ABSTRACT
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.
ABSTRACT
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.
ABSTRACT
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.
ABSTRACT
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.