Schistosomiasis Japonica In China Research Articles

Diagnostic Efficacy of Plasma-Based Real-Time PCR for Schistosomiasis Japonica in Mice before and after Treatment with Praziquantel.

The prevalence of schistosomiasis japonica in China is now characterized by a low epidemic rate and low-intensity infections. Some diagnostic methods with high sensitivity and specificity are urgently needed to better monitor this disease in the current situation. In this study, the detection efficacy of a real-time fluorescent quantitative PCR (qPCR) assay was assessed for schistosomiasis japonica in mice, and before and after treatment with praziquantel (PZQ). Our results showed that the sensitivity of the qPCR was 99.3% (152/153, 95% CI: 96.41-99.98%) and its specificity was 100% (77/77, 95% CI: 95.32-100%) in mice infected with different numbers of Schistosoma japonicum. After the oral administration of PZQ, mice infected with 10 cercariae or 40 cercariae were all Schistosoma japonicum-negative 6 weeks after treatment. However, the negativity rates on a soluble egg antigen (SEA)-based enzyme-linked immunosorbent assay (ELISA) were only 34.8% (8/23, 10 cercariae group) and 6.7% (1/15, 40 cercariae group) at the sixth week after PZQ treatment. These results demonstrated that the qPCR method had good sensitivity and specificity, and suggested that its sensitivity correlated with the infection intensity in mice. Moreover, this method had better potential utility for evaluating the treatment efficacy of PZQ in schistosome-infected mice than SEA-based ELISA.

The Cytokine Profile in Different Stages of Schistosomiasis Japonica.

To explore and profile the level of cytokines in the sera of patients infected with Schistosoma japonicum to explore the helper T-cell response of patients either at the chronic or advanced stage of the disease. We randomly selected 58 subjects from several areas endemic for schistosomiasis japonica in China and collected serum samples to be tested for 18 different cytokines secreted by (1) Th1/Th2 cells (GM-CSF, IFN-γ, IL-1β, IL-2, IL-4, IL-5, IL-6, IL-12p70, IL-10, IL-13, IL-18 and TNF-α) and (2) Th9/Th17/Th22/Treg cells (IL-9, IL-17A, IL-21, IL-22, IL-23 and IL-27). The Th1/Th2 cytokines in chronic patients were not significantly different from those in healthy people, while patients with advanced schistosomiasis had higher levels of IL-2, IL-23 and IL-27 and lower levels of IL-18 and IFN-γ. With respect to the Th9/Th17/Th22/Treg cell cytokines, there were higher levels of IL-23. Thus, a limited variation of the cytokine response between the three patient groups was evident, but only in those with advanced infection, while there was no difference between chronic schistosomiasis infection and healthy subjects in this respect. The cytokine expression should be followed in patients with advanced schistosomiasis who show a cytokine pattern of a weakened Th1 cell response and an increased Th17 response.

Long-term effectiveness of the integrated schistosomiasis control strategy with emphasis on infectious source control in China: a 10-year evaluation from 2005 to 2014.

Schistosomiasis is a neglected tropical parasitic disease of great public health significance worldwide. Currently, mass drug administration with praziquantel remains the major strategy for global schistosomiasis control programs. Since 2005, an integrated strategy with emphasis on infectious source control was implemented for the control of schistosomiasis japonica, a major public health concern in China, and pilot studies have demonstrated that such a strategy is effective to reduce the prevalence of Schistosoma japonicum infection in both humans and bovines. However, there is little knowledge on the long-term effectiveness of this integrated strategy for controlling schistosomiasis japonica. The aim of this study was to evaluate the long-term effectiveness of the integrated strategy for schistosomiasis control following the 10-year implementation, based on the data from the national schistosomiasis control program released by the Ministry of Health, People's Republic of China. In 2014, there were 5 counties in which the transmission of schistosomiasis japonica had not been interrupted, which reduced by 95.2% as compared to that in 2005 (105 counties). The number of schistosomiasis patients and acute cases reduced by 85.5 and 99.7% in 2014 (115,614 cases and 2 cases) as compared to that in 2005 (798,762 cases and 564 cases), and the number of bovines and S. japonicum-infected bovines reduced by 47.9 and 98% in 2014 (919,579 bovines and 666 infected bovines) as compared to that in 2005 (1,764,472 bovines and 33,736 infected bovines), respectively. During the 10-year implementation of the integrated strategy, however, there was a minor fluctuation in the area of Oncomelania hupensis snail habitats, and there was only a 5.6% reduction in the area of snail habitats in 2014 relative to in 2005. The results of the current study demonstrate that the 10-year implementation of the integrated strategy with emphasis on infectious source has greatly reduced schistosomiasis-related morbidity in humans and bovines. It is concluded that the new integrated strategy has remarkable long-term effectiveness on the transmission of schistosomiasis japonica in China, which facilitates the shift of the national schistosomiasis control program from transmission control to transmission interruption and elimination. However, such a strategy seems to have little effect on the shrinking of areas of snail habitats.

Strengthening the control of goat schistosomiasis to facilitate the progress towards elimination of schistosomiasis in China

Although great success has been achieved in schistosomiasis control, schistosomiasis japonica remains a publichealth concern in China. Schistosoma japonicum is found to naturally infect over 40 mammalian animals. The implementation of the integrated schistosomiasis control strategy emphasizing infectious source control since 2004, which integrates replacement of bovines with machines, breeding domestic animals in fences, building safe pastures and chemotherapy of infected bovines, results in a clear-cut reduction in the prevalence of S. japonicum infection in both humans and bovines, as well as the areas of infected snail habitats, and the national schistosomiasis control program is moving from transmission control towards transmission interruption and elimination. It has been found that goat is highly susceptible to S. japonicum infection, and previous epidemiological data have shown a high prevalence of infection in goat. However, the role of goat in the transmission of schistosomiasis japonica has not been paid much attention, and there are few systematic surveys to evaluate the role of goat in schistosomiasis transmission in China to date. Professor Liang Yousheng's group investigated S. japonicum development and reproduction (egglaying) in goat body, environmental contamination by goat feces, and the effect of temperature and humidity on the survival of S. japonicum eggs in goat feces. Their findings further demonstrate the role of goat in the transmission of schistosomiasis japonica. In addition, they proposed, based on their findings and previous reports, that the management of goat should be integrated into the national schistosomiasis control program in China, since goat is virtually one of the major infectious sources of schistosomiasis japonica in China. Moreover, this group improved the fecal hatching test and optimized the parasitological technique for diagnosis of S. japonicum infection in goats. These innovative studies fill in the gaps of goat schitsosomiasis japonica research in China, and the research outcomes will enrich the currently implemented integrated schistosomiasis control strategy emphasizing infectious source control, and are believed to play a critical role in schistosomiasis elimination in China. Since schistosomiasis seriously affects goat husbandry development and local famer income, and goat has become a major infectious source of schistosomiasis japonica in China, the control of goat schistosomiaiss will facilitate the progress towards the elimination of schistosomiasis in China, and the following research priorities are suggested: (1) to emphasize the control of goat schistosomiasis, and to integrate the comprehensive management of goat into the national schistosomiasis control program in China; and (2) to develop new techniques, products and interventions for the control of goat schistosomiasis.

Role of goat in transmission of schistosomiasis japonica IV Goat breeding in endemic regions and role of goat in schistosomiasis transmission

This review describes the major species, number, breeding pattern, ratio of fenced to freely grazed goat, susceptibility to Schistosoma japonicum, pattern of S. japonicum infection, infection rate, intensity of infection, fecal contamination of goat that were bred in 5 marshland and lake provinces of Hunan, Hubei, Jiangxi, Anhui and Jiangsu, and two mountainous provinces of Yunnan and Sichuan, and demonstrates the associations of infected goat distribution with the distribution of infected Oncomelania hupensis snails and humans. Considering the huge number of goat which were predominantly grazed freely in marshland and lake endemic regions of China, the high infection rate, numerous environmental pollution by goat feces, as well as the close correlation between the infected goat distribution and infected snail distribution, goat is considered as a major infectious source for schistosomiasis japonica in China, and to play a critical role in the transmission of the disease. Since the control of schistosomiasis in animals is critical to schistosomiasis interruption and elimination, it is suggested that the integrated management of goat schistosomiasis should be included in the national schistosomiasis control program of China.

Assessment of the effect of treatment and assistance program on advanced patients with schistosomiasis japonica in China from 2009 to 2014.

Schistosomiasis is one of the most important zoonoses, threatening approximately 800 million people in 78 countries with a loss of 70 million disability-adjusted life years. Over the past six decades, China has made remarkable achievements in morbidity control, but disability and mortality control remains much to desire; thus, advanced schistosomiasis is a growing problem when on the road to schistosomiasis elimination. Since 2005, China has initiated a national treatment and assistance program to advanced patients, aiming to improve patients' symptoms and quality of life. Here, we conducted a two-phase study to evaluate the program's implementation and effect on advanced patients from 2009 to 2014 in Jiangxi Province, China. A total of 6425 advanced schistosomiasis cases were included in this study. For those having been treated and assisted (90.7%), the cure or improvement rate was over 99.9%, with 668 (11.5%) cases having reached clinical cure and 5152 (88.4%) cases' condition having improved, which can be partially reflected in the significant decline of the proportion of hepatomegaly (splenomegaly), the degree of liver fibrosis, ascites-related indicators (abdominal girth and frequency of shifting dullness), and portal hypertension-related indices (inner diameter of portal vein and frequency of subcutaneous varicose vein of abdominal wall). Besides, it was estimated to have saved 2004years of life lost at total. Therefore, the government should continue support and increase input of treatment and assistance program so that this project can reach more patients, leading to consolidation of achievements of schistosomiasis control and contribution to schistosomiasis elimination.

Status and future development of surveillance of schistosomiasis in Jiangxi Province

Jiangxi Province is one of serious endemic provinces with schistosomiasis japonica in China. The transmission control of schistosomiais has been achieved in whole province in 2015 after more than 60 years' great efforts. Of them, the surveillance has played an important role in the control of schistosomiasis. Based on the comprehensive analysis of the status of schistosomiasis epidemic, surveillance and challenges, this article exports the priority and development trend of surveillance after the achievement of transmission control of schistosomiasis in Jiangxi Province.

Suppression of the Insulin Receptors in Adult Schistosoma japonicum Impacts on Parasite Growth and Development: Further Evidence of Vaccine Potential.

To further investigate the importance of insulin signaling in the growth, development, sexual maturation and egg production of adult schistosomes, we have focused attention on the insulin receptors (SjIRs) of Schistosoma japonicum, which we have previously cloned and partially characterised. We now show, by Biolayer Interferometry, that human insulin can bind the L1 subdomain (insulin binding domain) of recombinant (r)SjIR1 and rSjIR2 (designated SjLD1 and SjLD2) produced using the Drosophila S2 protein expression system. We have then used RNA interference (RNAi) to knock down the expression of the SjIRs in adult S. japonicum in vitro and show that, in addition to their reduced transcription, the transcript levels of other important downstream genes within the insulin pathway, associated with glucose metabolism and schistosome fecundity, were also impacted substantially. Further, a significant decrease in glucose uptake was observed in the SjIR-knockdown worms compared with luciferase controls. In vaccine/challenge experiments, we found that rSjLD1 and rSjLD2 depressed female growth, intestinal granuloma density and faecal egg production in S. japonicum in mice presented with a low dose challenge infection. These data re-emphasize the potential of the SjIRs as veterinary transmission blocking vaccine candidates against zoonotic schistosomiasis japonica in China and the Philippines.

Research and control of advanced schistosomiasis japonica in China.

Among the three main schistosomes (Schistosoma japonicum, Schistosoma mansoni, and Schistosoma haematobium) known to infect humans, S. japonicum causes the most serious pathological lesions. In China, only schistosomiasis japonica is transmitted. From the 1950s, massive epidemiological investigations and active control measures for schistosomiasis japonica have been carried out. At the early stage of schistosomiasis control program, there were about 12 million schistosomiasis patients, and about 5% of schistosomiasis patients belong to advanced patients, which was 600,000. After more than a half century of active schistosomiasis control work, the schistosomiasis situation has been reduced markedly. The nearest epidemiological investigation showed that, by the end of 2012, there were still 240,000 schistosomiasis patients with the descent rate of 98% and 30,000 advanced patients with the descent rate of 95%. This paper reviews the rich experiences of advanced schistosomiasis research and control in China, including that the epidemiology researches confirm there is a family aggregation of advanced schistosomiasis and advanced schistosomiasis patients have no significance to the schistosomiasis transmission in transmission-interrupted areas but still are an infection source in endemic areas; pathogenic mechanism researches verify that genetic factors and immunoregulation play important roles in the disease developing process; ultrasound image examinations are used not only in the diagnosis and differential diagnosis of advanced schistosomiasis but also in the guidance of treatment and evaluation of therapeutic effects and, furthermore, in the risk predictions of portal hypertension and upper gastrointestinal hemorrhage; clinical practices demonstrate that praziquantel can be used in most of advanced schistosomiasis patients, and the therapy not only can interrupt the schistosomiasis transmission somewhat but also is favorable for liver fibrosis improvement; the ascetic fluid concentration afflux is used in the therapy for obstinate ascites, and endoscopic varices ligation is used in the treatment of upper gastrointestinal bleeding, and both have good effects; hundreds and thousands of severe splenomegaly advanced schistosomiasis patients received splenectomy, and the long-term survival rate is more than 90%, most of them are basically cured from the disease and their labor force recovers, some dwarf patients begin growing and developing again, and some sterile women became fertile; the researches of traditional Chinese medicine in the treatment of liver fibrosis have made progress, such as Cordyceps sinensis showing some anti-fibrosis effect in the animal experiments and primary clinical trials; the animal experiments and epidemiological investigations indicate that schistosome infection is one of the carcinogenesis risk factors, especially for liver cancer. In conclusion, these experiences and lessons are plentiful and worth sharing with the peers of other endemic countries for reference.

Abnormal liver function in different patients with Schistosoma japonicum.

Schistosomiasis japonica, caused by Schistosoma japonicum, is still a serious public health problem in China. It is important for schistosomiasis control to prevent from infection and advanced patients. Recent years, however, the form of the prevalence of schistosomiasis japonica in China was changed these days. Paying attention to the quality of life of these patients already infected with S. japonicum becomes a new objective to schistosomiasis control program. Although most of the chronic infections with S. japonicum will finally appear as liver fibrosis symptoms, it is still unknown liver function abnormalities in patients with severe forms of schistosomiasis, and there is also no evidence whether S. japonicum infection will directly cause damage to liver cells. Thus, this study investigated 494 patients diagnosed with S. japonicum (87.7%) and 69 healthy subjects from a endemic areas belonging to Jiangxi Province of China and aimed to evaluate the liver function abnormalities in patients with severe forms of schistosomiasis and possible associations with coinfection with HBV. The results showed that the hepatic metabolism situation significantly changed in patients infected with S. japonicum; meanwhile, the abnormal rates of ALT and AST in patients with schistosomiasis were significantly higher than that in the control group, which confirmed that patients infected with S. japonicum not only had damaged liver function but also the hepatic cells were directly influenced. And the coinfection of CHB and schistosomiasis japonica can be a risk factor for more serious outcomes in patients from endemic areas. These results give us the advice that in the further treatment of patients infected with S. japonicum, especially these coinfections, we should better give the routine liver-protection treatment in advance.

New uses for old drugs: the tale of artemisinin derivatives in the elimination of schistosomiasis japonica in China.

Artemisinin (qinghaosu), extracted from the Chinese herb Artemisia annua L. in 1972, and its three major derivatives—artemether, artesunate and dihydroartemisinin—were firstly identified as antimalarials and found active against all species of the malaria parasite. Since the early 1980s, artemisinin and its derivatives have been found efficacious against Schistosoma spp., notably larval parasites, and artemisinin derivatives have played a critical role in the prevention and treatment of human schistosomiasis in China. Currently, China is moving towards the progress of schistosomiasis elimination. However, the potential development of praziquantel resistance may pose a great threat to the progress of elimination of schistosomiasis japonica in China. Fortunately, these three major artemisinin derivatives also exhibit actions against adult parasites, and reduced sensitivity to artemether, artesunate and dihydroartemisinin has been detected in praziquantel-resistant S. japonicum. In this review, we describe the application of artemisinin derivatives in the prevention and treatment of schistosomiasis japonica in China, so as to provide tools for the global agenda of schistosomiasis elimination. In addition to antimalarial and antischistosomal actions, they also show activities against other parasites and multiple cancers. Artemisinin derivatives, as old drugs identified firstly as antimalarials, continue to create new stories.

Identification of optimum scopes of environmental factors for snails using spatial analysis techniques in Dongting Lake Region, China.

BackgroundOwing to the harmfulness and seriousness of Schistosomiasis japonica in China, the control and prevention of S. japonica transmission are imperative. As the unique intermediate host of this disease, Oncomelania hupensis plays an important role in the transmission. It has been reported that the snail population in Qiangliang Lake district, Dongting Lake Region has been naturally declining and is slowly becoming extinct. Considering the changes of environmental factors that may cause this phenomenon, we try to explore the relationship between circumstance elements and snails, and then search for the possible optimum scopes of environmental factors for snails.MethodsMoisture content of soil, pH, temperature of soil and elevation were collected by corresponding apparatus in the study sites. The LISA statistic and GWR model were used to analyze the association between factors and mean snail density, and the values in high-high clustered areas and low-low clustered areas were extracted to find out the possible optimum ranges of these elements for snails.ResultsA total of 8,589 snail specimens were collected from 397 sampling sites in the study field. Besides the mean snail density, three environmental factors including water content, pH and temperature had high spatial autocorrelation. The spatial clustering suggested that the possible optimum scopes of moisture content, pH, temperature of the soil and elevation were 58.70 to 68.93%, 6.80 to 7.80, 22.73 to 24.23°C and 23.50 to 25.97 m, respectively. Moreover, the GWR model showed that the possible optimum ranges of these four factors were 36.58 to 61.08%, 6.541 to 6.89, 24.30 to 25.70°C and 23.50 to 29.44 m, respectively.ConclusionThe results indicated the association between snails and environmental factors was not linear but U-shaped. Considering the results of two analysis methods, the possible optimum scopes of moisture content, pH, temperature of the soil and elevation were 58.70% to 68.93%, 6.6 to 7.0, 22.73°C to 24.23°C, and 23.5 m to 26.0 m, respectively. The findings in this research will help in making an effective strategy to control snails and provide a method to analyze other factors.

Application of praziquantel in schistosomiasis japonica control strategies in China

Schistosomiasis remains a major public health problem with an estimated 200 million people infected in the world, and in China, schistosomiasis japonica is endemic in the south part of the country. In 1960s, before praziquantel was developed, there were about seven million patients. Praziquantel has a high efficacy against Schistosoma, few and transient side effects, simple administration and competitive cost, and is equally suited for both individual and large-scale treatment. Praziquantel has been widely used in the morbidity control, transmission control, and prevention of schistosomiasis japonica in China since 1980s. The schemes of praziquantel chemotherapy include the diagnostic selective chemotherapy, extensive chemotherapy, mass chemotherapy, stratified chemotherapy, phased chemotherapy, etc. Chemotherapy alone or combined with other control measure, such as Oncomelania snail control, health education, safety water supply, and so on, has achieved a great success, and there are only 0.33 million infected people now. This paper reviews the application of praziquantel in the schistosomiasis japonica control strategies in China so as to provide the rich experiences for reference of health workers of other countries where schistosomiasis is endemic.

Improving Access to Anti-Schistosome Treatment and Care in Nonendemic Areas of China: Lessons from One Case of Advanced Schistosomiasis Japonica

Schistosomiasis, caused by trematode blood flukes of the genus Schistosoma, is the second most prevalent disease after malaria in the tropical and subtropical world. Among five schistosome species, Schistosoma japonicum is the most serious, mainly because of its high egg output [1]. This parasite is mainly endemic in mainland China, the Philippines, and Indonesia. Advanced schistosomiasis, due to either an infection without chemotherapy or repeated infections over time, is the most serious form of schistosomiasis and is usually characterized by periportal liver fibrosis, spleen enlargement and congestion, portal hypertension, and other serious consequences [2]. The suffering for an advanced patient caused by schistosomes could last for a lifetime, as the associated pathological changes on the host, if not properly treated, could develop toward a more serious condition. In addition, S. japonicum in humans has been estimated to be able to live for an average of 4.5 years [3]. Prolonged survival of the parasite to as long as about 47 years has been seen in an American who emigrated from the Philippines and continued to show active eggs in rectal biopsies [4]. These eggs can continue to produce damages to organs where they are deposited. Therefore, the treatment of the disease usually includes both anti-schistosome treatment and symptomatic therapy. The former is based on fecal examinations and serological tests, which are usually negative in most cases [5], or endoscopic examination. The etiological treatment is comparatively easier when without any serious complication, and therefore, much more attention and financial aids are going to the latter. In the Zhejiang province of China for example, in 2003 there remained 1,187 advanced cases who still needed medical assistance, although the disease there had been interrupted a decade ago [6]. Such a looming problem has been suggested to exist for perhaps as long as another half century in China [7]. Fortunately, with the economic development and well-improved standards of living over the last decades in China, in 2004 the government of China redefined schistosomiasis control, together with the control of HIV/AIDS and tuberculosis, as one of its highest priorities in communicable disease control [8]. As one main part of the integrated control measures, the project for treatment of advanced schistosomiasis has been initiated across the endemic regions of China. Box 1 lists a series of regulations on that aspect made by the government. The main point of this is that a screening system for advanced schistosomiasis among local residents will be set up in each endemic county and, if a farmer is diagnosed with advanced schistosomiasis (see Box 2 for the diagnosis criteria), the involved medical expense will be mostly covered by different levels of government. Figure 1 shows the numbers of advanced cases and newly found cases in each province and, as the consequence of the project, the increasingly rising coverage rate of advanced cases [9]. The direct or long-term estimated benefit from this project, as estimated by the work [10], would be quite considerable. Here we presented a case observed in a nonendemic area within the Anhui Province of China to point out the demerit of the ongoing project and raise some aspects yet to improve. This follow-up investigation was approved by an ethics committee in both the Anhui Institute of Parasitic Diseases and Soochow University. A consent form was obtained from the patient, and she gave consent to have her case details published. Open in a separate window Figure 1 Numbers of advanced schistosomiasis japonica in China. (A) In each province by 2008; (B) in each province by 2003 and new cases found from 2004 to 2008; and (C) the coverage rates of the aid-project in the cases at the levels of nation or province (Anhui) over 2004 to 2008.

Factors impacting on progress towards elimination of transmission of schistosomiasis japonica in China.

Over the past decades China has made a great stride in controlling schistosomiasis, eliminating transmission of Schistosoma japonicum in 5 provinces and remarkably reducing transmission intensities in the rest of the seven endemic provinces. Recently, an integrated control strategy, which focuses on interventions on humans and bovines, has been implemented throughout endemic areas in China. This strategy assumes that a reduction in transmission of S. japonicum from humans and bovines to the intermediate Oncomelania snail host would eventually block the transmission of this parasite, and has yielded effective results in some endemic areas. Yet the transmission of S. japonicum is relatively complicated – in addition to humans and bovines, more than 40 species of mammalians can serve as potential zoonotic reservoirs. Here, we caution that some factors – potential roles of other mammalian reservoirs and human movement in sustaining the transmission, low sensitivity/specificity of current diagnostic tools for infections, praziquantel treatment failures, changes in environmental and socio-economic factors such as flooding in key endemic areas - may pose great obstacles towards transmission interruption of the parasite. Assessing potential roles of these factors in the transmission and implications for current control strategies aiming at transmission interruption is needed.

Differences in genomic architecture between two distinct geographical strains of the blood fluke Schistosoma japonicum reveal potential phenotype basis

The Chinese (SjC) and Philippine (SjP) strains of the blood fluke Schistosoma japonicum have been shown to present clearly different phenotypes in fecundity, pathology, drug sensitivity and immunology. We used microarray based comparative genomic hybridisation (aCGH) to investigate structural differences in the genomes of the two strains and identified seven distinct regions of the S. japonicum genome that present differential aCGH representing either deletion or duplication regions in SjP. Within these regions, genes predicted to be associated with the recognised phenotypic differences were identified and that may provide new insights into the biology and evolution of the two strains, with implications for the epidemiology and control of schistosomiasis japonica in China and the Philippines.

Artemether shows promising female schistosomicidal and ovicidal effects on the Egyptian strain of Schistosoma mansoni after maturity of infection

Artemether is an artemisinin derivative that is used as an antimalarial drug, especially in situations where chloroquine resistance is suspected. This compound has proved to be a good prophylactic agent against schistosomiasis japonica in China. In the present study, the therapeutic efficacies of different artemether-dosing protocols were evaluated in experimentally infected mice harbouring adult Schistosoma mansoni (Egyptian strain). Mice were treated on day 46 onwards with three dosing protocols (400 mg/kg/day for 2 days; 200 mg/kg/day for 4 days; 100 mg/kg/day for 6 days) after being infected. A number of parasitological and histopathological criteria were employed in the assessment of drug efficacies compared to infected untreated control 2 weeks post-treatment. The results of the present study suggest that artemether is efficacious against the Egyptian strain of S. mansoni with total worm reductions ranging from 40.7% to 59.7% and female worm reductions ranging from 69.3% to >90%. In addition, artemether induced significant reductions, ranging from 75.2% to 82.6%, in the liver tissue egg loads as well as significant reductions, ranging from 68.8% to 78.9% in the intestinal wall egg loads. It also induced significant alterations in the oogram pattern in the intestinal mucosa of infected mice with cessation of oviposition and increased rates of dead eggs. Antipathologic activities were also evident in the amelioration of granulomas in the liver with increased ratios of healed to active ones. In conclusion, artemether could be a promising agent in the control of schistosomiasis mansoni due to its schistosomicidal effects on female worms and to its ovicidal power as well as its potentiality in the improvement of hepatic lesions.

Evaluation of Kato–Katz examination method in three areas with low-level endemicity of schistosomiasis japonica in China: A Bayesian modeling approach

The Kato–Katz technique is widely used to determine faecal egg counts of intestinal schistosomiasis. Although numerous studies have reported considerable underestimation of the ‘true’ infection prevalence while using this method, little is known regarding how many infections are missed as a function of the overall endemicity of intestinal schistosomiasis. In the present study, we used a Bayesian modeling approach to assess how much the Kato–Katz technique underestimates the prevalence of Schistosoma japonicum in three low endemic areas, characterized by different levels of infection. We found that up to 83% of S. japonicum infections were missed in an average when only a single Kato–Katz thick smear was examined. We further analyzed inter- and intra-specimen variation using agreement analysis. The results revealed a clear trend of higher agreement with infection intensity. In addition, our data also confirmed that intra-specimen consistency was better than that of inter-specimen. Our results suggest that a single Kato–Katz thick smear could only detect a certain small part of infections in areas with low endemicity; the disagreement of Kato–Katz results are mainly driven by day-to-day variation of eggs in stool; and light intensities are characterized by very high underestimation rates. There is a pressing need to develop more sensitive diagnostic tools for accurate detection of light infection intensities of schistosome infections.

Conquering ‘snail fever’: schistosomiasis and its control in China

Schistosomiasis japonica is a serious parasitic disease and a major health risk for more than 60 million people living in the tropical and subtropical zones of south China. The disease is a zoonosis and its cause, the parasitic trematode Schistosoma japonicum, has a range of mammalian reservoirs, making control efforts difficult. Current control programs are heavily based on community chemotherapy with a single dose of the highly effective drug praziquantel. However, vaccines (for use in bovines and in humans) in combination with other control strategies are needed to eliminate the disease. In this review, we provide an overview of the transmission, clinical features, pathogenesis, diagnosis, treatment, genetics and susceptibility, epidemiology, and prospects for control of schistosomiasis japonica in China. The threat posed by the Three Gorges Dam may undermine control efforts because it will change the local ecology and associated schistosomiasis transmission risks over the next decade and beyond.

A multi-level analysis of risk factors for Schistosoma japonicum infection in China

The aim of this study was to explore the risk factors of schistosomiasis japonica in China, using a hierarchical multi-level model with individuals nested within villages. A cross-sectional survey of schistosomiasis japonica was conducted in 16 villages in the Chinese province of Hunan. A multi-level modeling technique (HLM version 6.04) was used to assess risk factors of schistosomiasis. The results from this multi-level model were compared with those from a conventional single-level logistic regression model. A total of 10,245 individuals were enrolled in this study, of whom about 4.1% were infected with Schistosoma japonicum. In the multi-level model analysis, individual level variables such as gender, age, and occupation, and village level variables such as type of S. japonicum endemic area, drinking water source, sewage treatment, June temperature, and April rainfall were associated with schistosomiasis japonica infection. Conventional single-level logistic regression analysis selected more independent variables, and had narrower confidence intervals around the corresponding regression coefficients. In particular, per capita income, precipitation in October, and density of infected snails were statistically significant in the conventional single-level logistic regression analysis but not in the multi-level model. Multi-level modeling is a useful tool in the analysis of risk factors of schistosomiasis japonica. Because the multi-level model captures the hierarchical structure of the data, it may be considered a more appropriate analytical tool for data of this type. This technique may also be useful in the analysis of other infectious diseases with a similar hierarchical structure.