Changing demographics of visceral leishmaniasis in northeast Brazil: Lessons for the future

Abstract

BackgroundVisceral leishmaniasis (VL) caused by Leishmania infantum became a disease of urban areas in Brazil in the last 30 years and there has been an increase in asymptomatic L. infantum infection with these areas.Methodology/Principal findingsA retrospective study of human VL was performed in the state of Rio Grande do Norte, Brazil, for the period of 1990–2014. The data were divided into five-time periods. For all VL cases, data on sex, age, nutritional status and childhood vaccination were collected. Geographic information system tools and statistical models were used to analyze the dispersion of human VL. The mean annual incidence of VL was 4.6 cases/100,000 inhabitants, with total 3,252 cases reported. The lethality rate was 6.4%. Over time the annual incidence of VL decreased in the 0–4 years (p<0.0001) and 5–9 (p <0.0001) age groups, but increased in ages 20–39 (p<0.001) and >40 years (p<0.0001). VL occurred more often in males (β2 = 2.5; p<0.0001). The decreased incidence of VL in children was associated with improved nutritional status and childhood immunizations including measles, poliomyelitis, BCG, and hepatitis B. Human VL correlated temporally and geographically with canine L. infantum infection (p = 0.002, R2 = 0.438), with rainfall and with Lutzomyia longipalpis density (r = 0.762). Overall, the incidence of VL decreased, while VL-AIDS increased, especially between 2010–2014. VL was more frequently found in areas that lacked urban infrastructure, detected by lack of garbage collection and sewers, whereas HIV infection was associated with higher levels of schooling and evidence of higher socioeconomic status.Conclusion/SignificanceThe demographics of VL in northeastern Brazil have changed. Disease incidence has decreased in children and increased in adults. They were associated with improvements in nutrition, socioeconomic status and immunization rates. Concurrent VL-AIDS poses a serious challenge for the future.

Leishmaniose visceral e sua relação com fatores climáticos e ambientais no Estado do Tocantins, Brasil, 2007 a 2014

“…Em relação a variável precipitação pluviométrica, os clusters com alta precipitação e alta taxa de incidência, e clusters com baixa precipitação e baixa taxa demonstram a correlação espacial positiva entre essas variáveis. A variável precipitação pluviométrica, que se correlaciona com a umidade, favorece o desenvolvimento e reprodução do vetor e consequente aumento da incidência de LV 30,31,32 . Como Tocantins apresenta características do bioma Amazônia e do cerrado, com o bioma Amazônia ocorrendo mais ao norte do estado, o regime de chuvas da floresta tropical exerce forte influência na pluviosidade e consequente umidade do estado, contribuindo para incidência da LV nessa região do estado.…”

Trans-Atlantic Spillover: Deconstructing the Ecological Adaptation of Leishmania infantum in the Americas

“…A shift in infection demographics has also become evident. Adult infection rates are increasing while those in children have decreased [23], probably due to improvements in nutrition and immunization rates for other diseases. Atypical cutaneous leishmaniasis caused by L. infantum has also been described in the country [24,25].…”

Solid Wastes Provide Breeding Sites, Burrows, and Food for Biological Disease Vectors, and Urban Zoonotic Reservoirs: A Call to Action for Solutions-Based Research

“…Community members in rural India report that visceral leishmaniasis-transmitting sand flies breed in trash (105). In two studies, the risk of visceral leishmaniasis increased in the absence of regular trash collection (104,106).…”

“…We conclude that solid waste accumulation is a risk factor for zoonotic and vector-borne disease transmission. However, measurements are not standardized, (107,123,197) and confounders are not rigorously controlled (106,112,123,197,198).…”