The human heart consist of four valves. One of these is the mitral valve which connects the left atrium to the left ventricle. During diastole, it opens to allow blood from the left atrium to flow to the left ventricle. But during ventricular systole, it closes to prevent backflow of blood back to the left atrium.
Answer: A carrier hosts. Hosts that do not show outward signs of a disease but can transmit it are carrier hosts as they host the disease in their body and carry it without symptoms.
