Interruption of schistosomiasis transmission in mountainous and hilly regions with an integrated strategy:a longitudinal case study in Sichuan,China

Background:Schistosomiasis remains a major public health concern in China.Since 2004,an integrated strategy was developed to control the transmission of Schistosoma japonicum in China.However,the long-term effectiveness of this integrated strategy for the interruption of schistosomiasis transmission remains unknown in the mountainous and hilly regions of China until now.This longitudinal study aims to evaluate the effectiveness of the integrated strategy on transmission interruption of schistosomiasis in Sichuan Province from 2005 through 2014.Methods:The data regarding replacement of bovines with machines,improved sanitation,access to clean water,construction of public toilets and household latrines,snail control,chemotherapy,and health education were captured from the annual report of the schistosomiasis control programmes in Sichuan Province from 2005 to 2014,and S.japonicum infection in humans,bovines and snails were estimated to evaluate the effectiveness of the integrated strategy.Results:During the 10-year period from 2005 through 2014,a total of 536568 machines were used to replace bovines,and 3284333 household lavatories and 15523 public latrines were built.Tap water was supplied to 19116344 residents living in the endemic villages.A total of 230098 hm2 snail habitats were given molluscicide treatment,and 357233 hm2 snail habitats received environmental improvements.There were 7268138 humans and 840845 bovines given praziquantel chemotherapy.During the 10-year study period,information,education and communication(IEC)materials were provided to village officers,teachers and schoolchildren.The 10-year implementation of the integrated strategy resulted in a great reduction in S.japonicum infection in humans,bovines and snails.Since 2007,no acute infection was detected,and no schistosomiasis cases or infected bovines were identified since 2012.In addition,the snail habitats reduced by 62.39%in 2014 as compared to that in 2005,and no S.japonicum infection was identified in snails since 2007.By 2014,88.9%of the endemic counties achieved the transmission interruption of schistosomiasis and transmission control of schistosmiasis was achieved in the whole province in 2008.Conclusion:The government-directed and multi-department integrated strategy is effective for interrupting the transmission of schistosomiasis in the mountainous and hilly regions of China.

LONG-TERM IMMUNOGENICITY AND EFFICACY OF RECOMBINANT YEAST DERIVED HEPATITIS B VACCINE FOR INTERRUPTION OF MOTHER-INFANT TRANSMISSION OF HEPATITIS B VIRUS

Recombinant DNA Yeast-Derived Hepatitis B Vaccine (RYHB vaccine) is comparable to and can replace Plasma-Derived Hepatitis B Vaccine (PHB vaccine) for the prevention of mother-nfant transmission of hepatitis B virus (HBV), but the duration of immune efficacy of RYHB vaccine is not clear. This study indicates the long-term efficacy for the prevention of mother-infant transmission of HBV. One hundred and six neonates born to HBsAg-arrier mothers with HBeAg positive were randomly divided into two groups, one receiving 20 μg per dose of RYHB vaccine and the another receiving 20 μg per dose of PHB vaccine on the day of birth, at 1 month and at 6 months (three times). Physical examination and blood tests were performed for all infants at 6, 12, 24, 36, 48 and 60 months of age. The results showed that the protective efficacies at 6, 12, 24, 36, 48 and 60 months were 67%, 75%, 63%, 62%, 57% and 56%, respectively for the RYHB vaccine group and 58%, 76%, 51%, 41%, 24% and 18%, respectively for the PHB vaccine group. The protective efficacy was notably significant in the last two years. The study indicates that the duration of protective efficacy is over 5 years with RYHB vaccine, being longer than that of PHB vaccine. These recipients of RYHB vaccine showed no side effects, and the vaccine is regarded as safe and effective.

Integrating ecological approaches to interrupt schistosomiasis transmission:opportunities and challenges

Background:The development of agenda for global schistosomiasis elimination as a public health problem generates enthusiasms among global health communities,motivating great interests in both research and practice.Recent China-Africa schistosomiasis control initiatives,aiming to enhance collaboration on disease control in African countries,reflect in part that momentum.Yet there is a pressing need to know whether the Chinese experiences can be translated and applied in African settings.Main body:China’s remarkable achievements in schistosomiasis control programme,associated experiences and lessons,have much to offer to those combating the disease.Central to the success of China’s control programmes is a strategy termed“integrated control”-integrating environmental approaches(e.g.improved sanitation,agricultural and hydrological development and management),which target different phases of the parasite transmission system,to chemical-based drug treatment and mollusciciding.Yet,despite significant measurable public health benefits,such integration is usually based on field experience and remains largely uncharacterized in an ecological context.This has limited our knowledge on relative contributions of varying components of the integrated control programme to the suppression of disease transmission,making it challenging to generalize the strategy elsewhere.In this opinion article,we have described and discussed these challenges,along with opportunities and research needs to move forward.Conclusions:There is an urgent need to formalize an ecological framework for the integrated control programme that would allow research towards improved mechanistic understanding,quantification,and prediction of the control efforts.

GPS-based fine-scale mapping surveys for schistosomiasis assessment: a practical introduction and documentation of field implementation

Background Fine-scale mapping of schistosomiasis to guide micro-targeting of interventions will gain importance in elimination settings,where the heterogeneity of transmission is often pronounced.Novel mobile applications offer new opportunities for disease mapping.We provide a practical introduction and documentation of the strengths and shortcomings of GPS-based household identification and participant recruitment using tablet-based applications for fine-scale schistosomiasis mapping at sub-district level in a remote area in Pemba,Tanzania.Methods A community-based household survey for urogenital schistosomiasis assessment was conducted from November 2020 until February 2021 in 20 small administrative areas in Pemba.For the survey,1400 housing structures were prospectively and randomly selected from shapefile data.To identify pre-selected structures and collect survey-related data,field enumerators searched for the houses’geolocation using the mobile applications Open Data Kit(ODK)and MAPS.ME.The number of inhabited and uninhabited structures,the median distance between the pre-selected and recorded locations,and the dropout rates due to non-participation or non-submission of urine samples of sufficient volume for schistosomiasis testing was assessed.Results Among the 1400 randomly selected housing structures,1396(99.7%)were identified by the enumerators.The median distance between the pre-selected and recorded structures was 5.4 m.A total of 1098(78.7%)were residential houses.Among them,99(9.0%)were dropped due to continuous absence of residents and 40(3.6%)households refused to participate.In 797(83.1%)among the 959 participating households,all eligible household members or all but one provided a urine sample of sufficient volume.Conclusions The fine-scale mapping approach using a combination of ODK and an offline navigation application installed on tablet computers allows a very precise identification of housing structures.Dropouts due to non-residential housing structures,absence,non-participation and lack of urine need to be considered in survey designs.Our findings can guide the planning and implementation of future household-based mapping or longitudinal surveys and thus support micro-targeting and follow-up of interventions for schistosomiasis control and elimination in remote areas.