A mathematical model for transmission of schistosomes is useful to predict effects of various control measures on suppression of these parasites. This review focuses on epidemiological and environmental factors in Schistosoma japonicum and Schistosoma mekongi infections and recent advances in mathematical models of Schistosoma transmission.
Animals ; Asia, Southeastern/epidemiology ; *Communicable Disease Control ; Disease Reservoirs/parasitology ; Humans ; Models, Theoretical ; Schistosoma/*physiology ; Schistosomiasis/epidemiology/parasitology/*transmission

OBJECTIVETo test Candonocypris novaezelandiae (Baird) (C. novaezelandiae), sub-class Ostracoda, obtained from the Nile, Egypt for its predatory activity on snail, Biomphalaria alexandrina (B. alexandrina), intermediate host of Schistosoma mansoni (S. mansoni) and on the free-living larval stages of this parasite (miracidia and cercariae).

METHODSThe predatory activity of C. novaezelandiae was determined on B. alexandrina snail (several densities of eggs, newly hatched and juveniles). This activity was also determined on S. mansoni miracidia and cercariae using different volumes of water and different numbers of larvae. C. novaezelandiae was also tested for its effect on infection of snails and on the cercarial production.

RESULTSC. novaezelandiae was found to feed on the eggs, newly hatched and juvenile snails, but with significant reduction in the consumption in the presence of other diet like the blue green algae (Nostoc muscorum). This ostracod also showed considerable predatory activity on the free-living larval stages of S. mansoni which was affected by certain environmental factors such as volume of water, density of C. novaezelandiae and number of larvae of the parasite.

CONCLUSIONSThe presence of this ostracod in the aquatic habitat led to significant reduction of snail population, infection rate of snails with schistosme miracidia as well as of cercarial production from the infected snails. This may suggest that introducing C. novaezelandiae into the habitat at schistosome risky sites could suppress the transmission of the disease.

Animals ; Crustacea ; physiology ; Pest Control ; Pest Control, Biological ; Predatory Behavior ; Schistosoma mansoni ; Schistosomiasis mansoni ; prevention & control ; transmission

OBJECTIVETo assess the potential impact of warming climate in winter to the scale and severity of schistosomiasis epidemics in China.

METHODSBased on the data of mean temperature and monthly minimum temperature in January from 126 (out of 733) weather observation stations in China, the trend and oscillation amplitude was analyzed. The impact of warming climate in winter to the scale of schistosomiasis spreading was assessed, using the indices of 0 degrees C mean temperature and -4 degrees C mean monthly minimum temperature in January. Correlation between these two indices was analyzed.

RESULTSEvidences showed the warming climate in winter was seen all over China with the mean monthly minimum temperature and the mean temperature in January had increased 1.3 degrees C and 0.9 degrees C since 1986. The contours of mean monthly minimum temperature -4 degrees C and mean temperature 0 degrees C in January moved 1 - 2 latitudes northward.

CONCLUSIONThe warming climate phenomenon seen in winter was considered favorable to the living of snails in winter, resulting in the possible increase of northward spreading of snails.Thus, monitoring of snails should be paid special attention.

Animals ; China ; epidemiology ; Climate ; Disease Reservoirs ; Female ; Health Education ; Humans ; Male ; Prevalence ; Schistosoma japonicum ; physiology ; Schistosomiasis japonica ; epidemiology ; prevention & control ; Seasons ; Snails ; parasitology ; physiology ; Temperature

BACKGROUND AND OBJECTIVES: Placenta and blood that remained in the umbilical cord is routinely available as a discarded tissue after deliveries and it is free of any legal, moral, ethical or religious objections, providing a high number of multipotent CD34+ progenitor and stem cells. Using ex vivo isolated CD34+ cells from human umbilical cord blood (hUCB) have emerged as promising candidates to treat various diseases, including exogenous pathogenic infections. We have expanded to build a rational approach to study the effect of CD34+ cells after damaged liver tissues by the devastating human parasitic flatworm Schistosoma mansoni. METHODS AND RESULTS: Experimental studies were conducted in the Department of Zoology, Faculty of Science and Departments of Parasitology and Physiology, Faculty of Medicine, SCU, Egypt. We have studied the impact of ex vivo preparation of CD34+ cells from hUCB on S. mansoni-induced liver fibrosis de novo, and treated for shorter and longer periods in vivo. Ova count, ALT and albumin were measured at specific time interval and histopathological examination of liver was conducted to confirm the biochemical results. The data obtained were statistically analyzed by ANOVA between groups. It was found that the administration of CD34+ cells have modestly reduced liver damage; reduced the S. mansoni infection associated elevation in serum levels of ALT; significantly improved serum levels of albumin and reduced egg granuloma diameter in the livers. CONCLUSIONS: We demonstrated that CD34+ cells can markedly ameliorated liver fibrosis in vivo and may be beneficial for therapy to recover organ structure and/or function of S. mansoni-infected mice.
Animals ; Egypt ; Fetal Blood ; Fibrosis ; Granuloma ; Humans ; Liver ; Liver Cirrhosis ; Mice* ; Ovum ; Parasitology ; Physiology ; Placenta ; Platyhelminths ; Schistosoma mansoni* ; Stem Cells ; Umbilical Cord ; Zoology

OBJECTIVETo explore the vegetation landscapes in marshland snail habitats using satellite image.

METHODSThe false-color composition image from band 2, 3 and 4 of LANDSAT ETM + images was classified in the ERDAS IMAGINE 8.5 to analyze the vegetation types in the marshland of Jiangning county, using the unsupervised classification. The efficiency of classification was evaluated by the transformed divergence. The overlaid layers of the classified vegetation image and the vector layer of snail habitats distribution were used to analyze the relationship between the snail distribution and the landscape types.

RESULTSThe land-cover of marshland in LANDSAT ETM234 image in Jiangning county could be classified into 10 types, including water, bare soil, sandy and other landscapes while the transformed divergence analysis showed that there were misclassified pixes between some types especially for the non-continuous types. The study indicated that through adding the NDVI image in the process of classification efficiency of classification and eliminate misclassification in the non-continuous type could be improved. Analysis on the overlaid layer of the vector of snail distribution and the classified image proved that the vegetation covers in marshland snail habitats in Jiangning mainly belonged to type 3, 5 and 6, that responded to the beach with sparse vegetation, exuberant weed and bulrush respectively. The density of snails in the bulrush was higher than that in other 2 landscapes.

CONCLUSIONThe vegetation type in the marshland snail habitats could be distinguished from the satellite image, which was helpful for the surveillance of snail habitat in marshland and for the prevention of schistosomiasis.

Animals ; Breeding ; China ; epidemiology ; Disease Vectors ; Ecology ; Environmental Monitoring ; Epidemiological Monitoring ; Humans ; Plants ; Satellite Communications ; instrumentation ; Schistosoma japonicum ; classification ; growth & development ; Schistosomiasis japonica ; epidemiology ; transmission ; Snails ; growth & development ; parasitology ; physiology

Although schistosomicidal drugs and other control measures exist, the advent of an efficacious vaccine remains the most potentially powerful means for controlling this disease. In this study, native fatty acid binding protein (FABP) from Fasciola gigantica was purified from the adult worm's crude extract by saturation with ammonium sulphate followed by separation on DEAE-Sephadex A-50 anion exchange chromatography and gel filtration using Sephacryl HR-100, respectively. CD1 mice were immunized with the purified, native F. gigantica FABP in Freund's adjuvant and challenged subcutaneously with 120 Schistosoma mansoni cercariae. Immunization of CD1 mice with F. gigantica FABP has induced heterologous protection against S. mansoni, evidenced by the significant reduction in mean worm burden (72.3%), liver and intestinal egg counts (81.3% and 80.8%, respectively), and hepatic granuloma counts (42%). Also, it elicited mixed IgG1/IgG2b immune responses with predominant IgG1 isotype, suggesting that native F. gigantica FABP is mediated by a mixed Th1/Th2 response. However, it failed to induce any significant differences in the oogram pattern or in the mean granuloma diameter. This indicated that native F. gigantica FABP could be a promising vaccine candidate against S. mansoni infection.
Animals ; Antibodies, Helminth/immunology ; Fasciola/*chemistry ; Fatty Acid-Binding Proteins/*administration & dosage/immunology/isolation & purification ; Female ; Helminth Proteins/*administration & dosage/immunology/isolation & purification ; Humans ; Immunization ; Mice ; Mice, Inbred Strains ; Schistosoma mansoni/immunology/*physiology ; Schistosomiasis mansoni/immunology/parasitology/*prevention & control

OBJECTIVETo clarify the change of vegetation types and its relationship between the density of alive-snails in the areas of "breaking dikes or opening sluice for water store" in Jicheng.

METHODSSynthesized false color images of Jicheng before and after 1998 (1994 and 2003) were classified without supervision and results were compared. Vegetation types were identified on the spot.

RESULTSNormalized difference vegetation index (NDVI) of snail habitats before 1998 were between 126 and 183 in Jicheng, whose vegetation types were mainly paddy, cotton and cabbage. NDVI of snail habitats in Jicheng after 1998 were between 152 and 193 whose vegetation types were mainly poplar forest, bulrush and grass. Areas of snail habitats increased from 64.64% to 66.47%. Snail habitats were mostly composed of mixed vegetation types and mono-typed vegetation was hardly found. According to the density of alive-snails orders from high to low were poplar forest and bulrush, poplar forest and grass, bulrush.

CONCLUSIONVegetation types would not be identified by unsupervised classification only. Poplar forest, bulrush and grass were closedly related to the density of alive-snails.

Animals ; Breeding ; China ; epidemiology ; Disease Vectors ; Ecology ; Environmental Monitoring ; Epidemiological Monitoring ; Fresh Water ; Plants ; Satellite Communications ; instrumentation ; Schistosoma japonicum ; isolation & purification ; Schistosomiasis japonica ; epidemiology ; transmission ; Snails ; growth & development ; parasitology ; physiology

The genetic diversity of Schistosoma haematobium remains largely unstudied in comparison to that of Schistosoma mansoni. To characterize the extent of genetic diversity in S. haematobium among its definitive host (humans), we collected S. haematobium eggs from the urine of 73 infected schoolchildren at 5 primary schools in White Nile State, Sudan, and then performed a randomly amplified polymorphic DNA marker ITS2 by PCR-RFLP analysis. Among 73 S. haematobium egg-positive cases, 13 were selected based on the presence of the S. haematobium satellite markers A4 and B2 in their genomic DNA, and used for RFLP analysis. The 13 samples were subjected to an RFLP analysis of the S. haematobium ITS2 region; however, there was no variation in size among the fragments. Compared to the ITS2 sequences obtained for S. haematobium from Kenya, the nucleotide sequences of the ITS2 regions of S. haematobium from 4 areas in Sudan were consistent with those from Kenya (> 99%). In this study, we demonstrate for the first time that most of the S. haematobium population in Sudan consists of a pan-African S. haematobium genotype; however, we also report the discovery of Kenyan strain inflow into White Nile, Sudan.
Adolescent ; Animals ; Base Sequence ; Child ; DNA, Helminth/genetics ; Female ; *Genetic Variation ; Genotype ; Humans ; Male ; Molecular Sequence Data ; Ovum/classification/cytology ; Parasite Egg Count ; Polymorphism, Restriction Fragment Length ; Schistosoma haematobium/*genetics/*isolation & purification/physiology ; Schistosomiasis haematobia/diagnosis/epidemiology/*parasitology/urine ; Students ; Sudan/epidemiology ; Urine/*parasitology