Understanding the viral battleground ---------------------------------------- Clinicians have traced the brutal rampage wrought by the coronavirus through the body, from the lungs – ground zero – to the heart and blood vessels, kidneys, gut, and brain ---------------------------------------- SARS-Cov-2 coronavirus Human cell Brain Brain stem Trachea Aorta Left ventricle Capillary Oxygen Air Alveoli Carbon dioxide Red cells ACE2 receptors mark tissues vulnerable to infection Oxygen crosses alveoli into capillaries and is carried by red blood cells around body White cells Alveoli White blood cells destroy virus-infected alveoli. Alveoli fill with fluid, white blood cells and mucus. Oxygen uptake is diminished, causing coughing, fever, and laboured breathing ---------------------------------------- 1 INFECTION: Virus infects nose and throat and enters Virus genome cells rich in surface receptor called ACE2 (angiotensin-converting enzyme 2). Virus hijacks cell, making multiple copies of itself to invade more cells ---------------------------------------- 2 LUNGS: Virus travels down trachea to attack tiny air sacs (alveoli) in lungs ---------------------------------------- 3 HEART: Virus may directly attack lining of heart and blood vessels – both rich in ACE2 receptors – and damage ventricles. Risk of thrombosis – blood clots that can cause organ failure ---------------------------------------- 4 BRAIN: Swelling (encephalitis), seizures or strokes. Infection depresses brain stem reflex that senses oxygen starvation, contributing to respiratory failure ---------------------------------------- 5 GUT: Virus infects and replicates in lining of lower gastrointestinal tract, where ACE2 receptors are abundant ---------------------------------------- 6 KIDNEYS: Reduced blood flow can cause acute kidney injury, increasing risk of death ---------------------------------------- Sources: Science, MIT, The Renal Association, BioMed Central Ltd © GRAPHIC NEWS