Mycology Report

Mycology
Rubella virus is the sole member of the genus Rubivirus, in the family Matonaviridae. It is an enveloped
virus with a single-stranded RNA of positive polarity and has a single antigenic type.
CHARACTERISTIC AND IMPORTANT PROPERTIES
 Rubella is a contagious disease caused by a virus. It is also called “German measles,” but it is caused
by a different virus than measles.
 Rubella was eliminated from the United States in 2004. Rubella elimination is defined as the
absence of continuous disease transmission for 12 months or more in a specific geographic area.
Rubella is no longer endemic (constantly present) in the United States. However, rubella remains a
problem in other parts of the world.
Most people who get rubella usually have mild illness, with symptoms that can include a low-grade
fever, sore throat, and a rash that starts on the face and spreads to the rest of the body. Some people
may also have a headache, pink eye, and general discomfort before the rash appears. Rubella can cause
a miscarriage or serious birth defects in an unborn baby if a woman is infected while she is pregnant.
Structure
 Rubella virus is a spherical 40- to 80-nm, positive-sense, single-stranded RNA virus consisting of an
electron-dense 30- to 35-nm core surrounded by a lipoprotein envelope. The RNA has a molecular
weight of about 3 × 10-6. The virus particles are generally spherical with spiky hemagglutinin-
containing surface projections.
TRANSMISSION AND EPIDEMIOLOGY
TRANSMISSION
 Rubella virus is transmitted through person-to-person contact or droplets shed from the respiratory
secretions of infected people. People can shed virus from 7 days before the onset of the rash
 Transmission from mother to fetus also can occur, with the highest risk for congenital rubella
syndrome (CRS) if infection occurs in the first trimester. Infants with CRS can transmit virus for ≤1
year after they are born.
EPIDEMIOLOGY
 In 2015, the World Health Organization Region of the Americas became the first in the world to be
declared free of endemic rubella virus transmission.
 Rubella virus continues to circulate widely, however, especially in Africa, East Asia, and South Asia;
≈49,000 cases were reported worldwide in 2019, and ≈10,000 cases were reported in 2020.
Globally, >100,000 infants are born each year with CRS; >80% are born in Africa and some countries
in South and Southeast Asia.
PATHOGENISIS AND IMMUNITY
PATHOGENISIS
 Following respiratory transmission, the virus replicates in the nasopharynx and regional lymph
nodes. In a pregnant woman, placental infection occurs during viremia and may lead to
transplacental fetal infection. Fetal damage occurs through destruction of cells, as well as
disruption of cell division leading to hearing impairment and ocular and cardiovascular
abnormalities
IMMUNITY
 Generally, persons can be considered immune to rubella if they were born before 1957, have
serologic evidence of rubella immunity or laboratory confirmation of disease, or have
documentation of adequate vaccination for rubella.
Acceptable presumptive evidence of immunity against rubella includes at least one of the following:
1. written documentation of vaccination with one dose of live rubella virus-containing vaccine
administered on or after the first birthday,
2. laboratory evidence of immunity,
3. laboratory confirmation of rubella disease, or
4. birth before 1957
Healthcare providers should not accept verbal reports of vaccination without written documentation as
presumptive evidence of immunity.
CLINICAL FINDINGS
CHILDREN
 rubella is usually mild, with few noticeable symptoms. For children who do have symptoms, a red
rash is typically the first sign. The rash generally first appears on the face and then spreads to the
rest of the body, and lasts about three days. Other symptoms that may occur 1 to 5 days before the
rash appears include:
a low-grade fever
headache
mild pink eye (redness or swelling of the white of the eye)
general discomfort
swollen and enlarged lymph nodes

cough
runny nose
 Most adults who get rubella usually have a mild illness, with low-grade fever, sore throat, and a
rash that starts on the face and spreads to the rest of the body.
 Some adults may also have a headache, pink eye, and general discomfort before the rash appears.
 About 25 to 50% of people infected with rubella will not experience any symptom
LAB DIAGNOSIS
 Diagnosis is based on serologic demonstration of specific rubella IgM or significant increase in

rubella IgG in acute- and convalescent-phase specimens. Reverse transcription PCR (RT-PCR) can be
used to detect virus infection; viral culture also is acceptable but is time consuming and expensive.
TREATMENT AND PREVENTION
TREATMENT
 Treatment of rubella involves supportive care. Counsel patients to isolate, and encourage
household contacts to get tested and vaccinated.
 Promptly isolate people suspected to have rubella and report them to the local health department
 There is no specific medicine to treat rubella or make the disease go away faster. In many cases,
symptoms are mild. For others, mild symptoms can be managed with bed rest and medicines for
fever, such as acetaminophen.
PREVENTION
 Rubella can be prevented with rubella-containing vaccine, which is primarily administered as the
combination measles-mumps-rubella (MMR) vaccine.
 The combination measles-mumps-rubella-varicella (MMRV) vaccine can be used for infants aged
6–11 months should receive 1 dose of MMR vaccine (for measles protection) children aged 12
months through 12 years for protection against measles, mumps, rubella and varicella. Adults born
during or after 1957 should receive at least one dose of rubella-containing vaccine. In addition,
Pregnant women should receive an MMR vaccination immediately postpartum. Ensure that all
people of childbearing age and recent immigrants are up to date on immunization against rubella or
have evidence of immunity to rubella, because these groups are at the greatest risk for maternal–
fetal transmission of rubella virus, which can result in CRS
One dose of MMR vaccine is about 97% effective at preventing rubella if exposed to the virus.
Congenital Rubella Syndrome (CRS)
Prevention of congenital rubella syndrome (CRS) is the main objective of rubella vaccination
programs, Infection with rubella virus is most consequential in early gestation and can lead to
miscarriages, stillbirths, and severe birth defects in infants. The risk of CRS is highest when a woman
acquires rubella during the first 12 weeks of gestation. Congenital infection with rubella virus can affect
many organ systems. Congenital rubella syndrome includes a constellation of birth defects, such as
deafness, eye abnormalities (cataracts, glaucoma, retinopathy, microphthalmia), and congenital heart
disease.

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Mycology

CHARACTERISTIC AND IMPORTANT PROPERTIES

TRANSMISSION AND EPIDEMIOLOGY

PATHOGENISIS AND IMMUNITY

mild pink eye (redness or swelling of the white of the eye)

swollen and enlarged lymph nodes

 Diagnosis is based on serologic demonstration of specific rubella IgM or significant increase in

TREATMENT AND PREVENTION

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