Perinatal infections

Question 1

What are prevention measures for CMV infection in pregnancy?

Answer 1

Routine hygiene practices for ALL pregnant women and those trying to conceive, regardless of their CMV serology status:
1. Avoid contact with saliva when kissing a child - e.g. kiss on forehead not on lips
2. Thoroughly wash hands with soap and water for 15-20 seconds after changing nappies, feeding a young child or wiping a young child’s nose or saliva
3. Clean toys, countertops and other surfaces that come into contact with children’s urine or saliva
4. Do not:
- Share food, drinks or utensils used by children under 3yo
- Share a toothbrush with a young child
- Put a child’s dummy in your mouth

Condoms

Question 2

How is CMV transmitted?

Answer 2

Maternal infection via many routes – close non-sexual contact (household and occupational exposure, especially contact with young children), sexual exposure, transfusion, organ transplant

Fetal infection via transplacental infection and direct contact from birth canal

Question 3

What are the high risk groups for CMV infection?

Answer 3

• Frequent, prolonged contact with young children, in particular children who are shedding CMV
• Day care workers – annual seroconversion rate 12.5%
• Parents with child in day care – annual seroconversion rate 2% for non-CMV shedding children, 24% for CMV shedding children

(Health care workers seroconvert at rate comparable to general population eg. annual seroconversion rate 2-3%)

Question 4

Interpret CMV serology -
IgG and IgM negative

Answer 4

• Not CMV infection, and CMV susceptible; repeat test if clinically concerned
• If seroconversion or rise in IgG, recent primary infection

Question 5

What is the incidence of toxoplasmosis in pregnancy?

Answer 5

2:1000 pregnancies

Question 6

List the prevention measures for toxoplasmosis

Answer 6

• Avoid raw / undercooked meat, unpasteurized milk
• Wash hands after gardening
• Wash raw vegetables
• Minimise contact with kittens / kitty litter

Question 7

What is the classic triad of toxoplasmosis?

Answer 7

Intracranial calcifications, hydrocephalus and chorioretinitis

Question 8

What is counted as a significant exposure for VZV?

Answer 8

• Living in same household as person with active chickenpox or herpes zoster
• Face-to-face contact with a case of chickenpox or zoster for at least 5 minutes or being in the same room for at least one hour

Question 9

What are the features of fetal varicella syndrome?

Answer 9

• Skin scars 78%
• Eye abnormalities 60%
• Limb abnormalities 68%
• Prematurity, low birth weight 50%
• Cortical atrophy, intellectual disability 46%
• Poor sphincter control 32%
• Early death 29%

Question 10

When are cases of chickenpox infectious?

Answer 10

From 2 days before rash until lesions crusted

Question 11

Interpret CMV serology -
IgG positive, IgM positive

Answer 11

• Perform CMV specific IgG avidity (test immediately, and also repeat testing on new sample)
• Results
  -Low avidity = recent primary infection
  -Intermediate avidity (cut off as defined by laboratory) = recent primary infection not excluded, manage as recent primary infection
  -High avidity = past infection *

Avidity is also not a perfect test; some patients have high intermediate avidity w recent infection

*In-utero transmission less likely in non-primary infection but if infected full range of cCMV is possible

Question 12

Interpret CMV serology -
IgG positive, IgM negative

Answer 12

= past infection *

*In-utero transmission less likely in non-primary infection but if infected full range of cCMV is possible