A cluster-randomised intervention trial against Schistosoma japonicum in the Peoples' Republic of China: bovine and human transmission.

Darren J Gray,Zheng Feng,Simon J Forsyth,Honggen Chen,Adrian G Barnett,Donald P Mcmanus,Yuesheng Li,Gail M Williams,Allen G Ross,Robert S Li,Jiagang Guo

doi:10.1371/journal.pone.0005900

Abstract

BackgroundZoonotic schistosomiasis japonica is a major public health problem in China. Bovines, particularly water buffaloes, are thought to play a major role in the transmission of schistosomiasis to humans in China. Preliminary results (1998–2003) of a praziquantel (PZQ)-based pilot intervention study we undertook provided proof of principle that water buffaloes are major reservoir hosts for S. japonicum in the Poyang Lake region, Jiangxi Province.Methods and FindingsHere we present the results of a cluster-randomised intervention trial (2004–2007) undertaken in Hunan and Jiangxi Provinces, with increased power and more general applicability to the lake and marshlands regions of southern China. The trial involved four matched pairs of villages with one village within each pair randomly selected as a control (human PZQ treatment only), leaving the other as the intervention (human and bovine PZQ treatment). A sentinel cohort of people to be monitored for new infections for the duration of the study was selected from each village. Results showed that combined human and bovine chemotherapy with PZQ had a greater effect on human incidence than human PZQ treatment alone.ConclusionsThe results from this study, supported by previous experimental evidence, confirms that bovines are the major reservoir host of human schistosomiasis in the lake and marshland regions of southern China, and reinforce the rationale for the development and deployment of a transmission blocking anti-S. japonicum vaccine targeting bovines.Trial RegistrationAustralian New Zealand Clinical Trials Registry ACTRN12609000263291

Highlights

Schistosomiasis is a major public health concern in China with approximately one million people infected and 59 million at risk of infection [1,2,3,4]
There is substantial evidence indicating that bovines, water buffaloes (Bubalus bubalis), play a major role in the transmission of S. japonicum to humans in China [1,2,4,9,10,11,12,13,14,15,16,17,18,19,20,21]
Baseline human and bovine prevalence (%) and intensity of infection (geometric mean eggs per gram (EPG) in infected individuals) for S. japonicum are shown in Tables 1 and 2

Summary

Introduction

Schistosomiasis is a major public health concern in China with approximately one million people infected and 59 million at risk of infection [1,2,3,4]. A praziquantel (PZQ)-based pilot intervention study we undertook (1998–2003) [15] provided proof of principle that water buffaloes are major reservoir hosts for S. japonicum around the Poyang Lake region of Jiangxi Province [15]. Further support came from a molecular field survey of S. japonicum in China using microsatellite markers, which showed that humans and bovines contribute considerably more to the parasite reservoir than other definitive host species [23]. Water buffaloes, are thought to play a major role in the transmission of schistosomiasis to humans in China. Preliminary results (1998–2003) of a praziquantel (PZQ)-based pilot intervention study we undertook provided proof of principle that water buffaloes are major reservoir hosts for S. japonicum in the Poyang Lake region, Jiangxi Province

Results

Discussion

Conclusion