Soil-transmitted Nematode Infections Research Articles

Effect of Soil Temperature on Canine Soil-Transmitted Nematodes in Kandy District with the First Record of Hookworm, Ancylostoma tubaeforme from Sri Lanka.

Soil-transmitted nematodes (STNs) are widespread in tropical and subtropical regions, particularly where the communities are socio-economically challenged. We investigated the effect of soil temperature on the prevalence and intensity of STN infection in free-roaming dogs. Fresh faecal samples collected from free-roaming dogs in Digana and Pussellawa town areas in the Kandy District, Sri Lanka, were microscopically analysed for canine STNs. Soil temperature was measured at each sampling site. Highly prevalent canine hookworm Ancylostoma, was further studied using PCR and sequencing, followed by phylogenetic analysis. The soil temperature ranged between 28 and 31°C (mean = 29.79°C) and 18-21°C (mean = 19.52°C) in Digana and Pussellawa, respectively, showing a significant difference in the two sites (Students t-test t = 1.68, p < 0.0001). Of the total 44 dogs sampled, 41 (93.2%) were positive for STNs. During microscopic analysis, five nematodes: Ancylostoma spp., Capillaria sp., Strongyloides sp., Toxocara canis, and Trichuris sp., were identified. Ancylostoma species (93.2%) were the most prevalent, followed by Strongyloides sp. (22.7%) and Toxocara canis (15.9%). Infection prevalence of Strongyloides sp. was higher in Digana (40.9%) compared to that in Pussellawa (4.5%; Chi-square test, χ2 = 8.28, p = 0.004) and also the infection intensity from Digana (EPG = 8.02 ± 20.2) compared to that from Pussellawa (0.45 ± 2.1; Mann Whitney U test, p = 0.006). Amplicons (ITS1-5.8S-ITS2) of the expected size for A. caninum, and A. tubaeforme were produced. An A. caninum sequence reported here (OQ101719) illustrated the highest similarity of 99.2% to one of the local sequences (MZ707153) upon pairwise comparison. Digana, with a higher soil temperature than Pussellawa, had a significantly higher prevalence and infection intensity, particularly Strongyloides sp. This study also signifies the first molecular identification of hookworm species A. tubaeforme in Sri Lanka.

Clinico-microbiological and Risk Factor Analysis of Strongyloides stercoralis Infections in South India

Strongyloides stercoralis is a soil-transmitted nematode infection. It is implicated in causing hyper infection syndrome in immunosuppressed patients. This infection can also present without symptoms. The study aims to analyze the demographic data and risk factors associated with acquiring this infection and detectStrongyloides stercoralis in the stool sample by microscopy and modified agar plate culture. Combining microscopy and culture can facilitate detecting the infection in cases of low worm burden. Evaluation of socio-demographic information and risk factors will help in implementing control measures. A total of 986 stool samples were received. All the samples were examined by saline and Iodine mount examination. All the stool samples were cultured by the modified agar plate method. The risk factors, patient demographic details and clinical features were analyzed for significant association using the Chi-square test and a p-value &lt; 0.05 was considered significant) by quick calls graph pad software. The overall prevalence of Strongyloides stercoralis infection was 22(1.23%), and all these cases were diagnosed on stool examination by the demonstration of rhabditiform larva ofStrongyloides stercoralis and adult females by modified agar plate culture. The positivity for Strongyloides larva was high among males, patients from rural areas and individuals working in agricultural settings. There was a significant association between walking barefoot and the demonstration of the larva. Patients presenting from endemic regions, even with vague, nonspecific gastrointestinal symptoms, especially with risk factors like Diabetes mellitus, should be screened for this infection and treated. Awareness, proper hygiene practices, and appropriate treatment are necessary to prevent this soil-transmitted helminthic infection.

Prevalence and influencing factors of human soil-transmitted nematode infections in Ningbo City from 2016 to 2021

To investigate the prevalence and influencing factors of soil-transmitted nematode infections in Ningbo City from 2016 to 2021, so as to provide insights into the development of targeted control measures against soil-transmitted nematodiasis. Permanent residents at ages of 3 years and older were sampled in Ningbo City using a multi-stage sampling method each year during the period from 2016 to 2021. Soil-transmitted nematode eggs were detected in stool samples using a modified Kato-Katz thick smear method (two slides for each stool sample), and Enterobius vermicularis eggs were additionally identified among children at ages of 3 to 12 years using the adhesive cellophane-tape perianal swab method. The time- and regions-specific prevalence of soil-transmitted nematode infections was calculated, and the factors affecting hookworm infections were identified using a multivariate logistic regression model. A total of 11 573 person-times were detected for soil-transmitted nematode infections in Ningbo City from 2016 to 2021, and 296 egg-positives were detected, with a mean prevalence rate of 2.56% [95% confidential interval (CI): (2.28%, 2.87%)]. Hookworm was the predominant species of soil-transmitted nematode among egg-positives in Ningbo City (98.31%, 291/296), and there was a significant difference in the prevalence of hook-worm infections among years (χ2 = 190.27, P < 0.01). The highest prevalence of hook-worm infections was observed in Ninghai County (4.06%), and there was a region-specific prevalence rate of hookworm infection in Ningbo City (χ2 = 148.43, P < 0.01). Multivariate logistic regression analysis showed that elderly residents at ages of over 60 years [odds ratio (OR)= 1.94, 95% CI: (1.07, 3.54), P < 0.05], males [OR = 2.19, 95% CI: (1.72, 2.80), P < 0.01], farmers [OR = 6.94, 95% CI: (3.37, 14.29), P < 0.01] and residents with a low education level [illiteracy or semi-illiterate: OR = 3.82, 95% CI: (1.56, 9.35), P < 0.05; primary school: OR = 2.70, 95% CI: (1.11, 6.59), P < 0.05] were at a higher risk for hookworm infections. The overall prevalence of soil-transmitted nematode infections was low among residents in Ningbo City from 2016 to 2021. The surveillance and health education for human hookworm disease remain to be reinforced among male farmers with a low education level at ages of over 60 years in Ninghai County.

Spatio-temporal distribution characteristics of soil-transmitted nematodiasis in Sichuan Province from 2016 to 2021

To investigate the trends in the prevalence of soil-transmitted nematode infections and the spatio-temporal distribution characteristics of soil-transmitted nematodiasis in Sichuan Province from 2016 to 2021, so as to provide the evidence for formulating the soil-transmitted nematodiasis elimination strategy in Sichuan Province. The soil-transmitted nematodiasis surveillance data in Sichuan Province from 2016 to 2021 were collected, and the epidemic trend of soil-transmitted nematode infections was identified. The distribution maps of soil-transmitted nematode infections in Sichuan Province were plotted to identify their spatial distribution characteristics. In addition, the spatial clusters of soil-transmitted nematode infections were detected using globa and local spatial autocorrelation analyses. The prevalence of soil-transmitted nematode infections appeared a decline with time in Sichuan Province from 2016 to 2021 (χ2= 400.24, P < 0.01). Global spatial autocorrelation analysis identified positive spatial autocorrelations in the prevalence of soil-transmitted nematode infections (Moran's I = 0.322, Z = 16.293, P < 0.01), hookworm infections (Moran's I = 0.425, Z = 21.290, P < 0.01), Ascaris lumbricoides infections (Moran's I = 0.102, Z = 5.782, P < 0.01) and Trichuris trichiura infections (Moran's I = 0.084, Z = 6.873, P < 0.01). Local spatial autocorrelation analysis showed that the high-high clusters of soil-transmitted nematode infections were mainly located in 37 counties (cities, districts) of Sichuan Province, and the high-high clusters of hookworm, A. lumbricoides and T. trichiura infections were mainly identified in 39 counties (cities, districts) in mountainous areas around Sichuan Basin and hilly areas, 9 counties (cities, districts) in mountainous areas in southwestern Sichuan Province, and 8 counties (cities, districts) in mountainous areas in southwestern Sichuan Province, respectively. The prevalence of soil-transmitted nematode infections appeared a tendency towards a decline in Sichuan Province from 2016 to 2021, which showed spatial clusters. The management of soil-transmitted nematodiasis requires to be reinforced in high-risk areas of Sichuan Province with adaptations to local epidemiological features.

Surveillance of soil-borne nematodiasis in Yancheng City from 2016 to 2020

To understand the prevalence of soil-transmitted nematode infections in Yancheng City from 2016 to 2020, so as to provide insights into the development of the scheme for further soil-transmitted nematodiasis surveillance. Soil-borne nematode infections were detected using the modified Kato-Katz method (two slides for one sample) among the permanent residents living in Yancheng City from 2016 to 2020, and Enterobius vermicularis infection was additionally detected among children at ages of 12 years and lower using the adhesive cellophane-tape perianal swab method. The prevalence and intensity of human soil-borne nematode and E. vermicularis infections were descriptively analyzed. A total of 51 259 person-time residents were detected for soil-borne nematode infections in Yancheng City from 2016 to 2020, and 48 egg-positives were identified, with a 0.09% prevalence. The soil-borne nematodes infecting residents included Ascaris lumbricoides, hookworm and Trichuris trichiura, with 0.04%, 0.05% and 0.002% prevalence rates of infections, and all infections were mild. There was a region-specific prevalence of soil-borne nematode infections in Yancheng City (χ2 = 18.21, P = 0.02), with the highest prevalence seen in Funing County (0.21%), while no infections were detected in Dafeng District for five successive years. The overall prevalence of E. vermicularis infections was 0.22% among children at ages of 12 years and lower in Yancheng City. The prevalence of soil-borne nematode infections appears a gradual decline in residents living in Yancheng City from 2016 to 2020, and is at an extremely low level. Further surveillance of soil-transmitted nematodiasis requires to be intensified targeting key regions and populations to consolidate the control achievements.

Surveillance of human soil-transmitted nematodiasis in Jurong City from 2016 to 2020

To investigate the prevalence of soil-transmitted nematode human infections in Jurong City from 2016 to 2020, so as to provide the scientific evidence for formulating the control strategy. During the period from 2016 to 2020, the permanent residents at ages of over 3 years living in Jurong City were selected as the study subjects. Stool samples were collected for the detection of soil-transmitted nematode eggs using the modified Kato-Katz thick smear method (two detections for one stool sample), and the species of hookworm was identified in stool-positive stool samples using the culture method. The prevalence and intensity of soil-transmitted nematode infections were calculated, and the change of the infection prevalence among years was examined using the Cochran-Armitage test for trend. A total of 10 011 people-time populations were detected for soil-transmitted nematode infections in Jurong City from 2016 to 2020, and 56 egg-positives were identified, with mean prevalence of 0.56%. The prevalence of soil-transmitted nematode human infections appeared a tendency towards a decline year by year in Jurong City (χ2trend = 5.15, P < 0.01). The mean prevalence of hookworm, Ascaris lumbricoides and Trichuris trichiura infections was 0.44%, 0.11% and 0.20% in Jurong City from 2016 to 2020, respectively, and individuals with hookworm infections accounted for 78.57% of all cases with soil-transmitted nematode infections. Single parasite (98.21%) and mild infection were pre-dominant in individuals with soil-transmitted nematode infections, and no multiple infections were seen after 2016. The prevalence of human soil-transmitted nematodiasis is low in Jurong City. Based on reinforcement of soil-transmitted nematodiasis surveillance, an increase in the health education investment is required to consolidate the control achievements.

Concurrent Intestinal Schistosomiasis and Soil-Transmitted Nematode Infections in Primary School Children, Benue State North Central Nigeria

Intestinal schistosomiasis and soil-transmitted nematode (STN) infections are among the major public health problems globally, especially in sub-Saharan Africa, Nigeria inclusive. School-aged children carry the highest burden of both infections with significant morbidities in Nigeria. Data on co-endemicity of these infections especially amongst internally displaced persons (IDP) is scarce. To fill this gap, we performed a school-based cross sectional study in three rural communities in North Central Nigeria in which internally displaced persons co-existed. The study aimed to determine the co-endemicity of Schistosoma mansoni and soil-transmitted nematodes infections among primary school children in six primary schools in Guma Local Government area, Benue State, north central Nigeria. Four hundred and forty three primary school pupils were included in the study between January and March 2018 by using simple random technique. A single stool specimen was collected from each participant, and a portion about 1 gram of each specimen was processed by Kato Katz technique. Of the 443 pupils examined, 219(49.4%) were found positive for the characteristic egg of at least one STN. Of the total children, 46(10.4%) had Schistosoma mansoni infection. Co-infection of atleast one STN and S.mansoni occurred in 21(4.7%) of the 443 pupils sampled. Co-infection of Schistosoma mansoni and Ascaris lumbricoides was observed in 11(23.9%) while Schistosoma mansoni and hookworm occurred in 10(21.7%) of the children. There was higher intensity in the total egg count among the males (51.99±60.67) than the females (48.42±59.89) in both genders. The intensity of egg count was highest in age group 7-9 years (55.27±65.03). The lowest intensity was observed in age group 13-15 (41.47±46.08).Integrated interventions such as health education, school feeding program for improved nutrition and mass chemotherapy is advocated.

Analysis of factors related to human soil-transmitted nematode infections in Chongqing City

To investigate the related factors of soil-transmitted nematode infections in Chongqing City, so as to provide the basis for scientific prevention and treatment of the infections. From 2011 to 2015, the stool samples of residents of the surveillance sites in Chongqing City were collected every year, and the soil-transmitted nematode eggs were examined by the modified Kato-Katz thick smear method (three smears for a single stool sample). The respondents were surveyed by questionnaires, and the factors affecting soil-transmitted nematode infections were identified. The prevalence of human soil-transmitted nematode infections were 6.44%, 7.30%, 6.85%, 6.93% and 5.56% in Chongqing City from 2011 to 2015, respectively. The more unclean drinking water and the lower frequency of washing hands after using the toilet were the risk factors for Ascaris lumbricoides infection. The more harmless toilets, the higher level of fertilizer application, the lower frequency of drinking raw water, and the lower frequency of food without washing were the protective factors for A. lumbricoides infection. The local soil-transmitted nematode infections are at a low epidemic level in Chongqing City, and it is necessary to ad-here to the classified guidance, comprehensive prevention and further monitoring on the basis of health education, water and toilet improvement, and environmental sanitation improvement in order to consolidate the prevention and control achievements.

Surveillance of soil-transmitted nematode infections in Zhenjiang City from 2006 to 2018

To understand the epidemic trend of soil-transmitted nematodiasis in Zhenjiang City from 2006 to 2018, so as to provide evidence for formulating targeted control measures. The permanent residents at ages of 3 years and greater and the immigrants who had lived in Zhenjiang City for more than one year were selected as the study subjects. Fecal samples were collected, and the soil-transmitted nematode eggs were detected in fecal samples with the modified Kato-Katz technique (three smears from one stool sample), while the children at ages of 12 years and lower were tested for Enterobius vermicularis eggs using the adhesive cellophane-tape perianal swab method. The prevalence and intensity of parasitic infections were estimated in Zhenjiang City each year from 2006 to 2018, and the data pertaining to the deworming for soil-transmitted nematode infections were collected during the study period. A total of 202 880 person-times were subjected to stool examinations in Zhenjiang City from 2006 to 2018, and 946 persons were detected with soil-transmitted nematode infections, with a mean prevalence of 0.47%. The overall prevalence of human soil-transmitted nematode infections appeared a decline tendency (P < 0.01), with a reduction from 1.10% in 2006 to 0.11% in 2018, and there was a region-specific overall prevalence (P < 0.01), with the highest prevalence seen in Runzhou District (1.65%) and the lowest detected in New District (0.04%). The mean prevalence of human Ascaris lumbricoides, hookworm and Trichuris trichiura infections was 0.33%, 0.09% and 0.04% in Zhenjiang City, respectively, and showed a decline tendency year by year from 2006 to 2018 (P < 0.01). Among all infections, mild infections were predominant. During the period from 2006 through 2018, a total of 45 427 children were examined in Zhenjiang City from 2006 to 2018, and 145 children were positive for E. vermicularis infections, with a mean prevalence of 0.32%. The prevalence of E. vermicularis infections decreased from 1.33% in 2006 to 0.22% in 2018 in children, and the overall prevalence appeared a decline tendency (P < 0.01). A single parasite infection was predominant in soil-transmitted nematode infections (97.46%), and mixed infection of two parasites were mainly detected before 2007. A total of 535 089 person-times received deworming in Zhenjiang City from 2006 to 2018, and the rate of adverse events was 0.002%. Currently, the soil-transmitted nematode infection is at a low level in Zhenjiang City, and the overall prevalence of soil-transmitted nematode infections shows a decline tendency year by year. The surveillance and health education of soil-transmitted nematodiasis should be further intensified to consolidate the control achievements.

Soil-transmitted nematode infections and influencing factors in pupils from rural areas of Yi Ethnicity in Butuo County, Sichuan Province

To understand the current situation of soil-transmitted nematode infections and influencing factors of pupils in rural areas of Yi Ethnicity in Butuo County, Sichuan Province, so as to provide the evidence for the prevention and control of soil-transmitted nematode infections. In 2016, the pupils of 2 villages in Butuo County were selected by the multi-stage random sampling method, and the relevant information was obtained by questionnaires, including social demographic information, diet and hygiene habits and acknowledge of parasitic disease prevention. The soil-transmitted nematode infections were examined by Kato-Katz technique. The results were statistically analyzed by the single factor analysis and multivariate logistic regression methods. A total of 160 pupils were investigated in this survey. The soil-transmitted nematodes included Ascaris lumbricoides, Trichuris trichiura and hookworm. The overall infection rate was 89.38%, and the multi-infection rate was 54.55%. The infection rates of A. lumbricoides and T. trichiura were higher. The infection densities were mild (75.68%) or moderate (22.97%). The logistic regression analysis showed that the protective factor of soil-transmitted nematode infections was the knowledge about correct diet and health habits notified by teachers (OR = 0.67), but the risk factor was drinking unboiled water (OR = 19.26). The infection rate of nematodes is still high in the pupils in rural areas of Yi Ethnicity in Butuo County, Sichuan Province. Therefore, we should strengthen the prevention and control of soil-transmitted nematode infections, especially A. lumbricoides and T. trichiura infections, and mostly develop the teachers'function in health education.

STUDY ON INTESTINAL PARASITIC INFECTION AND RELATIONSHIPS BETWEEN THE INFECTIONS AND CORRELATED FACTORS ON SCHOOLCHILDREN AT TRA VINH PROVINCE IN 2017

The research used a cross-sectional method, which was conducted on 800 primary students in Tap Son primary school and Laboratory school in TraVinh province in order to identify the prevalence of soil-transmitted nematode infections and the relationship between the infection and correlated factors. Stool samples were examined with direct smear method. The rate of intestinal parasitic infection on the primary students in TraVinh province was 4,4%. Of which, Laboratory school had the least rate of intestinal parasitic infection with 0,0%, while Tap Son primary school had the highest rate of intestinal parasitic infection with 8,8%. Hookworm was the predominant nematode (100%), followed Ascarislumbricoides (0,0%), and Trichuristrichiura (0,0%). These relationships show that Tap Son primary environment is heavily polluted with hookworm eggs and that directly behavioral exposure to soil is a risk related to hookworm infections in the community.

Surveillance results of national monitoring sites for soil-transmitted nematode infections in Xinchang County from 2009 to 2017

To understand the infection status of soil-transmitted nematodes in Xinchang County, so as to offer the evidence for the formulation of control measures. The infection of soiltransmitted nematodes in residents was investigated by using the Kato-Katz method and cellophane anal swab. A total of 3 069 people were examined in 2009, 2012 and 2017, of which 1 520 people were male and 61 people were infected, with the infection rate of 4.01%; 1 549 were women and 54 people were infected, with the infection rate of 3.48%. The infection rates of soil-transmitted nematodes in 2009, 2012 and 2017 were 4.60%, 4.29% and 2.35%, respectively, and the total infection rates were decreased (χ2 = 7.151, P < 0.05). The rate of soil-transmitted nematode infection in Xinchang County is declining, and it is at a low epidemic level.

Trends of soil-transmitted nematode infections in Jiangxi Province

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. 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. 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. 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.

Epidemic status of human key parasitic diseases in Tongcheng City, Anhui Province

To understand the current status of key parasitic diseases in Tongcheng City, so as to provide an epidemiological reference for formulating the scientific planning for "13th Five-year" parasitic diseases prevention and control. The villages of different levels in Tongcheng City were sampled to investigate the infection of parasitic diseases of residents aged three or more years. Soil-transmitted nemathelminth, intestinal protozoa and Enterobius vermicularis were investigated by the Kato-Katz technique (a fecal sample seized two), iodine smear method and cellophane tape method, respectively. Meanwhile a questionnaire survey was conducted on the basic situation, knowledge and health behaviors of the residents to soiltransmitted nemathelminth infection. Totally 1 023 residents were investigated, and 38 were positive of parasitic infection, with the total infection rate of 3.71%. The soil-transmitted nematodes infection rate was 3.62%, 36 people were infected with hookworm (3.52%), one person was infected with Trichuris trichiura (0.10%), one person was infected with intestinal protozoa (Blastocystis hominis). Ascaris lumbricoides, E. vermicularis and tapeworm infections were not founded. The total awareness rate of prevention knowledge, behavior and attitude was 76.93%. The infection rate of soil-transmitted nemathelminth infections is reduced below 5% in Tongcheng City. The main species of parasites is Necator americanus, and the population of the infection is mainly concentrated in the residents over the age of 60 years.

The importance of patient compliance in repeated rounds of mass drug administration (MDA) for the elimination of intestinal helminth transmission

BackgroundSystematic non-compliance to chemotherapeutic treatment among a portion of the eligible population is thought to be a major obstacle to the elimination of helminth infections by mass drug administration (MDA). MDA for helminths is repeated at defined intervals such as yearly or every 2 years, as a consequence of the inability of the human host to develop fully protective immunity to reinfection. As such, how an individual complies to these repeated rounds of MDA can have a significant impact on parasite transmission. The importance of this factor is poorly understood at present. Few epidemiological studies have examined longitudinal trends in compliance in the many communities in areas of endemic helminth infection that are undergoing MDA. Reducing systematic non-compliance will obviously increase the number of individuals treated, but it may also alter the dynamics of parasite transmission.MethodsHere we develop an individual-based stochastic model of helminth transmission and MDA treatment to investigate how different patterns of compliance influence the impact of MDA for two groups of helminths, the soil transmitted nematode infections and the schistosome parasites. We study the effect of several alternative treatment and compliance patterns on the dynamics of transmission.ResultsWe find that the impact of different compliance patterns, ranging from random treatment at each round of chemotherapy to systematic non-compliance by a proportion of the population, is very dependent on both transmission intensity in a defined setting and the type of infection that the treatment is targeted at. Systematic non-compliance has a greater impact on the potential for elimination of Schistosoma mansoni transmission by intensive MDA, than it does on Ascaris lumbricoides.ConclusionsWe discuss the implications of our findings for the prioritisation of resources in MDA programmes and for monitoring and evaluation programme design. The key message generated by the analyses is that great care must be taken to record individual longitudinal patterns of compliance at each round of MDA as opposed to just recording overall coverage.

Investigation on soil - transmitted nematode infections in national surveillance sites in Jiangsu Province from 2006 to 2015

To understand the status of soil-transmitted nematode infections in rural residents so as to provide the evidence for formulating the guidance for prevention and control of the diseases. The national surveillance sites of soil-transmitted nematode infections were established in Shuyang County, Suqian City, Jiangsu Province from 2006 to 2015. At least 1 000 fecal samples of residents aged 3 years or above were collected in every autumn, and the intestinal helminth eggs were detected with the Kato-Katz technique and the Enterubius vermicularis eggs were detected by the cellophane tape method for children aged 3-12 years. The soil samples were collected from vegetable fields, lavatories, courtyards and kitchens to examine Ascaris lumbricoides eggs and larvae of hookworm. The infection rates of soil-transmitted nematodes in residents and E. vermicularis in children reduced from 1.81% (19/1 049) and 4.72% (5/106) in 2006 to 0.25% (3/1 180) and 0 (0/263) in 2015, respectively, in the surveillance sites. The infection intensity was mild in all the infected cases. The soil samples were negative for detecting A. lumbricoides eggs and hookworm larvae. The infection rates of soil-transmitted nematodes in the residents and E. vermicularis in the children show a decreasing trend and keep at a low level of prevalence in Shuyang County.

Investigation of soil - transmitted nematode infections in Xiding Township, Menghai County, Yunnan Province

To understand the status of soil-transmitted nematode infections in Xiding Township, Menghai County, Yunnan Province, so as to provide the reference for formulating the strategy of soil-transmitted nematodosis control. Soil-transmitted nematode eggs in feces were detected by the Kato-Katz method, and the eggs of Enterobius vermicularis were detected by the cellophane tape method in children. The soil samples were collected from vegetable, fruit and other crop fields of 15 residents randomly to detect hookworm. The stool samples from 1 002 residents were examined and the soil -transmitted nematode infection rate was 20.06% (201/1 002). The infection rates of hookworm, Ascaris lumbricoides and Trichuris trichura were 18.96% (190 cases), 1.70% (17 cases) and 0.90% (9 cases) respectively. The percentages of people with light infection of hookworm, A. lumbricoides and T. trichura were 97.37% (185/190), 88.24% (15/17) and 100% (9/9) respectively. No infection of E. vermicularis was found. Fifteen soil samples were tested, and no hookworm was found in the soil. The infection rate of soil-transmitted nematode in Xiding Township, Menghai County is high, but the infectiosity is light. The control and monitoring of soil-transmitted nematodosis should be strengthened in this area.

Effect of different stages of Schistosoma mansoni infection on the parasite burden and immune response to Strongyloides venezuelensis in co-infected mice.

Multiple schistosome and soil-transmitted nematode infections are frequently reported in human populations living in tropical areas of developing countries. In addition to exposure factors, the host immune response plays an important role in helminth control and morbidity in hosts with multiple infections; however, these aspects are difficult to evaluate in human populations. In the current study, female Swiss mice were simultaneously co-infected with Strongyloides venezuelensis and Schistosoma mansoni or infected with St. venezuelensis at 2, 4, or 14weeks after Sc. mansoni infection. The simultaneously infected mice showed a similar parasite burden for St. venezuelensis compared with mono-infected mice. In contrast, there was a significant reduction of St. venezuelensis burden (primarily during the migration of the larvae) in mice that were previously infected with Sc. mansoni at the acute or chronic phase. Independent of the stage of Sc. mansoni infection, the St. venezuelensis co-infection was capable of inducing IL-4 production in the small intestine, increasing the IgE concentration in the serum and increasing eosinophilia in the lungs and intestine. This result suggests that the nematode infection stimulates local type 2 immune responses independently of the schistosomiasis stage. Moreover, previous Sc. mansoni infection stimulated early granulocyte infiltration in the lungs and trematode-specific IgM and IgG1 production that recognized antigens from St. venezuelensis infective larvae; these immune responses would act in the early control of St. venezuelensis larvae. Our data suggest that the effect of multiple helminth infections on host susceptibility and morbidity largely depends on the species of parasite and the immune response.

REASSESSMENT OF HELMINTH INFECTIONS IN GULU MUNICIPALITY NOTHERN UGANDA AFTER THE TWENTY YEARS OF INSURGENCY: USING THREE DIAGONOSTIC METHODS TO COMPARE THEIR SENSITIVITY.

During the period of insurgency there were several internally displace people camps all over the Northern Uganda. People who lived within ten kilometers from Gulu Municipality were forced to evacuate their villages and re-locate and build huts for themselves in areas identified for them by the government. There were several of such camps within the municipality creating influx of people from the villages to the municipality for security. Now with the situation restored to normal, there is need to re-assess and update information on the prevalence of helminth infections in Gulu municipality where many of the internally displaced people (IDP) settled. To find out if S. mansoni and soil transmitted nematode infections are so prevalent and very common in children aged betweenfive to 20 years. In Gulu municipality and that additional preventive and curative measure need to be considered. Further is there a strong need to reconsider more sensitive diagnostic methods at the hospitals or does the standard approach of direct smear examination recognise at least most heavy infected children with any of the parasites. Setting. The study was carried out in Gulu municipality. Purposive and random sampling methods were used. Study Population: Mainly Primary school children aged between five to 20 years randomly selected from four primary schools purposively selected around Gulu municipality were recruited for the study. For control 20 staff of each school randomly selected were also studied. Of the 582 samples tested, 117(20.1%) were found positive for Schistosoma mansoni. Fifteen (2.6%) other samples were found positive for other helminths like Ascaris lumbricoides, Trichuris trichiura H.nana Hookworm. The comparison between the methods showed that the results obtained by the three methods were similar for field research. There is a low intensity of infection with soil transmitted helminths found in the primary schools around Gulu municipality. We concluded that the prevalence and intensity of infection with soil transmitted helminths was low among the children aged between 5 to 20 years in the four primary school studied (2.6%) but there was medium infection with S.mansoi (20.1%). The sensitivity in detecting the helminthes eggs in the stool specimen were similar. Though the original Kato/Katz method recorded lowest egg count than the Polderman and Odongo-Aginya methods. This could be due to the fact that the slides were read immediately.

The promise and pitfalls of mass drug administration to control intestinal helminth infections

Intestinal helminth infections continue to cause significant morbidity in resource-limited settings. Recent efforts at global control have centered on mass drug administration (MDA) of praziquantel and benzimidazole anthelminthics to reduce the prevalence and intensity of schistosomiasis and soil-transmitted nematode infections, respectively. This review summarizes progress and potential challenges associated with MDA. Data from studies conducted in endemic areas show that chemotherapeutic interventions can reduce prevalence and intensity of infection with intestinal helminths, and have the potential to reduce transmission within populations. However, consistent benefits in high-risk groups, including children and pregnant women, have not been established. The long-term benefits of MDA remain to be determined, and the potential for emerging resistance to impact effectiveness have not yet been defined. Whereas studies evaluating MDA have shown benefit in certain populations, intensive monitoring and evaluation, as well as a commitment of resources for new drug development, are essential for long-term control or elimination of intestinal helminth infections.