This study investigated the association between Cyclops population and physico-chemical properties of pond water in villages selected from Odeda and Obafemi-Owode areas of Ogun State, Nigeria. Epidemiological data on ...This study investigated the association between Cyclops population and physico-chemical properties of pond water in villages selected from Odeda and Obafemi-Owode areas of Ogun State, Nigeria. Epidemiological data on guinea worm were collected from Global 2000 South-West Zonal Office. Two villages were selected from each of Odeda and Obafemi-Owode LGAs while one village was sampled from Abeokuta North LGA as control. Physico-chemical analysis and microscopic examination of pond water utilized for domestic purpose in the selected villages were conducted. Mean values of 6.78±0.10, 33.00±0.14℃, 1.09＋0.80 mg/L and 1.30±0.25 mg/L were recorded for pH, temperature, DO and nitrate respectively while control had 7.30±0.14, 36.30±14℃2, 2.72±0.14 mg/L and 5.80±0.57 mg/L. These values with the exception of DO and nitrate were within WHO standard but vary significantly （P〈0.05） between the villages. The results further showed that BOD, COD and acidity were positively correlated with Cyclops population during the rainy and dry seasons while temperature, nitrate, pH, and alkalinity have negative correlation coefficients （r=-0.81, -0.91） with Cyclops population during the two seasons. Regression analysis showed that nitrate, BOD and acidity levels explained 67.7 percent, 50.4 percent and 44.5 percent of Cyclops population in the ponds. Guinea worm eradication in endemic rural areas should incorporate ecological strategy.展开更多
To investigate the impacts of demographics on the spread of infectious diseases, a susceptib- le-infectious-recovered （SIR） pairwise model on heterogeneous networks is established. This model is reduced by using the...To investigate the impacts of demographics on the spread of infectious diseases, a susceptib- le-infectious-recovered （SIR） pairwise model on heterogeneous networks is established. This model is reduced by using the probability generating function and moment closure approximations. The basic reproduction number of the low-dimensional model is derived to rely on the recruitment and death rate, the first and second moments of newcomers＇ degree distribution. Sensitivity analysis for the basic reproduction number is performed, which indicates that a larger variance of newcomers＇ degrees can lead to an epidemic outbreak with a smaller transmission rate, and contribute to a slight decrease of the final density of infectious nodes with a larger transmission rate. Besides, stochastic simulations indicate that the low-dimensional model based on the log-normal moment closure assumption can well capture important properties of an epidemic. And the authors discover that a larger recruitment rate can inhibit the spread of disease.展开更多
文摘This study investigated the association between Cyclops population and physico-chemical properties of pond water in villages selected from Odeda and Obafemi-Owode areas of Ogun State, Nigeria. Epidemiological data on guinea worm were collected from Global 2000 South-West Zonal Office. Two villages were selected from each of Odeda and Obafemi-Owode LGAs while one village was sampled from Abeokuta North LGA as control. Physico-chemical analysis and microscopic examination of pond water utilized for domestic purpose in the selected villages were conducted. Mean values of 6.78±0.10, 33.00±0.14℃, 1.09＋0.80 mg/L and 1.30±0.25 mg/L were recorded for pH, temperature, DO and nitrate respectively while control had 7.30±0.14, 36.30±14℃2, 2.72±0.14 mg/L and 5.80±0.57 mg/L. These values with the exception of DO and nitrate were within WHO standard but vary significantly （P〈0.05） between the villages. The results further showed that BOD, COD and acidity were positively correlated with Cyclops population during the rainy and dry seasons while temperature, nitrate, pH, and alkalinity have negative correlation coefficients （r=-0.81, -0.91） with Cyclops population during the two seasons. Regression analysis showed that nitrate, BOD and acidity levels explained 67.7 percent, 50.4 percent and 44.5 percent of Cyclops population in the ponds. Guinea worm eradication in endemic rural areas should incorporate ecological strategy.
基金supported by the National Natural Science Foundation of China under Grant Nos.11331009,11471197,11501340,and 11601294the Youth Science Fund of Shanxi Province under Grant No.2015021020
文摘To investigate the impacts of demographics on the spread of infectious diseases, a susceptib- le-infectious-recovered （SIR） pairwise model on heterogeneous networks is established. This model is reduced by using the probability generating function and moment closure approximations. The basic reproduction number of the low-dimensional model is derived to rely on the recruitment and death rate, the first and second moments of newcomers＇ degree distribution. Sensitivity analysis for the basic reproduction number is performed, which indicates that a larger variance of newcomers＇ degrees can lead to an epidemic outbreak with a smaller transmission rate, and contribute to a slight decrease of the final density of infectious nodes with a larger transmission rate. Besides, stochastic simulations indicate that the low-dimensional model based on the log-normal moment closure assumption can well capture important properties of an epidemic. And the authors discover that a larger recruitment rate can inhibit the spread of disease.
