Zika might not be acting alone: Using an ecological study approach to investigate potential co-acting risk factors for an unusual pattern of microcephaly in Brazil
Open Access
- 15 August 2018
- journal article
- research article
- Published by Public Library of Science (PLoS) in PLOS ONE
- Vol. 13 (8), e0201452
- https://doi.org/10.1371/journal.pone.0201452
Abstract
Zika virus infections can cause a range of neurologic disorders including congenital microcephaly. However, while Zika infections have been notified across all regions in Brazil, there has been an unusual number of congenital microcephaly case notifications concentrated in the Northeast of the country. To address this observation, we investigated epidemiological data (2014–2016) on arbovirus co-distribution, environmental and socio-economic factors for each region in Brazil. Data on arbovirus reported cases and microcephaly were collected from several Brazilian Ministry of Health databases for each Federal unit. These were complemented by environmental management, social economic and Aedes aegypti infestation index data, extracted from multiple databases. Spatial time “ecological” analysis on the number of arboviruses transmitted by Aedes mosquitoes in Brazil show that the distribution of dengue and Zika was widespread in the whole country, with higher incidence in the West-Central region. However, reported chikungunya cases were higher in the Northeast, the region also with the highest number of microcephaly cases registered. Social economic factors (human development index and poverty index) and environmental management (water supply/storage and solid waste management) pointed the Northeast as the less wealthy region. The Northeast is also the region with the highest risk of Aedes aegypti house infestation due to the man-made larval habitats. In summary, the results of our ecological analysis support the hypothesis that the unusual distribution of microcephaly might not be due to Zika infection alone and could be accentuated by poverty and previous or co-infection with other pathogens. Our study reinforces the link between poverty and the risk of disease and the need to understand the effect on pathogenesis of sequential exposure to arboviruses and co-viral infections. Comprehensive large-scale cohort studies are required to corroborate our findings. We recommend that the list of infectious diseases screened, particularly during pregnancy, be regularly updated to include and effectively differentiate all viruses from ongoing outbreaks.Keywords
Funding Information
- Medical Research Council (MR/M01360X/1)
- Medical Research Council (MR/K000551/1)
- Medical Research Council (MC_PC_15103)
- Medical Research Council (MR/N010469/1)
- Fundação de Amparo à Pesquisa do Estado de São Paulo (2016/07030-0)
- FAPESP (2012/04755-3)
This publication has 65 references indexed in Scilit:
- Aedes ægypti control in urban areas: A systemic approach to a complex dynamicPLoS Neglected Tropical Diseases, 2017
- Transmission risk of two chikungunya lineages by invasive mosquito vectors from Florida and the Dominican RepublicPLoS Neglected Tropical Diseases, 2017
- Zika puzzle in Brazil: peculiar conditions of viral introduction and dissemination - A ReviewMemórias do Instituto Oswaldo Cruz, 2017
- Environmental and Social Change Drive the Explosive Emergence of Zika Virus in the AmericasPLoS Neglected Tropical Diseases, 2017
- Congenital Chikungunya Virus Infection after an Outbreak in Salvador, Bahia, BrazilAmerican Journal of Perinatology Reports, 2016
- Microcephaly in Brazil: how to interpret reported numbers?The Lancet, 2016
- Microcefalia no Estado de Pernambuco, Brasil: características epidemiológicas e avaliação da acurácia diagnóstica dos pontos de corte adotados para notificação de casoCadernos de Saude Publica, 2016
- Climate Change and Range Expansion of the Asian Tiger Mosquito (Aedes albopictus) in Northeastern USA: Implications for Public Health PractitionersPLOS ONE, 2013
- Systemic involvements and fatalities during Chikungunya epidemic in India, 2006Journal of Clinical Virology, 2009
- Zika Virus (I). Isolations and serological specificityTransactions of the Royal Society of Tropical Medicine and Hygiene, 1952