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Results for “HELMINTH INFECTIONS”

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PubMed2000

Epidemiology of single and multiple species of helminth infections among school children in Busia District, Kenya.

OBJECTIVE: To describe the patterns of single and multiple helminth infection in school children from Busia District, Kenya. DESIGN: A cross-sectional school survey using a randomly selected sample, forming part of an evaluation study of an ongoing deworming project. SETTING: Budalangi and Funyula divisions of Busia District, Western Province, Kenya. SUBJECTS: One thousand seven hundred and thirty eight school children aged 8-20 years randomly selected from those enrolled in standards 3-8 in 25 randomly selected primary schools. RESULTS: Overall, 91.7% of children were infected with either hookworm, Ascaris lumbricoides, Trichuris trichiura or Schistosoma mansoni. Infection prevalence of each species varied considerably among schools, being most marked for S. mansoni, where prevalence was highest in lakeshore schools. Children were typically infected with two or more species of helminth. Infection intensity of each geohelminth species was higher in school children infected with multiple species than in school children with single species infections, and intensity increased with the number of concurrent infections. CONCLUSION: Helminth infections are exceptionally common among school children in Busia district, thus confirming the good sense of the school-based approach adopted by the control programme. The study also shows that there is an association between concurrent infection and the intensity of infection, which may have consequences for nutritional and educational status.

Adolescent↗

PubMed2005

Intestinal helminth infection in an ethnic minority commune in southern Vietnam.

A program to control intestinal helminth infections, based on stool surveys, mass treatment of children below 17 years, improvement of sanitation and health education was performed between 1997 and 1999 in Phan Tien, an ethnic minority community in mountainous southern Vietnam. Before intervention, 28.6% of children excreted eggs of at least one parasite, hookworm being the most common (23%), followed by Trichuris trichiura (1.9%), Hymenolepis nana (1.9%), Enterobius vermicularis (0.9%), Ascaris lumbricoides (0.5%), and multiple kinds of helminthes (0.5%). Strongyloides stercoralis was never detected. Poor sanitation and personal hygiene, and walking barefoot were considered the main risk factors for intestinal helminth infections. The success of 400 mg albendazole single dose mass treatment was initially frustrated by the poor quality of the drug formulation used, only containing half of the indicated amount of albendazole. Using another formulation quickly reduced the hookworm infection rate. Praziquantel was used to treat H. nana infections. After three years of intervention, intestinal helminth infections were reduced to 3.3% (p<0.0001). We conclude that interventions combining health education, improvement of sanitation and mass treatment effectively control intestinal helminth infections, but the quality of the drugs used is an important factor.

Adolescent↗

PubMed1991

Blood eosinophil degranulation and vacuolation in helminthic infection.

Blood eosinophil degranulation and vacuolation were studied in 21 Nigerian medical patients with helminthic infection and in 10 uninfected controls. For both patients and controls, 200 blood eosinophils were assessed 'blind' by light microscopy for the number of cytoplasmic vacuoles and the loss of specific cytoplasmic granules. In the helminth-infected patients (N = 21) the mean percentage (+/- S.D.) of eosinophils with one or more but less than 10 cytoplasmic vacuoles was 0.7 +/- 0.8%, that with loss of less than half of specific cytoplasmic granules was 1.6 +/- 1.7%, that with 10 or more cytoplasmic vacuoles was 0.1 +/- 0.2%, and that with loss of half or more specific cytoplasmic granules was 0.3 +/- 0.6%. There was no significant difference between patients and controls (P less than 0.05). We conclude that helminthic infection is not associated with blood eosinophil degranulation and vacuolation. The finding of large numbers, e.g. 15% or more, of vacuolated and especially degranulated eosinophils in patients with helminth-related eosinophilia should not be attributed to the helminthic infection alone, but should raise the suspicion of eosinophil-mediated host tissue damage.

Adult↗

PubMed1993

Cytokines and immediate hypersensitivity in protective immunity to helminth infections.

Infection with tissue-invasive helminth infections characteristically induces immunological responses associated with immediate hypersensitivity such as IgE elevations, tissue and peripheral blood eosinophilia, and mast cell hyperplasia. Specific sets of cytokines appear to regulate these responses; the resulting responses reflect the balance of upregulatory and inhibitory signals these cytokines provide. The nature of these cytokines and their role in both protective immunity and pathogenesis in helminth infections of humans is the subject of this review.

Animals↗

PubMed2001

Atopy, intestinal helminth infection and total serum IgE in rural and urban adult Gambian communities.

BACKGROUND: The rarity of atopy in traditional societies has been attributed to high parasite-driven blocking IgE concentrations. Information is lacking on the relationship between atopy, IgE and intestinal helminth infection in African populations. OBJECTIVE: To determine the prevalence of atopy and intestinal helminth infection and to relate these to wheeze history and serum total IgE in a community sample of adults from an urban (Banjul) and a rural (Farafenni) area of the Gambia. METHODS: Six hundred and ninety-three adults were interviewed about respiratory symptoms using a modified version of the IUTLD questionnaire, and had skin prick testing using four allergens. Stools were examined after formol-ether concentration. Total serum IgE concentration was measured in a subset of participants. RESULTS: The prevalence of atopy (mean weal diameter > or = 3 mm) in the urban and rural area was 35.3% and 22.5% (P = 0.05); D. pteronyssinus and Mold mix being the common sensitizing allergens. Prevalence of wheeze in the previous 12 months was 4.4% and 3.5% for the urban and rural areas, respectively. Wheezing was not significantly associated with atopy. Seventeen per cent of urban and 8.2% of rural subjects had helminths detected in stools. There was an inverse association between atopy and intestinal helminth infection; 7% of atopic subjects had helminths, compared to 13% of non-atopic subjects (unadjusted odds ratio 0.51, 95%CI 0.24-1.1, P = 0.09; adjusted odds ratio 0.37, 95%CI 0.15-0.92, P = 0.03). Non-atopics had total serum IgE concentrations about 2.5 times the upper limit of the reference range in non-atopic Western populations. Geometric mean total serum IgE concentration was significantly higher among atopic subjects (570 IU/mL, IQR 91-833) than non-atopic subjects (259 IU/mL, IQR 274-1303) (P < 0.001). IgE concentration was not associated with the presence of helminth infection. CONCLUSION: Further studies are needed to clarify why asthma is still relatively uncommon in spite of the prevalence of atopy in Gambian adults. Our data are also compatible with the idea that atopy might protect against helminth infection.

Adolescent↗

PubMed1989

The effect on fetal growth of protozoan and helminthic infection during pregnancy.

This is a prospective study of 14,914 pregnant women conducted in Guatemala City, Guatemala. Stool samples were obtained from the studied patients before the first prenatal visit (mean gestational age 21.6 +/- 8.4 weeks) for the diagnosis of parasitic infections during pregnancy. Forty-four percent had at least one parasite detected, and 24% were infected with helminths. Ascaris lumbricoides was the most prevalent (14.5%). Infected mothers were less educated, had less adequate water and sanitary conditions, and had lower nutritional status. The incidence of intrauterine growth retardation (IUGR) increased with the number of parasitic species detected (up to two or more species, P less than .01). High levels of infection (greater than or equal to + +) were associated with an increased risk of IUGR for protozoa and helminths, except for Strongyloides stercoralis and Hymenolepis nana. Chronically malnourished women of short stature had significantly higher IUGR rates when infected with one or two or more species (P less than .01). Up to 10% of the IUGR rates may be attributed to parasitic infections among the malnourished women.

Adult↗

PubMed2001

Association of helminth infection with decreased reticulocyte counts and hemoglobin concentration in Thai falciparum malaria.

Following a study showing an association between Ascaris and protection from cerebral malaria, we conducted a cross-sectional study comparing admission hemoglobin concentrations in relation to exposure to helminth infection in 2 separate groups of patients: 111 cerebral malaria cases and 180 mild Plasmodium falciparum malaria cases. Hookworm infections were excluded. Mean hemoglobin concentrations were significantly lower in helminth-infected patients compared to those without helminths, both in the cerebral malaria group (10.1+/-3 [n = 47] versus 11.2+/-2.4 g/dl [n = 64], P = 0.04) and the mild malaria group (11+/-2.5 [n = 89] vs 12.2+/-2.7 g/dl [n = 91], P = 0.004). Median reticulocyte counts, only available in the cerebral malaria group, were lower in helminth-infected patients compared to those without helminths (15,340/23,760 per microl, P = 0.03). Adjustments for confounders such as body mass index did not alter these associations. These data are consistent with a mechanism causing anemia linked to differences in the immune response of helminth-infected patients during malaria.

Animals↗

PubMed2002

Intestinal helminth infections are associated with increased incidence of Plasmodium falciparum malaria in Thailand.

In a prospective study of the total population of 5 hamlets on the western border of Thailand, all subjects were screened for helminth infections; during the following year, the incidence of malaria was recorded. Patients were not treated for helminth infections. Among 731 villagers, helminth-infected subjects were more likely to develop falciparum malaria during the following year (adjusted risk ratio 2.24, range 1.4-3.6; P = 0.001). The risk of developing falciparum malaria increased with the number of helminth species (P =0.036). Whereas in other studies helminths were associated with protection from severe complications of malaria, it seemed here that helminth-infected patients were more likely to develop malaria. It is suggested that a helminth-mediated Th2 shift may have complex consequences on malaria, decreasing antisporozoite immunity, but protecting against severe malaria.

Adolescent↗

PubMed2005

Epidemiology of helminth infections and their relationship to clinical malaria in southwest Uganda.

It has recently been suggested that helminth infections may adversely influence susceptibility to other infections, including malaria. To investigate this hypothesis in a sub-Saharan African setting, surveys of helminth infections were conducted in 2003 among individuals who had been under weekly active case detection for clinical malaria during the preceding 18 months in four villages in Kabale District, southwest Uganda. Overall, 47.3% of individuals had at least one intestinal nematode species infection: hookworm, Ascaris lumbricoides and Trichuris trichiura were detected in 32.1, 17.4 and 8.1% of individuals, respectively. We found evidence of significant household clustering of A. lumbricoides, T. trichiura and hookworm, and clustering of heavy infection of each species. The association between helminth infection and clinical malaria was investigated in two villages and no evidence for an association was observed between the presence of infection or heavy infection and risk of malaria.

Animals↗

PubMed2001

Association of helminth infections with increased gametocyte carriage during mild falciparum malaria in Thailand.

The objective of this study was to determine whether pre-existing helminth infections could affect sexual forms of Plasmodium falciparum. A cross-sectional case record study compared 120 mild P. falciparum malaria cases with patent gametocyte carriage and 187 without gametocytes for helminth exposure. Relevant crude odds ratios and potential confounders were included in a logistic regression model. Helminth infections were associated with the presence of gametocytes with a crude odds ratio of 1.9 (95% confidence interval = 1.1-3.3) (P = 0.01). A positive linear trend was observed between the odds of having patent gametocytemia and the number of different helminth species (P = 0.003). However, when adjusting for hemoglobin concentration the significance of the association between helminths and gametocytes disappeared (P = 0.15). Pre-existing helminth infections may increase the severity of malarial anemia and therefore increase the likelihood of carrying gametocytes. At a population level, helminth infections may thus have a significant influence on malaria transmission.

Adolescent↗

PubMed2002

Helminth infections are associated with protection from cerebral malaria and increased nitrogen derivatives concentrations in Thailand.

Following a study showing an association between Ascaris and protection from cerebral malaria, we hypothesized helminths may have induced protection through immunoglobulin E (IgE) and the CD23/NO pathway. We compared the prevalence of helminth infections in 67 cerebral malaria patients and 217 hyperparasitemic controls with no complications. For 24 cerebral malaria cases and 56 controls, we compared reactive nitrogen intermediates (RNI) concentrations and their correlations to total IgE and sCD23 concentrations in helminth-infected and noninfected patients. We observed a dose-dependent association between helminth infections and protection from cerebral malaria (adjusted odds ratio [OR] = 0.36, 95% CI = 0.19-0.7, P = 0.002, linear trend P = 0.0007). Helminth-infected controls had higher RNI concentrations than those without helminths: 72 OD +/- 19 SD and 57 OD +/- 20 SD, respectively (P = 0.006). Logistic regression, including interaction terms between RNI and sCD23, showed that an increase of RNI could be both protective and pathogenic depending on the concentration of sCD23. Helminths increasing both the CD23 receptor and its ligand may have a role in the establishment of malaria tolerance through the CD23/NO pathway.

Animals↗

PubMed2000

Concurrent enteric helminth infection modulates inflammation and gastric immune responses and reduces helicobacter-induced gastric atrophy.

Helicobacter pylori is causally associated with gastritis and gastric cancer. Some developing countries with a high prevalence of infection have high gastric cancer rates, whereas in others, these rates are low. The progression of helicobacter-induced gastritis and gastric atrophy mediated by type 1 T-helper cells may be modulated by concurrent parasitic infection. Here, in mice with concurrent helminth infection, helicobacter-associated gastric atrophy was reduced considerably despite chronic inflammation and high helicobacter colonization. This correlated with a substantial reduction in mRNA for cytokines and chemokines associated with a gastric inflammatory response of type 1 T-helper cells. Thus, concurrent enteric helminth infection can attenuate gastric atrophy, a premalignant lesion.

Animals↗

PubMed2004

Anthropometric status, anaemia and intestinal helminthic infections in shantytown and apartment schoolchildren in the Sanliurfa province of Turkey.

OBJECTIVE: To study anthropometric status, anaemia and intestinal helminthic infections of schoolchildren living in better and worse socio-economic and environmental conditions in the Sanliurfa province of Turkey. DESIGN: Cross-sectional school-based survey. SETTING: The sample was selected using a multistage random cluster sampling technique. The urban area of the province is stratified into two strata on the basis of environmental conditions: shantytowns and apartment areas. A total of 12 schools in the shantytown areas and five schools in the apartment areas were randomly selected based on probability proportional size in the two strata. A third class (including 9-10 y-old children) was randomly selected in each school and all children in this class were selected for the survey. SUBJECTS: A total of 806 children, 572 of them from shantytown schools and 234 from apartment schools, took part in the surveys. Height for age, weight for age and weight for height were calculated by New Anthro software using the NCHS/WHO international reference values. The haemoglobin concentration was measured by the cyanmethaemoglobin method. Stool samples were examined by the semiquantative Kato-Katz technique. RESULTS: Evidence of chronic ill health was common due to undernutrition, anaemia and helminthic infections in shantytown schools. Both male and female children in shantytown schools had higher stunting rates than those of apartment schools. Underweight was significantly associated with the sex of the children in shantytown schools in that the boys had a significantly higher underweight rate than girls (P: 0.04), but this rate did not differ between sexes in apartment schools. Wasting was significantly associated with the type of settlements; the girls in apartment schools had a significantly higher wasting rate than those of shantytown schools (P: 0.02). The children in shantytown schools had significantly higher anaemia rates (45%) than those of apartment schools (15%) (P: 0.01). The prevalence of intestinal helminthic infections was significantly higher in shantytown schools (63%) than apartment schools (37%) (P < 0.0001). Ascaris lumbricoides was the most prevalent helminth and followed by Trichuris trichiura, Hymenolepis nana and Taenia species in both the study areas. Infection in children was significantly related to stunting in shantytown schools (multiple R = 0.147; P: 0.005) and in apartment schools (multiple R = 0.171; P: 0.02). CONCLUSION: These results indicated that the prevalence of stunting, anaemia and intestinal helminth infections constitutes an important public health problem among shantytown schoolchildren. School health programmes including deworming, feeding and micronutrient iron supplements through health education have a potentially beneficial effect on the health and education of schoolchildren.

Anemia↗

PubMedDate not supplied

Patterns of helminth infection and relationship to BCG vaccination in Karonga District, northern Malawi.

Surveys of enteric and urinary helminth infections were carried out in 1999 among 501 schoolchildren and among 320 adolescents and young adults participating in a study of immune responses to BCG vaccine in Karonga District, northern Malawi. Hookworm, Schistosoma mansoni and S. haematobium infections were detected in 64%, 27% and 20% of schoolchildren and in 55%, 40% and 25% of the immunology study subjects, respectively. Other helminths were appreciably less common. The prevalence of 'at least one' helminth infection was 76% among schoolchildren, ranging from 60% to 92% in the 4 schools, and was 79% in the immunology study participants. There was no evidence for an association between the presence of a BCG scar and presence or intensity of infection with worms in the schoolchildren, nor evidence that BCG vaccination of adolescents and young adults had any effect on the prevalence of helminth infections 1 year later.

Adolescent↗

PubMed2000

Urban/rural differences in prevalence and risk factors for intestinal helminth infection in southern Malawi.

Urbanization may increase the risk of human infection with intestinal helminths. A cross-sectional survey was conducted to investigate the prevalence, intensity and potential risk factors of acquiring such infection, among children aged 3-14 years in similar urban and rural communities in southern Malawi. Stool samples were collected from 553 children (273 urban and 280 rural). The overall prevalence of helminth infection was significantly higher in the urban subjects than in the rural (16.5% v. 3.6%; P < 0.001), mostly because of differences in the prevalence of Ascaris lumbricoides infection. Living in an urban community was associated with a significantly higher risk of infection [odds ratio (OR) = 5.3; 95% confidence interval (CI) = 2.6-12.1], even after controlling for potential confounding factors. In the urban community, risk factors included having pools of water/sewage around houses (OR = 3.0; CI = 1.4-6.5), not wearing shoes (OR = 7.1; CI = 2.7-19.2), not attending school (OR = 2.8; CI = 1.2-6.5), having mothers with 4-8 years of education (OR = 5.2; CI = 2.0-14.0), and having mothers below 35 years of age (OR = 4.09; CI = 1.39-16.28). In this part of Africa, efforts to reduce helminth infections may best be focused on reducing geohelminth burden in urban areas.

Adolescent↗

PubMed2001

Geo-helminth infections in a rural area of Sri Lanka.

School children carry the heaviest burden of morbidity due to intestinal helminth infection. The objective of this investigation was to study geo-helminth infections in 349 school children aged 6 to 13 years living in a rural area of Sri Lanka. Stool samples were examined by direct saline smear in an initial survey to determine the prevalence of intestinal parasitic infections and thereafter the children were followed up over a two year period with cross sectional surveys of stool samples being carried out at yearly intervals. Following collection of a stool sample, all the subjects were treated with mebendazole 500 mg as a single dose. Weights and heights were measured using standardized procedures. 2 ml of venous blood were collected from each subject under aseptic conditions to determine hematological indices. The prevalence of geo-helminth infections was low, and the prevalence declined during the two-year period from 5.4% in 1997 to 2.2% in 1998 and 2.0% in 1999 following yearly mass anti-helminth treatment. The incidence density was 0.021 cases per child year. The reduction in the prevalence from the baseline to the second survey is probably due to the reduction of the reservoir of infection among children as a result of mass treatment at baseline. The prevalence of infection during the second and third surveys were almost the same probably due to infections originating from other segments of the untreated population.

Adolescent↗

PubMedDate not supplied

Evaluation of the Integrated Management of Childhood Illness guidelines for treatment of intestinal helminth infections among sick children aged 2-4 years in western Kenya.

Anthelmintic treatment of sick preschool-age children at health facilities is a potentially effective strategy for intestinal helminth control in this age-group. We conducted a study from July 1998 to February 1999 in western Kenya to determine whether the Integrated Management of Childhood Illness (IMCI) guidelines' clinical assessment can be used to identify helminth-infected children, and to evaluate the nutritional benefit of treating sick children without pallor with an anthelmintic (mebendazole is already part of IMCI treatment for sick children aged 2-4 years with palmar pallor in areas where hookworm and Trichuris trichiura infections are endemic). Sick children aged 2-4 years seen at 3 rural health facilities were clinically evaluated and tested for haemoglobin concentration, malaria parasites, and intestinal helminths. Children without pallor were randomly assigned to receive a single dose of 500 mg of mebendazole or a placebo and re-examined 6 months later. Among the 574 children enrolled, 11% had one or more intestinal helminths. Most infections were of light intensity. Selected clinical signs and symptoms available from the IMCI assessment, including palmar pallor and low weight-for-age, were not associated with helminth infection. Six months after enrollment, no differences in growth of children without pallor were observed between the mebendazole (n = 166) and placebo (n = 181) groups. However, there was a significantly greater mean increase in weight, height, and weight-for-age Z score among the helminth-infected children in the mebendazole group (n = 22) as compared with helminth-infected children in the placebo group (n = 20). We conclude that even lightly infected preschool-age children without palmar pallor benefit from anthelmintic treatment; however, in this study setting of low helminth prevalence and intensity, helminth-infected children could not be identified using the IMCI guidelines. Cost-effectiveness studies are needed to help define helminth prevalence thresholds for routine anthelmintic treatment of sick preschool-age children seen at first-level health facilities.

Animals↗

PubMed2003

Integrated community-directed treatment for the control of onchocerciasis, schistosomiasis and intestinal helminths infections in Uganda: advantages and disadvantages.

Onchocerciasis is co-endemic with schistosomiasis and intestinal helminths infections, which are all diseases of the rural and the poorest communities in Africa. Community-directed treatment (ComDT) for the control of onchocerciasis is the only functional health approach in most of these communities and the strategy has proven to be effective for onchocerciasis control. This study was conducted to assess the feasibility of integrating ComDT with ivermectin for the control of onchocerciasis, and with praziquantel (PZQ) and mebendazole (MBD) for the control of schistosomiasis and intestinal helminths infections in children aged 5-14 years, and to assess advantages and disadvantages of the integrated ComDT over the routine ComDT and the school-based treatment approach. Integrated ComDT achieved higher treatment coverage (85%) for PZQ and MBD than the school-based treatment approach (79%) among children aged 5-14 years (P = 0.03). There were more reported adverse reactions after treatment with a combination of PZQ and MBD in the school-based treatment approach (33%) than for the combination of ivermectin and MBD on day 1 and PZQ on day 2 in the integrated ComDT (18%). However, all adverse reactions were mild (headache, nausea/vomiting and abdominal pain). The integrated ComDT also achieved higher ivermectin treatment coverage for all ages (81.3%) than routine ComDT (77.2%) (P = 0.0003). To achieve even better coverage for PZQ and MBD among the targeted high risk groups, integrated ComDT should treat all age groups in areas where the prevalence of schistosomiasis and intestinal helminths infections is >50%. This would minimize the shortage of the drugs targeted to treat the high risk groups, as the non-targeted groups, will inevitably demand and receive the treatment from the distributors. The results of this study show that PZQ and MBD treatment for the control of schistosomiasis and intestinal helminths, respectively, can be integrated with ivermectin treatment for the control of onchocerciasis without negatively affecting ivermectin treatment coverage.

Adolescent↗