A generalized risk assessment index for forecasting insect population under the effect of temperature.

Life history traits have been studied under various environmental factors, but the ability to combine them into a simple function to assess pest response to climate is still lacking complete understanding. This study proposed a risk index derived by combining development, mortality, and fertility rates from a stage-structured dynamic mathematical model. The first part presents the theoretical framework behind the risk index. The second part of the study is concerned with the application of the index in two case studies of major economic pest: the brown planthopper (Nilaparvata lugens) and the spotted wing drosophila (Drosophila suzukii), pests of rice crops and soft fruits, respectively. The mathematical calculations provided a single function composed of the main thermal biodemographic rates. This function has a threshold value that determines the possibility of population increase as a function of temperature. The tests carried out on the two pest species showed the capability of the index to describe the range of favourable conditions. With this approach, we were able to identify areas where pests are tolerant to climatic conditions and to project them on a geospatial risk map. The theoretical background developed here provided a tool for understanding the biogeography of Nilaparvata lugens and Drosophila suzukii. It is flexible enough to deal with mathematically simple (N. lugens) and complex (D. Suzukii) case studies of crop insect pests. It produces biologically sound indices that behave like thermal performance curves. These theoretical results also provide a reasonable basis for addressing the challenge of pest management in the context of seasonal weather variations and climate change. This may help to improve monitoring and design management strategies to limit the spread of pests in invaded areas, as some non-invaded areas may be suitable for the species to develop.

Spatial Pattern Analysis using Closest Events (SPACE)-A Nearest Neighbor Point Pattern Analysis Framework for Assessing Spatial Relationships from Digital Images.

The quantitative description of biological structures is a valuable yet difficult task in the life sciences. This is commonly accomplished by imaging samples using fluorescence microscopy and analyzing resulting images using Pearson's correlation or Manders' co-occurrence intensity-based colocalization paradigms. Though conceptually and computationally simple, these approaches are critically flawed due to their reliance on signal overlap, sensitivity to cursory signal qualities, and inability to differentiate true and incidental colocalization. Point pattern analysis provides a framework for quantitative characterization of spatial relationships between spatial patterns using the distances between observations rather than their overlap, thus overcoming these issues. Here we introduce an image analysis tool called Spatial Pattern Analysis using Closest Events (SPACE) that leverages nearest neighbor-based point pattern analysis to characterize the spatial relationship of fluorescence microscopy signals from image data. The utility of SPACE is demonstrated by assessing the spatial association between mRNA and cell nuclei from confocal images of cardiac myocytes. Additionally, we use synthetic and empirical images to characterize the sensitivity of SPACE to image segmentation parameters and cursory image qualities such as signal abundance and image resolution. Ultimately, SPACE delivers performance superior to traditional colocalization methods and offers a valuable addition to the microscopist's toolbox.

[Prevalence and geographical distribution of bovine sexually transmitted diseases in the province of Formosa, Argentina]. / Prevalencia y distribución geográfica de las enfermedades de transmisión sexual de los bovinos en la provincia de Formosa, Argentina.

Bovine genital campylobacteriosis (BGC) and bovine trichomonosis (BT) are sexually transmitted diseases (STDs) that affect bovine breeding herds, decreasing their reproductive efficiency. The objective of this work was to estimate the prevalence of these diseases and their temporal-spatial distribution in the province of Formosa, Argentina. The cross-sectional study conducted between 2018 and 2021 included a total of 15,571 bulls, inter-herd prevalence being 29.62% and 17.23% for BGC and BT, respectively. The prevalence of positive animals was 2.05% for BGC and 0.43% for BT. The temporal-spatial analysis of BGC showed two distinct spatial groupings, one group had a low risk of contracting the disease (RR = 0.13; p < 0.001; 2018-2021) while the other group had a high risk (RR = 2.84; p < 0.001; 2020-2021). BT had a high-risk group for the disease (RR = 35.24; p < 0.001; 2019). This study shows that STDs are endemic in the region, providing updated and valuable information as a tool for the health management of these diseases.

Analysis of spatial distribution and drivers of gaseous energy combustion pollution in China based on SDM.

Air pollution is an important part of ecological environment problems. Gaseous energy combustion pollution is a key part of air pollution. Analysis of its spatial distribution and drivers is important to effectively manage air quality and promote regional green development. This paper uses panel data of 30 provinces in China from 2006 to 2019 to analyze the spatial distribution and drivers of gaseous energy combustion pollution in each province of China through a combination of quantitative and qualitative analysis based on the spatial Durbin model, and further decompose the spatial effects of each influencing factor. The empirical results show, firstly, that inter-provincial gaseous energy combustion pollution in China shows significant spatial differences and cluster characteristics. Secondly, most areas are located in high-high aggregation area and low-low aggregation area. Finally, population, energy consumption and other independent variables have different impacts on gaseous energy combustion pollution in different regions. The changes of these variables will affect the adjacent areas through spatial transmission while affecting a region. According to the empirical results, this study proposes policy recommendations to balance the pollution degree of gaseous energy combustion in various regions and effectively reduce the emissions of various pollution sources. The research results are helpful to understand the spatial distribution of gaseous energy combustion pollution in various regions of China, provide reference for the future development of various regions, and have important practical significance for the reduction and balance of pollution levels.

Study on prediction model of mosquito breeding in small containers based on random forest / 环境与职业医学

Background Aedes albopictus is the dominant mosquito species in residential areas in Shanghai. There are many types of small containers with accumulated water in residential areas, providing a large number of breeding environments for Aedes alpopicuts and leading to an increasing transmission risk of mosquito-borne diseases. Objective To use random forest to predict breeding of Aedes mosquitoes in small aquatic container habitat in two concentrated reconstruction communities of rural areas in Shanghai, and to understand associated influence of environmental factors on the breeding of Aedes mosquitoes in the process of urbanization.Methods Small-scale habitat surveys of Aedes mosquitoes were carried out in two suburb concentrated reconstruction communities (Community A and B) in Shanghai, and the environment where the habitat was located was recorded and analyzed in both communities. The habitat where eggs, larvae, or pupae were found was recorded as positive. Spatial weight matrix was applied on a household basis, and global Moran's I index was used to carry out spatial autocorrelation analysis on the small-scale habitat and positive habitat in the environment of the two communities. When Moran's I is greater than 0, it means that the data present a positive spatial correlation; when Moran's I is less than 0, it means that the data are spatially negatively correlated; when Moran's I is 0, the spatial distribution is random. Combining the results of P and Z values, we explored the spatial distribution characteristics of small-scale habitat and positive habitat in the community environment. Random forest algorithm in machine learning was used to classify and sort environmental-related factors, and predict the breeding of Aedes mosquitoes in small aquatic habitat; receiver operating characteristic (ROC) curve was used to carry out model fitting evaluation. Results The environmental factors including building location (χ2=23.35, P<0.001), open space (χ2=8.83, P=0.003), and having trees (χ2=11.02, P=0.001) had a significant impact on the positive rate of small-scale habitat. The results of spatial characteristics analysis showed that the global Moran's I index of small-scale habitat was −0.092 (Z=−1.09, P=0.274) in Community A and 0.034 (Z=0.52, P=0.602) in Community B, and the global Moran's I index of positive habitat was −0.092 (Z=−1.14, P=0.255) in Community A and 0.070 (Z=0.95, P=0.342) in Community B. Since the P values of Community A and B were greater than 0.1 and the Z values were between −1.65 and 1.65, for both small-scale habitat and positive habitat the spatial characteristics were randomly distributed and no significant spatial aggregation was found. In the fitted random forest algorithm classification prediction model with the top 10 characteristic factors of importance, the area under curve (AUC) value was 0.95, and the prediction fitting effect was satisfactory. The results of classification and sorting indicated that counts of household small-scale habitat and positive habitat were the most important factors for breeding. Conclusion The random forest model constructed by environmental factor indicators can be used to predict the breeding situation of Aedes mosquitoes in small-scale aquatic habitat, and provide a basis for scientific prevention and control of mosquito breeding for the target area.

Molecular dynamics simulation of hyaluronic acid hydrogels: Effect of water content on mechanical and tribological properties.

BACKGROUND AND OBJECTIVE: Recently conducted biomedical studies have shown that the drug diffusivity of hyaluronic acid hydrogel plays an important role in the treatment of joint diseases. The drug diffusivity is closely related to the water content of hydrogel. In addition, different water content will not only affect its mechanical and tribological properties, but also change the effect of drug release. METHODS: In this work, a Molecular dynamics simulation was used to investigate the effect of water content on spatial distribution, tribological and mechanical properties of a hyaluronic acid hydrogel network. This paper focuses on the analysis and calculation of the radial distribution function of 20, 40, 60, and 80% water content model and the friction force and mechanical parameters under the influence of different load and friction speed. RESULTS: The results show that at 20 and 40% water content, the spatial distribution is loose and the intermolecular force is not strong, resulting in a major lack in tribological and mechanical properties; whereas at 60 and 80% water content, the spatial distribution becomes gradually compact and the intermolecular force is gradually increased. The tribological and mechanical properties manifest a marked improvement. CONCLUSIONS: The calculations reveal that the hydrogel model has the best wear resistance, pressure resistance, and plastic deformation resistance at 80% water content. In the range of 20-80% water content, the mechanical properties and friction properties of hydrogels become better and better with the increase of water content.

Observations of atmospheric CO2 and CO based on in-situ and ground-based remote sensing measurements at Hefei site, China.

The characteristics of long time series of CO2 and CO surface concentrations, tropospheric and total column dry-air mole fractions (DMF) from May 2015 to December 2019 were investigated. Both CO2 and CO show different seasonality for the three datasets. The annual increasing trend of CO2 is similar for all three datasets. However, the annual decreasing trend of CO for surface concentration is high compared to the other two measurements, mainly due to the improved combustion efficiency from power generation in recent years. The correlation between the tropospheric and total atmospheric CO2 and CO is higher than that between the surface concentration and tropospheric CO2 and CO. This is because the tropospheric and total atmospheric results both have common vertical profiles for CO2 and CO respective mole fractions that were observed in troposphere. Furthermore, the enhancement ratios of CO2 to CO derived from the three datasets during the period from 2016 to 2019 were compared. The ratio of ∆CO2 to ∆CO has an obvious increase with altitude each year, which means that the combustion efficiencies obtained from the three datasets are different. All ratios for the three datasets showed a slight increasing trend in recent years, which is attributed to increased combustion efficiency due to governmental measures for energy savings and emission reductions.

[Spatial Variation and Influencing Factors of Soil pH in Anshun City].

Exploring the spatial distribution characteristics and variation law of soil pH and analyzing the impact of environmental factors on the spatial differentiation of soil pH are of great significance to the accurate management of soil pH and the sustainable utilization of soil resources in the complex mountainous environment of Anshun City. Based on 22 851 field sampling points, using the methods of global Moran's I index, cold and hot spot analysis, semi-variance function, and Kriging interpolation, the spatial structure characteristics and distribution law of soil pH in Anshun City were revealed from different angles, and the influence of environmental factors on its spatial differentiation was analyzed with the help of geographic detectors. The results showed that:① the variation range of topsoil pH value in Anshun City was 3.56-8.61, the mean value was 6.28, and the coefficient of variation was 16.33%. ② In the global space, soil pH showed aggregation distribution; in the local space, the west and northwest were hot spots, whereas the east and south were cold spots. The nugget coefficient (40.19%) showed that the spatial variability in soil pH was determined by both structural and random factors, but the role of structural factors was greater. ③ In terms of spatial distribution, soil pH mainly presented a patchy mosaic distribution pattern, in which slightly acidic soil (57.14%) was concentrated in the east, northeast, and south of Anshun City; neutral soil (30.13%) was concentrated in the west, northwest, and southeast; and strongly acidic soil (6.12%) and alkaline soil (6.45%) were embedded in slightly acidic soil and neutral soil, respectively, in a block structure. ④ The geo-detector analysis showed that the explanatory power of various environmental factors to the spatial variation in soil pH was ranked as soil type (9.4%)>soil forming parent rock (7.9%)>altitude (2.1%)>land use (1.8%)>slope (0.1%), in which the q value of the interaction between soil type and parent rock type and other factors was large. Therefore, soil type and parent rock type were the main controlling factors of soil pH spatial variation in Anshun City.

[Spatial distribution of canine echinococcosis in Inner Mongolia Autonomous Region from 2012 to 2018].

OBJECTIVE: To investigate the distribution and changing trend of canine echinococcosis in Inner Mongolia Autonomous Region, so as to provide the scientific evidence for prevention and control of canine echinococcosis in high-risk areas of Inner Mongolia Autonomous Region. METHODS: All data pertaining to Echinococcus infections in canine feces and sampling survey of human echinococcosis were collected from the echinococcosis-endemic foci of Inner Mongolia Autonomous Region from 2012 to 2018, and the prevalence of Echinococcus infections was investigated in dogs and humans. In addition, the spatial distribution characteristics and clusters of canine echinococcoses were identified. RESULTS: A total of 164 139 canine fecal samples were detected in the echinococcosis-endemic foci of Inner Mongolia Autonomous Region from 2012 to 2018, and there were 2 136 fecal samples positive for Echinococcus coproantigens. The positive rates of Echinococcus coproantigens were 0.54% to 1.73% in dogs from 2012 to 2018, with a tendency towards a decline seen in the prevalence of Echinococcus infections in dogs (χ2 = 108.83, P < 0.01), and there was a significant difference in the positive rate of Echinococcus coproantigens in dogs among years (χ2 = 155.27, P < 0.01). Three-dimensional trend analysis showed that canine echinococcosis was mainly concentrated in east of central Inner Mongolia Autonomous Region, and a high prevalence was detected in New Barag Right Banner and Sonid Right Banner. The global spatial distribution of canine echinococcosis appeared a random pattern in Inner Mongolia Autonomous Region from 2012 to 2018 (Moran's I > 0, P > 0.05), and there were "high-high" and "high-low" clusters of canine echinococcosis in local areas. The prevalence of human echinococcosis was 0.08%, and there was a significant difference in the prevalence among regions (χ2 = 147.61, P < 0.01), with a high prevalence seen in West Ujimqin Banner, Jarud Banner and New Barag Right Banner. In addition, the prevalence of human echinococcosis correlated positively with the Echinococcus coproantigen-positive rate in dogs (r = 0.52, P < 0.01). CONCLUSIONS: The prevalence of Echinococcus infections shows an overall tendency towards a decline in dogs in Inner Mongolia Autonomous Region from 2012 to 2018, with a high prevalence found in New Barag Right Banner and Sonid Right Banner. Human echinococcosis is concentrated in clusters of canine echinococcosis, where health education and targeted control interventions requires to be intensified.

Spatial distribution of canine echinococcosis in Inner Mongolia Autonomous Region from 2012 to 2018 / 中国血吸虫病防治杂志

Objective To investigate the distribution and changing trend of canine echinococcosis in Inner Mongolia Autonomous Region, so as to provide the scientific evidence for prevention and control of canine echinococcosis in high-risk areas of Inner Mongolia Autonomous Region. Methods All data pertaining to Echinococcus infections in canine feces and sampling survey of human echinococcosis were collected from the echinococcosis-endemic foci of Inner Mongolia Autonomous Region from 2012 to 2018, and the prevalence of Echinococcus infections was investigated in dogs and humans. In addition, the spatial distribution characteristics and clusters of canine echinococcoses were identified. Results A total of 164 139 canine fecal samples were detected in the echinococcosis-endemic foci of Inner Mongolia Autonomous Region from 2012 to 2018, and there were 2 136 fecal samples positive for Echinococcus coproantigens. The positive rates of Echinococcus coproantigens were 0.54% to 1.73% in dogs from 2012 to 2018, with a tendency towards a decline seen in the prevalence of Echinococcus infections in dogs (χ2 = 108.83, P < 0.01), and there was a significant difference in the positive rate of Echinococcus coproantigens in dogs among years (χ2 = 155.27, P < 0.01). Three-dimensional trend analysis showed that canine echinococcosis was mainly concentrated in east of central Inner Mongolia Autonomous Region, and a high prevalence was detected in New Barag Right Banner and Sonid Right Banner. The global spatial distribution of canine echinococcosis appeared a random pattern in Inner Mongolia Autonomous Region from 2012 to 2018 (Moran’s I > 0, P > 0.05), and there were “high-high” and “high-low” clusters of canine echinococcosis in local areas. The prevalence of human echinococcosis was 0.08%, and there was a significant difference in the prevalence among regions (χ2 = 147.61, P < 0.01), with a high prevalence seen in West Ujimqin Banner, Jarud Banner and New Barag Right Banner. In addition, the prevalence of human echinococcosis correlated positively with the Echinococcus coproantigen-positive rate in dogs (r = 0.52, P < 0.01). Conclusions The prevalence of Echinococcus infections shows an overall tendency towards a decline in dogs in Inner Mongolia Autonomous Region from 2012 to 2018, with a high prevalence found in New Barag Right Banner and Sonid Right Banner. Human echinococcosis is concentrated in clusters of canine echinococcosis, where health education and targeted control interventions requires to be intensified.

Application of the phase-space distribution approach of Monte Carlo for radiation contamination dose estimation from the (n,γ), (γ,n) nuclear reactions and linac leakage photons in the megavoltage radiotherapy facility.

AIM: The aim of this study was to characterize the radiation contamination inside and outside the megavoltage radiotherapy room. BACKGROUND: Radiation contamination components in the 18 MV linac room are the secondary neutron, prompt gamma ray, electron and linac leakage radiation. MATERIALS AND METHODS: An 18 MV linac modeled in a typical bunker employing the MCNPX code of Monte Carlo. For fast calculation, phase-space distribution (PSD) file modeling was applied and the calculations were conducted for the radiation contamination components dose and spectra at 6 locations inside and outside the bunker. RESULTS: The results showed that the difference of measured and calculated percent depth-dose (PDD) and photo beam-profile (PBP) datasets were lower than acceptable values. At isocenter, the obtained photon dose and neutron fluence were 2.4 × 10-14 Gy/initial e° and 2.22 × 10-8 n°/cm2, respectively. Then, neutron apparent source strength (QN) value was found as 1.34 × 1012 n°/Gy X at isocenter and the model verified to photon and neutron calculations. A surface at 2 cm below the flattening filter was modeled as phase-space (PS) file for PDD and PBP calculations. Then by use of a spherical cell in the center of the linac target as a PS surface, contaminant radiations dose, fluence and spectra were estimated at 6 locations in a considerably short time, using the registered history of all particles and photons in the 13GB PSD file as primary source in the second step. CONCLUSION: Designing the PSD file in MC modeling helps user to solve the problems with complex geometry and physics precisely in a shorter run-time.

[Differences in Diffusive Fluxes of Nutrients from Sediment Between the Natural River Areas and Reservoirs in the Lancang River Basin].

A field survey was carried out to investigate the diffusive fluxes of nitrogen and phosphorus from sediment in the natural river areas and cascaded reservoirs in the Lancang River Basin from February through March in 2017. In the natural river areas, the mean value of total nitrogen (TN) concentrations in the sediment pore water was about 15.254 mg ·L-1, and the total phosphorus (TP) was only 0.654 mg ·L-1; while in the reservoirs, the mean value of TN and TP were 6.577 mg ·L-1 and 1.432 mg ·L-1, respectively. Both nutrients in the overlying water were less than that in the sediment pore water. The mean diffusive flux of total dissolved nitrogen (DTN) was almost 2.117 mg ·(m2 ·d)-1 in the natural river areas, and the mean value of total dissolved phosphorus (DTP) was 0.044 mg ·(m2 ·d)-1, while the mean value of DTN and DTP were 0.785 mg ·(m2 ·d)-1 and 0.053 mg ·(m2 ·d)-1 in the reservoirs, respectively. The TN content reaches the maximum in the overlying water-interstitial water vertical surface sediments. It was concluded that cascaded hydropower had greatly changed the nutrient exchange between the sediment and overlying water. Different hydrodynamics and varied chemical environments in the sediment could be additional causes.

Surface water pH variations and trends in China from 2004 to 2014.

With economic development and the increase of energy consumption, surface water acidification has been a potential environmental concern in China. Here, we analyzed variations and trends in surface water pH of 73 sites from ten river basins in China from 2004 to 2014 with nonparametric Seasonal Kendall test method. Our analysis showed that the variations of surface water pH in China ranged from 6.5 to 9.0 in the past decade (2004-2014), which satisfied the water quality criteria in pH for protection of aquatic ecosystems in China (6.0-9.0) and USA (6.5-9.0). However, significant decreasing trends in surface water pH were found in 31 monitoring sites, which were mainly located in Haihe River, Taihu Lake and Yangtze River, while the pH value showed significant increasing trends in 22 sites, which mainly were located in Songhua River and Pearl River. Our results suggested the increased potential acidification of susceptible water bodies in China. Besides the control policy of sulfur dioxide (SO2) emissions, the emissions of nitrous oxides (NOx) should also be reduced to protect the aquatic systems in China.

Estrutura populacional de capivaras na Estação Ecológica do Taim, Brasil, RS / Capybaras population structure in the Taim Ecological Station, Brazil, RS

Uma população de capivaras (Hydrochoerus hydrochaeris) foi monitorada na região limítrofe entre a Estação Ecológica do Taim e áreas de cultivo de arroz no extremo sul do Rio Grande do Sul, Brasil. O objetivo foi caracterizar a estrutura populacional, a densidade e os períodos reprodutivos da capivara na Estação Ecológica do Taim, RS, e em seu entorno. De agosto de 2003 a agosto de 2005, foram realizados 25 censos de contagem direta, em um transecto de 4.000 metros de comprimento, às margens da Lagoa Mangueira. Foi obtida a abundância de animais segundo seu sexo e classe etária. A abundância foi de 608,6±27,9 indivíduos e a densidade média foi de 5,1±0,2ind. ha-1. Houve variação no número de animais do primeiro para o segundo ano de amostragem, sendo significativamente maior no último. Foram identificados, em média, 22,0±0,8 grupos na área, constituídos predominantemente de fêmeas adultas (47,5 por cento), seguidas de juvenis (24,8 por cento), filhotes (17 por cento) e machos adultos (7,7 por cento). A abundância de animais variou segundo a distribuição espacial, sendo maior no interior da Estação Ecológica do Taim (9,5ind. ha-1). Houve flutuações sazonais no recrutamento da população, tendo suas maiores densidades de filhotes no outono.

A capybara population (Hydrochoerus hydrochaeris) was monitored in a borderline region between Taim Ecological Station and southernmost areas of rice cultivation located in the State of Rio Grande do Sul (RS, Brazil). The aim of this study was to characterize the structure, density, and reproductive periods of this population. A total of 25 censuses, obtained through direct count technique, were performed from August 2003 to August 2005. The samplings were performed in a 4000-meter length transect on the margins of Mangueira lagoon. The abundance was obtained considering the sex and age class of the animals. The abundance registered was of 608.6±27.9 individuals, and the average density was 5.1±0.2ind. ha-1. A variation in number of animals was observed between the first and the second year of sampling. This number was significantly higher in the last year. An average of 22.0±0.8 groups was identified in the sampling area, including female adults (47.5 percent), juveniles (24.8 percent), young (17 percent) and male adults (7.7 percent). The abundance of animals varied according to spatial distribution, and its highest value (9.5ind. ha-1) was registered in Taim Ecological Station. Seasonal fluctuations in the population recruitment were also observed during this study. The highest densities of young were registered in autumn. Population structure was similar to those registered in different areas of distribution, but it has presented a high potential of population growth.

Distribuição de dengue no norte de Mato Grosso, Brasil, 2001-2005. / Dengue distribution in the north of Mato Grosso, Brazil, 2001-2005.

A distribuição dos casos de dengue, notificados de 2001 a 2005 em 14 municípios que integram o Escritório Regional de Saúde de Sinop, foi analisada em relação aos índices pluviométricos e aos recursos financeiros para campanhas de combate a dengue, com base em dados fornecidos pelo Escritório Regional de Saúde de Sinop, Agência Nacional das Águas e Datasus. Foram notificados 6.789 casos de dengue, com maior incidência nos municípios de Cláudia, Vera e Sorriso. Em ambos os sexos, as maiores incidências ocorreram na faixa etária de 35 a 49 anos. Observouse uma associação positiva entre pluviosidade e distribuição de dengue. Os repasses financeiros para as campanhas de combate a dengue tiveram um aumento contínuo a partir do ano de 2001, de R$ 250,64 para cada caso notificado. A distribuição de dengue foi influenciada pelo crescimento populacional, saneamento precário e pelas características ambientais da região. Novos estudos devem também incluir variáveis, como temperatura e umidade, pois elas também podem influenciar o ciclo de transmissão e a distribuição do vetor, de forma a orientar o controle da dengue em regiões com características ambientais e sociais semelhantes.

Based on data provided by the Regional Office of Health of Sinop, the National Agency of Water and Datasus, we analyzed the distribution of reported dengue cases from 2001 to 2005 in relation to rainfall and resources to combat dengue for the 14 municipalities participating in the Regional Office of Health of Sinop. There were 6,789 cases of dengue, with higher incidence in the municipalities of Claudia, Vera and Sorriso. For both males and females, the highest incidence of dengue occurred in the age group 35 to 49 years. There was a positive association between rainfall and distribution of dengue. The financial resources to combat dengue increased continuously since the year 2001 (~US$ 125/year for each case reported). The distribution of dengue has been influenced by population growth, poor sanitation and the environmental characteristics of the region. Further studies should also take temperature and humidity into consideration, since they also may influence the cycle of transmission and vector distribution, in order to develop better control of dengue strategies suitable for regions with similar environmental and social characteristics.