RUBELLA VIRUS

Supervised by: Ms. Noura AlKubiasi

Prepared by:Amani Mushabab

AlahmariAmani Mukhled

AlharthiTahani Alhbabi

Fayzh Mofres Alsumairi

Introduction

Rubella virus is the pathogenic agent of the disease Rubella, and is the

cause of congenital rubella syndrome when infection occurs during the

first weeks of pregnancy. Humans are the only known host of this virus.

History of Rubella

The last major epidemic of rubella in the United States occurred in 1964

and 1965, when millions of cases led to 20,000 infants born with

congenital rubella syndrome.The vaccine was first licensed in the United

States in 1969.

Classification

Family : Togaviridae

Genus : Rubivirus

Species : Rubella virus

Genome

The Rubella Virus genome is composed of 9757 nucleotides and has

similar genomic structure to other Togaviruses. The Rubella Virus has the

highest concentration of G/C nucleotides of any RNA virus with 69.5% of

the genome consisting of those nucleotides. Rubella has been sequenced

completely for three strains shwoing >95% homology between the three

strains..

Structure

ss+RNA

Lipo protein enveloped

spherical

40- 80 nm

With spik like

Transmission

Following rubella transmission, a person does not immediately become

sick. Once the rubella virus enters the body, it travels to the nose and back

of the throat, where it begins to multiply. It can also travel to other parts of

the body through the bloodstream and lymph system.

Capsid protein

The capsid protein (CP) has different functions. Its main tasks

are the formation of homooligomeres to form the capsid, and

the binding of the genomic RNA. Further is it responsible for

the aggregation of RNA in the capsid, it interacts with the

membrane proteins E1 and E2 and binds the human host-

protein p32 which is important for replication of the virus in

the host.

Rubella statistics

It show that the disease has been on the decline in the United

States, especially after 1969, when the vaccine was licensed

for use. Statistics also show that the disease is primarily

decreasing in children. Adults account for the majority of

rubella cases reported today..

Antigenic Types

Rubella virus contains three major structural polypeptides:

two membrane glycoproteins, E1 and E2 and a single

nonglycosylated RNA-associated capsid protein, C, within the

virion. One of the envelope proteins, E1, is responsible for

viral hemagglutination and neutralization. E2 has been found

in two forms, E2a and E2b due to differences in glycosylation.

The differences among strains of rubella viruses have been

correlated with differences in the antigenicity of E2.

Causes:

Rubella is caused by a virus. It is spread in the same way as any viral cold

- by tiny droplets produced from the nose and mouth. It's not as contagious

as a cold or the measles, but it has a long incubation period (the time

between getting infected with the virus and getting sick) that varies from

12 to 23 days. People who get the virus are infectious (can spread it to

others) for up to 10 days before symptoms appear.

Penetration and the target organ measled (rubeola)

Virus starts in the respiratory mucosa and infects the tracheal and bronchial cells next it travels to the lymphatic system and multiples once multiplied the virus enters the bloodstream and infects the skin and organs

Replication cycle

The virus attach to the cell surface via specific receptors and

are taken up by an endosome being formed. At the neutral pH

outside of the cell the E2 envelope protein covers the E1

protein. The dropping pH inside the endosome frees the outer

domain of E1 and causes the fusion of the viral envelope with

the endosomal membrane. Thus, the capsid reaches the

cytosol, decays and releases the genome

Symptoms

The main symptom of rubella is a red rash, usually starting on the head

and neck. The rash doesn't appear until 14 to 21 days after infection, with

most people developing their rash on Day 17 or Day 18 after exposure.

Diagnosis

Because many people with rubella have mild symptoms, it can be difficult

to diagnose. Your doctor will perform a physical exam and ask you about

your symptoms. If your doctor suspects rubella, they may order blood

tests.

Lab Diagnosis

Samples

Identification

Molecular Methods

Serology

: control

The vaccine protects more than 95% or people who receive it and

protection lasts for life. It is important to be vaccinated if you've never had

the disease. Rubella symptoms tend to be more severe in adults than in

children, so it's worth a shot to avoid it.

A second dose of the vaccine is recommended to protect the 5 percent who

did not develop immunity in the first dose .

: Risks during pregnancy

is most dangerous to your baby if you catch it during the first 16 weeks of pregnancy. Rubella can cause miscarriage, stillbirth, or

birth defects in unborn babies

( : weeks 0 to 13 ) high risk (up to 90%

(weeks 14 to 26: )

They may develop problems with their sight or hearing

(week 27 to birth:)

After week 16, the risk to the baby is low

Treatment:

There is no specific treatment for the measles , The following may relieve symptoms

cetaminophen (Tylenol) Bed rest Humidified air vitamin A supplements

Epidemiology of rubella virus

Occurrence

Rubella occurs worldwide.

Reservoir

Rubella is a human disease. There is no known animal reservoir. Although

infants with CRS may shed rubella virus for an extended period, a true

carrier state has not been described.

Conclusion

The rubella virus resides in the mucus in the nose and throat of the infected person. When that person sneezes or coughs, droplets spray into the air. The infected mucus can land in other people's noses or throats when they breathe or put their fingers in their mouth or nose after touching an infected surface.

:Reference

Bakshi SS, Cooper LZ: Rubella (review). Clin Dermatol 7:8. 1989 . [PubMed]

Centers for Disease Control: Rubella and Congenital Rubella Syndrome — United States, January 1, 1991-May 7, 1994. MMWR 43:391, 1994 . [PubMed]

Centers for Disease Control: Rubella Prevention. MMWR, Recommendations http://www.sheknows.com/health-and-wellness/

articles/808663/does-your-child-really- http://www.sheknows.com/health-and-wellness/

articles/808663/does-your-child-really-need-vitamin-supplements

http://www.nhs.uk/chq/Pages/1104.aspx?CategoryID=54