What is rubella?
Rubella is also called German Measles or 3-Day Measles (because it forms a skin rash that last for 3 days ); it is one of the TORCH syndrome. Rubella is caused by a virus known as Rubella virus which is a spherical, enveloped RNA virus
Rubella disease can occur sporadically but epidemics may also occur. It has a world-wide distribution and has serious effects on a fetus than adult.
Rubella mode of transmission
- Rubella is mainly transmitted by inhaling the virus in air through droplets.
- Rubella can be spread to the fetus through the placenta from the mother
Rubella incubation period and infectivity
The incubation period of Rubella is 14 to 21 days; the average being 18 days. The maximum time of infectivity is before appearance of rubella rash and at the time the rash is present; infectivity drops when the rash disappears.
Rubella Symptoms and signs (Clinical features of Rubella)
- There may be no symptoms (asymptomatic) especially in children under the age of 5. For those under 5 years of age and are symptomatic, the symptoms may just be mild.
- Before appearance of Rubella rash, there may be a feeling of being sick (malaise), there could be fever too
- Mild Conjunctivitis: the eyes may become mildly red
- Lymphadenopathy (swelling of lymph nodes): the nature of the lymph nodes helps in making a clinical diagnosis. The characteristic distribution of the lymph nodes involve the suboccipital nodes, postauricular lymph nodes and posterior cervical groups of lymph nodes.
- Small petechial lesions occurring on the soft palate known as Forchheimer spots are suggestive that a patient has Rubella; please not that this is only suggestive and not diagnostic
- There may be Splenomegaly (enlargement of the spleen)
- Appearance of rubella Rash occurs within the first 7 days of the initial symptoms. This stage is called the Eruptive or Exanthematous phase of rubella. The rubella rash first appears on the forehead and then spreads to involve the trunk and the limbs. The rash is usually pinkish red, macular and discrete. Some rashes may coalesce but they usually fade on the second day; they rarely persists beyond the third day after their appearance this is the reason why rubella is also called 3 day Measles.
Rubella in pregnancy
Rubella occurring in pregnancy mainly affects the fetus and up to 80% of all women who contract Rubella while pregnant will transmit it to the baby especially during the first trimester of pregnancy (first 3 months of pregnancy).When a pregnant woman becomes infected with Rubella in the second trimester (4th to 6th months of pregnancy), the rate of infection decreases and when infection occurs in the last three months of pregnancy (3rd trimester) there will be no ill-effects. When it affects the fetus and forms congenital abnormalities, this is referred to as Congenital rubella syndrome or Rubella Embryopathy.
Congenital Rubella Syndrome or Rubella Embropathy ( Specific complications of Rubella on Fetus)
Congenital Rubella Syndrome is characterized by the presence of cardiac malformations affecting the fetus such Patent ductus arteriosus and ventricular septal defect, eye lesions such as cataracts, mental retardation, microcephaly (small head), spina bifida and deafness. The effects of rubella on a fetus vary and not all fetuses affected may have the same abnormalities; the major tetrad comprises cataracts, heart defects (pulmonary artery hypoplasia or stenosis, persistent ductus arteriosus , tetralogy of Fallot, and ventricular septal defect), deafness and mental retardation. Rubella may cause fetal death in some cases.
In the Expanded rubella syndrome, there is manifestation of the congenital rubella syndrome with additional abnormalities such as hepatosplenomegaly (enlargement of the both liver and spleen), interstitial pneumonia, myocarditis and metaphyseal bone lesions.
Diagnosis of rubella can be made clinically from the pattern of the rash, soft palate petechial lesions and the lymph nodes group involved but a confirmation is made by laboratory tests.
Rubella Laboratory Tests
- Rubella immune status tests are carried out to know if one has been infected or not. The tests include Hemagglutination inhibition (HI), Enzyme Immunoassay (EIA), or Latex Agglutination. The test is said to be Reactive when Hemagglutination inhibition titers are 1:10 or greater
- Immunoglobulin M tests (IgM) are also done for babies in suspected congenital rubella infection in order to distinguish maternal antibodies from fetal antibodies.
- Viral genome can be detected in throat swabs (or oral fluid samples), urine and, in the case of intrauterine infection, the products of conception
- Cerebral palsy
- Spina bifida
- Thrombocytopenia (due to destruction of the platelets leading to petechiae)
- Congenital Cataract
- Microphthalmia (a small eye):
- Congenital heart diseases such as patent ductus arteriosus, atrial septa defect and ventricular septa defect.
- Neonatal jaundice
- Bell palsy
- Hearing loss
- Viral hepatitis
- Congenital glaucoma
- Pulmonary bacterial super-infection
- Females most often may develop Arthralgia following rubella disease
The above listed complications are general complications even though most occur in the fetus; of particular importance are the effects on the fetus which are damaging and have been listed separately under congenital rubella syndrome.
Treatment of rubella is supportive as there is no current drug for cure; the body is only supported pending when antibodies are formed to fight the infection.
Rubella Prevention using Rubella Vaccine
Prevention of Rubella is done by vaccination of children to enable the body develop antibodies that will fight the infection should the baby get infected. The rubella vaccine is given together with Mumps and Measles vaccines (3 in 1 trivalent vaccine) called Measles-Mumps-Rubella (MMR) Vaccine. The vaccine is given subcutaneously by giving 0.5 mL, usually when the child is 12 to 15 months old. A booster dose is recommended at 4 to 6 years of age.