A quality assessment of reporting sources for microcephaly in Utah, 2003 to 2013

EUROlinkCAT protocol for a European population-based data linkage study investigating the survival, morbidity and education of children with congenital anomalies

INTRODUCTION

Congenital anomalies (CAs) are a major cause of infant mortality, childhood morbidity and long-term disability. Over 130 000 children born in Europe every year will have a CA. This paper describes the EUROlinkCAT study, which is investigating the health and educational outcomes of children with CAs for the first 10 years of their lives.

METHODS AND ANALYSIS

EUROCAT is a European network of population-based registries for the epidemiological surveillance of CAs. EUROlinkCAT is using the EUROCAT infrastructure to support 22 EUROCAT registries in 14 countries to link their data on births with CAs to mortality, hospital discharge, prescription and educational databases. Once linked, each registry transforms their case data into a common data model (CDM) format and they are then supplied with common STATA syntax scripts to analyse their data. The resulting aggregate tables and analysis results are submitted to a central results repository (CRR) and meta-analyses are performed to summarise the results across all registries. The CRR currently contains data on 155 594 children with a CA followed up to age 10 from a population of 6 million births from 1995 to 2014.

ETHICS

The CA registries have the required ethics permissions for routine surveillance and transmission of anonymised data to the EUROCAT central database. Each registry is responsible for applying for and obtaining additional ethics and other permissions required for their participation in EUROlinkCAT.

DISSEMINATION

The CDM and associated documentation, including linkage and standardisation procedures, will be available post-EUROlinkCAT thus facilitating future local, national and European-level analyses to improve healthcare. Recommendations to improve the accuracy of routinely collected data will be made.Findings will provide evidence to inform parents, health professionals, public health authorities and national treatment guidelines to optimise diagnosis, prevention and treatment for these children with a view to reducing health inequalities in Europe.

Congenital microcephaly hospitalizations in California infants: 1999-2013

INTRODUCTION

Population-level changes in microcephaly incidence risk (IR) could signal circulation of neurotropic pathogens or potential emerging teratogen exposure.

METHODS

In this retrospective population cohort study, we estimated the IR of hospitalizations with a microcephaly ICD-9-CM discharge diagnosis code among infants ≤1 year over a 15-year period (1999-2013) using the Electronic Health Record (EHR) database from all hospital discharges in California from the Office of Statewide Hospital Planning and Development (OSHPD) database. We calculated the overall and yearly IRs per 10,000 live births (LBs) and per 10,000 hospitalizations in infants ≤1 year, and explored the impact in the IR estimates when children with microcephaly associated comorbidities were excluded or not.

RESULTS

Among 8,860,153 hospital discharges of infants ≤1 year in the OSHPD database over this 15 year period, we identified 6,004 hospitalizations with a microcephaly discharge diagnosis code; 3,526 of those were in neonates ≤30 days. The IR of microcephaly hospitalizations for infants ≤1 year was 7.70/10,000 LB (for neonates it was 4.52/10,000 LB) and 6.78 per 10,000 hospitalizations ≤1 year. There was large heterogeneity in the yearly microcephaly IRs (I² = 66.6%).

DISCUSSION

EHR collected data could be used as a complementary approach to track epidemiologic changes in microcephaly IRs. However, standardization in the use of microcephaly discharge diagnosis code and harmonization in the types of additional comorbidities to be excluded across analyses is mandatory to allow for prompt identification of true changes in microcephaly rates over time.

Population-based microcephaly surveillance in the United States, 2009 to 2013: An analysis of potential sources of variation

BACKGROUND

Congenital microcephaly has been linked to maternal Zika virus infection. However, ascertaining infants diagnosed with microcephaly can be challenging.

METHODS

Thirty birth defects surveillance programs provided data on infants diagnosed with microcephaly born 2009 to 2013. The pooled prevalence of microcephaly per 10,000 live births was estimated overall and by maternal/infant characteristics. Variation in prevalence was examined across case finding methods. Nine programs provided data on head circumference and conditions potentially contributing to microcephaly.

RESULTS

The pooled prevalence of microcephaly was 8.7 per 10,000 live births. Median prevalence (per 10,000 live births) was similar among programs using active (6.7) and passive (6.6) methods; the interdecile range of prevalence estimates was wider among programs using passive methods for all race/ethnicity categories except Hispanic. Prevalence (per 10,000 live births) was lowest among non-Hispanic Whites (6.5) and highest among non-Hispanic Blacks and Hispanics (11.2 and 11.9, respectively); estimates followed a U-shaped distribution by maternal age with the highest prevalence among mothers <20 years (11.5) and ≥40 years (13.2). For gestational age and birth weight, the highest prevalence was among infants <32 weeks gestation and infants <1500 gm. Case definitions varied; 41.8% of cases had an HC ≥ the 10^th percentile for sex and gestational age.

CONCLUSION

Differences in methods, population distribution of maternal/infant characteristics, and case definitions for microcephaly can contribute to the wide range of observed prevalence estimates across individual birth defects surveillance programs. Addressing these factors in the setting of Zika virus infection can improve the quality of prevalence estimates. Birth Defects Research (Part A) 106:972-982, 2016. © 2016 Wiley Periodicals, Inc.

Zika Virus-Induced Microcephaly and Its Possible Molecular Mechanism

Zika virus is an arthropod-borne re-emerging pathogen associated with the global pandemic of 2015-2016. The devastating effect of Zika viral infection is reflected by its neurological manifestations such as microcephaly in newborns. This scenario evoked our interest to uncover the neurotropic localization, multiplication of the virus, and the mechanism of microcephaly. The present report provides an overview of a possible molecular mechanism of Zika virus-induced microcephaly based on recent publications. Transplacental transmission of Zika viral infection from mother to foetus during the first trimester of pregnancy results in propagation of the virus in human neural progenitor cells (hNPCs), where entry is facilitated by the receptor (AXL protein) leading to the alteration of signalling and immune pathways in host cells. Further modification of the viral-induced TLR3-mediated immune network in the infected hNPCs affects viral replication. Downregulation of neurogenesis and upregulation of apoptosis in hNPCs leads to cell cycle arrest and death of the developing neurons. In addition, it is likely that the environmental, physiological, immunological, and genetic factors that determine in utero transmission of Zika virus are also involved in neurotropism. Despite the global concern regarding the Zika-mediated epidemic, the precise molecular mechanism of neuropathogenesis remains elusive.