The dark spots on the leaves of these tomato plants are an early symptom of infection caused by the plant pathogen Pseudomonas syringae. The bacteria spread infection by water-logging the spaces between cells in the plant’s leaves, creating a moist, cozy place to feed and multiply. Credit: Goldlocki, Wikimedia Commons
This fish doesn’t rely on its eyes to tell if it got its color camouflage right -- it uses its skin.
Packed with microscopic Plasmodium parasites, this red blood cell (teal) and other infected cells around it will soon burst and spew their contents into the bloodstream, triggering the periodic fevers that are the hallmark of malaria. Credit: NIAID