| OBJECTIVETo evaluate the effection of integrated schistosomiasis control measures withemphasis on infectious source control in mountainous areas of Yunnan province andthen analyze the influence factors,to investigate and evaluate the role of all kinds ofhosts in schistosomiasis transmission in these areas, indentifing the major infectioussource at present. So as to provide the basic references and scientific grounds for theschistosomiasis control strategy.METHODSBy stratified sampling method, one plateau flat type (flat areas) administrativevillage and one mountains canyon type (mountains) administrative village wereselected as experimental communities from heavy epidemic areas of Schistosomiasisin mountainous areas of Yunnan; one mountains canyon type (mountains)administrative village with the similar epidemiological levels and economic conditionswas selected as comparison community. In experimental communities, we not onlydevelop extermination Oncomelania, detection and chemotherapy of Schistosomiasisand health education such normal prevention and control measures; but also developmany measures of control of source of infection and comprehensive control projects.In comparison community, we only develop extermination Oncomelania, detection andchemotherapy of schistosomiasis and health education such normal prevention andcontrol measures; or add few measures of control of source of infection andcomprehensive control projects. During2010-2011, we collected the relative data ofschistosomiasis comprehensive prevention and control systematically throughretrospective survey and status investigation, calculation and statistics of theprevention measures,control fees and epidemic indexes of human, animal,Oncomelania; then complete cost analysis, effectiveness analysis, cost-effectivenessanalysis and multiple linear regression analysis in experimental and comparison community by health statistics method and health economic evaluation method. In themeantime,three natural villages were randomly selected from the experimental andcomparison community respectively,develop the investigation of human, domesticanimals, wild animals infected schistosomiasis; develop the investigation of wild muckpolluted, analyze the hosts infection and wild muck pollution through statistic theinfection rate of hosts, positive rate of wild muck, infectiosity, the number ofmiracidium excreted from host per day, relative index of transmission, and index ofwild muck pollution.RESULTS1. During2005-2011, large sums of money were invested on developing variouscomprehensive measures of prevention and control of Schistosomiasis in experimentaland comparison community, and these measures were mainly control source ofinfection. The cost of control source of infection and comprehensive treatment in twoexperimental communities and one comparison community was76%,87%and65%respectively. The epidemic data of2005as baseline, in2011, human infection rate oftwo experimental community and one comparison community descended97.43%,97.42%and97.09%respectively; the total cost of infection rate descended1%per100persons was1900RMB,2900RMB and2400RMB respectively. Infection rate of14years old children descended97.17%,100%and95.45%respectively; the total cost ofinfection rate descended1%per100children of14years old was5700RMB,8600RMB,7400RMB respectively. Infection rate of cattle descended98.38%,100%and100%respectively; the total cost of infection rate descended1%per100cattle was3,200RMB,3,400RMB and4,300RMB respectively. The percentage of thedecreased number of Oncomelania was17.36%,67.28%and52.94%; the total cost ofdescended1%of Oncomelania per1h㎡area was41,200RMB,2,700RMB and1,000RMB respectively. The density of Oncomelania descended64.17%,63.88%and62.97%respectively; the total cost of the density of Oncomelania descended1%was71,700RMB,29,100RMB and35,900RMB respectively. The index ofcomprehensive effect was95.12,96.13and95.28respectively; the total cost of eachone increased index of comprehensive effect was13,240RMB,4,920RMB and8,470RMB respectively.2.By multiple linear regressions, it showed that there was statistical correlationbetween infection rate of cattle and Oncomelamia and the index such as the coveragerate of sanitation toilets construction, the coverage rate of Oncomelania extermination,the coverage rate of chemotherapy of cattle and human and infection rate of schistosomiasis in human,. There was statistical correlation between human serumpositive rate (or the crowd correction infection rate) and the index such as, thecoverage rate of sanitation toilets construction, the coverage rate of cattlechemotherapy, the coverage rate of Oncomelania extermination and infection rate ofSchistosomiasis in cattle. There were statistical correlation between the human serumpositive rate, infection rate of cattle and ratio of ditches sclerosis to paddy field, thecoverage rate of domestic animals in captivity and infection rate of Schistosomiasis inOncomelania.3. Based on field survey, the main hosts of Schistosoma japonicum were human,cattle, equus, dog and mouse in3natural villages Infection rate of these hosts was1.01%,0.91%,1.25%,5.61%and0.33%respectively. The result had statisticalsignificance (2=12.487, P＝0.014), hosts’ infectiosity MPG()was0.0105,0.0069,0.0142,0.0947and0.1574respectively, relative index of transmission was6.88%,46.44%,13.00%,32.11%and1.56%respectively. In flat area, infection rate of human,cattle and dog was0.76%,1.66%and9.30%respectively. It had statistical significance（=8.984, P＝0.011）, infectiosity of hosts MPG()was0.0084,0.0125and0.1589respectively, relative index of transmission was1.93%,56.08%and41.99%respecti-vely. In mountains, infection rate of human, equus, dog, mouse was1.19%,1.25%,3.31%and0.95%respectively, it had not statistical significanc（e=1.313, P＝0.726）,infectiosityof crowd MPG() was0.0122,0.0142,0.0516and0.4571respectively,relative index of transmission was22.52%,54.62%,22.87%and18.82%respectively.It had not statistical significance between the human infection rate(=0.012, P＝0.912), the dog infection rat(2=0.871,P＝0.351) and the cattle or equus infectionrate(=0.000, P＝1.0) in flat area and mountains area.4. The investigation and study showed that six kinds of hosts polluted environ-ment by their wild muck, these hosts were human, cattle, equus, sheep, pig, dog in3natural villages. In the range of50meters, we found the most amount of wild mucks.The rates is50.95%, in the range of300meters is91.98%, the density of wild muck ofsix hosts were0.88pile/h㎡,4.3pile/h㎡,2.93pile/h㎡,0.73pile/h㎡,0.41pile/h㎡and3.89pile/h㎡respectively. All kinds of environment’s wild muck wereinfected by Schistosomiasis. The positive rates had not statistical significant (=8.749,P=0.271). Positive wild mucks were from human, cattle, equus and dogs. Positive ratewas7.41%,0.72%,6.90%and14.29%respectively. The result was statistical signifi- cant（2=21.542, P＜0.001）, infectiosity MPG（）was0.0667,0.0038,0.0299and0.0738respectively. Relative polluted index was9.01%,2.25%,43.49%and45.26%respectively. In flat area, wild muck of dogs, cattle, human were positive, and positiverate was16.95%,9.52%and2.33%respectively, it had statistical significance(=6.596, P＝0.037), InfectiosityMPG（）was0.0842,0.0124and0.0857respectively.Relative polluted index was61.59%,19.70%and18.72%respectively. In mountains,wild muck of equus and dog were positive, positive rate was6.90%and11.94%, it hadnot statistical significance（=0.991, P＝0.340）, infectiosity MPG （）was0.0299and0.0637, relative polluted index was83.79%and16.21%. the wild muck positiverate had not statistical significance(=0.643, P＝0.423) between flat area andmountains.CONCLUSIONS1. The effect on integrated schistosomisis control in mountainous areas wasobvious, but the cost is relatively higher. The epidemic is low popular in general atpresent, Local epidemic situation is not optimistic The main factors to influences thecontrol effect can consider the construction of sanitary toilet, Population and livestocktreatment and chemotherapy, snail control with drug, livestock captive and ditchessclerosis.2. Sources of infection of schistosomiasis existed in mountainous areas of Yunnanmainly are cattle, dog, equus and human now. The dominant source of infection arecattle, dog and human in flat area, the dominant infection source are equus, dog andhuman in mountains area; mouse may be the reservoir host.3. Dogs as one of domiant source of infection at this stage, its roles in schistoso-miasis spread should be paid great attention, we should strengthen prevention andcontrol management to it,the targted technology and measure requires further study.Itcan be considerd as a sensitive indicate host in epidemic situation surveillance.4. One of dominant routes of transmission of Schistosomiasis is wild muck-borneinfection in Yunnan mountains areas. The areas with Oncomelania around300mwithin villages may be high risk environment. Investigation and monitoring index ofwild muck-borne can be considered as an important component to schistosomiasissource of monitoring in mountainous areas. |
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