Demographic and spatial study of visceral leishmaniasis in the state of Alagoas, Brazil, during 2007-2018

Abstract

Introduction: Visceral leishmaniasis has a broad worldwide distribution and constitutes a public health problem in the Northeast of Brazil. Located in this region is the state of Alagoas, where the disease is endemic in humans and where there has been a significant increase in the number of positive dogs. The objective of this study was to describe the temporal and spatial distribution of the cases of human VL in the state of Alagoas with the aim of identifying transmission risk areas in the period from 2007 to 2018. Methods: The data available in the National Disease Notification System (SINAN-NET) were used. The Bayesian incidence rate and the Moran's global index were calculated using the Terra View 4.2.2 program, and the maps were created using QGIS2.18.0. Results: From the 102 municipalities, 68.6% (n= 70) had at least one notified case of VL in the years of study. A total of 489 cases were registered, with an average of 40.7 cases per year and an incidence rate of 1.25/100,000 inhabitants. The highest number of confirmed cases (105) occurred in 2018. Male individuals and children between 1-4 years old were the most affected, and 64% of the cases were in rural areas. Spatial dependence was detected in all the intervals except for the first triennium, and clusters were formed in the west of the state. Conclusions: Alagoas presented an accentuated geographical expansion of VL, and it is necessary to prioritize areas and increase surveillance actions and epidemiological control.

Temporal trend in the incidence of human visceral leishmaniasis in Brazil

“…Another study, which had the state of Alagoas as its analysis space, confirms a progressive evolution of VL incidence rates in the Federation Unit, showing geographic expansion, a trend of zoonosis persistence in areas that already had reported cases, and overall strengthening of the endemic status of the disease in that territory between 2007 and 2018 20 .…”

“…The differences between the behavior of national and federation units' incidence rates suggest that different factors can influence the risk of VL among states and regions of the country. Rocha et al 29 , Braz et al 20, and Ribeiro et al 30 agree that the behavior of this zoonosis in the regions of the country is directly associated with the environmental and geographic conditions of the territory, where situations of high temperature and humidity predominate, which enable a good adaption and reproduction of the vector; and precarious socio-environmental issues such as lack of basic sanitation and water supply, poor housing conditions, accumulation of waste from the peridomicile both in an urban and rural area, the intense population of vectors and canine cases of the disease, presence of livestock close to residences and proximity of households to green areas, factors that directly interfere in the adaptation and reproduction of L. longipalpis.…”

Visceral Leishmaniasis Associated with HIV Coinfection in Pará, Brazil

“…The transmission cycle that used to take place in a wild and rural environment, today intensifies in urban centers. 49 …”

Hierarchical spatiotemporal modeling of human visceral leishmaniasis in Rio Grande do Norte, Brazil

“…Human visceral leishmaniasis (VL) is endemic in Brazil [1][2][3][4][5][6][7][8][9][10][11][12] and is recognized as a neglected tropical disease by the World Health Organization [13]. In Brazil, VL etiology stems from the protozoan Leishmania infantum, where the domestic dog serves as a sentinel host with the phlebotomine sand fly as the typical vector [14].…”

“…Silva et al [ 6 ] reported increasing VL cases from 2012 to 2017 in major cities of the Paraíba state in Brazil, Almeida et al [ 19 ] observed spatial expansion of VL from 2007 to 2017 in Fortaleza, a coastal city within the Ceará state in Brazil, and da Silva Lima et al [ 20 ] noted increasing VL fatality in the last decade in Piauí, Brazil. The state of Alagoas, Brazil also experienced geographic spread of VL from 2007 to 2018, primarily in rural areas [ 7 ]. Such trends warrant government awareness and require results from improved statistical modeling to better understand, and inform, the dynamics of VL transmission patterns to guide public health policy.…”