Sterility is a rare but potential complication, along with hepatitis, nephritis, myocarditis, thyroiditis and nerve deafness. The virus is present throughout the world. About one third of cases are without symptoms. Children are commonly affected, although when infection does occur in adults, this tends to be noticed because complications are more likely to be unpleasant. Cases usually occur in winter and spring.
Transmission is by droplet and direct contact with an infected individual.
Mumps is a potentially distressing illness with some particularly unpleasant side effects. The disease is theoreticallyeradicable, but has a low priority in terms of public health efforts to control it. Many countries have chosen to limit its effects by immunizing childhood populations. This is particularly important in terms of reducing the disease acquired in adults when the complications may be more severe. Live virus mumps vaccines, containing attenuated virus strains have been developed in the USA, Japan, USSR, and Switzerland.