Rubella

1. Rubella Dr hab.n. med. Ewa Majda - Stanisławska Department of infectious Diseases and Hepatology Medical University of Lodz

2. Rubella • characterized by rash, fever, and lymphadenopathy and resembles a mild case of measles (rubeola). • many infections with the agent are subclinical, • this virus has the potential to cause fetal infection, with resultant birth defects, • uncommonly, but especially in adults, may cause various forms of arthritis.

3. Classification • Rubella virus is classified in the Togaviridae family • placed in a separate genus, Rubivirus. • RNA virus, icosahedral capsid, and lipoprotein envelope.

4. Epidemiology • Epidemics of rubella of minor proportions occurred in the prevaccine era every 6 to 9 years, and large-scale epidemics occurred at intervals of up to 30 years. The most recent major epidemic in the United States occurred in 1964, during which some 12500000 persons were infected

5. Transmission • Rubella virus is spread in droplets that are shed from respiratory secretions of infected persons. • Patients are most contagious while the rash is erupting, • They may shed virus from the throat from 10 days before until 15 days after the onset of the rash. • Patients with subclinical cases of illness may also transmit the infection to others.

6. Transmission in case of congenital rubella • Infants with congenital rubella shed large quantities of virus from body secretions for many months and therefore may transmit the infection to those who care for them. • These babies continue to excrete rubella virus despite high titre of neutralizing antibody, a puzzling phenomenon that has yet to be explained • The possibility of immune tolerance due to fetal infection has been raised.

7. Pathogenesis • The incubation period for rubella ranges from 12 to 23 days (average, 18 days). • As in measles a primary and a secondary viremia are believed to accompany rubella. • Rubella virus has been detected in leukocytes of patients as early as 1 week before the onset of symptoms. • The rubella rash appears as immunity develops and the virus disappears from the blood, suggesting that the rash is immunologically mediated

8. Clinical manifestations - rash • Begins on the face and moves down the body • It is maculopapular but not confluent, • May desquamate during convalescence, • May be absent in some cases. • An enanthem consisting of petechial lesions on the soft palate (Forscheimer's spots) has been described for rubella, • This enanthem is not diagnostic for rubella (unlike Koplik's spots in measles). • The rash may be accompanied by mild coryza and conjunctivitis. • Usually the rash lasts 3 to 5 days. • Fever, if present, rarely lasts beyond the first day of rash.

9. Differential diagnosis of rubella • measles, • toxoplasmosis, • scarlet fever, • roseola, • parvovirus B19 infection, • certain enterovirus infections • monocytic angina

10. Complications of postnatal Rubella- arthritis • Arthritis or arthralgia has been reported in as many as one third of women with rubella; • this complication is less common in children and in men. • The arthritis tends to involve the fingers, wrists, and knees, and it occurs either as the rash is appearing or soon afterward. • It can be rather slow to resolve, as long as 1 month. • Rarely does chronic arthritis develop.

11. Complications of postnatal Rubella- hemorrhagic manifestations • occur in approximately 1 of every 3000 cases of rubella. • occur more often in children than in adults • may be secondary to both thrombocytopenia and vascular damage, • they are more is probably immunologically mediated • thrombocytopenia may last from weeks to months and may cause serious problems if bleeding into vital areas (e.g., brain, kidney, eye) occurs

12. Congenital rubella • Can lead to fetal death, premature delivery, and an array of congenital defects • The rubella epidemic of 1964 left 30000 affected infants

13. Congenital rubella • The effects of rubella virus on the fetus are dependent on the time of infection; • During the first 2 months of gestation, the fetus has a 65% to 85% chance of being affected, with an outcome of multiple congenital defects, spontaneous abortion, or both. • Rubella during the third month of fetal life is associated with a 30% to 35% chance of developing a single defect, such as deafness or congenital heart disease. • Fetal infection during the fourth month carries a 10% risk of a single congenital defect. • Occasionally, fetal damage (deafness alone) is seen if rubella occurs up to the 20th week of gestation.

14. Congenital rubella • Diabetes mellitus in late childhood has also been observed 50 times more frequently in children who had congenital rubella than in normal children

16. Clinical manifestations - postnatal rubella • Many cases of postnatal rubella are subclinical • Children do not experience a prodromal phase, • Adults may have a prodrome of malaise, fever, and anorexia for several days • The major clinical manifestations of postnatal rubella are: • adenopathy, which may last several weeks (the posterior auricular, posterior cervical, and suboccipital chains. the posterior auricular, posterior cervical, and suboccipital chains) • rash. • on occasion, splenomegaly

17. Diagnosis of rubella • The diagnosis of congenital rubella infection has been made by isolation of virus from amniotic fluid • The laboratory diagnosis of postnatal rubella is most conveniently made serologically (ELISA) • For a serologic diagnosis of congenital rubella in the neonatal period, antibody to rubella virus should be measured in both infant and maternal sera

18. Treatment • no treatment for postnatal rubella • for patients with fever and arthritis or arthralgia, the treatment of symptoms is indicated. • immune globulin (IG) was advocated for the prevention or modification of rubella in susceptible pregnant women who were exposed to the infection, although it would not necessarily prevent viremia. • IG may be given to a susceptible pregnant woman who are exposed to rubella and for whom abortion is not an option, when they develop the disease. • rubella vaccine- immunization of susceptible women of childbearing age before they become pregnant.