Esquistossomose mansônica no estado da Bahia, Brasil: tendências históricas e medidas de controle

Abstract

In order to aid the development of new approaches to schistosomiasis control, changes were analyzed in prevalence at the county level in the State of Bahia from the 1950s to the 1990s, as were determinants and the effect of community-based chemotherapy. In general, no substantial changes were observed in the basic pattern of spatial distribution of the prevalence of infection. However, during the period studied, there was an overall reduction in prevalence from 15.6% to 9.5% and an increase in prevalence rates in some counties from the western, southeastern, and northern areas of Bahia, indicative of new transmission areas. The effect of mass chemotherapy was analyzed. In the Paraguaçu Basin, where this control measure was used on a large scale, there was a reduction in prevalence similar to areas where this measure was not used. Correlation and regression analysis also failed to show links between mass chemotherapy and long term reduction in prevalence. The most powerful variables to explain these changes were those related with population dynamics. These findings strongly suggest that the reduction in prevalence observed in some areas of the State must be attributed to factors related with the spatial organization of this territory, causing a general decrease in the transmission rate, secondary to mass chemotherapy. At the same time, the incomplete form and the spatial inequalities that characterized the urbanization process created favorable conditions for the spread of schistosomiasis mansoni and the establishment of new foci.

Spatial analysis for the identification of risk areas for schistosomiasis mansoni in the State of Sergipe, Brazil, 2005-2014

“…The prevalence in each municipal period was stratified into three levels: low -less than 5% prevalence; average -prevalence between 5 to 19.9%; and high -prevalence equal or greater to 20% (10) . The kernel intensity estimator was also used by smoothing the statistically generated surface density for the visual detection of hot spots, indicating agglomeration in a spatial distribution and a continuous surface from point data (18) (19) .…”

“…In these endemic schistosomiasis areas, in addition to monitoring, the control of these conditions involves reducing the occurrence of severe forms and deaths, reducing the prevalence of the infection (to levels lower than 5%), and indicating measures to reduce the expansion of the endemic areas (10) (11) .…”

Distribuição da esquistossomose no espaço urbano. 2. Aproximação teórica sobre a acumulação, concentração, centralização do capital e a produção de doenças

“…Os conhecimentos específicos adquiridos nestes estudos, somados aos interesses dos ór-gãos internacionais em garantir o retorno de capital investido em projetos desenvolvimentistas no Brasil, encorajaram o governo brasileiro a implantar no Nordeste o Programa Especial de Controle da Esquistossomose (PECE, 1976), cujo benefício à população foi minimizar a gravidade da doença nos portadores de forma hepatoesplênica, e reduzir a carga parasitária nos indivíduos tratados em área endê-mica, mesmo sujeitos à reinfecção (Katz, 1986a), embora possa não estar associado à queda da prevalência (Carmo, 1994).…”

Análise espacial dos casos humanos de esquistossomose em uma comunidade horticultora da Zona da Mata de Pernambuco, Brasil

“…Certain infectious-parasitic diseases are still quite widespread and have high prevalence rates in this socio-environmental setting [1][2][3][4][5][6] . Endemic diseases such as schistosomiasis mansoni are chronic in individuals infested at sites where the health status is a manifestation of unhealthy environments 7 .…”

“…The World Health Organization (WHO) underscores the importance of identifying foci of transmission of diseases in environments of high prevalence and/or incidence of parasite infections, generating information to substantiate and support the implementation of health education programs capable of minimizing risks 1,12,13 .…”