OBJECTIVETo understand the risk factors of schistosomiasis transmission in the Three Gorges Reservoir Area (TGRA) and to provide evidence for the development of control strategy.

METHODSApproaches including epidemiology, immunology and field survey were applied to investigate the potential risk factors which would involve the importation of infectious resources live mobile and migrant population, and livestock in the reservoir area. Meanwhile, observation on survival and reproductive status of snail under simulation habitats was also carried out, using ecological methods on snails. Strategy in preventing the spread of snail as infectious resources was also provided.

RESULTS175 mobile people from schistosomaisis endemic area of were tested and one person showed immunology tests positive with indirect hemagglutination test (IHA) and circumoral precipitin test (COPT), with a positive rate of 0.57%. Through the two-year period under observation, data showed that the snails with ribbon/smooth shells could survive and reproduce under habitats of simulation.

CONCLUSIONSOnce the infectious resource of schistosomiasis was introduced into the TGRA, the area became a new schistosomiasis epidemic area in TGRA which called for countermeasures to be taken.

Animals ; China ; epidemiology ; Disease Reservoirs ; Humans ; Risk Factors ; Schistosomiasis japonica ; epidemiology ; prevention & control ; transmission ; Snails ; parasitology

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 study the dynamics of the reinfection of Schistosoma japonicum and related risk factors among the people in schistosomiasis endemic areas in China.

METHODSLiterature retrieval was conducted by using databases of PubMed, CNKI,VIP and Wanfang to collected all the data about the human re-infection of Schistosoma japonicum and related risk factors in the endemic areas in China. And a Mata-analysis was conducted on the literatures met the inclusion standards.

RESULTSEighteen studies involving 12 604 people for infection survey and 3 128 people for re-infection survey were included in the analysis. The overall infection rate was 20.8%, and the overall re-infection rate was 21.0% . The difference had no statistical significance (Z = 1.12, P = 0.26). The re-infection related factors included baseline infection intensity (OR = 3.58, 95% CI: 1.56-8.22); the index of contaminated water OR = 2.37, 95% CI: 1.08-5.22); distance from house to river-side (OR = 1.72, 95% CI: 0.41-7.30) and age (OR = 0.48, 95% CI: 0.19-1.23).

CONCLUSIONThe baseline infection intensity, the index of contaminated water and distance from house to river-side were the risk factors related to the re-infection of Schistosoma japonicum and age was a protective factor.

Animals ; Asian Continental Ancestry Group ; China ; Humans ; Risk Factors ; Schistosoma japonicum ; Schistosomiasis japonica ; epidemiology ; parasitology

OBJECTIVETo understand the infectious status of infection sources in some epidemic regions of Schistosomiasis japonica, and provide a scientific basis for further controlling infection sources in a comprehensive way.

METHODSLongshang village which lies in the area of hills and mountains and Yuye village which lies in the area of lakes and marshlands were chosen for field investigation. The study was targeted at snails and 1512 residents, while 197 samples of livestock were randomized (80 cattle, 46 pigs, 45 dogs, 18 cats, 8 sheep) and 32 wild animals (field rats) were screened in Anhui province between October to November in 2007. The infection rate and intensity of infection were calculated after pathogenic examination on the populations, livestock and wild animals (field rats).

RESULTS(1) The infection rate of snails in Longshang and Yuye village were 2.26%, 1.06% in 2007, and 0.55%, 0.72% in 2006 respectively. (2) Of the infection rate and geometric mean of egg per gram (EPG) of population, 3.8% and 0.14 (EPG) were in Longshang village and 3.4% and 0.13 (EPG) were in Yuye village. The positive rate of blood examination of the different sex in Longshang village was 17.5% (44/252) of the males, higher than that of the females 11.0% (25/227) (chi(2) = 4.026, P = 0.045), whereas, in Yuye village was 21.4% (66/309) of males and 19.4% (25/129) for the females, without significant differences (chi(2) = 0.217, P > 0.05). The positive rate of fecal examination of the different sex in Longshang village was 5.2% (14/268) of the men and 2.1% (5/236) of the women showing no statistical significance (chi(2) = 3.336, P > 0.05); whereas, in Yuye village was 5.7% (14/245) of the men and 1.2% (3/250) of the women (chi(2) = 7.603, P = 0.006). (3) The infection rate and the arithmetic mean of EPG of the cattle, 10.8% (8/74) and 135.00 (EPG) were in Longshang village, meanwhile, the infection rate of the bull was 9.1% (6/66) and 25.0% (2/8) for cow without statistical significance (chi(2) = 0.586, P = 0.444), whereas, the total number of cattle was 6 that had been examined and there was no positive case in Yuye village. Of 8 sheep examined in Yuye village, 6 was positive, with arithmetic mean of 254.82 (EPG), while there was no sheep in Longshang village. (4) Of the positive rate of the incubation for dog's feces and intensity of infection, 55.6% (24/36) and 20.00 (EPG) were in Yuye village whereas 23.81% (5/21) and 1.21 (EPG) were in Longshang village. (5) Of the infection rate of the field rats, 13.64% (3/22) in Longshang village whereas a total number of mouse was 10 that had been examined and there was no positive case in Yuye village.

CONCLUSIONThe farm cattle should be still the chief sources of infection in the regions of lakes and marshlands for schistosomiasis. Whereas, with the implementing in-depth of the strategy on controlling source of infection in a integrated way, high priorities should be given to the epidemiological factors of the animals such as sheep, dogs, field mouse and so on which are spreading schistosomiasis.

Animals ; Animals, Wild ; parasitology ; Cats ; Cattle ; China ; epidemiology ; Dogs ; Feces ; parasitology ; Female ; Humans ; Male ; Mice ; Parasite Egg Count ; Rats ; Schistosomiasis japonica ; epidemiology ; parasitology ; Sheep ; Swine

OBJECTIVETo evaluate the effect of comprehensive control strategy of schistosomiasis with emphasis on infection source control in Anhui province.

METHODSForty endemic villages in Guichi district, Chizhou city, Anhui province were selected as national pilot villages in the years from 2006 to 2008, and another 10 provincial pilot villages were respectively selected from 10 highly endemic villages in 7 cities in 2007. The comprehensive infection source control measures, including "replace cattle with machines", "raise livestock in pens", "improve the sanitary toilets", "supply safe water " and so on were carried out among the above pilot villages. At the end of 2008, 13 national pilot villages and 6 provincial pilot villages were selected to investigate the popularity of schistosomiasis, and the effect of the comprehensive control strategy in those villages were compared.

RESULTSAfter implementing the comprehensive control strategy, the infectious rate of schistosomiasis in national pilot villages decreased from 4.57% (487/10 659) to 1.76% (147/8370), with the reduction rate at 61.49%, whose difference showed statistical significance (χ(2) = 115.16, P < 0.01); and the density of infected snails decreased from 0.0067/0.1 m(2) to 0.0008/0.1 m(2), the infectious rate of snails decreased from 0.28% to 0.04%, whose reduction rates were 88.06% and 85.71% respectively. While as to the provincial pilot villages, the infectious rate of schistosomiasis decreased from 1.27% (54/4254) to 0.21% (14/6592), with the reduction rate at 83.46%, whose difference showed statistical significance (χ(2) = 94.57, P < 0.01); and the density of infected snails decreased from 0.0025/0.1 m(2) to 0.0003/0.1 m(2), the infection rate of snails decreased from 0.13% to 0.05%, whose reduction rates were 88.00% and 61.54% respectively.

CONCLUSIONThe comprehensive control strategy with emphasis on infection source control implemented in marshland and lake regions can effectively control the transmission of schistosomiasis.

Animals ; China ; epidemiology ; Disease Reservoirs ; parasitology ; Humans ; Infection Control ; methods ; Livestock ; Pilot Projects ; Rural Health ; Schistosomiasis ; epidemiology ; parasitology ; prevention & control ; Snails ; parasitology

OBJECTIVETo analyze the change of tendency on schistosomiasis epidemics in China in the last 5 years.

METHODSData on schistosomiasis epidemics in the history and particularly in the last 5 years were collected. Tendency and the re-emerging status after 1998 were analyzed.

RESULTSData in 2003 showed that in 42%, 40% and 53% of the provinces, counties and townships with epidemics, the transmission of the disease has been interrupted or controlled. The number of estimated patients of schistosomiasis and areas with snails were also reduced by 92.74% and 73.56%, in 2003. The annual estimated number of chronic cases was around 800 000 and 31 321.5 hectare of snail infested areas were newly identified in recent 5 years. Among 20 national villages under longitudinal surveillance, 30%, 70% and 35% of the villages were presented a tendency of increase in the rates of human infection, bovine infection and Oncomelania snails infection, respectively. A total of 38 counties from 7 provinces have re-emerged in schistosomiasis transmission after those counties having reached criteria of transmission under control or interrupted. In 6 non-endemic counties, snails were presented, and 16 marshlands in Xan river were found with appearance of acute cases of schistosomiasis. More snail infested areas were found in Shanghai, Zhejiang, and Fujian. Both snail infested areas and newly infected cases were occurred in urban areas along the Yangtze River.

CONCLUSIONThe tendency of increase was presented in focal areas along the Yangtze River, due to changes of environmental, ecological, societal and economic status, as well as on the forces of control.

Animals ; China ; epidemiology ; Disease Reservoirs ; Humans ; Praziquantel ; therapeutic use ; Prevalence ; Schistosomiasis japonica ; drug therapy ; epidemiology ; prevention & control ; Snails ; parasitology

Animals ; China ; epidemiology ; Disease Outbreaks ; prevention & control ; Endemic Diseases ; prevention & control ; Feces ; parasitology ; Humans ; Schistosomiasis ; epidemiology ; prevention & control

OBJECTIVETo analyze the impact of water transfer project from the Yangtze River to the Huaihe River on schistosomiasis transmission, and to evaluate the risk of the disease input to the potential endemic area in Anhui Province, namely the Chaohu Lake region.

METHODSFrom 2008 to 2012, 1 fixed and 3 mobile surveillance sites in the Chaohu Lake area were selected, and the schistosomiasis infection situation of 615 local residents in the fix surveillance site was investigated in autumn of 2008 and 2012, while the schistosomiasis infection situation of 1603 mobile population in the 3 mobile surveillance sites were investigated in autumn of 2008 to 2012. All people were screened by indirect hemagglutination assay (IHA), and the positive ones were then examined by sedimentation method. 303 local livestock and livestock from schistosomiasis endemic areas were examined by stool hatching method in autumn of 2008 to 2012. From 2008 to 2012, the distribution of Oncomelania snails was investigated in risk areas and suspicious areas, and the snail spreading pattern was conducted through salvaging floaters in rivers connected with the Yangtze River. In addition, the Oncomelania snails were raised in the cages on the beaches of the Chaohu Lake, a control area, from 2007 to 2010, and their survival and reproduction capacity was observed.

RESULTSIn 2008 and 2012, 301 and 314 local residents were detected by IHA, but there were no positive found. From 2008 to 2012, a total of 1603 mobile population were examined by IHA, and the positive rate of antibody was 3.1% (49/1603); 75 individuals were examined by sedimentation method, and the positive rate was 36.00% (27/75). A total of 303 livestock were examined by stool hatching method, but no one showed positive. A total of 1630 km(2) in risk areas and 3551 km(2) in suspicious areas were surveyed, but there were no Oncomelania snails found. A total of 457.6 kg floating debris were investigated, and 11 Oncomelania snails were found. From 2007 to 2010, the survival rate of Oncomelania snails in two trail areas in the Chaohu Lake and in the control area was 88% (86/98), 51% (45/89), 30% (25/71), 24% (20/84) and 92% (85/92), 54% (50/92), 23% (12/52), 17% (13/79) and 96% (85/89), 52% (44/85), 26% (18/69), 18% (14/76), respectively, there were no statistical significance between the trial areas and the control area (χ1(2) = 3.78, P > 0.01; χ2(2) = 0.27, P > 0.01; χ3(2) = 2.51, P > 0.01; χ4(2) = 1.50, P > 0.01), and filial generation snails were found in each observation area from 2008 to 2010, the number was 156-312.

CONCLUSIONThe imported infectious sources of schistosomiasis have been found in the Chaohu Lake region, the possibility of imported exogenous Oncomelania snails spreading into the Lake and surviving and reproducing there is high. The risk of schistosomiasis input to the potential endemic area in Anhui Province is predicted to be high.

Animals ; Cross-Sectional Studies ; Environmental Monitoring ; Humans ; Lakes ; parasitology ; Risk Assessment ; Rivers ; parasitology ; Schistosomiasis japonica ; epidemiology ; prevention & control ; transmission ; Snails ; parasitology

Intestinal helminths and schistosomiasis among school children were investigated in an urban and some rural communities of Ogun State, southwest Nigeria. Fecal samples of 1,059 subjects (524 males, 535 females) aged 3-18 years were examined using direct smear and brine concentration methods between June 2005 and November 2006. The pooled prevalence of infection was 66.2%. Ascaris lumbricoides showed the highest prevalence (53.4%) (P < 0.001) followed by hookworms (17.8%), Trichuris trichiura (10.4%), Taenia sp. (9.6%), Schistosoma mansoni (2.3%), Strongyloides stercoralis (0.7%), Schistosoma haematobium (0.6%), and Enterobius vermicularis (0.3%). The prevalences of A. lumbricoides, hookworms, Taenia sp., S. mansoni, and S. stercoralis in the urban centre were similar (P > 0.05) to those in the rural communities. The fertile and infertile egg ratios of A. lumbricoides in the urban centre and the rural communities were 13: 1 and 3.7: 1, respectively. Each helminth had similar prevalences among both genders (P > 0.05). The prevalence of A. lumbricoides increased significantly with age (P < 0.001). The commonest double infections were Ascaris and hookworms, while the commonest triple infections were Ascaris, hookworms, and Trichuris. The study demonstrates the need for urgent intervention programmes against intestinal helminthiases and schistosomiasis in the study area.
Adolescent ; Age Factors ; Animals ; Child ; Child, Preschool ; Feces/parasitology ; Female ; Helminthiasis/*epidemiology/parasitology ; Humans ; Intestinal Diseases, Parasitic/*epidemiology/parasitology ; Male ; Nigeria/epidemiology ; Prevalence ; Questionnaires ; Rural Population ; Schistosomiasis/*epidemiology/parasitology ; Sex Factors ; Urban Population

OBJECTIVETo investigate water exposure modes and times of different populations in mountainous schistosomiasis endemic areas and to inform about the control strategies.

METHODSAll 1054 residents from populations around Qionghai Lake were randomly sampled according to occupation for a retrospective questionnaire survey in November 2001. Each individual was interviewed for his/her mode, frequency, and duration of water exposure occurring between April and October 2001.

RESULTSThe average exposure times and intensity were higher in farmers (median: 16 - 18 min/day and 2.41 - 2.5, respectively) who grow rice, tobacco, and vegetables than others (median: 3.74 - 7.39 min/day and 0.81 - 1.52, respectively); exposure frequency was found highest in farmers (median: 2.04 times/day) in all occupations; schoolchildren had low exposure frequency and times, but very high exposure intensity (median 2.34). Between April and June it is an agriculturally busy season, that is also a peak season of water exposure of adults. Schoolchildren's water exposure peaks on July and August, mainly due to playing water and swimming. Exposure times and intensities were higher in females than in males.

CONCLUSIONWater exposure modes, times, and intensities of different populations were different in mountainous schistosomiasis endemic areas of Xichang. Between April and June should be the peak infection season of adults who are engaging in agricultural activities, while July to August should be the peak infection season for schoolchildren with non-agricultural activities.

Adult ; China ; Environmental Exposure ; analysis ; Female ; Humans ; Male ; Retrospective Studies ; Schistosomiasis ; epidemiology ; Surveys and Questionnaires ; Topography, Medical ; Water ; parasitology