Spatio-temporal correlation between human and bovine schistosomiasis in China: insight from three national sampling surveys

Abstract

Abstract. Insight into the spatial and temporal contamination of the environment by bovine faeces in China can provide important information on the significance of bovines in the transmission of human schistosomiasis. This insight will be useful for the new evidence-based strategy of the Chinese national schistosomiasis control programme. To enhance our understanding of the spatio-temporal relationship between the prevalence of human and bovine schistosomiasis, we performed correlation and regression analyses using data from three national sampling surveys on schistosomiasis, carried out in 1989, 1995 and 2004. In addition, we established a geographical information system and performed spatial analyses to identify the high-risk areas of the disease. We found that schistosomiasis is mainly concentrated in the marshlands along the Yangtze River. It was also noted that, although the human prevalence and force of transmission in highly endemic areas has been reduced since 1989, the relative importance of bovine schistosomiasis has increased. This is seen in a declining Spearman correlation coefficient between the infection prevalence in humans and in bovines over time (0.812 in 1989, 0.754 in 1995 and 0.376 in 2004). In parallel, the slope of the linear regression decreased from 0.395 in 1989 to 0.215 in 2004. Our data therefore suggest that future schistosomiasis control efforts in China should more vigorously address the important role of bovines in the transmission of human schistosomiasis, and to reduce the environmental contamination of Schistosoma japonicum eggs by bovines.

Schistosomiasis in the People's Republic of China: the Era of the Three Gorges Dam

“…Estimates that 75 to 90% of egg contamination comes from this source have been made through drug intervention studies and mathematical modeling, underpinning the rationale for developing a veterinary vaccine against S. japonicum (77,78,79,83,202). The possibility that this strategy could pay off already is supported by Chinese studies showing that the animal-snail-human transmission cycle is more prominent than the human-snailhuman one in sustaining the infection (77,79,210).…”

“…This can make chemotherapy an expensive and often impractical approach. In China, there is the additional challenge that transmission control necessitates interventions targeting animal reservoirs, particularly buffaloes (77,78,79,210). Moreover, in situations of ongoing high transmission and interrupted chemotherapy campaigns, severe "rebound morbidity" in terms of hepatosplenic disease is now well documented for schistosomiasis, contributing to the disease burden (68,165).…”

Helmintic infections in water buffaloes on Italian farms: a spatial analysis

“…For example, a GIS model for mapping the risk of fasciolosis in buffaloes was developed and validated for the Kingdom of Cambodia using determinants of inundation, proximity to rivers, land use, slope, elevation, and the density of cattle and buffaloes (Tum et al, 2004(Tum et al, , 2007. GIS analysis on the transmission of schistosomiasis in water buffaloes were performed in China (Zhou et al, 2000;Wu et al, 2007). Finally, GIS analysis on the transmission of cystic echinococcosis in water buffaloes were performed in southern Italy .…”

Schistosomiasis japonica: Modelling as a tool to explore transmission patterns

“…China) Zhou et al, 2000). For example, applying spatial analysis, Wu et al (2007) found that schistosomiasis is mainly concentrated in the marshlands along the Yangtze River. The results of their investigations based on linear correlation and regression analysis showed a positive correlation between infection prevalence in humans and in bovine, i.e.…”