To determine the time-lag effect of meteorological factors on the relative risk (RR) of dengue incidence in Coronel Fabriciano city, Brazil, we applied a distributed lag nonlinear model, a modeling framework that can simultaneously represent nonlinear exposure-response dependencies and delayed effects, to establish the association between dengue incidence and weather predictors. The weekly number of notified dengue cases during the period 2004-2010 was used for analysis. When considering the rainfall, the highest RR (1.2) was observed for lag 10. Observing the cumulative effect of the precipitation, the RR for 12th and 13th week was RR = 4. The highest risk, 1.25, was observed at 25 °C, denoting that the risk of dengue transmission increases with temperature. Climate-based models that take into account the time lag between rainfall, temperature, and dengue can be useful in dengue control programs to be applied in tropical countries.
Although many studies have now demonstrated that both richness and abundance of gall-inducing insect species are directly and indirectly (via the host plant) influenced by soil quality, the empirical evaluation of it in the field remains anecdotal at best. The effects of soil fertility on richness and abundance of gall-inducing insects associated with a widespread savanna species,Eremanthus glomerulatus, were evaluated under experimental field conditions in Brasilia, central Brazil. The effect of soil fertility on gall-inducing insects species richness was evaluated using three treatments: (1) plots fertilized with nitrogen; (2) plots fertilized with phosphorus; and (3) control plots: soils without fertilization. Species richness of gall-inducing insects (six species of Cecidomyiidae) did not differ among the treatments. Leaves with galls had higher nitrogen concentrations (mean = 15.0 ± 0.5 mg g−1), compared with leaves without galls (mean = 9.0 ± 0.7 mg g−1) on plants that occurred in soils with addition of nitrogen. Similarly, leaves with galls had higher foliar phosphorus concentration (mean = 1.0 ± 0.04 mg g−1) than leaves without galls (mean = 0.6 ± 0.05 mg g−1) in plots with addition of phosphorus. In galled leaves, a negative relationship between gall density and nitrogen concentration was found for one gall-inducing insect species, while three species showed a positive relationship between gall density and leaf nitrogen concentration. A negative relationship between gall density and concentration of leaf phosphorus was observed for four of the six gall-inducing insect species studied. No relationship was found between gall density and leaf nitrogen and phosphorus concentration in ungalled leaves. We argue that foliar nitrogen and phosphorus concentration respond to gall density in galled leaves and therefore, gall-inducing insect species are capable of manipulating their host plant, modifying the foliar nutrients ofE. glomerulatusin sclerophyllous savanna.
This study evaluated the effects of Atlantic Rain Forest remnants on the natural biological control of Euselasia apisaon (Dahman) by the parasitoid Trichogramma maxacalii (Voegelé e Pointel) in Eucalyptus plantations. The number of E. apisaon eggs/leaf was higher in the center than in the edge of the plantations (23.5 +/- 7.61 vs. 14.8 +/- 3.14), but parasitism showed the reversed pattern (72.4% in the center and 80.5% in the edge). The results indicated that natural regulation exerted by T. maxacalii on populations of E. apisaon may be enhanced by the preservation of fragments of native vegetation surrounding Eucalyptus plantations.
30 December 2013 in Revista Brasileira em Promoção da Saúde
Objective: To analyze the spatial and temporal dynamics of dengue in Coronel Fabriciano, Minas Gerais State, Brazil, and to associate cases to the growth of urban areas and loss of natural areas in recent years. Methods: This is a descriptive, exploratory study, with a quantitative approach. Dengue cases of 2009 were obtained from the Health Municipal Secretariat, including the suspected and confirmed cases. Shape files were obtained, containing information about the municipal boundary, boundary of the urban area, census tracts, areas with buildings and natural areas. Based on the distribution of dengue cases, the Kernel estimator was used to measure data dispersion. Results: Dengue cases reported were georeferenced in GIS (Geographic Information System) environment. The landscape showed changes in the units of urban area and pasture, as an urban growth over the pasture matrix. No changes were observed in the areas of remaining forest and eucalyptus. There are cases spatially spread with a tendency to form clusters. Conclusion: Cases of dengue were observed spatially clustered in the northern region of the city, where new neighborhoods have emerged in recent years, following the population growth without proper structure of urbanization and urban planning. In addition, urban growth have reduced the margin of watercourses providing a bare soil, suitable for accumulation of trash and formation of breeding sites for mosquitoes. Efficient public policies and appropriate urban planning might reduce the impact of dengue in endemic regions.\ud \ud doi: http://dx.doi.org/10.5020/18061230.2013.p53
4 October 2023 in The American Journal of Tropical Medicine and Hygiene
: We used spatial analysis tools to examine the epidemiological situation and spatial distribution of American tegumentary leishmaniasis in the municipality of Caratinga between 2016 and 2021. In addition, potential sandfly vectors were captured. All information used in this study was retrieved from public health archives and confirmed in the state health services databases. All cases were analyzed using Geographic Information Systems software. In addition, sandfly collections and molecular detection of Leishmania were carried out in areas with the highest number of cases. During the analyzed period, American tegumentary leishmaniasis (ATL) cases increased and remained high in the last years. The hotspots included urban areas of Caratinga city and the districts of Patrocínio of Caratinga and Sapucaia. The species Nyssomyia whitmani, Nyssomyia intermedia, and Migonemyia migonei were the most abundant species and the ITS1-polymerase chain reaction technique detected Leishmania DNA in these species. On the basis of our analyses, the urbanization of ATL in Caratinga has taken place in recent years. Because of the increase in the number of human cases and the presence of vectors, it is recommended that health authorities focus on control measures in hotspots.
1 January 2021 in Revista do Instituto de Medicina Tropical de São Paulo
COVID-19 is an infectious disease caused by the recently discovered coronavirus SARS-Cov-2. The disease became pandemic affecting many countries globally, including Brazil. Considering the expansion process and particularities during the initial stages of the epidemic, we aimed to analyze the spatial and spatiotemporal patterns of COVID-19 occurrence and to identify priority risk areas in Minas Gerais State, Southeast Brazil. An ecological study was performed considering all data from human cases of COVID-19 confirmed from the epidemiological week (EW) 11 (March 08, 2020) to EW 26 (June 27, 2020). Crude and smoothed incidence rates were used to analyze the distribution of disease patterns based on global and local indicators of spatial association and space-time risk assessment. Positive spatial autocorrelation and spatial dependence were found. Our results suggest that the metropolitan region of the State capital Belo Horizonte (MRBH) and Vale do Rio Doce mesoregions, as major epidemic foci in the beginning of the expansion process, have had important influence on the dispersion of SARS-CoV-2 in Minas Gerais State. Triangulo Mineiro/Alto Paranaiba region presented the highest risk of infection. In addition, six statistically significant spatiotemporal clusters were identified in the State, three at high risk and three at low risk. Our findings contribute to a greater understanding of the space-time disease dynamic and discuss strategies for identification of priority areas for COVID-19 surveillance and control.