Role of ecological approaches to eliminating schistosomiasis in Eryuan County evaluated by system modelling

Background:Schistosomiasis was severely prevalent in Yunnan Province,and it is difficult to achieve its elimination by convention approaches due to complexity of the nature.We explored the comprehensive model to eliminate schistosomiasis in Eryuan County,Yunnan Province,the People’s Republic of China,through integration with the ecological protection programme in Erhai Lake,in order to promote an efficient elimination strategy.We expected that this model is able to be tailored to other local settings,which help achieve the goal of precisely eliminating the disease in Yunnan Province.Methods:Eryuan County of Yunnan Province was chosen as the study area,where the data on environmental protection activities in Erhai Lake and on the schistosomiasis control programme were collected through different departments of Erhai County government since 2015.System modelling was performed using system dynamics software to establish a simulation model in order to evaluate the effectiveness of intervention activities.Results:Ecological approaches to control schistosomiasis in Eryuan County consist of three major components:(i)implementing precise interventions to stop schistosomiasis transmission by means of controlling the source of infection,blocking the biological transmission chains and cutting off the route of disease transmission;(ii)employing ecological approaches to improve the co-effectiveness of environmental protection and schistosomiasis prevention in the study area;and(iii)strengthening the professional skills of personnel involving in the schistosomiasis control programme.Simulation results showed that this strategy could speed up the progress of schistosomiasis control programme moving from the control stage to the elimination stage.Conclusions:Ecological approaches implemented in schistosomiasis endemic areas of the Eryuan region are able to improve the co-effectiveness of environmental protection and schistosomiasis control,providing a new avenue for eliminating schistosomiasis thanks to the application of precise interventions.

A large-scale fatal outbreak of Pasteurella multocida among wild rodents in southwestern China

Background:Pasteurella multocida is an important and old zoonotic pathogen worldwide which has an impressive host spectrum including numerous domestic and wild animals as well as birds,causing specific diseases or outbreak with great economic impact.It has never been reported that P.multocida can cause an epidemic in wild rodents.In June 5–17,2016,more than 1000 rodent deaths of an unknown cause quickly spread in the PuEr City,Yunnan province,southwestern China.Methods:The rodents in affected areas and outside of the epidemic areas were collected and screened for possible known pathogens including Yersinia pestis,rabies virus and hantavirus as well as other bacteria.The possible bacterial pathogens were isolated both by culture medium and by mouse inoculation in parallel.The isolates were identified by the Vitek GNI card and PCR assays for 16S rRNA genes.The pathogen strains were selected for whole genome sequencing analysis.Results:A total of 123 rodents were collected from 25 sample sites at affected area,among of which,all 119 dead rodents were negative for the pathogen under consideration except P.multocida,and all four live rodents were negative for P.multocida.In addition,480 rodents collected from other 23 counties outside of the epidemic area in Yunnan were negative for with P.multocida.A total of 14 strains of P.multocida(six directly isolated from the field rodents and eight from the experimental mice that were injected with the organ substrates from the dead rodents)belonged to serogroup A and serogroup F represented by 9 N and 20 N were identified in these epidemic areas.Whole genome sequencing revealed that the serogroup F strain shared 99%similarity to P.multocida Pm70 from chicken,but contained a 50 k bp insertion sequence.The serogroup A strain shared 95%similarity to P.multocida FDAARGOS_385 from a human patient,but contained four large structural differences.Histological abnormalities were identified in the livers,lungs,hearts and brains of the inoculated mice.Conclusions:The simultaneous occurrence of both serotypes of P.multocida may have caused this sudden onset of mortality across the local rodent population in Yunnan Province,China.Further attention should be paid to this old bacterium in the world.