Parvovirus B19 is a small virus that primarily infects humans and is known for causing a common childhood illness called fifth disease, or erythema infectiosum. It spreads through respiratory droplets when an infected person coughs or sneezes, and it can also be transmitted through blood. Symptoms often include a mild fever, fatigue, and a distinctive rash that appears on the cheeks, giving a "slapped cheek" appearance. In most cases, parvovirus B19 infection is mild and resolves on its own without treatment. However, it can pose risks for certain groups, such as pregnant women, as it may lead to complications like anemia in the fetus. Individuals with weakened immune systems or certain blood disorders may also experience more severe symptoms.