Risk areas for Human Visceral Leishmaniosis 2007-2018: A temporal and spatial analysis in Ceará, Brazil

Visceral leishmaniasis (VL) is considered as an important tropical disease because it rapidly spreads across a wide geographical area. This study aimed to analyse the temporal and spatial patterns of incidence, mortality and case fatality rates due to human VL in Ceará, Brazil, from 2007 to 2018. This is an ecological study involving time series and spatial analyses, and data were obtained from human VL notifications. Temporal trend analysis was carried out using the Joinpoint Regression Program. SaTScan 9.6 was used for conducting spatial analyses, and ArcMap 9.2 was used for building maps. There were 6,066 incident cases and 516 deaths due to human VL. There was an increasing trend in the incidence rate from 2007 to 2014 (annual per cent change [APC] = 3.8; 95% confidence interval [CI]:0.5 to 7.3; p = .031). Mortality (APC = -0.3; 95%CI: -2.5 to 1.9; p = .765) and VL case fatality rates (APC = -3.0; 95%CI: -4.3 to -1,7; p = .188) showed non-significant decline. The incidence rates were higher in the northwest and south regions of the state, with 11 high incidence rate clusters from 2007 to 2010, seven clusters in 44 municipalities from 2011 to 2014, and six clusters in 49 municipalities from 2015 to 2018. During 2007-2010, only one significant mortality rate cluster was identified in the southern region (relative risk [RR] = 7.6); during 2011-2014, two clusters in the northwest region were identified (RR=3.9 and RR=4.6). In the last period, a cluster of 11 municipalities in the southern region was identified (RR = 4.2). Mortality rate clusters were identified in the centre-south (2007-2010), northwest and south (both from 2011 to 2018). VL has a heterogeneous distribution, with maintenance of clusters with high incidence and mortality rates, as well as case fatality rates in municipalities in the northwest and south regions. These clusters present areas with the greatest risk of transmission of human VL.