Abstract
Schistosomiasis remains a serious public health issue in many tropical countries, with more than 700 million people at risk of infection. In China, a national integrated control strategy, aiming at blocking its transmission, has been carried out throughout endemic areas since 2005. A longitudinal study was conducted to determine the effects of different intervention measures on the transmission dynamics of S. japonicum in three study areas and the data were analyzed using a multi-host model. The multi-host model was also used to estimate the threshold of Oncomelania snail density for interrupting schistosomiasis transmission based on the longitudinal data as well as data from the national surveillance system for schistosomiasis. The data showed a continuous decline in the risk of human infection and the multi-host model fit the data well. The 25th, 50th and 75th percentiles, and the mean of estimated thresholds of Oncomelania snail density below which the schistosomiasis transmission cannot be sustained were 0.006, 0.009, 0.028 and 0.020 snails/0.11 m2, respectively. The study results could help develop specific strategies of schistosomiasis control and elimination tailored to the local situation for each endemic area.
Highlights
We extended the multi-host model on the basis of the Williams’ two-host model[33] to assess and predict the effectiveness of different interventions on the transmission dynamics of S. japonicum and to estimate the threshold value of Oncomelania snail density for interrupting the transmission of S. japonicum
We calculated the following prevalences of human infection: 1) the “observed” prevalence is the proportion of individuals with positive stool examination; 2) the adjusted prevalence is the “observed” prevalence of human infection after taking the sensitivity and specificity of the Kato-Katz method into consideration; and 3) the multi-host model provides a modeled prevalence of human infection based on control strategies implemented
The two-host model might no longer reflect the dynamic transmission of S. japonicum when the schistosomiasis transmission is in the phase of elimination
Summary
Mathematical models are an important tool for predicting the transmission dynamics of a neglected tropical disease and provide critical insights to decision makers to develop and improve strategies of disease control and elimination. Oncomelania hupensis snail is the only intermediate host for S. japonicum, and its control is one of the key measures to eliminate the transmission of S. japonicum. An important question has been raised whether there is a ‘breakpoint’ (threshold) for Oncomelania snail population density concerning the risk of human infection. We extended the multi-host model on the basis of the Williams’ two-host model[33] to assess and predict the effectiveness of different interventions on the transmission dynamics of S. japonicum and to estimate the threshold value of Oncomelania snail density for interrupting the transmission of S. japonicum
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
