TY - JOUR T1 - Population-based surveillance of severe microcephaly and congenital Zika syndrome in Canada JF - Archives of Disease in Childhood JO - Arch Dis Child DO - 10.1136/archdischild-2020-320968 SP - archdischild-2020-320968 AU - Shaun K Morris AU - Daniel S Farrar AU - Steven P Miller AU - Marianna Ofner AU - Ari Bitnun AU - Chantal R M Nelson AU - Michael Shevell AU - Aideen M Moore AU - Joanne Tataryn AU - Jane A Evans AU - Amy R Zipursky AU - Charlotte Moore Hepburn Y1 - 2021/01/07 UR - http://adc.bmj.com/content/early/2021/01/08/archdischild-2020-320968.abstract N2 - Purpose To estimate the minimum incidence of congenital Zika syndrome (CZS) and severe microcephaly in Canada and describe key clinical, epidemiological, aetiological and outcome features of these conditions.Methods Two separate national surveillance studies were conducted on CZS and severe microcephaly using the well-established Canadian Paediatric Surveillance Program from 2016 to 2019. Over 2700 paediatricians across Canada were surveyed monthly and asked to report demographic details, pregnancy and travel history, infant anthropometry, clinical features and laboratory findings of newly identified cases. Reports were reviewed to assign an underlying aetiology of severe microcephaly. Incidence rates were estimated using monthly live birth denominators.Results Thirty-four infants met the case definition for severe microcephaly and <5 met the case definition for CZS. The associated minimum incidence rates were 4.5 per 100 000 live births for severe microcephaly and 0.1–0.5 per 100 000 live births for CZS. Of severe microcephaly cases, 53% were attributed to genetic causes, 15% to infectious or ischaemic causes and 32% to unknown causes. The median head circumference-for-age Z-score at birth was −3.2 (IQR −3.8 to −2.6), and catch-up growth was often not achieved. Common clinical features included intracranial abnormalities (n=23), dysmorphology (n=19) and developmental delays (n=14). Mothers of infants with non-genetic aetiologies travelled during pregnancy more often (10/16) than mothers of infants with genetic aetiologies (<5/18; p<0.01).Conclusion Severe microcephaly and CZS are both rare in Canada. Minimum incidence rates can be used as a baseline against which novel or re-emergent causes of severe microcephaly or CZS can be compared. ER -