Concurrent urinary and intestinal schistosomiasis and intestinal helminthic infections in schoolchildren in Ilobu, South-western Nigeria

A cross-sectional study was conducted in a schistosome-endemic rural community in Southwestern Nigeria. We assessed prevalence and intensity of soil-transmitted nematodes and the co-occurrence with Schistosoma haematobium and Schistosoma mansoni. Urine and stool samples from 419 schoolchildren were examined, and a questionnaire was administered to obtain socio-demographic characteristics. In total, 78.3% (328/419) were infected with at least one helminth species, with a prevalence (mean egg-count) of 55.1% (3069.2) of Ascaris lumbricoides, 41.1% (127.5) of S. haematobium, 22.7% (98.6) of hookworms, 17.9% (161.3) of Trichuris trichiura, and 10.3% (12.9) of S. mansoni. Multiple infections were significantly more common among children from households with more playmates, absence of toilet facilities and low income level (all p<0.001). Children with heavy hookworm burden were at a significantly higher chance of acquiring S. mansoni (OR=36.35; 95% Cl: 13.22-100.97; p<0.0001). The risk of S. mansoni and A. lumbricoides infections was increased in co-infections with S. haematobium. Logistic regression analysis revealed infections by hookworms and S. mansoni (adjusted odds ratio [aOR]=3.90, 95% Cl: 2.03-7.46; p<0.0001), and by hookworms and T. trichiura (aOR=2.46, 95% Cl: 1.44-4.22; p=0.001) as significant risk factors for multiple infections. Our study shows that polyparasitism is common in the study area. Focused interventions such as mass treatment with anthelminthics and health education are needed to improve the well-being of the affected population.     

Moderate- and low-intensity co-infections by intestinal helminths and Schistosoma mansoni, dietary iron intake, and anemia in Brazilian children

To determine the role of moderate- and low-intensity infections with Schistosoma mansoni and intestinal helminths (hookworm, Trichuris trichiura, Ascaris lumbricoides) on the prevalence of anemia and their relationship to iron consumption, a cross-section of 1,709 children in rural Brazil was studied. All participants were selected for infection with one or multiple helminthic parasites, and demographic, anthropometric, and dietary intake were surveyed. The prevalence and intensity were as follows: hookworm infection, 15.7% and 8.6 eggs/g; T. trichiura, 74.8% and 190.5 eggs/g; A. lumbricoides, 63% and 1,905.5 eggs/g; S. mansoni, 44.5% and 60.3 eggs/g. There was no increase in odds ratio for anemia with any combination of intestinal helminths without S. mansoni infection. By logistic regression, the odds ratio for having anemia when infected with S. mansoni and two intestinal helminths was 1.7 (95% CI, 1.1-2.5) and for S. mansoni and three intestinal helminths was 2.4 (95% CI, 1.2-4.6) compared with children with a single parasite species. Children with an adequate intake of iron had no increased odds of anemia independent of the combination of parasite infections.     

Reinfection and infection rates of soil-transmitted-helminths in Kemiri Sewu, Yogyakarta, Indonesia

A study on the reinfection and infection rates of soil-transmitted helminths was conducted in Kemiri Sewu, Godean District, Sleman Regency, Yogyakarta Special Province, Indonesia, from August 1988 to June 1990. A total 61 individuals rendered Ascaris lumbricoides egg-negative by drug treatment were used in the reinfection study and 412 individuals found negative for Ascaris eggs in the pretreatment stool examination were used for the infection rate study. In both groups, children had higher and faster reinfection and infection rates than adults. The start of reinfection was 4 months after treatment, and the start of infection was at the 1st month. At 20 months after treatment, the reinfection rate of ascariasis was 14.8% and the infection rate was 11.4% among both children and adults. There were 140 subjects rendered Trichuris trichiura egg-negative by drug treatment, and 317 Trichuris egg-negative at the pretreatment stool examination which were used in the reinfection and infection rates studies. In general, the reinfection rates of T. trichiura among adults were higher than those among children. The start of reinfection was 4 months after treatment, and the infection was at the 1st month. At the end of 20 months, the reinfection rate was 36.4% and the infection rate was 21.8% among both children and adults. A total 83 subjects rendered Necator americanus egg-negative by drug treatment and 365 N. americanus egg-negative at pretreatment stool examination were used in the reinfection and infection rate studies. Throughout the study, adults had always higher reinfection and infection rates than children, while adults males had higher reinfection rates than adults females. The start of reinfection was 4 months after treatment, and the start of infection was at the 1st month; they were 25.3% and 9.3% respectively. At the end of 20 months, the reinfection rate was 65.1%, and the infection rate was 47.9% among both children and adults.     

Survey for soil-transmitted helminths in Asahan Regency, North Sumatra, Indonesia

The survey on soil-transmitted helminthiasis was carried out in the three villages of Asahan Regency, North Sumatra, Indonesia, between October 1981 and December 1982. The prevalence rates of geohelminthiasis proved to be extremely high (average 97%) in the three villages and more than 70% harboured three or more helminths, especially Ascaris lumbricoides, Trichuris trichiura and hookworm. Necator americanus and Ancylostoma duodenale were detected in 61.1% and 52.2% of 835 fecal specimens, respectively. The effects of two anthelmintics, Combantrin and Trivexan, were essentially the same against A. lumbricoides and hookworm, although Trivexan was better than Combantrin against T. trichiura. The kinetic changes of parasitic infection in community after mass treatment were examined. Ten months after the first drug treatment, the incidence of Ascariasis or trichuriasis reverted nearly to pre-treatment level, while hookworm infection rate remained significantly low. Four months after the second mass treatment, the reinfection rate of A. lumbricoides was most prevalent followed by trichuriasis and hookworm infection. The reinfection rate (63.6%) of A. lumbricoides in children was about six times higher than that (10.4%) in adults at four month after the mass treatment. This study indicates that mass treatment with Trivexan at two month intervals for children and four month intervals for adults is necessary for the effective helminth control scheme in highly endemic areas of North Sumatra.     

The distribution of helminth infections along the coastal plain of Kwazulu-Natal province, South Africa

The results of a previous study indicated that, in the province of KwaZulu-Natal, South Africa, Necator americanus and Strongyloides stercoralis were endemic to the coastal lowlands only. The prevalences of these helminths, as well as those of Trichuris trichiura and Ascaris lumbricoides, have now been investigated along a 1000-km-long transect through the coastal plain, at altitudes of < 300 m, from the Mozambique border (26 degrees 57'S) to the border with Eastern Cape province (30 degrees 53'S). Necator americanus was by far the most dominant hookworm species. Although prevalences of N. americanus and S. stercoralis infection decreased with increasing southerly latitude, those of T. trichiura and A. lumbricoides did not. Determinants of these distribution patterns are examined in terms of a suite of temperature- and rainfall-related variables.     

Prevalence of intestinal parasitic infections in Riyadh district, Saudi Arabia

A total of 23,516 stool specimens collected from patients attending three medical centres in Riyadh, Saudi Arabia, were examined for intestinal parasites. Of these 5737 (24.4%) were positive. Entamoeba histolytica (8.8%) and Giardia lamblia (6.3%) were the commonest parasites found, and in the age group of one to 15 years. Giardia was found in 14.8% of males and 11.9% of females. Other intestinal parasites present included Ascaris lumbricoides, Trichuris trichiura, Schistosoma mansoni, Hymeolepis nana. Ancylostoma duodenale, Enterobius vermicularis. Taenia saginata and Schistosoma hematotium.     

Follow-up of Ascaris lumbricoides and Trichuris trichiura infections in children living in a community treated with ivermectin at 3-monthly intervals.

Ivermectin treatment was administered every 3 months over a 1-year period (April 1993-April 1994) to the whole eligible population of a village in South Cameroon where both Ascaris lumbricoides and Trichuris trichiura were hyper-endemic. A parasitological stool examination was performed before each treatment. Thirty children, aged 5-15 years, were not only found egg-positive for A. lumbricoides and/or T. trichiura before the first treatment but were also each treated and examined in each treatment round. Among these children, the intensity of infection with A. lumbricoides decreased significantly following the first treatment but thereafter remained steady. In contrast, the repeated ivermectin treatments had no significant impact on the intensity of the T. trichiura infections or on the prevalence of infection with T. trichiura or A. lumbricoides among the 30 children.     

Polyparasitism with Schistosoma haematobium and soil-transmitted helminth infections among school children in Loum, Cameroon

Prevalence and abundance of Schistosoma haematobium and soil-transmitted helminths (STH) were assessed among a total of 1600 pupils (urine, n = 1190; faecal samples, n = 1454) attending five schools in Loum, Littoral Province, Cameroon, with the specific aim of assessing the extent of polyparasitism and the extent to which infections were focused in particular subsets of the study group. Prevalence of S. haematobium was 62.8% with an abundance (arithmetic mean of egg counts) of 54 eggs/10 ml urine. For the STH these were 47.7% and 619 eggs per gram of faeces (EPG) for Trichuris trichiura, 65.5% and 3636 EPG for Ascaris lumbricoides, and 1.4% and <0.1 EPG for hookworms. Most children (90.3%) were infected with at least one of these four species, the largest proportion (34.3%) carrying two species; 27.4% carried three and 1.1% carried concurrently all four species of parasites. The average number of species harboured increased with age, as did the prevalences of S. haematobium and T. trichiura but not that of A. lumbricoides. All STH showed marked differences in prevalence between the five schools but only T. trichiura varied significantly between sexes. Mean abundance of infection varied significantly between age classes, among schools and between the sexes, with females showing heavier mean EPGs for A. lumbricoides and T. trichiura and males higher mean eggs/10 ml urine for S. haematobium infections. A highly significant association was detected between A. lumbricoides and T. trichiura, that was not context-dependent. This was confirmed in quantitative analyses after controlling for differences in abundance between schools, sexes and age classes. A weaker context-dependent association (prevalence data) was detected between S. haematobium and A. lumbricoides (sex- and age-dependent) but quantitative associations between these two species, as well as between S. haematobium and T. trichiura, were not convincing.     

Parasitological and serological studies on amoebiasis and other intestinal parasitic infections in the rural sector around Recife, northeast Brazil

Parasitological examinations were carried out during July to December, 1989, on 485 inhabitants of four villages in S?o Louren?o da Mata, 25 km northwest of Recife, Pernambuco, Brazil. Approximately 99.6% of the inhabitants were infected with at least one species of intestinal parasites. A high prevalence of Schistosoma mansoni (82.1%), hookworm (80.2%) Trichuris trichiura (69.9%), Ascaris lumbricoides (61.9%) and Entamoeba coli (36.7%) infections were demonstrated. Test tube cultivation revealed that the most common species of hookworm in this region was Necator americanus (88.4%), and also that the prevalence of Strongyloides stercoralis was 5.8%. Three hundred and thirty-four sera were serologically examined for amoebiasis by the gel diffusion precipitation test (GDP) and enzyme-linked immunosorbent assay (ELISA). No positive reaction was observed in all sera as examined by GDP, while 24 sera were positive by ELISA.     

杭州市3～6岁儿童常见肠道线虫感染现状

于2006年4～6月对杭州市14所幼儿园按分层整群随机抽样调查1 667例3～6岁学龄前儿童的肠道线虫感染情况。用生理盐水直接涂片法和饱和盐水浮聚法检查蛔虫卵、钩虫卵、鞭虫卵。用透明胶纸肛拭法检查蛲虫卵。肠道线虫总感染率为12.96%，其中蛲虫4.44%、蛔虫8.28%、鞭虫0.54%、钩虫0.24%；肠道线虫感染率的高低与幼儿园环境和卫生设施的水平成反比。     

Intestinal parasitic infection and associated symptoms in children attending day care centres in Trujillo,Venezuela

OBJECTIVES: To examine the presence of intestinal protozoan and helminth infections and their association with clinical signs and symptoms in children in Trujillo, Venezuela. METHODS: Conventional microscopic methods (thick-smear, saline and iodine solutions) were used to identify parasites in stool samples of 301 children attending day care centres. A subgroup of 45 children was evaluated clinically and parasitologically five times during a 1-month period using conventional methods and the Kinyoun acid-fast stain for Cryptosporidium identification. RESULTS: The point prevalence of protozoan infections was 21% for Giardia duodenalis, 1.0% for Entamoeba histolytica/dispar, 4% for Entamoeba coli, 16% for Blastocystis hominis, and 89% for Cryptosporidium parvum. Prevalence of helminth infection was 11% for Ascaris lumbricoides, 10% for Trichuris trichiura, 0.3% for Strongyloides stercoralis, and 1.3% for Hymenolepis nana. Over a 1-month time frame, new infections were observed at a rate of 11% for G. duodenalis, 4% for E. histolytica/dispar, 7% for A. lumbricoides, 11% for T. trichiura, 0% for S. stercoralis, and 2% for H. nana. Intestinal symptoms (diarrhoea, vomiting, gas, stomach pain, and loss of appetite) were associated with presence of one or more of C. parvum or B. hominis organisms in stool samples. CONCLUSIONS: Intestinal parasitic infections contribute significantly to the enteric disease burden experienced by this group of children. The organisms most strongly implicated by this study are common and difficult-to-treat protozoan pathogens.     

Intestinal parasitic infection among five interior communities at upper Rejang River,Sarawak, Malaysia

Intestinal parasitic infection among five interior communities at Bakun Valley, upper Rejang River, Sarawak, Malaysia, was investigated as part of a public health impact assessment of the proposed US$ 3 billion Bakun Hydroelectric Project. Coproparasitological examination of 355 stool samples from 7 of 16 villages representing 5 of 7 tribes in the area revealed infection rate of 41%. A higher infection rate was found among the settled Kayans (56%) than the seminomadic Penans (29%). Infection rate was high (68%) among children less than 14 years old. Trichuris trichiura accounted for more than 90% of all infections; less common were Ascaris lumbricoides, hookworms and Strongyloides stercoralis. Polyparasitism was found in 8% of the individuals surveyed with dual infection due to T. trichiura and A. lumbricoides being more common than dual infection with T. trichiura and hookworm. Women had higher infection rates (57%) than men (33%).     

Epidemiology of soil-transmitted nematode infections in Ha Nam Province, Vietnam

Baseline epidemiological data are presented from a parasitological survey conducted in Thuy Loi commune, Ha Nam province, Vietnam; a farming community where night soil is routinely used as fertilizer for crops. 177 households were visited and 543 individuals (aged 1–88 years) recruited to the study. Helminth infection intensity was assessed by Kato-Katz to determine the density of parasite eggs per gram of stool (epg). Ascaris lumbricoides, Trichuris trichiura and hookworm infections were the only species detected. 83% of individuals were infected with A. lumbricoides (mean epg = 11971), 94% with T. trichiura (mean epg = 793) and 59% with hookworm (mean epg = 302). Age-dependent patterns of infection prevalence and intensity were similar for A. lumbricoides and T. trichiura , but markedly different for hookworm infection. Similarly, age-dependency in the k-values for the three infections was due to covariance with the respective mean intensities with age rather than to independent age effects, with similar patterns for A. lumbricoides and T. trichiura , and a different pattern for hookworm. Three major conclusions can be drawn from the multiple-species analyses: There is positive interaction between A. lumbricoides and T. trichiura infections; high-intensity A. lumbricoides infections are significantly associated with high-intensity T. trichiura infections; and there is positive interaction between these two species such that infection intensity of A. lumbricoides is higher in individuals with concurrent T. trichiura infection than in individuals without and vice versa.     

Cross-sectional parasitological survey for helminth infections among fish farmers in Nghe An province, Vietnam

A total of 964 adult fish farmers in five eastern districts in Nghe An province, Vietnam were investigated in late 2004 for food-borne trematodes and other helminth infections using duplicate Kato-Katz thick smears prepared from single stool samples. Eggs of fish-borne trematodes and of Fasciolopsis buski were found in 0.6 and 0.7% of farmers, respectively. Infection prevalences with soil-transmitted helminths (STHs), namely Ascaris lumbricoides, Trichuris trichiura and hookworm, were 34.8, 50.7 and 51.3%, respectively, and 81.8% were infected with at least one of the three STHs. While A. lumbricoides and T. trichiura were more prevalent in the eastern districts compared to the more western districts, the opposite was true for hookworm infections. The widespread prevalence of STH infections in fish farmers suggests that control of these infections in school-age children only may be inadequate. Identification of the human behavioural factors and environmental features responsible for the distribution and frequency of STHs among adults is needed as well as a sensitive diagnostic test of fish-borne trematodes at species level.     

Helminthic infestation of the primary school-going children in Manipur

A total of 1010 stool samples collected from the primary school-going children between the age group of 5 to 10 years from September 1998 to October 2000, were studied to find out the prevalence of intestinal helminths in this paediatric age group and in the urban and rural areas of Manipur. The samples were processed in the Microbiology Department, RIMS, Imphal by wet film, iodine preparation and concentration techniques (formol-ether concentration) to find out the presence of eggs, larvae of the intestinal parasites (helminths). A total of 248 (24.5%) were positive for various helminths. Among the positive cases, 110 (26.3%) were from the urban area (city) and 138 (23.4%) from the rural areas of Manipur. Of the 552 males and 458 females tested, 136 (24.6%) males and 112 (24.5%) females respectively were positive for various helminths. Maximum number of parasitic infection occurred in the age group of 5 to 6 years (27.0%) in both sexes. Among the parasites, Ascaris lumbricoides was the commonest (19.6%) followed by Trichuris trichiura (2.18%), Hymenolepis nana (0.99%), Tapeworm (0.19%), Hookworm (0.09%), Strongyloides stercoralis (0.09%), Enterobius vermicularis (0.09%). Mixed infection of Ascaris lumbricoides with T. trichiura (1.08), T. trichiura with E. vermicularis (0.09%) and T. trichiura with S. stercoralis (0.09) were also encountered. Antihelminthic drugs were prescribed to those who were found positive for the helminths.     

Cure and reinfection patterns of geohelminthic infections after treatment in communities inhabiting the tropical rainforest of Assam, India

Mass de-worming targeted at socio-economically poor communities can be considered as an option for communities living in the tropical forests of Assam who do not have access to safe drinking water and proper sanitation, and consequently have a higher risk of suffering from geohelminthic infection and associated morbidity. A random sample of 265 subjects was included in this study (134 males and 131 females). The chemotherapeutic regimen followed was a single dose of albendazole 400 mg. Stools samples were collected in 10% formol-saline for detection of infection before treatment. Post-treatment stool samples were collected 10 to 14 days after treatment to determine the cure rate. Stool samples were again collected 3 to 6 months post-treatment to study the rate of reinfection. Multiple logistic regression was used to find possible associations between age, sex and treatment failure. The chi-square test was used wherever appropriate. The cure rates for Ascaris lumbricoides, Trichuris trichiura and hookworms were 70.8%, 68.7% and 93.0%, respectively. Logistic regression revealed that age was associated with treatment failure in A. lumbricoides infection. Re-infection rates after 3 months of successful treatment were 19.6% for A. lumbricoides, 30.9% for T. trichiura and 11.3% for hookworms. Six months post-treatment, the prevalence of re-infection was highest with T. trichiura (43.6%); followed by A. lumbricoides (35.3%). The rate of reinfection with hookworms was lower (11.3%) six months post-treatment. The rates of re-infection with A. lumbricoides and T. trichiura was higher in children below 15 years of age, compared with adults. Hookworm reinfection was higher in the adult age group (15 to 39 years). The rates of new infection in previously uninfected subjects were lower compared with the rates for re-infection.     

Prevalence, intensity and risk factors for soil-transmitted helminth infection in a South Indian fishing village

A study of the prevalence, intensity and risk factors for soil-transmitted helminth infection was undertaken among school children aged 5-9 years attending a primary school in the fishing village in Peda Jalaripet, Visakhapatnam, South India. One hundred and eighty nine (92.6%) of 204 children were infected with one or more soil transmitted helminth parasites. The predominant parasite was Ascaris lumbricoides (prevalence of 91%), followed by Trichuris trichiura (72%) and hookworm (54%). Study of age-specific prevalence and intensity of infection revealed that the prevalence and intensity of A. lumbricoides infection was higher among younger children than older children. While aggregation of parasite infection was observed, hookworm infection was more highly aggregated than either A. lumbricoides or T. trichiura. Multivariate analysis identified parental occupation, child's age and mother's education as the potential risk factors contributing to the high intensity of A. lumbricoides infection. Children from fishing families with low levels of education of the mother had the highest intensity of A. lumbricoides infection. As the outcome of chemotherapy programs to control soil transmitted helminth infection is dependant on the dynamics of their transmission, there is a need for further studies to better define the role of specific factors that determine their prevalence, intensity and aggregation in different epidemiological settings.     

Soil-transmitted nematode infections and mebendazole treatment in Mafia Island schoolchildren

In August 2000, a cross-sectional study was performed to assess the prevalence and intensity of soil-transmitted nematode infections in schoolchildren on Mafia Island. Hookworm infection was widespread (72.5% prevalence) whereas Trichuris trichiura was less prevalent (39.7%) and Ascaris lumbricoides was present at a low prevalence (4.2%), mainly in urban areas. In a subsample of the study population, both Necator americanus and Ancylostoma duodenale were found, although N. americanus was more prevalent. This survey was followed by a parasitological evaluation of mebendazole treatment using a single, 500-mg dose. The data on outcome were used for comparison with those from recent studies of similar treatment regimens in the neighbouring island of Pemba, Zanzibar, where periodic chemotherapy with mebendazole to schoolchildren has been implemented as part of a helminth-control programme since 1994. A higher efficacy of mebendazole against hookworm infection was found in Mafia Island (where a cure 'rate' of 31.3% and an egg-reduction 'rate' of 78.1% were recorded) when compared with that observed in Pemba Island, possibly indicating that hookworms may be developing mebendazole resistance on Pemba Island as a result of intense exposure to the drug there.     

我国西南彝族农村地区HIV与血吸虫 蛔虫及鞭虫感染现状调查

目的 目的 了解我国西南彝族农村地区HIV、 血吸虫、 蛔虫及鞭虫感染状况, 调查是否存在混合感染。 方法 方法 在我 国西南部某山区随机选取一个彝族乡开展横断面调查, 检测村民HIV、 血吸虫、 蛔虫及鞭虫感染情况; 并对村民进行问卷 调查, 了解HIV及寄生虫感染的危险因素。 结果 结果 我国西南彝族农村地区居民HIV、 血吸虫、 蛔虫和鞭虫感染率分别为 2.33%、 2.05%、 13.47%和30.59%, 鞭虫与蛔虫共同感染检出率为7.08%, HIV与蛔虫和鞭虫共同感染检出率均为0.23%。 男性以及吸毒是HIV感染的危险因素 ［OR = 3.26, 95% CI：（0.97, 10.95）; OR = 72.86, 95% CI： （18.51, 286.76）］; 厕所与蛔 虫和鞭虫感染间均存在负相关关系 ［OR = 0.51, 95% CI：（0.27, 0.98）; OR = 0.48, 95% CI：（0.28, 0.80）］。与居住在村4的 居民相比, 村1村民感染蛔虫风险较高 ［OR = 3.14, 95% CI：（1.35, 7.27）］; 与居住在村4的居民相比, 居住在村2和村3的 村民鞭虫感染风险较高 ［OR = 3.73,95% CI：（1.92, 7.26）; OR = 4.53, 95% CI：（2.12, 9.68）］。此外, 11～20岁年龄组村民 鞭虫感染风险高于>50岁村民 ［OR = 3.72, 95% CI：（1.59, 8.67）］; 蛔虫与鞭虫感染间存在相关关系 ［OR = 3.11, 95% CI： （1.63, 5.93）］, 未发现与血吸虫感染相关的因素。 结论 结论 我国西南彝族农村居民HIV及寄生虫感染率尤其是鞭虫感染 率较高; 应进一步探索HIV与寄生虫感染, 尤其是与血吸虫感染间的关系。