Assessment of morbidity due to Schistosoma japonicum infection in China

Abstract

This paper presents a historical assessment of morbidity due to the Schistosoma japonicum infection in China. Due to the socio-economic situation, which did not allow for a control program to be implemented until the early 1950s, morbidity was serious and mortality was high before this. Based on a few investigations and published papers, it can be said that the disease caused millions of deaths, and destroyed numerous families and villages. Since the 1950s, there has been a national control program, intensive control and prevention work has been carried out, and consequently the disease is being controlled. At present, both the prevalence and the morbidity of the disease have been decreasing substantially. The morbidity of the three phases of the disease is outlined in this paper. Comparatively higher morbidity is seen in the acute and advanced phases of the disease. The four major forms of advanced schistosomiasis i.e., ascites, megalosplenia, dwarfism, and colonic tumoroid proliferation, are outlined with their characteristic clinical presentations; their proportions are different during various periods of the national control program. Ectopic schistosomiasis and the relationship between the S. japonicum infection and colorectal cancer are also discussed. Post-transmission schistosomiasis is briefly discussed (which can happen even if the disease reaches the criteria of elimination, and the infection and transmission have stopped, but yet it still develops). The problem of mammalian reservoir hosts of S. japonicum makes the epidemiology and control of schistosomiasis in China even more complicated and arduous, and the control progress in animal reservoirs is briefly presented.

Pulmonary nodules in African migrants caused by chronic schistosomiasis

“…29 By contrast, S japonicum eggs (and, rarely, adults) have occasionally been found in ectopic sites almost all over the body. 22 In the scientifi c literature, we found 16 cases of patients with an in-vivo diagnosis of pulmonary lesions due to chronic schistosomiasis. In four of these patients, adult worms were found by histological examination of biopsy specimens (tables 2 and 3).…”

“…21 The latter has also been associated with dwarfi sm and granulomatous disease of the large intestine (colonic tumoroid proliferation) in the advanced stage of the disease. 22 The involvement of the lungs in the chronic phase is usually described in relation to pulmonary hypertension. The pathophysiological mechanisms that might cause pulmonary hypertension are hepatosplenic disease, leading to portal hypertension …”

Schistosomiasis japonica: Modelling as a tool to explore transmission patterns

“…Schistosoma mansoni in Africa, Middle East and Latin America, S. haematobium in Africa and the Middle East and S. japonicum in Southeast Asia (Chan and Isham, 1998). S. japonicum causes the most severe pathology (Chen and Mott, 1998) and the epidemiology is more complex than that of the other species because of its zoonotic nature that involves more than 40 species of animal reservoirs, including cattle, dogs, pigs and rodents as discussed by Gryseels et al (2006). The impact of schistosomiasis is not only related to Kloos' three factors, but also to demographic, environmental, political, socioeconomic and cultural factors (Collins et al, 2012).…”

Study of the variation of schistosomiasis risk in Lake Poyang in the People’s Republic of China using multiple space-borne sensors for monitoring and modelling

“…China), control of schistosomiasis has reduced the number of infected people from over 11 million in the 1950s to approximately one million in 1995 (Utroska et al, 1989;Utzinger et al, 2005;Wu et al, 2005). The number has been further reduced reaching ~326,000 in 2010 and 289,000 in 2011 (Lei et al, 2011;Chen, 2014). However, a remarkable re-emergence of schistosomiasis took place between 1995 and 2005.…”