Rubella

Rubella, commonly known as German measles, is a disease caused by Rubella virus. The name is derived form the Latin, meaning little red. Rubella is also known as German measles because the disease was first described by two German physicians in the mid-eighteenth century. This disease is often mild and attacks often pass unnoticed. The disease can last 1-5 days. Children recover more quickly than adults. The virus is transmitted by the respiratory route. Infection of the mother by Rubella virus during pregnancy can be serious; if the mother is infected within the first 20 weeks of pregnancy, the child may be born with congenital rubella syndrome, which is a range of serious incurable illnesses. The disease has an incubation period of 2 to 3 weeks.

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Signs and Symptoms

  About half of rubella infections are asymptomatic. The primary symptom of infection is the appearance of pink macules on the face which spread to the trunk and limbs and fade within two days. Other symptoms include low grade fever, swollen glands, joint pains, headache, conjunctivitis.^[1]The swollen glands or lymph nodes can persist for up to a week and the fever rarely rises above 38 degrees Celsius [100.4 degrees Fahrenheit]. The rash disappears after a few days with no staining or peeling of the skin. Forchheimer's sign occurs in 20% of cases, and is characterized by small, red papules on the area of the soft palate.

Rubella can affect anyone of any age and is generally a mild disease, rare in infants or those over the age of 40. The older the person is the more severe the symptoms are likely to be. Up to one-third of older girls or women experience joint pain or arthritic type symptoms with rubella. The virus is contracted through the respiratory tract and has an incubation period of 2 to 3 weeks. During this incubation period, the carrier is contagious but may show no symptoms.

Congenital Rubella Syndrome

Main article: Congenital rubella syndrome

Rubella can cause congenital rubella syndrome in the newly born. CRS is the main reason a vaccine for rubella was developed. Many mothers who contract rubella within the first critical trimester either have a miscarriage or a still born baby. If the baby survives the infection, it can be born with severe heart disorders, blindness, deafness, or other life threatening organ disorders.

Cause

The disease is caused by Rubella virus, a togavirus that is enveloped and has a single-stranded RNA genome. The virus is transmitted by the respiratory route and replicates in the nasopharynx and lymph nodes. The virus is found in the blood 5 to 7 days after infection and spreads throughout the body. It is capable of crossing the placenta and infecting the foetus where it stops cells from developing or destroys them.

Diagnosis

Rubella virus specific IgM antibodies are present in people recently infected by Rubella virus but these antibodies can persist for over a year and a positive test result needs to be interpreted with caution. The presence of these antibodies along with, or a short time after, the characteristic rash confirms the diagnosis.^[2]

Prevention

Rubella infections are prevented by active immunisation programs using live, disabled virus vaccines. The vaccine is given as part of the MMR vaccine. The WHO recommends the first dose is given at 12 to 18 months of age with a second dose at 36 months. Pregnant women are usually tested for immunity to rubella early on. Women found to be susceptible are not vaccinated until after the baby is born because the vaccine contains live virus.^[3]

The immunization program has been quite successful with Cuba declaring the disease eliminated in the 1990s. In 2004 the Centers for Disease Control and Prevention announced that both the congenital and acquired forms of rubella had been eliminated from the United States.^[4][5]

Treatment

Symptoms are usually treated with paracetamol until the disease has run its course. Treatment of newly born babies is focused on management of the complications. Congenital heart defects and cataracts can be corrected by surgery.

Prognosis

Rubella infection of children and adults is usually mild, self-limiting and often asymptomatic. The prognosis in children born with CRS is poor.^[6]

Epidemiology

Rubella is a disease that occurs worldwide. The virus tends to peak during the spring in countries with temperate climates. Before the vaccine to rubella was introduced in 1969, widespread outbreaks usually occurred every 6-9 years in the United States and 3-5 years in Europe, mostly affecting children in the 5-9 year old age group. Since the vaccine, occurrences have become rare but do still arise, usually in underprivileged countries where the vaccine is not as accessible or in schools or daycares where contact is close and frequent. During the last epidemic in the United States between 1964-1965, at least 11,000 foetuses died and 20,000 children were born impaired or disabled as a result of CRS.

History

Friedrich Hoffmann made a clinical description of rubella in 1740.^[7] Later descriptions by de Bergen in 1752 and Orlow in 1758 supported the belief that this was a derivative of measles. In 1814, George de Maton first suggested that it be considered a disease distinct from both measles and scarlet fever. All these physicians were German, and the disease was known medically as Rötheln (from the German name Röteln), hence the common name of "German measles".^{[7][8][9][10][11][12]}

English Royal Artillery surgeon, Henry Veale, observed an outbreak in India. He coined the euphonious name "rubella" (from the Latin, meaning "little red") in 1866.^[11] It was formally recognized as an individual entity in 1881, at the International Congress of Medicine in London.^[12] In 1914, Alfred Fabian Hess theorised that rubella was caused by a virus, based on work with monkeys.^[13] In 1938, Hiro and Tosaka confirmed this by passing the disease to children using filtered nasal washings from acute cases.^[10]

In 1940, there was a widespread epidemic of rubella in Australia. Subsequently, ophthalmologist Norman McAllister Gregg found 78 cases of congenital cataracts in infants and 68 of them were born to mothers who had caught rubella in early pregnancy.^[8][10] Gregg published an account, Congenital Cataract Following German Measles in the Mother, in 1941. He described a variety of problems now know as congenital rubella syndrome (CRS) and noticed that the earlier the mother was infected, the worse the damage was.^[12] The virus was isolated in tissue culture in 1962 by two separate groups led by physicians Parkman and Weller.^[11][8]

There was a pandemic of rubella between 1962 and 1965, starting in Europe and spreading to the United States.^[11] In the years 1964-65, the United States had an estimated 12.5 million rubella cases. This led to 11,000 miscarriages or therapeutic abortions and 20,000 cases of congenital rubella syndrome. Of these, 2,100 died as neonates, 12,000 were deaf, 3,580 were blind and 1,800 were mentally retarded. In New York alone, CRS affected 1% of all births.^[12]

In 1969 a live attenuated virus vaccine was licensed.^[10] In the early 1970s, a triple vaccine containing attenuated measles, mumps and rubella (MMR) viruses was introduced.^[11]

See also

• Eradication of infectious diseases

References