1. Rubella Virus
Dr Sumitha J

2. Morphology
• The rubella virus, also known as the German measles virus, belongs
to the Togaviridae family and is part of the Rubivirus genus.
• It is an enveloped, single-stranded RNA virus with a positive-sense
genome. The virus particles are spherical and relatively small, typically
ranging from 40 to 80 nanometers in diameter.

3. Epidemiology
• Rubella virus is highly contagious and is transmitted primarily through
respiratory droplets when an infected person coughs or sneezes.
• The virus can also be transmitted from mother to fetus during
pregnancy or through direct contact with respiratory secretions.
• Rubella is typically a childhood disease, and widespread vaccination
has significantly reduced its incidence in many countries.

4. Pathogenicity
• Rubella virus is generally considered to be of moderate pathogenicity,
especially in children and adults.
• It is characterized by its ability to cause a relatively mild illness with a
distinctive rash. However, its pathogenicity is more significant when it
infects pregnant women, as it can lead to congenital rubella syndrome
(CRS), which can have severe and lifelong consequences for the
developing fetus.

5. Clinical Features
• Rubella infection can present with a range of clinical features:
• Prodromal Phase: The initial phase of rubella infection is often mild and
includes symptoms such as:
• Low-grade fever
• Generalized malaise
• Mild upper respiratory symptoms
• Lymphadenopathy (enlarged lymph nodes), especially in the posterior
cervical and postauricular regions

6. • Rash: Typically, within 1 to 5 days after the onset of prodromal
symptoms, a characteristic maculopapular rash appears. This rash
starts on the face and then spreads to the trunk and extremities. It is
often described as "rosy" and may be itchy. The rash usually lasts for
about 2 to 3 days.
• Arthritis: In some cases, especially in adult females, joint pain and
swelling (arthritis) can occur. This symptom is usually temporary and
self-limiting.

7. • Complications: While rubella is usually a mild illness in children and
adults, it can have more serious consequences if a pregnant woman
becomes infected. Rubella during pregnancy can lead to congenital
rubella syndrome (CRS) in the developing fetus, resulting in a range of
birth defects, including deafness, eye abnormalities, heart defects, and
developmental delays.

8. Diagnosis
• Clinical Evaluation:
• Rubella infection typically presents with a characteristic rash and mild
flu-like symptoms. A healthcare provider may initially suspect rubella
based on the clinical presentation, especially if there is an outbreak in
the community or if the patient has had potential exposure to the virus.

9. • Patient History:
• Gathering a detailed patient history is important. Information about
recent travel, contact with individuals with rubella, and vaccination
status can be helpful in assessing the likelihood of rubella infection.

10. Serological Tests
• Serological tests are the primary method for confirming rubella virus
infection. These tests detect antibodies against the virus in the patient's
blood. The following serological tests are commonly used:
• Enzyme-Linked Immunosorbent Assay (ELISA): ELISA tests can detect
rubella-specific IgM and IgG antibodies. IgM antibodies are typically
produced early in the course of infection and are a sign of recent or acute
infection, while IgG antibodies indicate past or prior infection or vaccination.
• Hemagglutination Inhibition (HI) Assay: The HI assay can also detect rubella-
specific antibodies, and it may be used in some diagnostic laboratories.

11. • PCR (Polymerase Chain Reaction):
• While serological tests are the primary diagnostic tools for rubella, PCR
can be used to detect viral RNA in clinical specimens (e.g., throat swabs,
urine, or cerebrospinal fluid). This method is particularly useful for
diagnosing rubella in pregnant women and infants.
• Virus Isolation:
• Virus isolation techniques can be used to grow the rubella virus in cell
culture from clinical specimens. This method is less commonly used than
serological tests and PCR.

12. Vaccination
• Rubella can be effectively prevented through vaccination. The measles, mumps,
and rubella (MMR) vaccine or the measles, mumps, rubella, and varicella
(MMRV) vaccine is commonly used to immunize individuals against rubella.
• Vaccination is typically given to children in two doses, with the first dose
administered at 12-15 months of age and the second dose at 4-6 years of age.
• Catch-up vaccinations are recommended for older individuals who may not have
received the recommended doses during childhood, including adolescents and
adults.
• Vaccination not only protects individuals from rubella but also contributes to herd
immunity, reducing the overall transmission of the virus in the population.

13. • Preventative Measures for Pregnant Women:
• It is essential for pregnant women to ensure their immunity to rubella
before becoming pregnant. If a woman is not immune and is planning
to conceive, she should get vaccinated at least one month before
getting pregnant.
• Pregnant women should avoid contact with individuals who have
rubella or are suspected of having the virus to minimize the risk of
infection.