Current Status of Schistosomiasis Control and Prospects for Elimination in the Dongting Lake Region of the People’s Republic of China

Abstract

Schistosomiasis japonica is an ancient parasitic disease that has severely impacted human health causing a substantial disease burden not only to the Chinese people but also residents of other countries such as the Philippines, Indonesia and, before the 1970s, Japan. Since the founding of the new People’s Republic of China (P. R. China), effective control strategies have been implemented with the result that the prevalence of schistosomiasis japonica has decreased markedly in the past 70 years. Historically, the Dongting Lake region in Hunan province is recognised as one of the most highly endemic for schistosomiasis in the P.R. China. The area is characterized by vast marshlands outside the lake embankments and, until recently, the presence of large numbers of domestic animals such as bovines, goats and sheep that can act as reservoir hosts for Schistosoma japonicum . Considerable social, economic and environmental changes have expanded the Oncomelania hupensis hupensis intermediate snail host areas in the Dongting lake region increasing the potential for both the emergence of new hot spots for schistosomiasis transmission, and for its re-emergence in areas where infection is currently under control. In this paper, we review the history, the current endemic status of schistosomiasis and the control strategies in operation in the Dongting Lake region. We also explore epidemiological factors contributing to S. japonicum transmission and highlight key research findings from studies undertaken on schistosomiasis mainly in Hunan but also other endemic Chinese provinces over the past 10 years. We also consider the implications of these research findings on current and future approaches that can lead to the sustainable integrated control and final elimination of schistosomiasis from the P. R. China and other countries in the region where this unyielding disease persists.

Schistosomiasis in the People's Republic of China – down but not out

“…The Chinese government has, for some time, been removing cattle and water buffalo from schistosomiasis-endemic areas and replacing them with motorized tractors, or has fenced off these bovines to limit environmental contamination of the area with S. japonicum eggs (McManus et al ., 2011; Li et al ., 2020). As indicated, bovines are recognized as major reservoir hosts of S. japonicum in China and contribute substantially to human transmission due to the large numbers of schistosome eggs they excrete daily (Guo et al ., 2001; Gray et al ., 2009 b ; He et al ., 2018).…”

“…Schistosomiasis in the People's Republic of China (China), caused exclusively by infection with the species Schistosoma japonicum, is a zoonotic parasitic disease that goes back to antiquity with eggs identified in mummies from the Han dynasty (206 BC) (McManus et al ., 2010; 2018; Yeh and Mitchell, 2016). Historically, schistosomiasis ranks as the most important helminth infection in China, with the main hotspots being the river bank areas of the five provinces along the middle and lower reaches of the Yangtze River (Hunan, Hubei, Jiangxi, Anhui and Jiangsu) and the mountainous areas of Sichuan and Yunnan (McManus et al ., 2010; Li et al ., 2020). The major endemic foci are found in the marshlands of the Dongting and Poyang lakes, China's two largest inland lakes (Fig.…”

Identification of the high-risk area for schistosomiasis transmission in China based on information value and machine learning: a newly data-driven modeling attempt

“…This is likely due to the wide distribution and high density of O. hupensis in those areas [ 27 ]. Further, there are numerous water conservancy projects, frequent population flow, developed animal husbandry industries, and increased opportunities for human and animal contact, placing these regions at risk for schistosomiasis rebound [ 28 , 29 ]. With the implementation of comprehensive control strategy focused on the control of infectious source, the distribution pattern of intermediate host, the composition and distribution trend of infectious source, and the mode of population activity in epidemic area have changed significantly.…”

Identification of the High-Risk Area for Schistosomiasis Transmission in China Based on Information Value and Machine Learning—A Newly Data-Driven Modeling Try

“…This is likely due to the wide distribution and high density of O. hupensis in those areas [25]. Further, there are numerous water conservancy projects, frequent population ow, developed animal husbandry industries, and increased opportunities for human and animal contact, placing these regions at risk for schistosomiasis rebound [26][27]. Comprehensive control strategies have focused on infection control, the distribution pattern of intermediate schistosomiasis hosts, composition, and distribution of infection sources.…”