OBJECTIVE:To analyze the spread of human American visceral leishmaniasis and identify the key municipalities for developing surveillance and control activities. METHODS:The area of the study was composed of the 316 municipalities in the state of Sao Paulo belonging to the fi ve health districts in which human American visceral leishmaniasis occurs, using data on autochthonous cases and deaths according to the reporting year and municipality in which the death occurred. The incidence, mortality and case fatality rates for each municipality and for the entire area were calculated. An empirical Bayes estimator was used to calculate the local Bayesian incidence and rates of mortality per municipality, and Kriging was used to visualize the spatial distribution of temperature and rainfall. RESULTS:A total of 73 municipalities with transmission of the disease were identifi ed. Human American visceral leishmaniasis was fi rst detected in areas with higher temperatures and lower rainfall, but it also spread in cooler and wetter areas. The expansion of human American visceral leishmaniasis occurred along a main axis of dissemination, from Northwest to Southeast, following the Marechal Rondon highway and the Bolivia-Brazil gas pipeline, and along a secondary axis that was derived from the main axis, which runs both North and South, following the highway network. Rates of incidence according to health district exhibit a peak, followed by a fall, except the Sao Jose do Rio Preto region. Higher concentrations of municipalities with high incidence and mortality rates were observed in the Araçatuba, Presidente Prudente and Marília health districts. CONCLUSIONS:This study indicates possible determinants of the spread of disease, including the Marechal Rondon highway and the construction of the Bolivia-Brazil gas pipeline. Climatic factors seemed to play no role in the spread. The use of spatial analysis techniques allowed the municipalities where cases and deaths are possibly underreported to be identifi ed, which indicated the municipalities which should be prioritized for the development of surveillance and control activities.
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.
Visceral leishmaniasis (VL), a neglected disease, is a serious public health problem that affects millions of people worldwide. The objectives of the study were to evaluate the sensitivity of Lutzomyia longipalpis and canine VL (CVL) autochthony early detection and describe the spatial and temporal dispersal of vector and expansion of VL in a Brazilian state. We obtained data on the leishmaniasis vector and VL cases in São Paulo State (SP), Brazil, from the Division of Endemic Disease Control and from the Epidemiological Surveillance Center of the São Paulo State Department of Health. Data were analyzed for 645 municipalities and 63 microregions and presented as thematic and flow maps. Following the verified presence of L. longipalpis in Araçatuba in 1997, the first autochthonous cases of canine VL (CVL) (1998) and of human VL (HVL) (1999) in São Paulo were reported, both in Araçatuba. From 1997 to 2014, the urban presence of the leishmaniasis vector was verified in 167 (25.9%) municipalities with cases of CVL reported in 108 (16.7%) and cases of HVL in 84 (13%). The sensitivities for vector presence early detection in relation to the identification of CVL and HVL autochthony were, respectively, equal to 76.4 and 92.5%. The sensitivity for CVL autochthony early detection in relation to the HVL autochthony identification was 75.8%. Vector dispersal and expansion of CVL and HVL were from the northwest to the southeast of the state, primarily flanking the Marechal Rondon highway at a constant rate of progression of 10, seven, and six new municipalities affected per year, respectively. We concluded that the sensitivity for vector presence and CVL autochthony presented reasonable accuracy and most of the time the vector presence and, specially, the CVL and HVL autochthony were identified in the main cities of the microregions of SP. Vector dispersal and expansion of VL started in 1997 near the state border of SP with the state of Mato Grosso do Sul. It has advanced from the northwest to the southeast flanking the Marechal Rondon highway at an arithmetic progression rate outward from the main cities of the microregions. Autochthonous cases of CVL and HVL emerged in SP, in general, after the verified presence of L. longipalpis.
BackgroundIn Brazil, visceral leishmaniasis (VL) is a serious public health problem because of its magnitude, geographical expansion and potential harms caused by illnesses, including death. However, VL is largely ignored in discussions of tropical disease priorities. Thus, this study aimed to identify factors associated with the expansion of VL and the dispersion of its vector, Lutzomyia longipalpis, in the municipalities of the State of São Paulo, Brazil.MethodsInformation about the date of vector detection and the confirmation of autochthonous VL occurrence in humans and canines in São Paulo were obtained between 1997 and 2014. Survival curves were calculated by the Kaplan-Meier and the Cox multiple regression models was used.ResultsThe presence of the Marechal Rondon highway showed the highest positive association with vector dispersion and canine and human VL expansion. The monthly maximum and minimum temperature averages recorded in the municipalities during the study period were also positively associated with these events. The presence of transverse highways was positively associated with the presence of the vector; the border with the State of Mato Grosso do Sul, the presence of a prison, microregion headquarters, and the presence of the Tietê River were positively associated with the occurrence of canine cases, while only the presence of prison was positively associated with the occurrence of human cases. The construction of the Bolivia-Brazil gas pipeline was not associated with any events.ConclusionsSurvival analysis enabled the identification of factors associated with vector dispersion and VL expansion, thus the results of this study may be useful to the improvement of VL surveillance and control activities in the State of São Paulo and throughout Brazil.Electronic supplementary materialThe online version of this article (10.1186/s13071-018-3084-1) contains supplementary material, which is available to authorized users.
Oliveira AM. Estudo da expansão da Leishmaniose Visceral no estado de São Paulo e de fatores intervenientes [tese doutorado]. São Paulo: Faculdade de Saúde Pública da USP; 2016. INTRODUÇÃO: Leishmaniose visceral (LV) é uma doença negligenciada que afeta milhões de pessoas no mundo e que constitui um grave problema de saúde pública. OBJETIVOS: Descrever no tempo e no espaço, a dispersão de Lutzomyia longipalpis e a expansão da LV no estado de São Paulo (SP); identificar fatores associados a estes processos. MÉTODOS: Foram realizados estudos descritivos, ecológicos e de análise de sobrevida. Informações sobre o vetor e os casos foram obtidas na Superintendência de Controle de Endemias e no Sistema de Informações de Agravos de Notificação para o período de 1997 a 2014. A área de estudo foi composta pelos 645 municípios de SP. Foram produzidos mapas temáticos e de fluxo e calcularam-se incidência, mortalidade e letalidade por LV em humanos (LVH). Utilizou-se a técnica de análise de sobrevida (Curvas de Kaplan-Meier e Regressão de Cox) para a identificação de fatores associados à dispersão do vetor e expansão da LV. RESULTADOS: Foi detectado Lu. longipalpis em Araçatuba em 1997, registro do primeiro caso canino (LVC) (1998) e o primeiro caso humano (LVH) autóctones (1999) em SP. Até 2014, foi detectada a presença do vetor em 173 (26,8%) municípios, LVC em 108 (16,7%) e LVH em 84 (13%). A expansão dos três fenômenos ocorreu no sentido noroeste para sudeste e se deram a velocidades constantes. Na região de São José do Rio Preto, a dispersão do vetor deu-se por vizinhança com municípios anteriormente infestados, a expansão da LV relacionou-se com os municípios sede das microrregiões e a doença ocorreu com maior intensidade nas áreas periféricas dos municípios. A presença da Rodovia Marechal Rondon e a divisa com o Mato Grosso do Sul foram fatores associados à ocorrência dos três eventos, assim como a presença da Rodovia Euclides da Cunha para presença do vetor e casos caninos, e, presença de presídios para casos humanos. CONCLUSÕES: A dispersão do vetor e da LV em SP iniciou-se, a partir de 1997, próximo à divisa com o estado do Mato Grosso do Sul, avançou no sentido noroeste para sudeste, na trajetória da rodovia Marechal Rondon, e ocorreu em progressão aritmética, com as sedes das microrregiões de SP tendo papel preponderante neste processo. A ocorrência autóctone de LVC e LVH iniciou-se na sequência da detecção de Lu. longipalpis em Araçatuba e de seu espalhamento por SP e não a partir dos locais onde anteriormente ele já estava presente. O uso da análise de sobrevida permitiu identificar fatores associados à dispersão do vetor e a expansão da LV. Os resultados deste estudo podem ser úteis para aprimorar as atividades de vigilância e controle da LV, no sentido de retardar sua expansão e/ou de mitigar seus efeitos, quando de sua ocorrência.
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