Supervised by: Ms. Noura AlKubiasi RUBELLA VIRUS Prepared by: Amani Mushabab Alahmari Amani Mukhled Alharthi Tahani Alhbabi Fayzh Mofres Alsumairi Supervised by: Ms. Noura AlKubiasi

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