Temporal, spatial and spatiotemporal analysis of the occurrence of visceral leishmaniasis in humans in the City of Birigui, State of São Paulo, from 1999 to 2012

Abstract

Introduction:In 1999, Birigui and Araçatuba were the fi rst municipalities in the State of São Paulo to present autochthonous cases of visceral leishmaniasis in humans (VLH). The aim of this study was to describe the temporal, spatial and spatiotemporal behaviors of VLH in Birigui. Methods: Secondary data were obtained from the Notifi able Diseases Information System from 1999 to 2012. The incidence, mortality and case fatality rates by sex and age were calculated. The cases of VLH were geocoded and grouped according to census tracts. Local empirical Bayesian incidence rates were calculated. The existence of spatial and spatiotemporal clusters was investigated using SaTScan software. Results: There were 156 confi rmed cases of autochthonous VLH. The incidence rate was higher in the 0-4-year-old children, and the mortality and case fatality rates were higher in people aged 60 years and older. The peaks of incidence occurred in 2006 and 2011. The Bayesian rates identifi ed the presence of VLH in all of the census tracts in the municipality; however, spatial and spatiotemporal clusters were found in the central area of the municipality. Conclusions: Birigui, located in the Araçatuba region, has recently experienced increasing numbers of VLH cases; this increase is contrary to the behavior observed over the entire region, which has shown a decreasing trend in the number of VLH cases. The observations that the highest incidence is in children 0-4 years old and the highest mortality is in people 60 years and older are in agreement with the expected patterns of VLH.

Spatial and spatiotemporal occurrence of human visceral leishmaniasis in Adamantina, State of São Paulo, Brazil

“…The highest fatality rate was observed in the 40-59-year-old group, followed by the 0-4-year-old age group. These results differ from those of other studies (16) (18) (19) , wherein the ≥60 age group demonstrated the highest mortality and fatality rates. Mortality rates would presumably be higher in this age group owing to a combination of HLV with other diseases already acquired, leading to adverse reactions caused by medicines (18) (19) .…”

“…However, this phenomenon was not verifi ed in the present study, because there was a balance in the incidence between sexes, which was also observed in Birigui (16) . The incidence curve for HVL in Adamantina shows that the HVL incidence rates were higher in the early years of the occurrence of the disease, but since 2007, there has been a downward trend in the number of reported cases, a situation similar to the one observed in the AR of Aracatuba (9) .…”

Using the Kulldorff’s scan statistical analysis to detect spatio-temporal clusters of tuberculosis in Qinghai Province, China, 2009–2016

“…It is a known fact that time is a critical confounder that might directly bias the determination of the high-risk regions of TB. The Kulldorff 's space-time scan statistical method can detect the distribution characteristics in both the temporal and spatial axes, bringing them closer to real-world conditions [12][13][14][15]. Additionally, the relative risk of disease in a cluster area can be estimated by comparing it with the area outside the cluster area.…”

Spatial and temporal distribution of American cutaneous leishmaniasis in Acre state, Brazil

“…Therefore, geographical information systems (GISs) and spatial analysis, in view of their usefulness in terms of understanding and visualizing the epidemiological behaviour of diseases such as leishmaniasis, have been important tools in achieving these objectives both in Brazil [4–6] and in other countries [7–10]. …”