To invade red blood cells, the deadly protists create temporary molecular portals that disappear behind them — doors we can now see in fine detail.

Plasmodium , the parasite that causes malaria, invades and proliferates inside red blood cells. Researchers imaged the proteins (dark purple ovals) it places on the cell membrane that let it slip through unnoticed.

Ada Zejun Shen for Quanta Magazine

Introduction

In medieval Italy, it was accepted wisdom that anyone walking near a swamp risked falling ill from “bad air” — mala aria . Victims were struck with fever, headache, nausea, and chills, and occasionally the illness escalated to vomiting, jaundice, and death. Today, we still call this affliction malaria. For much of human history, it has ravaged populations in humid tropical and subtropical regions, killing untold numbers.…