Malaria spreads to human hosts via bite of an infected mosquito. Upon bite, the parasite travels to the liver where it grows until it breaks out into the blood 8-9 days later, initiating symptomatic disease. This image shows 2 liver stage parasites (exoerythrocytic forms) in primary human hepatocytes. You can see that both parasites push against the nuclei of the hepatocytes (in blue) to make room for themselves inside the cells. In green is the membrane of the parasite (UIS4) and in red is the endoplasmic reticulum of the parasite (BIP).