Zika virus: What does a physician caring for children in Canada need to know?

Question 1

What is the zika virus?

Answer 1

RNA virus member of flavivirus family

Question 2

Where is zika prevalent?

Answer 2

1. South America
2. Caribbean
3. Mexico
4. United States in Florida and Texas only

Question 3

How is Zika spread?

Answer 3

Aedes aegypti mosquitoes

Less commonly Aedes albopictus

Question 4

What is the estimated incubation period?

Answer 4

3-12d

Question 5

What percentage of infections are asymptomatic?

Answer 5

75-80%

Question 6

What are common features of symptomatic zika?

Answer 6

1. Maculopapular rash (usu. pruritic, starting proximally and spreading to limbs with assoc. edema)
2. Low grade fever
3. Arthralgias (esp. small joints in hands and feet)
4. Myalgias
5. Headache
6. Non-purulent conjunctivitis

Question 7

What is the usual recovery time?

Answer 7

3-14d

Question 8

What are some unusual features of zika?

Answer 8

1. Myelitis
2. Encephalitis
3. Hearing loss
4. GU symptoms
5. Hematospermia
6. Hypotension
7. Thrombotic thrombocytopenia
8. Death
9. GBS

Question 9

What is congenital zika virus syndrome (CZS)?

Answer 9

(1) severe microcephaly with partially collapsed skull;
(2) thin cerebral cortices with subcortical calcifications;
(3) macular scarring and focal pigmentary retinal mottling;
(4) congenital contractures; (5) marked early hypertonia and symptoms of extrapyramidal involvement

Question 10

What is the estimated risk of zika virus infection during pregnancy?

Answer 10

1-13% risk

Question 11

How is the diagnosis made?

Answer 11

1. Serology (Immunoglobulin M [IgM] or Immunoglobulin G [IgG] or neutralizing antibody) or
2. Detection of ZIKV RNA by polymerase reaction (PCR) testing.

PCR positive in first 4d
IgM positive at 7d post symptoms and persists about 3 months
IgG positive at 10d post symptoms and persisted for life

Question 12

What are prevention or treatment for zika virus?

Answer 12

1. No treatment
2. Use personal protective measures to avoid germs
3. Avoid travel to affected areas if pregnant
4. Consider breastfeeding with caution during acute zika infections

Question 13

What populations should be investigated for congenital Zika syndrome?

Answer 13

1. > 2016 birth
2. Unexplained microcephaly
3. Intracranial calcifications
4. Ventriculomegaly
5. Major structural CNS abnormalities
6. Maternal history:
   a) travel to ZIKV endemic country during pregnancy
   b) sexual contact during pregnancy with a male who travelled to a ZIKV endemic country in the preceding 6m

Question 14

See figures in text for details re: screening?

Answer 14

See CPS statement