Assessment of the spatio-temporal distribution of Hepatitis-a virus transmission in the state of Pará, Brazil

Abstract

The hepatitis-A virus (HAV) is a worldwide healthcare problem, mainly affecting countries with poor sanitation and socioeconomic conditions. Spatio-temporal analyses have become an important scientific asset for identifying the clustering of disease infection, providing support for planning interventions and control strategies. This study aims to determine the spatio-temporal variability of HAV infection and related population-based demographic factors in a endemic region. The selected area of study was Pará state, Brazil. Brazilian Ministry of Health Notifiable Diseases Information System (SINAN) epidemiological report, MS vaccination coverage and Brazilian National Sanitation System (SNIS) sanitation condition datum have been analyzed. Spatial (Moran and Local Moran index)and space-time scan statistics techniques have been applied over Pará state using SINAN database for the assessment of the hepatitis-A incidence for a period of 10 years (from 2008 up to 2017). A total of 5500 cases has been reported. Gender specific incidence analysis indicated that men have higher risk of contamination than women. Sociodemographic (lack of sanitation), socioeconomic (municipality governments investments in infra-structure) presented relationship with the disease incidence. There have been evidences that extreme events of severe precipitation and severe droughs were also related to increase in hepatitis-A notification cases. Spatial statistics denoted a heterogeneous geographical structure in the disease`s incidence: isolated high and low HAV incidence clusters through the years, implying in a complex disease outbreak system that is partially controlled by public vaccination actions. Space-time scan statistics denoted that hepatitis-A incidence is highly attached to the public HAV vaccination program and to municipality specific social infrastructure.Lower incidence risk were majorly aggregated over the Nordeste Paraense and Metropolitana de Belém meso-regions. Distinct clusters of hepatitis-A incidence have been found over the studied area (Pará state), and these clusters varied over the years centered at northwest and northeast mesoregions, mainly time-located prior to the national vaccination program start (prior to 2014). National public vaccination program has not been capable of erradicating the disease in the state. Further studies are required to better assess the relationship between climate change efffects over weather events and their relation to HAV transmission outbreaks.