The Dynamics of Hepatic Fibrosis Related to Schistosomiasis and Its Risk Factors in a Cohort of China.

China has had a long history against schistosomiasis japonica. The most serious prognosis of chronic schistosome infection is hepatic fibrosis, which develops into advanced schistosomiasis if the process is not effectively controlled. After a more than seven decades endeavor, China has gained remarkable achievements in schistosomiasis control and achieved transmission control nationwide (infection rate of schistosomes in residents and domestic animals both less than 1%) by 2015. However, new advanced schistosomiasis cases emerge annually in China, even in areas where the transmission of schistosomiasis had been interrupted. In the present study, the residents (>5 years old) in a schistosomiasis endemic village were examined for schistosomiasis every year during 1995-2019 by the modified Kato-Katz thick smear method and/or miracidium hatching technique. Residents who were identified to have an active infection method were treated with praziquantel at a dose of 40 mg/kg body weight. Ultrasonography was carried out to assess the liver morbidity related to schistosomiasis in 1995 and 2019, respectively. The prevalence of schistosomiasis among residents presented a downward trend annually, from 17.89% (175/978) in 1995 to 0 (0/475) in 2019. Among 292 residents who received ultrasound scan both in 1995 and 2019, 141 (48.29%) presented stable liver damage, while liver fibrosis was developed severely in 86 (29.45%) and reversed in 65 (22.26%) residents. Univariate and multivariate analysis showed that anti-fibrosis treatment was the protective factor against schistosomiasis hepatic fibrosis. Males, residents aged 38 and above, fishermen, and people who did not receive anti-fibrosis treatment were groups with higher risk of liver fibrosis development. Our results revealed that although the infection rate of schistosome dropped significantly in endemic areas, liver fibrosis was still developing among some residents, even though they had received deworming treatment. Liver protection/anti-fibrosis treatment should be administered in endemic regions and regions with historically uncontrolled transmission to slow down the deterioration of hepatic fibrosis among patients in schistosomiasis endemic areas.

[Study on immune status of patients with schistosomiasis japonica in Poyang Lake region III Humoral and cellular immune characteristics between Schistosoma japonicum high and low antibody responders].

OBJECTIVE: To explore the immune mechanism of negative results of immune tests of schistosomiasis japonica patients. METHODS: Totally 142 schistosomiasis patients (positive stool examinations) of Poyang Lake region were tested by ELISA method, and the ROC curve was applied to determine the high and low response of the patients. The levels of cellular immunity and cytokines of high and low responders were compared. RESULTS: Totally eight schistosomiasis patients were found as low responders. Besides SWAP-IgA (t = -1.588, P > 0.1), the levels of isotype antibodies were significantly lower in the low responders compared with those in the high responders (t = -14.517 to -2.866, all P < 0.05). In the low responders, the propor- tion of CD3⁺T was increased; and the proportions of CD4⁺T, CD8⁺T, CD4⁺CD25⁺Treg, and the ratio of CD4⁺/CD8⁺ were all de- creased, but all of them were not significant (t = -1.72 to 0.974, all P > 0.05) compared with those in the high responders. The differences of IFN-γ and IL-10 between the high and low responders were both not significant (t = -2.426 to 0.216, all P > 0.05). CONCLUSIONS: There is a significant difference between the high and low responders only in the levels of isotype antibodies. One of the reasons of low response in the immune tests is the much lower antibody level after the antigen-antibody compound is completely formulated.

[Preservation of live eggs of Schistosoma japonicum].

OBJECTIVE: To observe the preservation time and activity of miracidium hatching from schistosome eggs preserved in different solutions, so as to obtain the optimal preservation conditions and then provide quality control products for field application. METHODS: The rectum stool of rabbits infected with Schistosoma japonicum was collected and the coarse fecal residue was removed with a series of sample sieves of 80, 100, 160 and 200 meshes respectively, and then the schistosome eggs were concentrated with the sample sieve of 260 meshes. The concentrated eggs were preserved in 0.9% sodium chloride solution, 1.2% sodium chloride solution, phosphate buffered saline solution (PBS, PH 7.2), 1.0% sucrose solution, and Mili-Q water, respectively, and then were conserved in a 4 °C refrigerator and 15 °C constant temperature incubator, respectively. The preserved eggs were hatched in different time (7-day interval) , the vitality and quantity of the miracidia were observed, and the hatching rates were calculated. RESULTS: Under the condition of 4 °C, the hatching rates of eggs dropped to 0 in 1.0% sucrose solution and 1.2% sodium chloride solution at the 49th and 126th day, respectively, and the hatching rates of eggs in the 0.9% sodium chloride solution and PBS solution dropped to 10% at the 112th day, and the activity of miracidium was weakened since 140th. In the Mili-Q water, the hatching rate dropped less than 10% at the 196th day and the activity of miracidia was weakened since the 280th day. Under the condition of 15 °C, the hatching rate of eggs in different solutions gradually dropped to 0 from the 49th day to 105th day. CONCLUSION: The eggs preserved in Mili-Q water at the temperature of 4 °C can be used as the positive reference for hatching tests within 196 days.

[Investigation of infections of soil-transmitted nematodes in Fusheng Village of Poyang Lake area in Jiangxi Province].

OBJECTIVE: To understand the status of soil-transmitted nematode infections in Poyang Lake area in Jiangxi Province. METHODS: The parasitic eggs of stools of residents aged 6-65 years were detected with the Kato-Katz technique in Fusheng Village of Poyang Lake area in Jiangxi Province in 2008. RESULTS: In 2008, the total average infection rate of soil-transmitted nematodes was 37.97%, and the infection rates of Ascarid lumbricoid, Trichuris trichiura and hookworm were 20.39%, 6.67% and 18.45%, respectively. The total infection rate of soil-transmitted nematodes and the rate ofA. lumbricoid were higher in the female than in the male with a statistically significant difference (P < 0.01). The infection rates of T. trichiura and hookworm in the female were higher than those in the male, but there was no significant difference between them (P > 0.05). The total infection rate of soil-transmitted nematodes and the rate of hookworm in different age groups had a similar change pattern which had an increasing trend with the age growing. The infection rate ofA. lumbricoid was the lowest in the age group of 10-19 years and was the highest in the age group of 20-29 years, and then the rate showed a gradually declining trend with the age increasing. The infection rate of T. trichiura had a decreasing trend as the age grew with 2 peaks in the age groups of 10-19 and 40-49, respectively. CONCLUSIONS: The infection rates of soil-transmitted nematodes in population of Fusheng Village in Jiangxi Province are still high. The effective control measures include health education, regular anthelminthic treatment, innoxiously processing of stool and environment reform, and the interruption of the transmitting chain is the fundamental strategy.

[Development and assessment of Schistosoma japonicum antibody test kit (IHA)].

OBJECTIVE: To develop a Schistosoma japonicum antibody test kit (IHA). METHODS: According to the requirement of Good Manufacturing Practice (GMP) and Quality Control (QC) of drugs, the components of kit as well as its preparation method and procedure were studied, and the test kit was assembled and its diagnostic effect was assessed. RESULTS: The sensitivity and specificity were up to 94.49% and 97.14% when testing the serum samples of chronic schistosomiasis patients and normal serum samples by the kit, respectively. The Youden Index of the Kit was 0.92. The cross reaction rates with paragonimus and trichina were 15.00% and 10.00%, respectively. Compared with ELISA and another IHA kit produced by An'Ji company which were used to test schistosome antibody in residents of endemic areas at the same time, the coincident rates of the developed kit were 93.06% and 92.25%, respectively. CONCLUSION: The IHA kit for Schistosomajaponicum antibody has a high sensitivity and specificity, and has the value of application and popularization in the field.

A novel procedure for precise quantification of Schistosoma japonicum eggs in bovine feces.

Schistosomiasis japonica is a zoonosis with a number of mammalian species acting as reservoir hosts, including water buffaloes which can contribute up to 75% to human transmission in the People's Republic of China. Determining prevalence and intensity of Schistosoma japonicum in mammalian hosts is important for calculating transmission rates and determining environmental contamination. A new procedure, the formalin-ethyl acetate sedimentation-digestion (FEA-SD) technique, for increased visualization of S. japonicum eggs in bovine feces, is described that is an effective technique for identifying and quantifying S. japonicum eggs in fecal samples from naturally infected Chinese water buffaloes and from carabao (water buffalo) in the Philippines. The procedure involves filtration, sedimentation, potassium hydroxide digestion and centrifugation steps prior to microscopy. Bulk debris, including the dense cellulosic material present in bovine feces, often obscures schistosome eggs with the result that prevalence and infection intensity based on direct visualization cannot be made accurately. This technique removes nearly 70% of debris from the fecal samples and renders the remaining debris translucent. It allows improved microscopic visualization of S. japonicum eggs and provides an accurate quantitative method for the estimation of infection in bovines and other ruminant reservoir hosts. We show that the FEA-SD technique could be of considerable value if applied as a surveillance tool for animal reservoirs of S. japonicum, particularly in areas with low to high infection intensity, or where, following control efforts, there is suspected elimination of schistosomiasis japonica.