What is Rubella?

Rubella is an acute respiratory infection caused by rubella virus (RV), including congenital and acquired infections. Clinically, the prodromal period is short, low fever, rash, and enlarged lymph nodes behind the ear and occipital area. Generally the disease is mild, the course is short, and the prognosis is good. However, rubella is extremely likely to cause outbreaks and infections, which can occur all year round. The majority are winter and spring. The susceptible age is mainly 1 to 5 years old, so the epidemic is more common in preschool children. After the pregnant woman is infected with rubella virus early, although the clinical symptoms are mild, the virus can infect the fetus through the fetal blood barrier. Whether the infection is dominant or not, it can cause congenital rubella syndrome (CRS), which is mainly caused by congenital defects. ), Such as congenital fetal malformation, stillbirth, premature birth, etc. Therefore, the early diagnosis and prevention of rubella is extremely important. There is currently no specific way to treat rubella, but the disease can be prevented by immunization.

Basic Information

English name: rubella
Visiting department: Infectious Diseases
Multiple groups: Preschool children
Common causes: Rubella virus infection

Common symptoms: Low fever, rash and swollen lymph nodes behind the ear and occipital
Contagious: Have
way for spreading: It is mainly transmitted by the droplets through the respiratory tract, and can also be transmitted from person to person through contact.

Causes of rubella

Rubella virus is an RNA virus, belonging to the Togaviridae family, and is a virus restricted to humans. The antigenic structure of rubella virus is quite stable, and it is known that there is only one antigenic type. Rubella virus can survive and proliferate in the placenta or fetus (and months or even years after birth), producing long-term, multi-system, chronic, progressive infections. The virus can grow in rabbit kidney, milk rat mole kidney, green monkey kidney, rabbit cornea and other cell cultures, and can agglutinate poultry, flying birds and human "O" red blood cells. The virus has a weak vitality in vitro and is sensitive to ultraviolet light, ether, cesium chloride, and deoxycholic acid. It can be inactivated by pH <3.0. The virus is not heat-resistant.

Source of infection

Patients are the only source of infection for rubella, including subclinical or recessive infections. The actual number of subclinical or recessive infections is higher than that of the onset, so it is an important source of infection that is easily overlooked. The infectious period is 5 to 7 days before the onset and 3 to 5 days after the onset. The day of the onset and the day before is the most contagious. The virus can be isolated from the patient's mouth, nose, and throat secretions, as well as from blood and urine.

2. Ways of transmission

Rubella is usually transmitted by droplets through the respiratory tract in children and adults. Close contact between people can also be transmitted through contact. Infants with infected fetuses can drain the virus for weeks, months, or even more than one year. Therefore, they can be caused by contaminated feeding bottles, teats, clothing, diapers, and direct contact with infection-deficient medical services, family members, or Spread in the baby room. Infected fetuses can cause miscarriages, stillbirths, premature births, or congenital rubella with various congenital malformations.

3. Susceptible people

Rubella is more common in children, and it is not uncommon in young people, adults, and the elderly. Rubella is more common in winter and spring. In recent years, there have been more cases in spring and summer, which can be prevalent in clusters such as kindergartens, schools, and the military.

Clinical manifestations of rubella

Rubella is clinically divided into acquired rubella and congenital rubella syndrome, the former being the most common.

Acquired rubella

(1) The incubation period is 14 to 21 days.

(2) Prodromal period of 1 to 2 days, showing mild upper respiratory tract symptoms such as low fever or moderate fever, headache, loss of appetite, fatigue, fatigue, cough, sneezing, runny nose, sore throat, conjunctival congestion, and occasionally vomit , Diarrhea, nosebleeds, swollen gums, etc. Some patients saw rose or hemorrhagic macules in the pharynx and soft palate, but there were no rough buccal mucosa, hyperemia and mucosal plaques.

(3) Rashing period Rash usually occurs 1 to 2 days after the fever. The rash first appeared on the face and neck, quickly expanded the trunk and limbs, and covered the whole body within 1 day, but most of the palms and soles were free of rash. The rash initially appeared as fine reddish spotted macular rash, maculopapular rash, or pimples, with a diameter of 2 to 3 mm. The rash on the face and distal limbs is relatively sparse, and some fusions are similar to measles. The trunk, especially the back, has a dense rash that fuses into pieces and resembles scarlet fever. The trunk rash usually subsides for 3 days (1 to 4 days). It is also called "three-day measles". There may be swollen lymph nodes behind the ears, behind the pillow, and neck, conjunctivitis, or joint pain (arthritis).

(4) Patients with rubella-free rubella only have fever, upper respiratory tract inflammation, and lymphadenopathy without rash; they can also have no symptoms or signs after rubella virus infection. Serum tests are positive for rubella antibodies, which is the so-called recessive infection or Subclinical patients. The proportion of patients with dominant infection and patients without rash or recessive infection is 1: 6 to 1: 9.

2. Congenital Rubella Syndrome (CRS)

Maternal infection with RV in the first 3 months of pregnancy can cause multiple systemic birth defects in the fetus, that is, GRS. The earlier the infection occurs, the more severe the damage to the fetus. After the fetus is infected, severe cases can cause stillbirth, miscarriage, and premature delivery; mild cases can cause fetal growth retardation, and even affect the entire system, causing a variety of deformities. Newborn congenital malformations are mostly caused by congenital rubella. Most congenital patients have clinical symptoms at birth, and symptoms and new deformities can appear months to years after birth.

Rubella test

Laboratory inspection

(1) Peripheral blood image The total number of white blood cells is reduced, lymphocytes are increased, and abnormally shaped lymphocytes and plasma cells appear.

(2) Nasopharyngeal secretions are taken from patients with virus-isolated rubella, and urine, cerebrospinal fluid, blood, bone marrow, etc. from patients with congenital rubella are cultured in RK-13, African green monkey kidney aneuploid cell lines (verocells) or normal rabbit corneal aneuploidy Passive cells such as somatic cell lines (SIRCcells) can be used to isolate rubella virus and then identify it by immunofluorescence.

(3) Determination of serum antibodies Such as the erythrocyte agglutination inhibition test, neutralization test, complement binding test and immunofluorescence measurement, the antibody titer of the duplicate serum was increased by more than 4 times to be positive. The hemagglutination inhibition test is the most applicable and has the advantages of being fast, simple, and reliable. This antibody appears at the time of the rash, it rises rapidly in 1 to 2 weeks, and decreases to the initial level after 4 to 12 months, and can be maintained for life, used to detect rubella-specific antibodies IgM and IgG. Locally secreted IgA antibodies can be found in nasopharyngeal secretions, which is helpful for diagnosis. Dot hybridization can also be used to detect rubella virus RNA. Rubella retinitis is often an important sign in the diagnosis of congenital rubella. Brown or black-brown pigment spots of varying sizes often appear on the retina. In severe cases, the patients are accompanied by yellow lenses in addition to the large spots. Retinal blood vessels are often narrower and narrower than normal.

2. Auxiliary inspection

The electrocardiogram and cardiac enzyme spectrum of patients with myocarditis were changed.

Rubella diagnosis

The diagnosis of typical rubella patients is mainly based on the etiology, clinical manifestations and examination.

1. Have a history of contact with a confirmed rubella patient within 14 to 21 days.

2. Has the following main clinical symptoms

(1) Fever.

(2) Red maculopapular rash appears within 1 to 2 days of onset of skin.

(3) Swollen lymph nodes behind the ear, behind the pillow, and neck; conjunctivitis; or with joint pain (arthritis).

3. Laboratory diagnosis

(1) Rubella virus was isolated from pharyngeal swab specimens, or rubella virus nucleic acid was detected.

(2) No rubella IgM antibody was detected in the serum without receiving live attenuated rubella vaccine within 1 month.

(3) The serum rubella IgG antibody titer of patients in the recovery period is 4 times or more than that in the acute phase, or the antibody in the acute phase is negative and the antibody in the recovery phase is positive.

Differential diagnosis of rubella

The form of rash in rubella patients is between measles and scarlet fever. Therefore, it is important to identify these three common fever-like rashes. In addition, rubella needs to be associated with infantile rash, drug eruption, infectious mononucleosis, and enterovirus infections, such as Coxsackievirus A group 2, 4, 9, 16 and group B 1, 3, 5 Types, Ecovirus 4, 9, 16 infections are identified. Congenital rubella syndrome needs to be distinguished from intrauterine infection with toxoplasma gondii, cytomegalovirus infection, and herpes simplex virus. These three types of intranatal infections have similar symptoms to congenital rubella.

Rubella treatment

1. General symptomatic treatment

Patients with rubella generally have mild symptoms and do not require special treatment, mainly symptomatic treatment. Those with more significant symptoms should stay in bed and have a liquid or semi-liquid diet. Those with high fever, headache, cough and conjunctivitis can be treated symptomatically.

2. Complications treatment

Those with high fever, drowsiness, coma, and convulsions should be treated according to the principle of Japanese encephalitis. Severe bleeding tendency can be treated with adrenal cortex hormones, and fresh whole blood is transfused if necessary.

3. Congenital rubella

Asymptomatic infection does not require special treatment. Those with severe symptoms should be dealt with accordingly: those with obvious bleeding can consider intravenous immunoglobulin and transfusion if necessary; pneumonia, respiratory distress, jaundice, heart valve deformity, retinopathy and other treatment principles are the same as other newborns; congestive heart failure and glaucoma Patients need to be actively treated, cataract treatment is best postponed to 1 year old; early and regular auditory brainstem evoked potential examinations, early diagnosis of deafness and timely intervention.

Rubella prevention

1. Immunization is an effective method to prevent rubella. Rubella vaccine is a live attenuated virus strain that has been used for more than 40 years. A single dose of inoculation can obtain more than 95% of long-term immunity, which is close to the immunity induced by natural infection.

2. Rubella vaccine can be formulated monovalently (a vaccine against only one pathogen) or combined with other vaccines, such as measles (MR), measles and mumps (MMR), or measles, mumps and Chickenpox (MMRV) formulated vaccine.

3. Adverse reactions after vaccination are generally mild. Possible reactions include pain, redness at the injection site, low fever, rash, and muscle pain.