Rubella (German Measles)
Rubella or German Measles is an acute childhood (congenital) infection, usually mild, of short duration (approximately three days), and accompanied by low–grade fever. Lymphadenopathy and a maculopapular rash infection in early pregnancy may result in serious congenital defects, including death of the fetus. The disease is worldwide in distribution and tends to occur in epidemics, in the non–immunized populations, about every six to eight years.

History of Rubella
Rubella was considered a mild and benign disease until 1941, when Norman Gregg, an ophthalmologist reported an epidemic of congenital cataracts associated with other congenital defects in children born to mothers who had Rubella during their pregnancies due to various factors. This discovery changed the concept that Rubella is not merely a benign disease of childhood but also one with teratogenic potential. In 1962, the virus was isolated, in 1967, an attenuated vaccine was developed.

Congenital Rubella
The Congenital Rubella Syndrome (CRS) refers to infants born with defects secondary to intrauterine infection, or who manifest symptoms or signs of intrauterine infection some time after birth. Congenital infection is considered to have occurred if the infant has lgM Rubella antibodies shortly after birth or if lgG antibodies persist for more than six months, by which time, maternally derived antibodies would have disappeared.

Rubella infection inhibits cell division, and this is probably the reason for congenital malformations and low birth weight. The most common congenital defects are deafness, cardiac malformations and cataracts. Other resulting defects include glaucoma, retinopathy, microcephalus, cerebral palsy, intrauterine growth retardation, hepato–splenomegaly mental and motor retardation. These defects occurring singly or in combination have become known as “Congenital Rubella syndrome”.

Congenital Rubella is a chronic infection, while acquired Rubella is an acute one. The fetus remains infected throughout gestation and for months and sometimes years post–natally. The gestation age at which maternal infection occurs is a major determinant for the extent of fetal infection as well as effects on the fetus.

The first trimester of pregnancy is the most disastrous time for the fetus as the organs are developing. If the infection is serious, spontaneous abortion and stillbirth may occur, or the infant may develop multiple defects such as the classical triad of patent ductus arteriosus, cataract and deafness. Infection in the second trimester may cause deafness, but those infected after week 16 suffer no major abnormalities.

Incubation period of Rubella
The incubation period ranges from about two to three weeks. The average incubation period is for about 18 days.