Reconstruction of Derogenes varicus Miracidium (Digenea: Derogenidae): First Ultrastructural Description of Spines on the Surface of Hemiurata Larvae.

We performed a detailed ultrastructural reconstruction of the "passive" miracidium of Derogenes varicus Muller, 1784 , a species from Hemiurata group. The miracidium is highly miniaturized and simplified in comparison with the "active" miracidia. For the first time we elucidate the nature of the spines on the surface of hemiuroid larva: they are derivatives of the epithelial plates. The anterior end of the larva is equipped with three epithelial plates that bear both spines and cilia. The major part of the miracidial surface is formed by tegument. The nervous and excretory systems of the D. varicus miracidium are extremely reduced. Single undifferentiated cell comprises the germinal material of the miracidium. We discuss the trends of evolution of hemiuroid miracidia that are associated with transition to passive strategy of infection.

Time series analysis of tegument ultrastructure of in vitro transformed miracidium to mother sporocyst of the human parasite Schistosoma mansoni.

The transformation of Schistosoma mansoni miracidia into mother sporocysts is induced, either in vivo by the penetration of the free-living larval stage, the miracidium, in the snail Biomphalaria glabrata or in vitro following the incubation of the miracidium in Chernin's Balanced Salt Solution (CBSS) or Bge (B. glabrata embryonic cell line) culture medium. The in vitro development of S. mansoni miracidium into mother sporocyst was monitored by Scanning Electron Microscopy (SEM) from 2.5 h to 120 h in CBSS. The transformation starts when the miracidium ciliate plates detach due to the proliferation of the intercellular ridge associated with the degeneration of mid-body papillae of the miracidium. The loss of ciliated plates causes the appearing of scars, filled across time by the proliferation of a new tegument originating from the interplate ridge. This new tegument covers the entire body of the metamorphosing parasite and differentiates over time, allowing some exchanges (uptakes or secretion/excretion) between the parasite and its host. In contrast to the well-described development of adult and free-living larval stages of S. mansoni using SEM, the developmental transformation of intramolluscan stages, especially tegumental changes in the mother sporocyst, has been sparcely documented at the ultrastructural level. In addition, taking into account the latest literature on miracidium electron microscopy and the advances in SEM technologies over the last thirty years, the present study gathers three main objectives: (i) Fill the gap of tegument scanning electron micrographs of in vitro transforming sporocysts; (ii) Update the current bibliographic miracidia and sporocysts image bank due to rapid evolution of SEM technology; (iii) Understand and describe the critical steps and duration of the in vitro miracidium-to-sporocyst transformation process to assist in understanding the interaction between the larval surface and snail immune factors.

A new accumulation assay of Schistosoma mansoni miracidia using square capillary glass tubes.

Current control measures for schistosomiasis have only been partially successful in endemic areas due to socioeconomic constraints. One possibility for controlling the disease is to aim at the miracidial stage of the trematode to avoid infecting intermediate snail hosts by introducing more attractive substances for miracidia in the environment. Here, we introduce an accumulation assay of Schistosoma mansoni miracidia using a square glass tube for analysis of the positive responses of miracidia toward several substances, including snail-conditioned water of Biomphalaria glabrata, Bulinus globosus and insusceptible snails collected in the Nagasaki area in Japan. The substances are not proteins because miracidia accumulated in boiled snail-conditioned water and the secretion or emission level of substances depended on the feeding conditions of Biomphalaria glabrata. The present study also showed that substances emitted from Biomphalaria glabrata with a molecular weight around 10 kDa accumulated Schistosoma mansoni miracidia. Further, we showed that Schistosoma mansoni miracidia did not accumulate in response to mono- or disaccharides tested in the study.

Hybridization increases genetic diversity in Schistosoma haematobium populations infecting humans in Cameroon.

BACKGROUND: Hybrids between Schistosoma haematobium (Sh) and S. bovis (Sb) have been found in several African countries as well as in Europe. Since the consequences of this hybridization are still unknown, this study aims to verify the presence of such hybrids in Cameroonian humans, to describe the structure of S. haematobium populations on a large geographic scale, and to examine the impact of these hybrids on genetic diversity and structure of these populations. METHODS: From January to April 2019, urine from infected children was collected in ten geographically distinct populations. Miracidia were collected from eggs in this urine. To detect the presence of hybrids among these miracidia we genotyped both Cox1 (RD-PCR) and ITS2 gene (PCR-RFLP). Population genetic diversity and structure was assessed by genotyping each miracidium with a panel of 14 microsatellite markers. Gene diversity was measured using both heterozygosity and allelic richness indexes, and genetic structure was analyzed using paired Fst, PCA and Bayesian approaches. RESULTS: Of the 1327 miracidia studied, 88.7% were identified as pure genotypes of S. haematobium (Sh_Sh/Sh) while the remaining 11.3% were hybrids (7.0% with Sh_Sh/Sb, 3.7% with Sb_Sb/Sh and 0.4% with Sb_Sh/Sb). No miracidium has been identified as a pure genotype of S. bovis. Allelic richness ranged from 5.55 (Loum population) to 7.73 (Matta-Barrage) and differed significantly between populations. Mean heterozygosity ranged from 53.7% (Loum) to 59% (Matta Barrage) with no significant difference. The overall genetic differentiation inferred either by a principal component analysis or by the Bayesian approach shows a partial structure. Southern populations (Loum and Matta Barrage) were clearly separated from other localities but genetic differentiation between northern localities was limited, certainly due to the geographic proximity between these sites. CONCLUSIONS: Hybrids between S. haematobium and S. bovis were identified in 11.3% of miracidia that hatched from eggs present in the urine of Cameroonian schoolchildren. The percentages of these hybrids are correlated with the genetic diversity of the parasite, indicating that hybridization increases genetic diversity in our sampling sites. Hybridization is therefore a major biological process that shapes the genetic diversity of S. haematobium.

Histological and electron microscopic analysis of germinal material in miracidia of Schistosoma mansoni.

We performed histological and electron microscopic analysis of miracidia of Schistosoma mansoni in order to examine their germinal elements. In total, about 20 germinal cells at different stages of maturation were found. We described their ultrastructure and proposed a scheme of reproduction of mother sporocysts of S. mansoni based on our data and literature information. According to this scheme, the only germinal elements present in the miracidia are germinal cells (undifferentiated cells were not found). Regardless of their size and localisation, none of the germinal cells in the miracidia has undergone full differentiation. This process is completed after the metamorphosis of the larva into the sporocyst.

The genetic variation of different developmental stages of Schistosoma japonicum: do the distribution in snails and pairing preference benefit the transmission?

BACKGROUND: Schistosoma japonicum is a waterborne parasite that causes schistosomiasis in humans and in more than 40 animal species. Schistosoma japonicum shows distinct genetic differentiation among geographical populations and multiple hosts, but the genetic diversity of different developmental stages of S. japonicum from is less studied. Such studies could elucidate ecological mechanisms in disease transmission by analysing feedbacks in individual physiology and population state. METHODS: After infection using cercariae from a pool of snails shedding together (Method I) and infection using mixed equal numbers of cercariae from individually shed snails (Method II), different developmental stages of S. japonicum were genotyped with microsatellite loci, including 346 cercariae, 701 adult worms and 393 miracidia. Genetic diversity and molecular variation were calculated at different population levels. Kinships (I') among cercariae at intra-snail and inter-snail levels were evaluated. Genetic distance (Dsw) was compared between paired and unpaired worms, and partner changing was investigated through paternity identification for miracidia. RESULTS: The cercaria clones in individual snails varied from 1 to 8 and the kinship of cercariae within individual snails was significant higher (P < 0.001) than that among different snails after deleting near-identical multi-locus genotypes (niMLGs). The allelic diversity of worms in Method I was lower (P < 0.001) than that in Method II, and allele frequency among mice in Method I was also less consistent. The parents of some miracidia were worms that were not paired when collected. The Dsw between each female of paired and unpaired males was much larger (P < 0.001) than that between the female and male in each pair. CONCLUSIONS: Most of the infected snails contained multiple miracidia clones. The aggregation of genetically similar S. japonicum miracidia in individual snails and the unbalanced distribution of miracidia among snails suggests a non-uniform genetic distribution of cercariae among snails in the field. This further influenced the genetic structure of adult worms from infections with different cercariae sampling methods. Schistosoma japonicum in mice can change paired partner, preferring to mate with genetically similar worms. These characteristics provide implications for understanding the balance in genetic diversity of S. japonicum related to the transmission of schistosomiasis.

[Application value of a dynamic automatic identification system in Schistosoma japonicum miracidium hatching test].

OBJECTIVE: To evaluate the value of a dynamic automatic identification system in routine miracidium hatching test with nylon gauzes. METHODS: Different quantities of fresh Schistosoma japonicum eggs were added to bovine fecal samples and divided into the low-infection group, medium-infection group and high-infection group, while the bovine feces without S. japonicum eggs served as negative controls. The detection efficiency and accuracy were compared between the identification system and manual detection in different groups. RESULTS: The identification system can automatically identify S. japonicum miracidium. The detection rate and efficiency of S. japonicum miracidium in bovine fecal samples were both higher by using the identification system than by manual detection. Notably in the low-infection group, the identification system had a significantly higher rate of detection of S. japonicum miracidium than manual detection (χ2 = 10.769, P = 0.002). The identification system completed the detection of bovine fecal samples in the field within 1 min. CONCLUSIONS: The dynamic automatic identification system may effectively improve the detection efficiency and accuracy of routine miracidium hatching test with nylon gauzes, and it may replace manual detection to be used in the field schisotsomiasis examinations and related researches.

Application value of a dynamic automatic identification system in Schistosoma japonicum miracidium hatching test / 中国血吸虫病防治杂志

Objective To evaluate the value of a dynamic automatic identification system in routine miracidium hatching test with nylon gauzes. Methods Different quantities of fresh Schistosoma japonicum eggs were added to bovine fecal samples and divided into the low-infection group, medium-infection group and high-infection group, while the bovine feces without S. japonicum eggs served as negative controls. The detection efficiency and accuracy were compared between the identification system and manual detection in different groups. Results The identification system can automatically identify S. japonicum miracidium. The detection rate and efficiency of S. japonicum miracidium in bovine fecal samples were both higher by using the identification system than by manual detection. Notably in the low-infection group, the identification system had a significantly higher rate of detection of S. japonicum miracidium than manual detection (χ2 = 10.769, P = 0.002). The identification system completed the detection of bovine fecal samples in the field within 1 min. Conclusions The dynamic automatic identification system may effectively improve the detection efficiency and accuracy of routine miracidium hatching test with nylon gauzes, and it may replace manual detection to be used in the field schisotsomiasis examinations and related researches.

Application value of a dynamic automatic identification system in Schistosoma japonicum miracidium hatching test / 中国血吸虫病防治杂志

Objective To evaluate the value of a dynamic automatic identification system in routine miracidium hatching test with nylon gauzes. Methods Different quantities of fresh Schistosoma japonicum eggs were added to bovine fecal samples and divided into the low-infection group, medium-infection group and high-infection group, while the bovine feces without S. japonicum eggs served as negative controls. The detection efficiency and accuracy were compared between the identification system and manual detection in different groups. Results The identification system can automatically identify S. japonicum miracidium. The detection rate and efficiency of S. japonicum miracidium in bovine fecal samples were both higher by using the identification system than by manual detection. Notably in the low-infection group, the identification system had a significantly higher rate of detection of S. japonicum miracidium than manual detection (χ2 = 10.769, P = 0.002). The identification system completed the detection of bovine fecal samples in the field within 1 min. Conclusions The dynamic automatic identification system may effectively improve the detection efficiency and accuracy of routine miracidium hatching test with nylon gauzes, and it may replace manual detection to be used in the field schisotsomiasis examinations and related researches.

The potential effects of silver and gold nanoparticles as molluscicides and cercaricides on Schistosoma mansoni.

Schistosomiasis seriously affects human health in tropical regions. Its prevention is more important than treatment, raising the need for effective control methods. Recently, the role of nanomaterials in medical science has been growing. The present study aimed to evaluate the potential effects of silver (Ag) and gold (Au) nanoparticles (NPs) on Biomphalaria alexandrina snails and Schistosoma mansoni cercariae in vitro and to assess their effects on the infectivity of cercariae in vivo. The in vitro study proved that Ag and Au NPs were effective in killing B. alexandrina snails, with 30 µg/ml Ag and 160 µg/ml Au causing 100% mortality. The LC50 of 9.68 µg/ml for Ag NPs and 133.7 µg/ml for Au NPs prevented snail infection with S. mansoni miracidia. Furthermore, Ag NPs at 50 µg/ml and Au NPs at 100 µg/ml increased the mortality of S. mansoni cercariae in a dose- and time-dependent manner, reaching 100% mortality after 1 h. The in vivo study found that Ag NPs prevented the occurrence of infection when cercariae were treated before the infection by either the tail immersion (TI) or subcutaneous (SC) route, as proven by parasitological parameters and by the absence of granuloma formation in hepatic tissue. Meanwhile, infection of mice by untreated cercariae followed by treatment with NPs 1 h post-infection (PI) caused a decrease in egg count/g intestine and egg count/g liver in the TI-infected group only. The oogram patterns and granuloma formation results were similar between infection control and the SC-infected group. On the other hand, Au NPs led to a decrease in total worm burden (TWB) in all tested groups, with a decrease in egg count/g intestine and egg count/g liver in TI-infected groups with either pre-treated or post-treated cercariae, in contrast to SC-infected groups. However, the oogram patterns and granuloma formation showed similar results to infection control. Ag and Au NPs have potential as molluscicides and cercaricides in vitro and can prevent or modulate the infectivity of cercariae in vivo.

[Detection effect of an automatic identification system of Schistosoma japonicum miracidia].

OBJECTIVE: To evaluate the effect of an automatic identification system of Schistosoma japonicum miracidia, and compare it with the traditional eye detection method in the simulation field. METHODS: A total of 260 fecal samples were collected from schistosomiasis non-endemic areas, and the test sample bottles containing schistosome miracidia were prepared according to different experimental needs. Thirty fecal samples for the sensitivity test were separately added with five fresh miracidia per sample, and then the mixed samples were detected by two experienced technicians (with more than 15 years' traditional test experience) or the automatic system. The positive detection rates were compared between the two methods. Thirty fecal samples for repetition test were separately added with ten fresh miracidia per sample, and then the mixed samples were detected separately with the automatic identification system by two experienced technicians. The results were compared between two persons. The two methods including the automatic identification system and the traditional eye detection method were carried out blindly with totally 200 samples in the simulation field. There were three groups (each with 30 samples) : Group 1 with more than 21 fresh miracidia, Group 2 with 6 to 20 fresh miracidia, and Group 3 with 1 to 5 fresh miracidia. The other 110 samples were as a negative group. The detection time, accuracy, missed detection rate, and false detection rate of the two methods were statistically compared. RESULTS: The positive detection rates of the 30 positive samples were 43.33% and 33.33% by the two technicians with the traditional eye detection method, respectively, while the detection rate was 80.00% by the automatic identification system, and the difference was statistically significant (χ2 = 7.05, χ2 = 12.97, both P < 0.01). Thirty positive samples were detected by the two technicians using the same automatic identification system, and the positive detection rates of the two were 96.67% and 86.67%, respectively, with no significant difference (χ2 = 0.27, P > 0.05). The experiments showed that the correct detection rate of the positive samples was 98.00% by the automatic identification system, which was higher than 79.75% by the traditional eye detection method. The detection time of the automatic identification system was shortened by half compared with that of the traditional eye detection method. The missed detection rate, and false detection rate of the automatic identification system were 2.22% and 1.82%, respectively, which were much lower than 35.56% and 7.73% of the traditional eye detection method. CONCLUSIONS: Compared with the traditional eye detection method, the automatic identification system of S. japonicum miracidia has the advantages of high sensitivity, good repeatability, short detection time, high accuracy, low missed detection rate, and low false detection rate. It can be used in the field and clinical detection in replacement of the traditional eye detection method.

[Effectiveness evaluation of dynamic automatic identification system (device) of Schistosoma japonicum miracidia].

OBJECTIVE: To develop a dynamic automatic identification system (device) of Schistosoma japonicum miracidia to achieve the automatic detection and improve the detection rate and efficiency of schistosome miracidia. METHODS: The dynamic automatic identification system (device) of S.japonicum miracidia was composed of an optical stereoscope, a digital camera, dynamic automatic tracking recognition software, and a computer. Under different conditions, the detection rates and efficiency of the system were compared with those of five professional persons. RESULTS: The basic function of the system was to identify, label and warn the miracidia of S. japonicum, and the records could be saved automatically. The laboratory tests showed that the missing rate of the system was 0. The total consistent rates of the manual detection were 74.67% and 66.67% in the condition with and without water bug, while the total consistent rates of the system were 100.00% and 96.67%, respectively (χ2 = 9.634, 11.081, both P < 0.01) . CONCLUSIONS: The system is much superior to manual detection in the accuracy and speed, and the system could completely replace the manual detection. Therefore, the system could be used in the field and basic research of schistosomiasis.

Real-time PCR diagnosis of Schistosoma japonicum in low transmission areas of China.

BACKGROUND: Schistosomiasis in the People's Republic of China (PRC) can be traced back to antiquity. In the past 60 years, the Chinese government has made great efforts to control this persistent disease with elimination slated by 2020 through the implementation of a comprehensive control strategy. This strategy aims to reduce the role of bovines and humans as sources of infection as a pre-requisite for elimination through transmission interruption. The goal of elimination will be achievable only by the implementation of a sustainable surveillance and control system, with sensitive diagnosis a key feature so that the true disease burden is not underestimated. Currently used diagnostics lack the necessary sensitivity to accurately determine the prevalence of Schistosoma japonicum infection in areas with low infection intensities. It is of critical importance to find and treat people and to identify animals with low-level infections if the National Control Programme for China is to achieve schistosomiasis elimination. METHODS: We evaluated a real-time polymerase chain reaction (qPCR) assay using 633 human stool samples collected from five villages in Hunan, Anhui, Hubei, and Jiangxi provinces, and 182 bovine (70 cattle and 112 buffalo) stool samples obtained from four villages in Hunan, Anhui, and Jiangxi provinces in the PRC. All stool samples were subjected to the miracidium hatching test (MHT, a diagnostic procedure used in the National Schistosomiasis Control Programme) and the qPCR assay. Samples positive by MHT were subjected to either the Kato-Katz technique for humans, or the formalin-ethyl acetate sedimentation-digestion (FEA-SD) procedure for bovines, to determine infection intensities. RESULTS: The qPCR assay exhibited a high level of sensitivity in the detection of S. japonicum infections. With both the human and bovine samples, a significantly higher prevalence was determined using the qPCR assay (11.06% humans, 24.73% bovines) than with the MHT (0.93% humans, 7.69% bovines). The animal contamination index (calculated using data obtained with the qPCR technique) for all positive bovines was 27 618 000 eggs per day, indicating a considerable amount of environmental egg contamination that would be underestimated using less sensitive diagnostic procedures. CONCLUSIONS: The qPCR assay we have evaluated will be applicable as a future field diagnostic and surveillance tool in low-transmission zones where schistosomiasis elimination is targeted and for monitoring post-intervention areas to verify that elimination has been maintained.

Detection effect of an automatic identification system of Schistosoma japonicum miracidia / 中国血吸虫病防治杂志

To evaluate the effect of an automatic identification system of Schistosoma japonicum miracidia, and compare it with the traditional eye detection method in the simulation field.A total of 260 fecal samples were collected from schistosomiasis non-endemic areas, and the test sample bottles containing schistosome miracidia were prepared according to different experimental needs. Thirty fecal samples for the sensitivity test were separately added with five fresh miracidia per sample, and then the mixed samples were detected by two experienced technicians (with more than 15 years’ traditional test experience) or the automatic system. The positive detection rates were compared between the two methods. Thirty fecal samples for repetition test were separately added with ten fresh miracidia per sample, and then the mixed samples were detected separately with the automatic identification system by two experienced technicians. The results were compared between two persons. The two methods including the automatic identification system and the traditional eye detection method were carried out blindly with totally 200 samples in the simulation field. There were three groups (each with 30 samples) : Group 1 with more than 21 fresh miracidia, Group 2 with 6 to 20 fresh miracidia, and Group 3 with 1 to 5 fresh miracidia. The other 110 samples were as a negative group. The detection time, accuracy, missed detection rate, and false detection rate of the two methods were statistically compared.The positive detection rates of the 30 positive samples were 43.33% and 33.33% by the two technicians with the traditional eye detection method, respectively, while the detection rate was 80.00% by the automatic identification system, and the difference was statistically significant (χ2 = 7.05, χ2 = 12.97, both P < 0.01). Thirty positive samples were detected by the two technicians using the same automatic identification system, and the positive detection rates of the two were 96.67% and 86.67%, respectively, with no significant difference (χ2 = 0.27, P > 0.05). The experiments showed that the correct detection rate of the positive samples was 98.00% by the automatic identification system, which was higher than 79.75% by the traditional eye detection method. The detection time of the automatic identification system was shortened by half compared with that of the traditional eye detection method. The missed detection rate, and false detection rate of the automatic identification system were 2.22% and 1.82%, respectively, which were much lower than 35.56% and 7.73% of the traditional eye detection method.Compared with the traditional eye detection method, the automatic identification system of S. japonicum miracidia has the advantages of high sensitivity, good repeatability, short detection time, high accuracy, low missed detection rate, and low false detection rate. It can be used in the field and clinical detection in replacement of the traditional eye detection method.

Effectiveness evaluation of dynamic automatic identification system(de-vice)of Schistosoma japonicum miracidia / 中国血吸虫病防治杂志

Objective To develop a dynamic automatic identification system(device)of Schistosoma japonicum miracidia to achieve the automatic detection and improve the detection rate and efficiency of schistosome miracidia.Methods The dynamic automatic identification system(device)of S.japonicum miracidia was composed of an optical stereoscope,a digital camera,dy-namic automatic tracking recognition software,and a computer.Under different conditions,the detection rates and efficiency of the system were compared with those of five professional persons.Results The basic function of the system was to identify,la-bel and warn the miracidia of S.japonicum,and the records could be saved automatically.The laboratory tests showed that the missing rate of the system was 0.The total consistent rates of the manual detection were 74.67% and 66.67% in the condition with and without water bug,while the total consistent rates of the system were 100.00% and 96.67%,respectively(χ2=9.634, 11.081,both P<0.01).Conclusions The system is much superior to manual detection in the accuracy and speed,and the sys-tem could completely replace the manual detection.Therefore,the system could be used in the field and basic research of schis-tosomiasis.

[Diagnosis and treatment of an imported case of schistosomiasis haematobium].

OBJECTIVE: To report the diagnosis and treatment of an imported case of schistosomiasis haematobium, including the pathological features of the disease and therapeutic efficacy of praziquantel. METHODS: The data of the patient with schistosomiasis haematobium were collected, and the pathological features of the bladder tissue were observed under a microscope. More-over, the patient was treated with praziquantel, and his urine was collected before and after the treatment. The eggs in the urine were examined by a microscope after sediment and the miracidia were hatched. RESULTS: The patient once worked in Angola for three months, and after returning home he had the symptoms of intermittent painless terminal hematuresis. It was ineffective after anti-inflammatory treatment in a number of hospitals. There were no sand spots discovered under the cystoscope. However, the inflammatory reaction to parasite with a lot of eosinophils infiltration in the bladder mucosa was found on the pathological sections under a microscope, and the egg structure was observed with individual characteristics. The eggs were detected in the urine and the miracidia were hatched before the praziquantel treatment. The hematuria symptoms disappeared after the praziquantel treatment. The eggs were still detected in the urine 7 days post-treatment, but the miracidium could not be hatched. One month and 6 months post-treatment, the eggs were not detected in the urine. CONCLUSIONS: The imported cases of schistosomiasis haematobium are often misdiagnosed, and therefore, it is necessary to strength the health education to the workers overseas and also to improve the ability of diagnosis in medical staff. For the case reported in this paper, there are typical structure of Schistosoma haematobium eggs and egg-granulomas on the pathological sections of bladder tissues. Praziquantel has satisfactory treatment results.

[Study on Oncomelania hupensis snails infected with Schistosoma japonicum miracidia under different conditions in snail-existent non-endemic areas of schistosomiasis in Nantong City].

OBJECTIVE: To understand the forming cause of the Oncomelania hupensis snail-existent non-endemic areas of schistosomiasis (SENEAS), and to verify the conclusion of previous studies, so as to provide the evidence for schistosomiasis monitoring in such areas in Nantong City, Jiangsu Province. METHODS: The controlled field tests were carried out to observe the O. hupensis snails artificially infected by schistosome miracidia in SENEAS. The influence of the soil from SENEAS and the endemic areas on O. hupensis snails artificially infected by miracidia were observed. RESULTS: All the experimental snails could be infected by schistosome miracidia except the smooth-shell snails from Tangyuan Village in the controlled field test environment of SENEAS or the endemic areas. The infection rates of the smooth-shell snails were lower than those of the ribbed-shell snails, but there were no statistically significant differences. The mortality rates of the smooth-shell snails were higher than those of the ribbed - shell snails, which were statistically significant (χ2Xindian = 135.118, χ2Shuangdian = 122.836, χ2Baipu =154.436, χ2Dingyan = 138.288, χ2Control = 151.923, all P < 0.01). There were no significant differences in the infection rates of snails between each test group of the soil from SENEAS and the endemic areas (χ2Rugao = 0.071, χ2Rudong = 0.216, both P > 0.05). Also there was no significant difference between each test group and the control group without soil (χ2 = 7.148, P > 0.05). CONCLUSIONS: It is likely to form the spread of schistosomiasis in SENEAS in Nantong City with sufficient amount of infection source of schistosomiasis imported. It is still necessary to implement the surveillance of schistosomiasis and O. hupensis snails in Nantong City.

Diagnosis and treatment of an imported case of schistosomiasis haematobi-um / 中国血吸虫病防治杂志

Objective To report the diagnosis and treatment of an imported case of schistosomiasis haematobium,including the pathological features of the disease and therapeutic efficacy of praziquantel. Methods The data of the patient with schistoso?miasis haematobium were collected,and the pathological features of the bladder tissue were observed under a microscope. More?over,the patient was treated with praziquantel,and his urine was collected before and after the treatment. The eggs in the urine were examined by a microscope after sediment and the miracidia were hatched. Results The patient once worked in Angola for three months,and after returning home he had the symptoms of intermittent painless terminal hematuresis. It was ineffective af?ter anti?inflammatory treatment in a number of hospitals. There were no sand spots discovered under the cystoscope. However , the inflammatory reaction to parasite with a lot of eosinophils infiltration in the bladder mucosa was found on the pathological sec?tions under a microscope,and the egg structure was observed with individual characteristics. The eggs were detected in the urine and the miracidia were hatched before the praziquantel treatment. The hematuria symptoms disappeared after the praziquantel treatment. The eggs were still detected in the urine 7 days post?treatment,but the miracidium could not be hatched. One month and 6 months post?treatment,the eggs were not detected in the urine. Conclusions The imported cases of schistosomiasis hae?matobium are often misdiagnosed,and therefore,it is necessary to strength the health education to the workers overseas and also to improve the ability of diagnosis in medical staff. For the case reported in this paper,there are typical structure of Schistosoma haematobium eggs and egg?granulomas on the pathological sections of bladder tissues. Praziquantel has satisfactory treatment re?sults.

Study on Oncomelania hupensis snails infected with Schistosoma japonicum miracidia under different conditions in snail-existent non-endemic areas of schistosomiasis in Nantong City / 中国血吸虫病防治杂志

Objective To understand the forming cause of the Oncomelania hupensis snail-existent non-endemic areas of schistosomiasis(SENEAS),and to verify the conclusion of previous studies,so as to provide the evidence for schistosomiasis monitoring in such areas in Nantong City,Jiangsu Province. Methods The controlled field tests were carried out to observe the O. hupensis snails artificially infected by schistosome miracidia in SENEAS. The influence of the soil from SENEAS and the en-demic areas on O. hupensis snails artificially infected by miracidia were observed. Results All the experimental snails could be infected by schistosome miracidia except the smooth-shell snails from Tangyuan Village in the controlled field test environment of SENEAS or the endemic areas. The infection rates of the smooth-shell snails were lower than those of the ribbed-shell snails , but there were no statistically significant differences. The mortality rates of the smooth-shell snails were higher than those of the ribbed-shell snails,which were statistically significant (χ2Xindian = 135.118,χ2Shuangdian = 122.836,χ2Baipu =154.436,χ2Dingyan =138.288,χ2Control=151.923,all P<0.01). There were no significant differences in the infection rates of snails between each test group of the soil from SENEAS and the endemic areas(χ2Rugao=0.071,χ2Rudong=0.216,both P>0.05). Also there was no signifi-cant difference between each test group and the control group without soil(χ2=7.148,P>0.05). Conclusion It is likely to form the spread of schistosomiasis in SENEAS in Nantong City with sufficient amount of infection source of schistosomiasis im-ported. It is still necessary to implement the surveillance of schistosomiasis and O. hupensis snails in Nantong City.