RUBELLA
DR HADEEL FADHIL
Mild febrile viral disease with diffuse rash.
Children usually present few or no constitutional symptoms.
In adults may experience of low grade fever , headache , malaise, mild corysa, & conjunctivitis , lymphadenopathy( ccic CF & precedes the rash by 5-10 days)
Up to half of infections occur without recognized rash .
Leukppenia is common thrombocytopenea can occur , arthralgia , arthritis.
Encephalitis & thrombocytopenia ( rare complication in children , encephalitis occur more in adults ) Rubella is important bec. Of its ability to produce anomalies in the developing fetus .
Congenital rubella syndrome (CRS) occurs in up90% of infants born to women who are infected with rubella during the 1st trimester of pregnancy .
Infected fetus are at risk of IUD .spontaneous abortion , congenital malformation .
Differentiation of rubella :
* measles
*scarlet fever
Diagnosis :
*clinical dx
* lab : significant rise in specific antibody between acute & convalescent phase by ELISA
OR by presence of rubella specific IgM indicating recent infection .
Virus may be isolated from the pharynx 1 wk before & up to 2 wk after onset of rash .
Blood , urine , or stool specimens may yield virus .
Virus may be shed from the throat and urine for as long as year .
Infectious agent : Rubella virus ( family Togaviridae)
Occurrence :
Worldwide, usually endemic except in remote & isolated communities that have epidemics every 10-15 years .
* it is prevalent in winter & spring .
Reservoir: humans
Mode of transmission :
* contact with nasopharyngeal secretions of infected people .
Infection is by droplet spread or direct contact with patients .
Incubation period : from 14-17 days with range 0f 14-21 days.
Period of communicability : for about 1 wk before and at least 4 days after onset of rash .
Susceptibility & resistance :
Suscp. Is general after loss of transplacentally acquired maternal antibodies .
Active immunity is acquired by natural infection or by immunization , it is usually permanent or lifelong .
Infants born to immune mothers are protected for 6-9 months depending on the amount of maternal antibodies aquired transplacentally.
Methods of control prevent Rubella control is needed primarily to defect in the offspring of women who infected during pregnancy
A- PREVENTIVE MEASURES :
1- educate the general public on mode of transmission & need for rubella immunization
2- single dose of live , attenuated rubella virus vaccine elicits a significant antibody response in about 98-99% of susceptible
Immunization of all children is recommended at 12-15 months of age part of MMR , with 2nd dose of MMR at school entry or at adolescence .
Vaccine is recommended for :
*non pregnant females without contraindication.
*Susceptible young adults who have contact with young children
* medical personnel should be immune to rubella , particularly those who are contact with patients in prenatal clinics.
Vaccine contraindications :
* immunodeficiency or on immunsuppressive therapy .
*women known to be pregnant or who are planning to get pregnant in the next 3 months
In some countries routine immunization is
given to girls between 11&13 years of age with or without prier antibody testing .
3- in case of natural infection early in pregnancy ,abortion should be considered because of high risk of damage to the fetus .
4- IG given after exposure early in pregnancy may not prevent infection or viremia , but it modify or suppress symptoms. It is sometimes given in huge doses ( 20 ml) to a susceptible pregnant women exposed to the disease who would not consider abortion under any circumstances , but its value has not been established.
B- Control of patient , contact and immediate environment:
1- report to local health authority: all cases of rubella should be reported , report is obligatory
2- isolation: in hospitals & institutions, patients suspected of having rubella should be managed under contact isolation percussions & placed in a private room to prevent exposure of non-immune pregnant women
Exclude children from school & adults from work for 7 days after onset of rash.
3- concurrent disinfection: none
4- quarantine: none
5- immunization of contact: immunization , if not contraindicated, will not necessary prevent infection or illness.
Passive immunization with IG is not indicated
6- investigation of contact & source of infection: identify pregnant female contacts, especially those in the 1st trimester .
7- specific treatment: none