Controlling the COVID-19 outbreak remains a challenge for Cameroon,as it is for many other countries worldwide.The number of confirmed cases reported by health authorities in Cameroon is based on observational data,wh...Controlling the COVID-19 outbreak remains a challenge for Cameroon,as it is for many other countries worldwide.The number of confirmed cases reported by health authorities in Cameroon is based on observational data,which is not nationally representative.The actual extent of the outbreak from the time when the first case was reported in the country to now remains unclear.This study aimed to estimate and model the actual trend in the number of COVID-19 new infections in Cameroon from March 05,2020 to May 31,2021 based on an observed disaggregated dataset.We used a large disaggregated dataset,and multilevel regression and poststratification model was applied prospectively for COVID-19 cases trend estimation in Cameroon from March 05,2020 to May 31,2021.Subsequently,seasonal autoregressive integrated moving average(SARIMA)modeling was used for forecasting purposes.Based on the prospective MRP modeling findings,a total of about 7450935(30%)of COVID-19 cases was estimated from March 05,2020 to May 31,2021 in Cameroon.Generally,the reported number of COVID-19 infection cases in Cameroon during this period underestimated the estimated actual number by about 94 times.The forecasting indicated a succession of two waves of the outbreak in the next two years following May 31,2021.If no action is taken,there could be many waves of the outbreak in the future.To avoid such situations which could be a threat to global health,public health Abbreviations:ACF,Autocorrelation Function;AIC,Akaike information criterion;COVID-19,Coronavirus Disease 2019;MAE,Mean Absolute Error;MAPE,Mean Absolute Percentage Error;MASE,Mean Absolute Scaled Error;ME,Mean Error;MPE,Mean Percentage Error;MRP,Multilevel Regression and Post-stratification;PACF,Partial Autocorrelation Function;PLACARD,Platform for Collecting,Analyzing and Reporting Data;SARIMA,Seasonal Autoregressive integrated moving average;SARS-CoV-2,Severe Acute Respiratory Syndrome Coronavirus 2.展开更多
Bacteriophages or phages are viruses that infect bacteria and are increasingly used to control bacterial infections.We develop a reaction-diffusion model coupling the interactive dynamic of phages and bacteria with an...Bacteriophages or phages are viruses that infect bacteria and are increasingly used to control bacterial infections.We develop a reaction-diffusion model coupling the interactive dynamic of phages and bacteria with an epidemiological bacteria-borne disease model.For the submodel without phage absorption,the basic reproduction number Ro is computed.The disease-free equilibrium(DFE)is shown to be globally asymptotically stable whenever Ro is less than one,while a unique globally asymptotically endemic equilibrium is proven whenever Ro exceeds one.In the presence of phage absorption,the above stated classical condition based on Ro,as the average number of secondary human infections produced by susceptible/lysogen bacteria during their entire lifespan,is no longer suficient to guarantee the global stability of the DFE.We thus derive an additional threshold No,which is the average offspring number of lysogen bacteria produced by one infected human during the phage-bacteria interactions,and prove that the DFE is globally asymptotically stable whenever both Ro and No are under unity,and infections persist uniformly whenever Ro is greater than one.Finally,the discrete counterpart of the continuous partial differential equation model is derived by constructing a nonstandard finite difference scheme which is dynamically consistent.This consistency is shown by constructing suitable discrete Lyapunov functionals thanks to which the global stability results for the continuous model are replicated.This scheme is implemented in MatLab platform and used to assess the impact of spatial distribution of phages,on the dynamic of bacterial infections.展开更多
South Africa underwent dramatic political and social changes since 1991.This study documents changes in household size and structure from 1991 to 2022 using population census data.The average household size declined f...South Africa underwent dramatic political and social changes since 1991.This study documents changes in household size and structure from 1991 to 2022 using population census data.The average household size declined from 4.9 to 3.5 persons;the proportion of female-headed households increased from 30 to 50%;the proportion of single person households increased from 10 to 25%.These changes were found in all social strata,by residence status,by population group(race),and by province.They were associated with major changes:the dismantling of Apartheid,economic development and restructuration,rising unemployment,fertility decline,decline in marriage rates,new housing arrangements,and the HIV/AIDS crisis.In addition,a new wave of freedom from traditional structures seems to explain the outstanding development of people living alone,especially among young men.展开更多
基金funded by the French Ministry for Europe and Foreign Affairs via the project“REPAIR COVID-19-Africa”coordinated by the Pasteur International Network association.
文摘Controlling the COVID-19 outbreak remains a challenge for Cameroon,as it is for many other countries worldwide.The number of confirmed cases reported by health authorities in Cameroon is based on observational data,which is not nationally representative.The actual extent of the outbreak from the time when the first case was reported in the country to now remains unclear.This study aimed to estimate and model the actual trend in the number of COVID-19 new infections in Cameroon from March 05,2020 to May 31,2021 based on an observed disaggregated dataset.We used a large disaggregated dataset,and multilevel regression and poststratification model was applied prospectively for COVID-19 cases trend estimation in Cameroon from March 05,2020 to May 31,2021.Subsequently,seasonal autoregressive integrated moving average(SARIMA)modeling was used for forecasting purposes.Based on the prospective MRP modeling findings,a total of about 7450935(30%)of COVID-19 cases was estimated from March 05,2020 to May 31,2021 in Cameroon.Generally,the reported number of COVID-19 infection cases in Cameroon during this period underestimated the estimated actual number by about 94 times.The forecasting indicated a succession of two waves of the outbreak in the next two years following May 31,2021.If no action is taken,there could be many waves of the outbreak in the future.To avoid such situations which could be a threat to global health,public health Abbreviations:ACF,Autocorrelation Function;AIC,Akaike information criterion;COVID-19,Coronavirus Disease 2019;MAE,Mean Absolute Error;MAPE,Mean Absolute Percentage Error;MASE,Mean Absolute Scaled Error;ME,Mean Error;MPE,Mean Percentage Error;MRP,Multilevel Regression and Post-stratification;PACF,Partial Autocorrelation Function;PLACARD,Platform for Collecting,Analyzing and Reporting Data;SARIMA,Seasonal Autoregressive integrated moving average;SARS-CoV-2,Severe Acute Respiratory Syndrome Coronavirus 2.
基金The second author(B.T.),acknowledges the support of the University of Pretoria Senior Postdoctoral Program Grant(2018-2020).
文摘Bacteriophages or phages are viruses that infect bacteria and are increasingly used to control bacterial infections.We develop a reaction-diffusion model coupling the interactive dynamic of phages and bacteria with an epidemiological bacteria-borne disease model.For the submodel without phage absorption,the basic reproduction number Ro is computed.The disease-free equilibrium(DFE)is shown to be globally asymptotically stable whenever Ro is less than one,while a unique globally asymptotically endemic equilibrium is proven whenever Ro exceeds one.In the presence of phage absorption,the above stated classical condition based on Ro,as the average number of secondary human infections produced by susceptible/lysogen bacteria during their entire lifespan,is no longer suficient to guarantee the global stability of the DFE.We thus derive an additional threshold No,which is the average offspring number of lysogen bacteria produced by one infected human during the phage-bacteria interactions,and prove that the DFE is globally asymptotically stable whenever both Ro and No are under unity,and infections persist uniformly whenever Ro is greater than one.Finally,the discrete counterpart of the continuous partial differential equation model is derived by constructing a nonstandard finite difference scheme which is dynamically consistent.This consistency is shown by constructing suitable discrete Lyapunov functionals thanks to which the global stability results for the continuous model are replicated.This scheme is implemented in MatLab platform and used to assess the impact of spatial distribution of phages,on the dynamic of bacterial infections.
文摘South Africa underwent dramatic political and social changes since 1991.This study documents changes in household size and structure from 1991 to 2022 using population census data.The average household size declined from 4.9 to 3.5 persons;the proportion of female-headed households increased from 30 to 50%;the proportion of single person households increased from 10 to 25%.These changes were found in all social strata,by residence status,by population group(race),and by province.They were associated with major changes:the dismantling of Apartheid,economic development and restructuration,rising unemployment,fertility decline,decline in marriage rates,new housing arrangements,and the HIV/AIDS crisis.In addition,a new wave of freedom from traditional structures seems to explain the outstanding development of people living alone,especially among young men.
