| Objective(s): The aim of this study is to investigate the current status and influencing factors of hookworm infection in the environment of Pu ’er City and County and Xishuangbanna Prefecture,so as to provide evidence for the scientific prevention and control of hookworm disease.Methods: According to the previous surveillance data,the survey sites were selected for soil and vegetable sampling and the influencing factors were investigated according to the epidemiological method.10 to 20 soil samples and vegetable samples were collected from each village.At the same time,questionnaire survey was conducted on the sampled families,which mainly included the basic information of villagers,their hygiene habits,family environment and toilet hygiene conditions,as well as the basic information of villages,including population distribution,sources of income,basic information of public toilets and village water supply.The soil sample is about 500 g per serving and the vegetable sample is about 100 g per serving.The collected soil samples were collected by the separation method of hydatid and hookworm adults,and then examined by anatomic microscope.The positive samples were placed under an optical microscope for the identification of hookworm species.Eggs were collected by saturated sodium citrate solution,which could be directly identified under microscope.The collected vegetable samples were panned to collect hookworm larvae and eggs,and the microscopic examination method was the same as that of soil samples.Results:(1)A total of 441 samples were collected from Xishuangbanna Prefecture and Pu ’er city,and the total positive samples were 213,with a positive rate of 48.299%.A total of 261 samples were collected from Xishuangbanna Prefecture,and 136 were positive,with a positive rate of 52.107%.A total of 158 samples were collected from Menghai county,86 samples were positive,the positive rate was 54.430%.Of the 50 samples from Mengla county,25 were positive,with a positive rate of 50.000%.A total of 53 samples were collected from Gasa Town,Jinghong City,and 25 samples were positive,with a positive rate of 47.170%.The total number of samples from Pu ’er county was 180,and 77 samples were positive,with a positive rate of 42.778%.The total number of samples in Mojiang County was 31,and 15 were positive,with a positive rate of 48.387%.Among the 32 samples from Ninger County,15 samples were positive,and the positive rate was 46.875%.Among the 30 samples from Menglian County,9 samples were positive,and the positive rate was 30.000%.Among the 30 samples from Jingdong County,11 samples were positive,and the positive rate was36.667%.Among the 27 samples from Lancang County,14 were positive,with a positive rate of 51.852%.Among the 30 samples from Jingdong County,11 samples were positive,and the positive rate was 36.667%.Among the 20 samples from Jiangcheng County,13 were positive,with a positive rate of 65.000%.Among the 213 positive specimens,88.263% were identified as Necator americanus,and 10.798% were identified as Ancylostoma duodenale.(2)There was a significant difference in the prevalence of hookworm infection between Xishuangbanna Prefecture and Pu ’er City(χ2=11.440,P<0.05).There was no significant difference in the prevalence of hookworm infections among Menghai,Mengla and Jinghong cities(χ2=1.371,P>0.05).There was no significant difference in the prevalence of hookworm infection among the 5 counties(χ2=3.989,P>0.05).There was a significant difference in the positive rate of hookworm between soil and vegetable samples(χ2=48.583,P<0.05).The positive rate of hookworm was 49.074% in tropical areas and 48.048% in non-tropical areas,and there was no significant difference in the positive rate of hookworm between the two areas(χ2=0.034,P>0.05).The average density of C.mesoamericanus was84.762± 7.251/1000 g in Xishuangbanna Prefecture and 79.921± 9.683/1000 g in Puer City.There was no significant difference in the density of Necator americanus(t=0.402,P=0.695),but there was a significant difference in the density of Ancylostoma duodenale(t=2.41,P=0.020)and the density of hookworm eggs(t=-3.833,P<0.001)between the two areas.The positive rates of hookworm in the soil near vegetable fields and toilets were 35.398% and 60.869%,respectively,and the difference in the positive rates of hookworm was statistically significant(χ2=5.763,P<0.05).There was no significant difference in the positive rate of hookworm among different vegetables(χ2=10.110,P>0.05).(3)The prevalence of hookworm infection in the environment was negatively correlated with economic factors(r=-0.709,p<0.05),and the linear regression equation was ?=59.377-0.001 X.There was no correlation between the positive rate of hookworm in the environment and the hardening degree of the village roads(r=0.520,p>0.05).The positive rate of hookworm was 52.381% in the villages with public toilets,and 66.667% in the villages without public toilets,and the difference in the positive rate of hookworm was statistically significant(χ2=4.706,P<0.05).The prevalence of hookworm infections was 72.131%,67.924% and 55.102% in dry toilets,simple flush toilets and sanitary toilets,respectively,and there was a significant difference in the prevalence of hookworm infections among the three toilets(χ2=6.385,P<0.05).A total of 97 households were surveyed,and one person was surveyed in each household.There were 66 males,accounting for 68.041%.39 students were below primary school,accounting for 40.206%;The number of Dai was 37,accounting for38.144%;76 workers(86.264%)worked in the field without bare feet.When working in the field,69(78.409%)of them would defecate in the open if they wanted to use the toilet.There was a significant association between going to the toilet in the field and the positive rate of hookworm infection in the environment(χ2=4.839,P<0.05),and there was a significant association between the frequency of washing hands after going to the toilet or being in contact with dirty objects and the rate of hookworm contamination in the environment(χ2=5.798,P<0.05).Among the 97 families surveyed,73(75.258%)families had a good hygienic environment.The main type of toilet was simple flush toilet,accounting for 91.753%;The number of households with hardening around toilets was 93,accounting for 95.876;The number of households without fecal exposure around the toilet was 51,accounting for 52.577%.Conclusion(s):(1)According to the survey,the positive rate of hookworm in the soil and vegetables(mainly root vegetables)in the three counties of Xishuangbanna Prefecture and Pu ’er City was relatively high.The main species of hookworm in the environmental samples was Necator americanus,and the infection rate was higher than that in the local population monitored or surveyed.(2)The results showed that the positive rate of hookworm in Xishuangbanna Prefecture was higher than that in Pu ’er City.The positive rate of hookworm in vegetables was higher than that in soil.However,there was no significant difference in the prevalence of hookworm infection between tropical and non-tropical areas.There was no significant difference in the positive rate of hookworm among different vegetables.(3)The survey found that economic factors,the availability and type of public toilets,and the frequency of washing hands after going to the toilet and touching dirty things were the main factors affecting the positive rate of hookworm in the environment. |
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