Microbiology Flashcards
When does Rubella infection not cause infection?
Rubella infection that occurs after 16 weeks gestation does not typically cause fetal abnormalities.
When should the rubella vaccine be given to a pregnant woman?
Rubella vaccine is live and should not be given during pregnancy. The mother should be offered vaccination after giving birth.
Is the MMR vaccine safe in breastfeeding?
Yes
Rubella key facts
Caused by rubella virus - a togavirus.
Single stranded RNA genome
Transmission primarily via the respiratory route.
Infection in children and adults usually mild
Where does rubella viral replication occur?
In the nasopharynx and lymph nodes
What is the incubation period of Rubella?
12-23 days (average 14 days)
Congenital rubella infection symptoms?
Congenital rubella infection teratogenic with poor prognosis and significant complications:
Sensorineural deafness
Cataracts
Cardiac abnormalities - most common.
Treatment for rubella congenital infection?
No specific treatment. Key prevention through vaccination programme.
Rubella vaccination in pregnancy?
Vaccination is via live attenuated virus so cannot be given to pregnant women who are found to be non-immune.
What percentage of infants with congenital CMV infection are symptomatic?
10-15% at birth, 10-15% will develop symptoms in later life.
Features of congenital CMV infection
Sensorineural Hearing loss
Visual impairment
Microcephaly
Low birth weight
Seizures
Cerebral palsy
Hepatosplenomegaly with jaundice
Thrombocytopenia with petechial rash
Cytomegalovirus (CMV) Key points
> 50% women seropositive
Congenital CMV infection refers to infection during the perinatal period and tends to effect mothers who have their first CMV infection during pregnancy.
Risk of congenital infection with primary infection of CMV during pregnancy?
30-40%
Risk of congenital infection with recurrent CMV infection during pregnancy?
1-2%
Can CMV be transmitted in breastmilk? T/F
True
What is the incubation period for CMV>
3-12 weeks.
How is fetal CMV infection diagnosed?
Via amniocentesis
When should amniocentesis be performed in fetal CMV infection?
Amniocentesis should be not be performed for at least 6 weeks after maternal infection and not until the 21st week of gestation.
What is the mortality rate of treated disseminated neonatal herpes?
30%
Herpes simplex in pregnancy key facts
- Type 1 and 2 (type 2 accounts for 70% of genital herpes infections)
- Double stranded DNA virus
How is herpes simplex virus transmitted?
HSV infection may be transmitted to neonates. Transmission is typically due to the neonate coming into contact with infected maternal secretions during delivery (transplacental infection reported but very rare).
When is the risk of primary herpes infection highest?
Highest risk with primary herpes infection within 6 weeks of delivery. Viral shedding can continue after lesions have healed.
How common is neonatal herpes?
Rare - UK incidence 3/100,000 live births
What are the 3 types of neonatal herpes?
- Restricted to skin/superficial infection (eye/mouth) - least severe.
- CNS infection (mortality with antiviral treatment 6% neurological sequelae 70%)
- Disseminated infection (mortality with antiviral treatment 30% neurological sequelae 17%)
- 70% of cases are disseminated or CNS involvement