erythema infectiosum, in the pre-vaccination era, it was frequently the fifth disease that a child would develop. It is caused by a virus known as parvovirus B 19. Symptoms include low-grade fever, fatigue, a slapped cheeks rash, and a rash over the whole body. While the illness is not serious in children, 80% of adults have joint aches and pains (arthritis) which may become long-term with stiffness in the morning, redness and swelling of the same joints on both sides of the body (a symmetrical arthritis), most commonly involving the knees, fingers, and wrists. Pregnant women (who have not previously had the illness) should avoid contact with patients who have fifth disease. The fifth disease virus can infect the foetus prior to birth. And, while no birth defects have been reported as a result of fifth disease, it can cause the death of the unborn foetus. The risk of foetal death is 5-10% if the mother becomes infected.