Epidemiological and morbidity assessment of Schistosoma japonicum infection in a migrant fisherman community, the Dongting Lake region, China

Abstract

We assessed the epidemiology and morbidity related to Schistosoma japonicum infection by both parasitological (Kato-Katz method and miracidium hatching test) and ultrasound examination in a migrant fisherman community (n = 106) from the Dongting Lake region in China in 2001. A prevalence of 69.8% and a mean infection intensity of 66.5 eggs per gram (epg) were recorded for this group. Males had a higher level of infection (77%) and intensity (92.2 epg) compared with females (58% and 28.6 epg, respectively). Subjects aged 11-20 years had the highest prevalence of infection (91%) and the heaviest infection intensity (85.3 epg) among all age groups. Twenty-six percent of the subjects had not been treated previously for schistosomiasis. Parenchymal fibrosis (> or = stage II) detected by ultrasound and spleen enlargement (or splenectomy) occurred in 37% and 9% of subjects, respectively. Portal vein dilation was detected in 18% subjects, and 58% (11/19) of those patients with portal vein enlargement were shown to have parenchymal fibrosis (> or = stage II). These results indicate that S. japonicum infection and related morbidity in mobile fisherman is still unacceptably high despite the fact that China has implemented a Schistosomiasis Control Project financed by a World Bank Loan for a period of 8 years since 1992. Clearly, new approaches for schistosomiasis control, especially in communities like these mobile fishermen, should be explored.

Cd4+ T-Cell Counts, Cd4+/Cd8+ T-Cell Count Ratios, and Antibody Levels in Migrant Fishermen Infected With Schistosoma Japonicum in the Dongting Lake, China

“…The geographic and population information and prevalence of schistosomiasis for this community were described in a previous report. 6 The study focused on individuals who live and work on fishing boats on the lake and who are highly exposed to S. japonicum because of their lifestyle and occupation. A total of 94 subjects (men ‫ס‬ 59; women ‫ס‬ 35) with an average age of 31 years participated in the survey in 2002.…”

“…7 Both methods, based on one stool sample, were described in detail in a previous re-port. 6 Infection intensity (eggs per gram of stool [epg]) was determined by the Kato-Katz technique.…”

“…This study aimed to explore the relationship between immune responses and infection intensity or pathologic changes in the liver among a group of migrant fishermen who live and work on boats in the Dongting Lake in Hunan Province, China; these fishermen have a very high level of water exposure and a high frequency of infection. 6 The completed analysis was based on infection studies, morbidity measurements, and estimates of the levels of CD4 + and CD8 + T cells and antibodies in infected individuals compared with controls.…”

Approaches being used in the national schistosomiasis elimination programme in China: a review

“…Boatman and fisherman have a high frequency of contacting S. japonicum -infested water, and play a dual role in the transmission of schistosomiasis [50–52]. They act as both victims (health-harming after being infected) and transmitter of schistosomiasis (source of S. japoncum infection) [53–55].…”

Cross-sectional associations between intensity of animal and human infection with Schistosoma japonicum in Western Samar province, Philippines

“…1 Unlike the other three schistosome species aff f fecting humans, Schistosoma japonicum is a true zoonosis, infecting 46 species of mammals, including humans, all of which are definitive hosts necessary for transmitting the infection. [2][3][4] S. japonicum is endemic in China, parts of Indonesia and the Philippines. 5 These parasites are found in the 22 provinces in the Philippines that do not have a definite dry season; this leads to continual transmission.…”