tick larvae then molt into nymphs, emerging aggressively in spring to infect new hosts, including humans. The nymphs molt to become adult ticks, which seek new hosts, mate, and produce eggs.

Lyme disease cycle. Tick eggs become larvae and feed on small mammals or birds infected with the Lyme disease bacterium, Borrelia burgdorferi. Infected tick larvae then molt into nymphs, emerging aggressively in spring to infect new hosts, including humans. The nymphs molt to become adult ticks, which seek new hosts, mate, and produce eggs.

Artist's concept of the vascular endothelial growth factor (VEGF) pathway within a cell. The pathway is labeled.

Artist's concept of the vascular endothelial growth factor (VEGF) pathway within a cell. The pathway is labeled.

Artist's concept of the vascular endothelial growth factor (VEGF) pathway within a cell. The pathway is labeled.

Artist's concept of vascular endothelial growth factor (VEGF) stimulated angiogenesis.

Artist's concept of angiogenesis stimulated by vascular endothelial growth factor (VEGF) released by tumor cells.

Artist's concept of angiogenesis stimulated by vascular endothelial growth factor (VEGF) released by tumor cells, with labels.

Artist's concept of the paramyxovirus that causes mumps, cross section view, illustrating proteins and RNA inside the virus.

Artist's concept of the paramyxovirus that causes mumps, cross section view, illustrating proteins and RNA inside the virus, with labels.

Artist's concept of the paramyxovirus that causes mumps, cross section view, illustrating proteins and RNA inside the virus.

Artist's concept of the paramyxovirus that causes mumps, cross section view, illustrating proteins and RNA inside the virus, labeled.

Artist's concept of the life cycle of the paramyxovirus that causes mumps.

Artist's concept of the life cycle of the paramyxovirus that causes mumps. Cross section of the virus and stages of development within a host cell are labeled.

Artist's concept of the life cycle of the paramyxovirus that causes mumps. Cross section of the virus and stages of development within a host cell are labeled.

Artist's concept of the life cycle of the paramyxovirus that causes mumps. Stages of development within a host cell are labeled.

Illustration showing a cancerous breast cell producing too many HER genes, which in turn produce an excessive number of HER2 receptors. The receptors attract growth factors, which stimulate the growth of more cells. Herceptin (generic name trastuzumab) and other antibodies inhibit HER2 receptors and VEGF growth factors.

Illustration showing a cancerous breast cell producing too many HER genes, which in turn produce an excessive number of HER2 receptors. The receptors attract growth factors, which stimulate the growth of more cells. Herceptin (generic name, trastuzumab) and other antibodies inhibit HER2 receptors and VEGF growth factors. The growth signal is green.