ABSTRACT
Objective To investigate the prevalence of Schistosoma japonicum infections in Elaphurus davidianus released to Poyang Lake areas and evaluate the impact of the project of “E. davidianus released to wild environments for natural reproduction and growth” “(E. davidianus return home project”) on the transmission of schistosomiasis in Poyang Lake areas. Methods During the period from April 2018 to December 2019, the population distribution, inhabiting activity and natural reproduction of E. davidianus released to Poyang Lake areas were investigated by means of GPS and artificial observations. The S. japonicum infection was identified in animal feces in E. davidianus inhabitats using a hatching test, and snail distribution was surveyed in E. davidianus inhabiting grass islands using a systematic sampling method. Results A total of 51 E. davidianus were released to the Poyang Lake areas in 2018, which subsequently produced 5 E. davidianus habitats in Yinlong Lake, Longkou, Nanchi Lake, Lianzi Lake and Zhu Lake. E. davidianus was found to predominantly inhibit in grass islands, farmlands and forest lands in hilly regions around the Poyang Lake areas. The natural reproduction rate of E. davidianus was 25% in the habitats in 2019, and the mean density of snails was 0.009 to 0.039 snails/0.1 m2 in E. davidianus inhabitats; however, no S. japonicum infection was identified in snails. In addition, the mean densities of wild E. davidianus and bovine feces were 4.6 samples/hm2 and 2.1 samples/hm2, Conclusions The E. davidianus released to Poyang Lake areas may get infections with S. japonicum, and cause schistosomiasis transmission through fecal contamination in grass islands. The impact on and the prevalence of S. japonicum infection was 4.35% and 13.16% (P = 0.236), respectively; however, the intensities of S. japonicum infections were “+++” and “+”, respectively. Conclusions The E. davidianus released to Poyang Lake areas may get infections with S. japonicum, and cause schistosomiasis transmission through fecal contamination in grass islands. The impact on local schistosomiasis transmission and the response strategy requires to be investigated following the release of E. davidianus to lake regions, to ensure the achievement of the goal of schistosomiasis elimination and the successful implementation of the “E. davidianus return home project” in Poyang Lake areas.
ABSTRACT
Objective To understand the situation of Schistosoma japonicum infections in wild animals in transmission-controlled schistosomiasis-endemic areas in Jiangxi Province, so as to provide scientific evidence for implementing precision control interventions and achieving the goal of transmission interruption and elimination of schistosomiasis. Methods Five endemic villages from Ruichang City and Pengze County that were heavily endemic for schistosomiasis in Jiangxi Province, were selected as the study villages. Wild animals like wild mice were captured, and the livers of wild animals were purchased from the snail habitats in the study villages for detection of S. japonicum infections. In the study villages, S. japonicum human infections were screened using indirect hemagglutination assay (IHA) followed by parasitological examinations with miracidial hatching test and Kato-Katz method, and the S. japonicum infection in livestock was tested using a miracidial hatching test with a plastic tube. In addition, snail survey was conducted in the study villages by means of systematic sampling combined with environmental sampling, and the S. japonicum infection in snails was detected using a loop-mediated isothermal amplification (LAMP) assay. Results A total of 240 liver specimens were sampled or purchased from 5 species of wild animals in the study villages, including wild mice, weasels, pigs, deer and rabbits. A total of 172 wild mice were captured, with a 2.91% rate of S. japonicum infection, and there was no S. japonicum infection detected in other wild animals. The prevalence of Capillaria hepatica infection was 12.21%, 1.96% and 12.50% in wild mice, deer and pigs, respectively. In addition, there was no S. japonicum infection found in either humans or livestock in the study villages, and the mean snail density varied from 0.13 to 0.80 snails/0.1 m2 in the study villages. LAMP assay detected S. japonicum infection in 2 tubes in a study village. Conclusions The role of wild animals in schistosomiasis transmission and their potential risks can not be neglected in hilly schistosomiasis-endemic areas of Jiangsu Province after transmission control. Intensified surveillance and targeted control measures should be implemented to consolidate schistosomiasis control achievements.
ABSTRACT
Objective To understand the situation of Schistosoma japonicum infections in wild animals in transmission-controlled schistosomiasis-endemic areas in Jiangxi Province, so as to provide scientific evidence for implementing precision control interventions and achieving the goal of transmission interruption and elimination of schistosomiasis. Methods Five endemic villages from Ruichang City and Pengze County that were heavily endemic for schistosomiasis in Jiangxi Province, were selected as the study villages. Wild animals like wild mice were captured, and the livers of wild animals were purchased from the snail habitats in the study villages for detection of S. japonicum infections. In the study villages, S. japonicum human infections were screened using indirect hemagglutination assay (IHA) followed by parasitological examinations with miracidial hatching test and Kato-Katz method, and the S. japonicum infection in livestock was tested using a miracidial hatching test with a plastic tube. In addition, snail survey was conducted in the study villages by means of systematic sampling combined with environmental sampling, and the S. japonicum infection in snails was detected using a loop-mediated isothermal amplification (LAMP) assay. Results A total of 240 liver specimens were sampled or purchased from 5 species of wild animals in the study villages, including wild mice, weasels, pigs, deer and rabbits. A total of 172 wild mice were captured, with a 2.91% rate of S. japonicum infection, and there was no S. japonicum infection detected in other wild animals. The prevalence of Capillaria hepatica infection was 12.21%, 1.96% and 12.50% in wild mice, deer and pigs, respectively. In addition, there was no S. japonicum infection found in either humans or livestock in the study villages, and the mean snail density varied from 0.13 to 0.80 snails/0.1 m2 in the study villages. LAMP assay detected S. japonicum infection in 2 tubes in a study village. Conclusions The role of wild animals in schistosomiasis transmission and their potential risks can not be neglected in hilly schistosomiasis-endemic areas of Jiangsu Province after transmission control. Intensified surveillance and targeted control measures should be implemented to consolidate schistosomiasis control achievements.
ABSTRACT
OBJECTIVE: To analyze the status and trends of soil-transmitted nematode infections in Jiangxi Province from 1989 to 2014, so as to provide the evidence for generating the strategy of soil-transmitted nematode prevention and control. METHODS: The data of three epidemiological surveys on human parasitic diseases (in 1989, 2002 and 2014) were classified and analyzed. The stool examination by Kato-Katz's thick smear method was adopted for the investigation of soil-transmitted nematode infections. RESULTS: The total infection rate of soil-transmitted nematodes decreased by 91.89% from 77.67% in 1989 to 6.30% in 2014, in which the infection rate of Ascaris lumbricoides decreased by 98.78% from 71.11% to 0.87%, the infection rate of Trichuris trichiura decreased by 96.80% from 29.67% to 0.95%, and the infection rate of hookworm declined by 73.57% from 17.63% to 4.66%. The infection rates of soil-transmitted nematodes in the female were higher than those in the male in three surveys. In different ecological districts, the infection rates of soil-transmitted nematodes in the female were also higher than those in the male, except in Zhe-Min Ecological District in 2002 and 2014. A declined trend of the infection was showed in all age-groups in the three surveys, but it slowed down by the growth of age, i.e., the reduction rate was 97.03% in the age group of < 10 years while 80.62% in the age group of >70 years. In 2014, the number of persons infected with soil-transmitted nematodes occupied 65.4% of the whole number of persons infected with intestinal parasites. CONCLUSIONS: The mean infection rates of soil-transmitted nematodes decrease obviously in human population in different ecological districts, but the soil-transmitted nematodes are still the main species in intestinal parasite infections. The sequence of dominant species changes from A. lumbricoides, hookworm and T. trichiura in 1989 to hookworm, T. trichiura and A. lumbricoides in 2014. The rural female and elder people are the key population, while hookworm is the key species for the prevention and control of soil-transmitted nematodes.
Subject(s)
Intestinal Diseases, Parasitic/epidemiology , Nematode Infections/epidemiology , Soil/parasitology , Ancylostomatoidea , Animals , Ascaris lumbricoides , China/epidemiology , Female , Humans , Male , Prevalence , TrichurisABSTRACT
OBJECTIVE: To explore the cut-off value of the indirect haemagglutination test (IHA) method for schistosomiasis japonica diagnosis in different endemic areas. METHODS: Totally 55 nature villages of the lake-type endemic counties, Yugan and Xinzi, in Poyang Lake Region of Jiangxi Province were chosen as the study fields, and all the villagers over 5 years old were parallelly examined by Kato-Katz method + miracidial hatching test and IHA method. The detection data were analyzed by the correlation analysis, and the threshold values of the IHA method in different endemic areas were decided by the receiver operating characteristic (ROC) curve. RESULTS: The positive rate of stool examinations of the villagers was correlated with the distribution trend of the antibody level of whole population (r = 0.588, P ï¼ 0.05), but no correlation with the antibody level of the positive population (r = 0.221, P ï¼ 0.05). The antibody level of stool-negative population during the period of 2008 to 2011 detected by IHA method dropped year by year, and the annual difference was statistically significant (F = 3.650, P ï¼ 0.05). While the antibody level of stool-positive population found during the period of 2008 to 2011 maintained a certain high level in the 4 years, and there was no statistically significant difference among them (F = 2.461, P ï¼ 0.05). When the positive rates were <1%, 1%-5% or >5%, the specificity of diagnosis could be improved when 1â¶80, 1â¶20 and 1â¶10 were used as the cut-off values of IHA correspondingly. CONCLUSIONS: The different threshold values for diagnosis of schistosomiasis japonica should be considered while using IHA method to screen out patients in different endemic areas.
