COMMUNICABLE DISEASES German Measles (Rubella) Professor Qayser Sahib Al Habeeb Specialist in Internal and Community Medicine Department of Family and Community Medicine College of Medicine University of Duhok
CDC LECTURES: Learning Objectives: By the end of the lecture, the students should be able to describe: 1- The disease, its occurrence and susceptibility. 2- Causative agent, incubation period and communicability. 3- Mode of transmission , reservoir of infection and carrier state if any. 4- Principles of management(Dx and treatment). 5- Main preventive and control measures
German Measles Rubella --- It is an acute viral infection caused by rubella virus Genus : Rubivirus Family : Togaviridae --- Generally it is a mild viral infection that occurs most often in children and young adults.
--- Rubella infection in pregnant women may cause fetal death or congenital defects known as congenital rubella syndrome (CRS). --- Worldwide, over 100 000 babies are born with CRS every year. --- There is no specific treatment for rubella but the disease is preventable by vaccination.
C.P : 7 days before to 5-7 days after rash onset
Reservoir : --- humans --- up to 50% of infections may be subclinical or asymptomaticI.P : 2 – 3 weeks MOT : --- droplets --- contact ( direct and indirect)
Clinically: The disease starts with --- fever, --- mild upper respiratory symptoms, --- punctate macular rash (50–80% of cases) resembling measles or scarlet fever and lasts 1–3 days . --- lymphadenopathy
Lymphadenopathy usually affects posterior cervical, post auricular & sub occipital groups. -- It is the most characteristic clinical feature. -- It precedes the rash by 5–10 days. -- It can be generalized.
The disease is usually mild but infection with rubelladuring the “1st trimester of pregnancy” is associated with a high risk of Congenital Anomalies (Destruction of cells and mitotic arrest)
Fetuses infected early are at greatest risk of ■ intrauterine death ■ spontaneous abortion and ■ congenital malformations of major organs (single or combined defects)
Common Defects are:
cataract , deafness, cardiac defects, microphthalmia & microcephalyother lifelong disabilities, include autism, diabetes mellitus and thyroid dysfunction.
Complications:1- Idiopathic thrombocytopenic purpura. ….. usually transient, lasting 1-3 weeks. 2- Encephalitis ….. occurs in 1 / 5000 cases and is variable in severity.Meissner, H. C. et al. Pediatrics 2006;117:933-935
Reported rubella and CRS: United States, 1966-2004Face of adult with rubella
CDCThis patient presented with a generalized rash on the abdomen caused by German measles (rubella). The rash usually lasts about 3 days, and may be accompanied by a low-grade fever.
Rash of rubella on skin of child's back. Distribution is similar to that of measles but the lesions are less intensely red.
This adolescent presented with a 2-day history of fever, malaise, rash, and lymphadenpathy, including these post auricular lymph nodes.
Post-auricular lymphadenopathy in a 17-year old with rubella.
This infant has the rash of congenital rubella These infants are at great risk for severe mental retardation, deafness, blindness (atrophic eyes, cataracts and chorioretinitis) as well as congenital heart disease and other abnormalitiesNewborn with congenital rubella rash.
A 4 year - old boy with congenital rubella syndrome with unilateral microphthalmos and cataract formation in the left eye.A 4 year - old female with congenital rubella with micro cephaly.
Differential Diagnosis: --- measles, --- human parvovirus infection (‘slapped cheek’) --- human herpes virus 6 (roseola) --- large number of other rashes of varied etiology.Diagnosis: ► clinical suspicion ► confirmation by specific IgM Abs or rising titer (4 fold rise in paired sera) ► virus isolation might also be done. ► detection of rubella specific RNA fragments using PCR.
Congenital Rubella Syndrome (CRS) ◘ Occurs in up to 90% of infants born to women infected during the 1st trimester. ◘ The risk of a single congenital defect falls to ~ 10%–20% by the 16th week. ◘ The risk is minimal in the 3rd trimester.◘ Congenital malformations and fetal death may occur following inapparent maternal rubella.
Management Antenatal mothers < 16 weeks pregnant with rubella are best advised to terminate pregnancy.
Note: infants with congenital rubella syndrome might shed the virus through nasopharyngeal secretion & urine FOR LONG TIME
Prevention and Control Measures:♦ Active immunization (LAV) CI in pregnancy & immuno suppression ♦ If exposed during pregnancy, ---- counsel the family ---- consider abortion.
♦ Contact isolation of the patients in hospitals and institutions. Affected infants should be considered contagious until at least they are one year old. ♦ Exclusion from school for at least 7 days after the onset of rash.
♦ Investigation of contacts and source of infection: Identify pregnant female contacts, especially those in the first trimester. Such contacts should be tested serologically for susceptibility or early infection (IgM antibody) and advised accordingly. ♦ Educate the general public on transmission modes and stress the need for rubella immunization. Health care providers must be aware of the risk of rubella in pregnancy.