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Objective To quantitatively estimate the range and area of environmental contamination by the feces of Schistoso?ma japonicum?infected that were freely grazed,so as to provide the theoretical evidence for the scientific assessment of the role of the freely grazed goat in the transmission of schistosomiasis japonica and development of control strategy. Methods All the fecal samples excreted by the infected goat at daytime(12 h)were collected by using a self?made goat fecal collector,weighed and counted. The quantity and dispersal of the feces excreted by the freely grazed goat at daytime under a natural condition were investigated,and the walking route and speed of the freely grazed goat at daytime were recorded with a multifunction GPS data logger. The maximum range and area of the environment contaminated by the feces of the freely grazed goat at daytime were esti?mated,and the maximum range and area of the Oncomelania hupensis snails that may be infected by the schistosome miracidium released from the eggs in the fecal samples of the freely graze goat at daytime were calculated. Results During the walking along the marshland at daytime(12 h),the quantity of the feces execrated by the freely grazed infected goat was(232.8 ± 39.8) g per goat,and the fecal samples were composed of(819.2 ± 152.1)pellets. The goat had a mean walking speed of(0.522 7 ± 0.099 7)km/h,and the longest distance,largest radius and largest range of walking activity were(6.272 4 ± 1.195 8)km, 3.136 2 km and(3 191.113 0 ± 1 189.709 4)hm2at daytime,respectively. The area of the snails that may be infected by the mi?racidium released from the eggs in the fecal samples of the freely graze goat(range of key regions for infected snails detection and control)at daytime was estimated to be(3 210.717 5 ± 1 190.907 3)hm2. Conclusions The intensity of environmental contamination by the eggs in the fecal samples of the freely grazed goat is linked to the number of infected goat. The contamina?tion range caused by the feces of the freely grazed goat with fixed fences is relatively stably kept within the walking range at day?time,and the range and area of goat fecal contamination is associated with the number of households that breed goat and the dis?tribution of goat fence. The area of the snails that may be infected by the miracidium released from the eggs in the fecal samples of the freely graze goat is larger than the area of setting contaminated by the eggs in the goat feces ,indicating that the range of in?fected snail examination and control is larger than the range of goat feces detected.
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Objective To describe the growth and development of Schistosoma japonicum in goat and the intensity and tem?poral distribution of eggs excreted by goat feces,so as to provide baseline data for the control and elimination of the role of goat in the transmission of schistosomiasis. Methods The goat animal models of schistosomiasis were established,and stool sam?ples were collected for parasitological examinations. The number of adult worms recovered,variation of schistosomes in goat at different time points post?infection,number of eggs in schistosomes,variation in number and temporal profiles of eggs excreted from goat feces were observed. Results Of the 6 schistosome?infected goat,415 adult worms were recovered,with a mean adult worm recovery of 34.58%(range,23.00%to 45.50%). Among the 5 goat infected with 200 cercariae each,47,93,77, 74 and 73 adult worms were recovered 2,5,8,11 and 14 months post?infection,respectively. There were(200.00 ± 42.33), (226.20±45.88),(168.20±25.85),(183.80±55.13)and(190.80±53.53)eggs detected in female schistosomes. The mean pre?patent period of eggs excreted by 10 infected goat was(37.7±3.02)d. From 2 to 14 months post?infection,7 batches of goat fe?ces were hatched,and there were 30,23,14,1 and 2 times for miracidium intensity of“++++”,“+++”,“++”,“+”and“-”, respectively,with 42.86%,32.86%,20.00%,1.43%and 2.86%constituent ratios of miracidium intensity. Conclusions Ap?proximately 1/3 S. japonicum cercariae may develop to adults in goats post?infection,and the prepatent period of eggs is(37.7± 3.02)d. There is no remarkable decrease seen in the number of adult worms,eggs in female schistosomes and eggs in goat feces within 14 months post?infection. Our findings suggest a long duration for infected goat in the transmission of schistosomiasis ,and there is no evidence to prove the“self?cure”phenomenon in goat,indicating that goat is an important source of infection for schistosomiasis japonica.
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Objective To develop a simple,feasible goat feces collector to improve the collection accuracy and integrity of goat fecal samples without pollution,and to modify the miracidium hatching test with a plastic tube to achieve simple,standard and comparative procedures,so as to provide technical support for pathogenic diagnosis and scientific research of goat schistoso?miasis japonica. Methods According to the body features of goat in marshland regions,a goat fecal collector,which was made of coarse fabric cottons,was devised,which was able to be fixed onto the goat buttocks and avoid urine pollution. Prior to mira?cidium hatching test,the goat fecal samples were pieced by using a mechanical method instead of the conventional artificial piec? ing method,and the effect of mechanical piecing treatment on miracidium hatching was evaluated. A filter membrane was added between the tube and rubbery ring to block the floater in fecal residues into the tube. The effects on miracidium hatching by us?ing thin fat?free cotton,thick fat?free cotton,nylon gauze at 100 pores/25.4 mm2 and 150 pores/25.4 mm2 were compared. Re?sults The goat feces collector was composed of foreleg fixing garment,hindleg fixing garment and stool bag. The functions of the fixing garment were as a fixed collector to allow non?shift and tolerance of weight during goat activity ,while the major func?tion of stool bag was in storage of stool. The goat activity was not influenced by the use of collector ,and all fecal samples were ex?creted to the bag. This collector was easy to perform and could avoid urine pollution,which was reusable after cleaning. Prior to miracidium hatching,the goat fecal samples,together with water,were pieced at 18 000 to 23 000 r/min for successive three times in a cooking machine,of 10 s each time at an interval of 5 s. Mechanical piecing had no clear?cut effect on miracidium hatching of eggs in fecal samples. A total of 541,620,344 and 211 miracidia were detected by using the miracidium hatching test with nylon gauze at 100 pores/25.4 mm2 and 150 pores/25.4 mm2,thin fat?free cotton and thick fat?free cotton respectively, indicating a better detection efficacy by using nylon gauze at 100 pores/25.4 mm2 and 150 pores/25.4 mm2. Conclusions The goat fecal collector is an easy?to?perform,accurate,unpolluted and reusable device to collect goat feces,which is suitable for pathogenic diagnosis of goat schistosomiasis. Mechanical piecing and use of nylon gauze at 150 pores/25.4 mm2 allow a simple, accurate and stable technique for parasitological diagnosis of schistosomiasis japonica,which provides a reliable tool for schisto?somiasis control and research.
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Objective To investigate the survival of Schistosoma japonicum eggs in goat feces in natural marshlands and the factors affecting its survival,so as to provide evidences for understanding of the role of eggs in goat feces in the transmission of schistosomiasis and the development of the interventions pertaining to disease control and elimination. Methods The goat ani?mals of schistosomiasis japonica were modeled in laboratory,and the feces of infected goat were collected. In laboratory,the ef?fects of environmental temperature and water content in goat feces on egg hatching were evaluated,and in the field,the effect of duration of goat feces on marshland on egg hatching and the effect of direct sunshine on egg survival were evaluated. Results At 25℃in laboratory,the hatching rate of eggs in goat feces was high?positively correlated with the water content in goat feces (r=0.87). If the water content reduced to 7.6%in goat feces,the eggs in goat feces lost the ability to hatch. Under the same wa?ter content in goat feces,the hatching rate of eggs gradually decreased with the extension of the duration of exposure of goat feces to-5℃,which reduced to 0 following 5 h exposure. At 5,15 and 25℃,the hatching rates of eggs gradually decreased with the extension of the duration of exposure of goat feces,and the miracidium hatching rates of eggs were 2.3%,5%and 0.9%respec?tively following the exposure for 52 d. At 35℃,the hatching rate of eggs gradually decreased with the extension of the duration of exposure,which reduced to 0 following 13 d exposure. In winter(-2?10℃),the hatching rate of eggs gradually decreased with the extension of the duration of exposure of goat feces on marshlands,which reduced to 0 after 21 d of exposure,and in spring(16?19℃),the hatching rate of eggs gradually decreased with the extension of the duration of exposure of goat feces on marshlands,which reduced to 0.9%after 5 d of exposure. At the same time point on the same marshland,the hatching rate of eggs in goat feces exposed to marshlands with direct sunshine was lower than that without direct sunshine. Conclusion The sur?vival of S. japonicum eggs in goat feces is associated with environmental temperature and water content(humidity)in goat feces, and the temperature and humidity are major natural factors affecting egg hatching.
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The surveillance of schistosomiasis in Sanzhou Village, Dantu District, Zhenjiang City, a national schistosomiasis surveillance site, showed that in 2008, the area with snails was 27 hm~2, among which the area with infected snails was 14 hm~2, the densities of living snails and infected snails were 0. 86 and 0.002 1 snails/0. 1 m~2, respectively. The infection rate of snails was 0.25% , the positive rate of IHA was 3. 10% and the infection rate of schistosome in human populations was 1%. There were no infected domestic animals found, and there were no acute schistosomiasis and newly advanced schistosomiasis cases found in the surveillance site in 2008. It is indicated that the endemic situation of schistosomiasis is stable. The comprehensive control, including molluciciding and environmental modification, should be implemented for snail control. The comprehensive measures with emphasis on infectious source control should be further strengthened.
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Objective To probe into regul ar patterns of move and diffusing of Oncomelania s nails in rivers with cement banks and determine the control strategy. [WT5 ”HZ]Methods The part of Sunan Canal from the estuary to Xin feng Railway Bridge was taken as the experimental zone. The revival of snail spo ts destroyed before the canal dredging, snail status on cement banks, snails on obstacles, floaters and ships in the rivers and floating snails were investigate d and compared with the situations before the dredging. Results Twelve destroyed snail spots were investigated and two of them presented snails, apart from the estuary 3.2 km and 4.3 km. The rate with sna il s on obstacles in frame in the rivers was 0, significantly lower than the 87% be fore the dredging(P
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ObjectiveTo evaluate the app li cation value of the Dipstick Dye Immuno assay (DDIA) for screening chemotherapy targets of schistosomiasis in a lower endemic area. Methods[ WT5”BZ]In a lower endemic area of schistosomiasis a random sample of 463 individuals from a natural village were examined using miracidium hatching metho d, Kato Katz's method, DDIA, DGS COPT and ELISA. The positive rates of these a ss ays were compared. ResultsThe positive rate of stool examination was 3.9% in 463 individuals. The positive rate of DDIA was 15 8%. The positive rate in 18 stool positive subjects was 94 4% with Youden In dex 0 81. The positive rate of DGS COPT was 8 9% . The positive rate in 18 stool po sitive subjects was 72 2% with Youden Index 0 66. The positive rate of ELISA w as 18 4%. The positive rate in 18 stool positive subjects was 83 3% with Youden In dex 0 68. ConclusionDDIA was more suitable for application in screening target population in lower endemic areas than other im munoassys.