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Background This cross-sectional study was carried out in different settlements of Gabon to determine the influence of single or multiple parasite carriage on haemoglobin (Hb) levels. Methods Between April 2015 and June 2016, healthy volunteers from urban, peri-urban and rural areas were screened for malaria, blood filariasis and intestinal parasitic infections using microscopic methods. Hb concentration was measured with a Hemocue analyser. The association between parasite carriage and anaemia was assessed. Results Among the 775 volunteers examined, 319 (41.2%) were from rural villages and 76.0% were adults. Filariasis, intestinal parasitic infections, Plasmodium falciparum and polyparasitism were detected in 15.6, 14.6, 9.5 and 6.8% of participants, respectively. Anaemia prevalence was 72.6%, with rates of mild, moderate and severe anaemia being 30.9, 61.1 and 8.0%, respectively. The median Hb level was lowest in the presence of hookworms (7.1 g/dl [interquartile range {IQR} 6.8–7.5]), Schistosoma intercalatum (6.9 g/dl), Trichuris trichiura (10.1 g/dl [IQR 8.9–11.5]) and Plasmodium falciparum (10.0 g/dl [IQR 9.1–11.2]) compared with filariaemia (12.1 g/dl [IQR 10.5–13.2]) (p=0.03). Moderate to severe anaemia predominated among those single-infected with P. falciparum (69.5%) or co-infected with intestinal parasitic infections and P. falciparum (76.2%), while it was found in only 23.2% of individuals with filariasis. All participants with soil-transmitted helminths and more than half with a Blastocystis sp. (68.8%) infection had moderate anaemia. Conclusions The prevalence of anaemia is high. Asymptomatic parasite carriage is associated with anaemia in this surveyed population in Gabon.

Background Yearly, millions of children are treated globally with ivermectin mainly for neglected tropical diseases. Anatomical, physiological and biochemical differences between children and adults may result in changes in pharmacokinetics. However, paediatric pharmacokinetic data of ivermectin are lacking. Methods In the framework of a randomized controlled dose-finding trial in rural Côte d’Ivoire, Trichuris trichiura-infected pre-school-aged children (PSAC, 2–5 years) and school-aged children (SAC, 6–12 years) were assigned to 100 or 200 μg/kg and 200, 400 or 600 μg/kg ivermectin, respectively (ISRCTN registry no. ISRCTN15871729). Capillary blood was collected on dried blood spot cards until 72 h post-treatment. Ivermectin was quantified by LC-MS/MS, and pharmacokinetic parameters were evaluated by non-compartmental analysis. Results C max and AUC increased in PSAC and SAC with ascending doses and were similar in both age groups when the current standard dose (200 μg/kg) was administered (∼23 ng/mL and ∼350 ng×h/mL, respectively). PSAC with lower BMI were associated with significantly higher AUCs. AUC and Cmax were ∼2-fold lower in children compared with parameters previously studied in adults, whereas body weight-adjusted CL/F (∼0.35 L/h/kg) was significantly higher in children. Tmax (∼6 h), t1/2 (∼18 h), mean residence time (MRTINF) (∼28 h) and V/F (∼8 L/kg) were similar in all paediatric treatment arms. Conclusions A positive association of AUC or Cmax with dose was observed in both age groups. Undernutrition might influence the AUC of ivermectin in PSAC. Ivermectin shows a lower exposure profile in children compared with adults, highlighting the need to establish dosing recommendations for different age groups.

Although trichuriasis affects millions of children worldwide, recommended drugs lack efficacy and new treatment options are urgently needed. Ivermectin has promising potential to complement the anthelminthic armamentarium.; A randomized placebo-controlled trial was conducted in rural Cote d'Ivoire to provide evidence on the efficacy and safety of ascending oral ivermectin dosages in preschool-aged children (PSAC) and school-aged children (SAC) infected with Trichuris trichiura. The primary outcome was the cure rate (CR) for T. trichiura infection, and the secondary outcomes were safety, egg-reduction rates (ERRs) against T. trichiura infection, and CRs and ERRs against other soil-transmitted helminth species.; A total of 126 PSAC and 166 SAC were included in an available case analysis. In PSAC, efficacy against T. trichiura did not differ between 200 µg/kg ivermectin and placebo treatment arm, as expressed in CRs (20.9% [95% confidence interval {CI}, 11.9%-52.8%] vs 19.5% [10.4%-49.9%]) and geometric mean ERRs (78.6% [60.1%-89.5%] vs 68.2% [40.5%-84.8%]). In SAC, the highest administered ivermectin dose of 600 µg/kg had a low CRs (12.2% [95% CI, 4.8%-32.3%]) and moderate ERRs (66.3% [43.8%-80.2%]). Only mild adverse events and no organ toxicity, based on serum biomarkers, was observed.; Ivermectin can be administered safely to PSAC with trichuriasis. Given the low efficacy of ivermectin monotherapy against T. trichiura infection, further research should investigate the optimal drug combinations and dosages with ivermectin against soil-transmitted helminthiasis.; ISRCTN15871729 (www.isrctn.com).

BACKGROUND The present study was carried out to assess the prevalence of intestinal parasite infections among children in Department of Rio San Juan (Nicaragua), to explore the extent of polyparasitism, and to identify the risk factors that might favour transmission of these parasites. METHODS A coprological study of single stool specimen, collected at random from 382 children (167 boys and 215 girls) aged 2-15 years from two municipalities, and a questionnaire, concerning demographic and epidemiological data on sanitary and behavioural habits, was filled in to identify risk factors. RESULTS About 93% of the children presented infection. Blastocystis hominis, the most frequently protozoa, and Trichuris trichiura, Ascaris lumbricoides and hookworm, the most prevalent helminths. Polyparasitism (85.4%[326/382]), with the highest percentages detected in females (p=0.001), in the 6-11 year age group (p

As biofuel projects may be associated with positive and negative effects on people's health and wellbeing, a health impact assessment was performed for the Addax Bioenergy Sierra Leone (ABSL) project. We present data from the baseline health survey, which will provide a point of departure for future monitoring and evaluation activities.; In December 2010, a cross-sectional survey was carried out in eight potentially affected communities. A broad set of clinical and parasitological indicators were assessed using standardised, quality-controlled procedures, including anthropometry and prevalence of anaemia, Plasmodium falciparum and helminth infections.; Complete datasets were obtained from 1221 individuals of 194 households and eight schools. Of children aged >5 years (n=586), 41.8% were stunted, 23.2% were underweight and 4.8% were wasted. Very high prevalences of anaemia and P. falciparum were found in children aged 6-59 months (n=571; 86.1% and 74.0%, respectively). Overall, 73.7% of women of reproductive age (n=395) were anaemic. In school-aged children (n=240), 27.9% had light- to moderate-intensity hookworm infections, whereas Ascaris lumbricoides, Trichuris trichiura and Schistosoma mansoni were rare (>3% each).; The detailed description of the baseline health conditions, in combination with future health surveys, will deepen the understanding of how a biofuel project impacts on community health in a rural setting in sub-Saharan Africa.

Background The purpose of this study is to evaluate the prevalence and intensity and examine the risk factors of soil transmitted helminth (STH; i.e., roundworm [Ascaris lumbricoides], hookworms [Ancylostoma duodenale and Necator americanus], and whipworm [Trichuris trichiura]) infections in Nepal. Methods Five hundred and ninety-four adults (256 men and 338 women) were selected via convenience sampling from five communities in Nepal. The Kato-Katz method was used to assess the prevalence and intensity of STH infection in this population. Results Prevalence of STH infection ranged from 3.3% in Birendranagar in Chitwan, 3.5% in Kuleshor in Kathmandu, 11.7% in Kanyam in Ilam, 17.0% in Dhikurpokhari in Kaski and 51.4% in Khokana in Lalitpur District [corrected]. Multivariable regression analysis revealed that not using soap for hand-washing was significantly associated with the prevalence and infection intensity of roundworm, hookworms and whipworm. Similarly, not wearing sandals or shoes outside was significantly associated with the prevalence and infection intensity of roundworm and hookworms, but not with infection intensity of whipworm. Literacy, being underweight or overweight, anemia and occupation were not associated with prevalence and intensity of roundworm and hookworms infection, but there was an association between occupation and the prevalence of whipworm infection. Conclusion STH infection was associated with individual hygiene behavior, but not with nutritional status or socio-demographic characteristics. Health policy focusing on changing individual hygiene behaviors might be useful in addressing STH infection in Nepal.

Background Albendazole is one of two standard drugs for the control of soil-transmitted helminthiasis. Methods A total of 149 schoolchildren from Port Elizabeth, South Africa, were examined for soil-transmitted helminth infections using duplicate Kato-Katz thick smears before and 2 weeks after administration of albendazole (400 mg). Results Trichuris trichiura was the predominant soil-transmitted helminth species (prevalence 60.4%), followed by Ascaris lumbricoides (47.7%). While albendazole was highly efficacious against A. lumbricoides (cure rate [CR] 97.2%; egg reduction rate [ERR] 94.3%), it lacked efficacy against T. trichiura (CR 1.1%; ERR 46.0%). Conclusions Our study confirms low efficacy of single dose albendazole against T. trichiura. There is a need for safe and efficacious drugs against T. trichiura.

Ascariasis and trichuriasis are highly prevalent parasitoses in tropical countries caused by Ascaris lumbricoides and Trichuris trichiura, respectively. Their prevalence is associated with poor sanitation and hygiene, among other biological and social factors. In this study, the associations of household social determinants with these soil-transmitted helminthiases in North Central Venezuela was assessed in the context of a National Study on Human Growth and Development (SENACREDH). This was a probabilistic, stratified, cross-sectional survey with a sample of 3388 individuals that weighted represents 4 675 433 inhabitants from the region. The prevalence of ascariasis and trichuriasis was 3.73% and 1.13%, respectively. In the univariate and multivariate analyses, these prevalences were significantly higher in those living in vulnerable houses [adjusted OR (AOR) = 1.479, 95% CI 1.428-1.532; and AOR = 10.519, 95% CI 9.971-11.097, respectively], houses located in rural areas (AOR = 2.067, 95% CI 2.035-2.101; and AOR = 1.918, 95% CI 1.868-1.970, respectively) and houses with a soil floor (AOR = 5.027, 95% CI 4.895-5.162; and AOR = 5.190, 95% CI 4.944-5.448, respectively), among other factors. People living in rural households with inappropriate building materials, insufficient basic public services such as water and waste disposal, and surrounding disease-prone environments are at higher risk of acquiring A. lumbricoides and T. trichiura infections.

Background: This study was designed to reevaluate the importance of screening for intestinal parasites in elective surgery patients so as to prevent the complications associated with intestinal parasitism in this group of patients. Methods: The study was carried out in Jos, North Central Nigeria, to determine the prevalence of intestinal parasitism in 130 consecutive elective surgery patients using the direct wet mount and formol ether concentration methods. Results: The overall distribution of intestinal parasites was 31.5%, with the helminthes recording 30.8% while protozoans had 1.5%. Patients for lower abdominal surgery recorded 33.3%, while 24.0% was recorded for the other types of surgery. Hookworms recorded the highest distribution with 17.7% followed by Ascaris lumbricoides with 10.8%, Schistosoma mansoni and Strongyloides stercoralis with 2.3% each, and Entamoeba histolytica /dispar and Trichuris trichiura with 0.8 % each. The age group of 61 years and above had the highest prevalence of 45.5% followed by the 41–50 year age group with 36.4%. The 11–20 and 51–60 year age groups had the least prevalence at 23.1% each. The females recorded a higher prevalence of 37.5% against 31.0% in males. Farmers had 35.3% while civil servants had the least prevalence of 7.1%. Subjects who defecate in toilet pits had a prevalence of 35.5%, closely followed by those who defecate in bushes and cultivated farmlands with 34.0%. Subjects using the water-closet toilet system recorded only 6.7%. In relation to sources of drinking water, those using water from streams and rivers recorded the highest prevalence of 35.1%, while those using tap water recorded 27.0%. Conclusion: These results emphasize the importance of screening elective surgery patients, especially in endemic areas for intestinal parasites, so as to prevent possible complications associated with intestinal parasites during and after the surgery.

The current widespread school-based control of soil-transmitted helminth (STH) infections is also advocated for preschool children. The objective of this study was to assess infection with STHs as well as their determinants in preschool children (

Background. Single-dose albendazole and mebendazole show limited efficacy in the treatment of trichuriasis. The combination of albendazole with ivermectin improves efficacy, but a mebendazole-ivermectin combination has not been previously investigated. Methods. We performed a randomized controlled trial in 2 schools in Zanzibar, Tanzania, to assess the efficacy and safety of albendazole (400 mg) plus placebo, albendazole plus ivermectin (200 mug/kg), mebendazole (500 mg) plus placebo, and mebendazole plus ivermectin in children with a parasitologically confirmed Trichuris trichiura infection. Cure rate (CR) and egg reduction rate were assessed by intent-to-treat analysis. Adverse events were monitored within 48 h after treatment. Results. Complete data records were available for 548 children. The highest CR against T. trichiura was achieved with a mebendazole-ivermectin combination (55%). Low CRs were observed with albendazole-ivermectin (38%), mebendazole (19%), and albendazole (10%). Compared with placebo, the use of ivermectin statistically significantly increased the CRs from 14% to 47% (odds ratio, 0.19; 95% confidence interval [CI], 0.12-0.28). The highest egg reduction rate (97%; 95% CI, 95%-98%) was observed using the mebendazole-ivermectin combination, followed by albendazole-ivermectin (91%; 95% CI, 87%-94%), mebendazole (67%; 95% CI, 52%-77%), and albendazole (40%; 95% CI, 22%-56%). The adverse events, reported by 136 children, were generally mild, with no significant difference between the treatment arms. Conclusions. Addition of ivermectin improves the therapeutic outcomes of both albendazole and mebendazole against T. trichiura and may be considered for use in soil-transmitted helminth control programs and individual patient management. Trial registration. isrctn.org Identifier: ISRCTN08336605

Three groups of Trichuris trichiura-infected school-age children were treated with one dose 400mg albendazole, 100mg mebendazole twice daily for 3 d, or 100mg mebendazole twice daily for 5 d. The albendazole study investigated cure and egg reduction rates and found that only 5 of 66 infected children were egg-negative 7 d post-treatment, giving a cure rate of 8% and a geometric mean egg reduction rate of 89%. However, at day 14 post-treatment, all children were again egg-positive with significantly higher egg counts than at day 7 (P0.001). The two mebendazole studies aimed for the recovery of adult T. trichiura worms. After the 3 d course of mebendazole treatment, only four worms were recovered on days 3-5 after start of treatment from 2 of 34 infected children. With the 5 d course of mebendazole treatment, 10 of 21 infected children expelled a total of 27 worms. In the last case the first worm appeared on day 4 post-treatment, and the highest number of worms was recovered when the study ended at day 7. In conclusion, even with the longest treatment regimen and collecting stool samples over seven consecutive days, only very few worms were recovered. The results of this study suggest that alternative drugs and/or alternative regimens in current control programmes against T. trichiura need renewed attention.

Accurate diagnostic tools are pivotal for patient management and surveillance of helminth control programmes, particularly in the current era of preventive chemotherapy. Three consecutive stool samples were obtained from 279 schoolchildren from Zanzibar, an island where anthelminthic drugs have been administered on a large scale for more than a decade. All stool samples were examined with the Kato-Katz method. Additionally, one sample per child was preserved in sodium acetate-acetic acid-formalin solution, and examined with the FLOTAC technique. Considering the pooled results of both methods as diagnostic 'gold' standard, the observed prevalences of Trichuris trichiura, hookworm and Ascaris lumbricoides were 63.4, 35.8 and 22.9%, respectively. The sensitivity of examining a single stool sample by FLOTAC for diagnosing T. trichiura, hookworm and A. lumbricoides was 88.7, 83.0 and 82.8%, respectively. Lower sensitivities were observed for Kato-Katz even after examining three stool samples: 71.8, 46.0 and 70.3%, respectively. Kato-Katz revealed considerably higher infection intensities than FLOTAC. The kappa agreement between a single FLOTAC and triplicate Kato-Katz was 0.63 for diagnosing A. lumbricoides and 0.50 for T. trichiura, but only 0.30 for hookworm. The high sensitivity of FLOTAC holds promise for patient management, monitoring soil-transmitted helminth transmission and endpoint(s) of control at the population level.

International audience; A baseline epidemiological survey for parasite infections was conducted between December 2007 and January 2008 in 155 villagers in a rural commune in Hoa Binh province, Vietnam. The prevalence of Ascaris lumbricoides, Trichuris trichiura and hookworm infection was 13.5%, 45.2% and 58.1%, respectively. At least one of the parasites was detected in 72.3% of the samples. We found no association between infection with A. lumbricoides or T. trichiura and engagement in agriculture, while hookworm infection was more prevalent in populations having frequent contact with soil. Agricultural use of human faeces was not correlated with any of the infections. We suggest that the consumption of vegetables that are commonly fertilized with human faeces in the community has led to the high infection rates with A. lumbricoides and T. trichiura, rather than the manipulation of faeces in farming activity. This also explains the high infection prevalence, despite high latrine coverage (98.1%) in the study population. The presence of latrines alone is not sufficient to reduce the prevalence of helminthiasis in a rural agricultural community if fresh faeces are used as fertilizer.

The combined effect of the Lymphatic Filariasis Elimination Programme (LFEP) and the National Schistosomiasis and Soil-transmitted Helminthiasis Control Programme (NSSCP) on soil-transmitted helminthiasis (STH) was evaluated. In September 2004, before mass drug administration (MDA) with ivermectin and albendazole by the LFEP in October, the prevalence and intensity of STH were recorded in 228 pupils in one primary school. After 8 months, all available pupils were re-examined, and the prevalence of Ascaris lumbricoides, Trichuris trichiura and hookworm had decreased from 0.9 to 0.7% (P = 0.84), from 4.8 to 0.7% (P = 0.004) and from 45.6 to 11.9% (P

In Sanliurfa, Turkey, externally funded temporary deworming activities have led to an internally funded self-sufficient programme in 2004-05 academic year. A total of 200,000 doses of mebendazole were distributed to schoolchildren, absentee children and small children and women through both schools and health centres. We interviewed 64 representative teachers, 82 administrative teachers, 112 schoolchildren and 108 parents using questionnaires, department interviews and focus groups discussions. We also collected 162 stool samples from third- and fourth-grade schoolchildren and examined them using the Kato-Katz technique. The evaluation of second year's of deworming program indicated that the programme's methodology of training representative teachers to play a major role in organizing the activities within schools and liaising with health staff was found to be successful by most of the teachers. The results showed that 85.2% of the women had benefited from the extended anthelmintic coverage. A total of 67.4% of them received the drugs from schools and 10.9% obtained them from health centres. The prevalence of helmintic infection had declined from 77 to 35% in shantytown schoolchildren and from 53 to 6.4% in apartment schoolchildren. The prevalence of Ascaris lumbricoides and Trichuris trichiura decreased from 63.2 to 17% and from 16.8 to 1.1%, respectively, in schoolchildren. The results also indicated that 53.5% of the schoolchildren changed over to clean habits and began to use soap after using the toilet. The evaluation of the second year's deworming programme showed that the programme was sustainable and there was no risk of the programme being discontinued. Political commitment was obtained from the local business community, academic sector, the local governmental administrations and the city municipality. These organizations realized the programme's rapid and clear benefits and collaborated in a multipartners' programme. The cost of treatment per child was $0.05 and in total $11 000 was sufficient to implement a broad-range programme including education of children about cleanliness and treatment of infection to improve their health.

The relationship between HIV, lymphatic filariasis, malaria (Plasmodium falciparum) and intestinal helminths (Ascaris lumbricoides, Trichuris trichiura and hookworm) was assessed in a cross-sectional study conducted in 2002 among 907 adults in Tanga Region, Tanzania. Overall prevalences were 7.9% for HIV, 43.5% for Wuchereria bancrofti-specific circulating filarial antigen (CFA), 12.3% for P. falciparum, 1.2% for A. lumbricoides, 7.1% for T. trichiura and 75.7% for hookworm. Anaemia was assessed separately for males and females and was found to be more prevalent among females (58.8%) than males (34.8%). When sex and age were controlled for, there was a statistically significant positive association between HIV and W. bancrofti (CFA) infection and between malaria and HIV, but not between malaria and W. bancrofti (CFA) infection. Hookworm infection was positively associated with W. bancrofti (CFA) infection but, surprisingly, negatively associated with HIV. Infection with HIV and hookworms, but not malaria, was associated with a significant reduction in haemoglobin concentration. These associations are likely to reflect underlying mechanisms that need to be clarified to better understand the role of co-infections in HIV pathogenesis, and vice versa.

Background: The migration of foreign workers from developing regions to developed countries may potentially lead to transmission of intestinal parasitic infections. In order to determine the relationship between intestinal parasitic infections and the health status of foreign workers, 302 Thai laborers brought to Taiwan were examined in this study. Nine species of parasites were found in 64.9% of laborers; Opisthorchis viverrini, hookworm, Strongyloides stercoralis, Giardia lamblia, Trichuris trichiura, Fasciolopsis buski, Taenia sp, Echinostoma sp, Entamoeba coli. Methods: From June 1992 to December 1993, a total of 302 Thai laborers, participating in the mandatory entry health examination at Chang-Gung Memorial Hospital, Lin-Kou Medical Center were interviewed and examined. These subjects underwent a physical examination, chest roentgenography, and serological tests for human immunodeficiency virus antibody, syphilis (VDRL), and hepatitis B surface antigen. Results: Among the 302 Thai laborers examined, 196 (64.9%) were found to be infected with 1 to 5 species of parasites. All 193 infected Thai laborers were treated in Taiwan. Two or 3 courses of pyrantel pamoate, mebendazole, praziquantel, and metronidazole were administered to 119, 45, 24, and 5 infected patients respectively. After 1 week of treatment, all results of stool examinations were negative. Conclusion: Acquisition of infection has been determined to be related to the consumption of koipla, a dish prepared from uncooked freshwater fish. Not unexpectedly, in the present study, it was found that this species was the most important intestinal parasite among Thai laborers and was significantly associated with the consumption of koipla.

The possibility that positive or negative associations occur between the filarial nematode Onchocerca volvulus and the gastrointestinal nematodes Ascaris lumbricoides and Trichuris trichiura was investigated in 205 children attending three schools in central Cameroon. Despite the closeness of their locations, marked differences between the schools were detected with respect to the number of species carried, the prevalence of O. volvulus and T. trichiura and the interaction between the prevalence of these two species. The number of species carried and these same prevalences varied significantly across the narrow age range of the study group. In addition, we observed an interaction between the prevalences of O. volvulus and A. lumbricoides that was dependent upon school but independent of host age and sex. Quantitative analyses revealed that the abundances of O. volvulus, A. lumbricoides and T. trichiura were affected by both school and age whereas host sex was significant only for O. volvulus. Finally, we observed significant positive interactions between the intensities of A. lumbricoides and T. trichiura and between O. volvulus and T. trichiura, that were school, age and sex independent. Our data suggest that associations do occur between filarial and gastrointestinal nematodes and that certain individuals are prone to multiple and high-level infections.

Some humans are persistently more susceptible to gastrointestinal nematodes than others. Here, for the first time, susceptibility to reinfection has been linked to host cytokine responses. Ascaris lumbricoides and Trichuris trichiura abundance was assessed immediately before and 8-9 months after deworming in a Cameroonian population (starting n=191). Profiles of whole-blood cytokine responses to parasite antigens (for interleukin [IL]-5, IL-13, IL-10, IL-12p40, tumor necrosis factor- alpha , and interferon- gamma), assayed before treatment, were significantly related both to an overall measure of host susceptibility and to susceptibility to reinfection. Significant effects were primarily due to a negative association between IL-13 and IL-5 responses and infection. Persistently susceptible individuals were, therefore, characterized by a weak T helper cell type 2 response. The apparent plasticity of age-specific cytokine response-worm abundance relationships between different populations is also discussed.

Cross-sectional surveys of parasitic infection were performed using the agar plate culture technique (APCT) and modified formalin-ethyl acetate concentration technique (MFECT) to assess the true prevalence of Strongyloides stercoralis relative to other parasites in north-east Thailand. The enzyme-linked immunosorbent assay (ELISA) for diagnosis of S. stercoralis infection was used to estimate the seroprevalence for comparison with coproprevalence. Faecal and serum samples were collected from study participants during October-November 2000. Within the sample population of 332 rural northeast Thais from 3 communities, S. stercoralis was the most common parasitic infection (average 28.9%, range 27.7-30.3%) as determined by APCT; by MFECT the average was 5.4% (range 1.8-8.6%). Other intestinal parasites by order of prevalence were Opisthorchis viverrini (average 14.2%, range 8.6-19.4%), hookworm (average 12.3%, range 4-20.2%), Echinostoma sp. (7.5%), Giardia intestinalis (0.9%), Trichuris trichiura (0.6%), and Taenia sp., Hymenolepis nana and Entamoeba coli (all 0.3%). In an analysis of a subset of the sample population for which serum samples were available (n = 120), coproprevalence by APCT was 33.3% (range 27-53.8%) and seroprevalence was 47.5% (range 29.7-57.9%) by modified unit-based ELISA and 34.2% (range 21.6-42.1%) by conventional optical density (OD)-based ELISA. Taking APCT as the reference method for diagnosis of strongyloidiasis, the sensitivity and specificity of the OD-based ELISA were 65% and 81.3%, respectively, and of the unit-based ELISA were 77.5% and 71.3%, respectively. Our results indicate that S. stercoralis is the predominant parasite in rural north-east Thailand, and that APCT and ELISA should be used as complementary diagnostic methods for community-based parasite surveys, at least among those in high-risk groups.

A randomized controlled trial comparing the efficacy of pyrantel-oxantel (10 mg/kg) with mebendazole (500 mg) was performed on 1329 schoolchildren aged 6-9 years on Pemba Island in September-October 2000 to evaluate alternative single-dose drugs for regular treatment of intestinal nematode infections. Both mebendazole and pyrantel-oxantel were very effective in eliminating Ascaris lumbricoides infection, inducing cure rates of more than 96% and reducing the mean egg counts by more than 95%. Both drugs had a moderate efficacy against Trichuris trichiura infection, but pyrantel-oxantel had a higher cure rate (31.5% vs. 23.3%, P < O.Ol), though the reductions in egg counts did not differ significantly and were more than 80%. Pyrantel-oxantel and mebendazole had a similar, poor efficacy in curing hookworm infections and had a moderate effect in reducing the egg counts by 67% and 68%, respectively. Pyrantel-oxantel (10 mg/kg) offers a valuable alternative to mebendazole as a single-dose treatment for the control of intestinal nematode infections in children in endemic areas of sub-Saharan Africa, due to its comparable efficacy, its low cost and its suitability for use in young children.

The social pattern of geophagy (soil-eating) and its possible role in the transmission of Ascaris lumbricoides, Trichuris trichiura and hookworm were investigated in a rural area of South Africa between March 1998 and July 1999. Schoolchildren (median age = 10.7 years; interquartile range 8.3-14.8 years) were examined for geohelminth infection at baseline and re-examined 3 and 29 weeks after treatment with albendazole. Interviews were conducted with the pupils in order to find out about their socio-economic background and their behaviour regarding geophagy. Soil-eating was less frequent in boys (39%), where it decreased with age, than in girls (53%), where no such age trend was apparent. The habit was more common in children from families of higher socio-economic status. The baseline prevalence of A. lumbricoides infection was higher in pupils who regularly ate soil from termite mounds (28%) when compared with non-geophageous pupils (19%; prevalence ratio (PR) = 1.46; 95% confidence interval (95% CI) 1.04-2.03). In contrast it was markedly lower in the groups who preferred eating tree termite soil (13%; PR = 0.67; 95% CI 0.43-1.04) or soil from other sources (8%; PR = 0.40; 95% CI 0.15-1.04). This pattern was still apparent after adjusting for possible confounders and was also found when analysing A. lumbricoides reinfection. In contrast, differences in prevalence of T. trichiura and hookworm infection between groups with different soil preference were small.

The cytokine and antibody response to Trichuris trichiura infection was determined for 96 persons living in an area where the parasite is highly endemic and infection exhibits a convex age intensity profile. In response to stimulation with T. trichiura antigen, a small proportion of the study group produced interleukin (IL)-4 (7%), IL-9 (5%), and IL-13 (17%). A larger proportion produced IL-10 (97%), tumor necrosis factor (TNF)-alpha (93%), and interferon (IFN)-gamma (32%). The levels of TNF-alpha (P =.016) and IFN-gamma (P =.012) significantly increased with age, suggesting a switch to a more chronic infection phenotype. The predominant parasite-specific antibodies produced were IgG1, IgG4, IgA, and IgE. Unlike the IgG subclasses and IgA, parasite-specific IgE correlated negatively with infection intensity, as defined by egg output (P =.008), and positively with host age (P =.010). These findings suggest a mixed cytokine response in trichuriasis and an IgE-associated level of protection.

A cross-sectional survey was undertaken in children aged 9-14 years in Beyla and Macenta Prefectures, Forest Guinea. Stool samples were examined by Kato-Katz and urine samples were examined by the centrifugation method. The overall prevalence and intensity of infection was 66.2% and 462.4 eggs per gram of faeces (epg) for Schistosoma mansoni, 21.0% and 17.8 eggs per 10ml of urine for S. haematobium, 51.2% and 507.5 epg for hookworm, 8.1% and 89.1 epg for Ascaris lumbricoides and 2.4% and 16.7 epg for Trichuris trichiura. The overall prevalence of schistosomiasis (S. mansoni and/or S. haematobium) was 70.7%. The prevalence of schistosomiasis was similar to those reported in the 1990s in the region; however, the prevalence of soil-transmitted helminths has since fallen. These findings illustrate the need for schistosomiasis control in Guinea.

A cross-sectional study of soil-transmitted helminthiases in the Northern Bolivian Altiplano was carried out over the 6-year period 1992-97. Prevalences, intensities and associations were analysed from coprological results obtained in 31 surveys (28 in schools and 3 in individuals of all age-groups) performed in 24 Aymara communities located between the city of La Paz and Lake Titicaca, at an altitude of 3800-4200 m. Ascaris lumbricoides and Trichuris trichiura were detected, with local prevalences in the range 1.2-28.0% and 0.0-24.0%, respectively. Significant differences in prevalence rates of trichuriasis were detected, with highest prevalences in male schoolchildren and in subjects aged > 40 years. The global intensity ranged from 24 to 86,544 eggs per gram of faeces (epg) and from 24 to 4560 epg for ascariasis and trichuriasis, respectively. Higher intensities were noted in girls. A. lumbricoides egg counts were statistically significantly higher in the 5-8-years age-group. A positive association between A. lumbricoides and T. trichiura infections was detected. The proportion of heavy infections for A. lumbricoides was 0.1% and 1.0% in the school and community surveys, respectively. No heavy infection for T. trichiura was detected. The very high altitude and its severe environmental conditions may determine the relatively low prevalences and intensities in this area.

A cross-sectional study of 6897 schoolchildren in 59 out of the 155 primary schools in Magu District on the shores of Lake Victoria, Tanzania, was undertaken in 1997 to determine the prevalence of single- and multiple-species helminth infection. Schistosoma haematobium, hookworm (primarily Necator americanus) and S. mansoni were the most common helminth species infecting schoolchildren in the district. The prevalences of Ascaris lumbricoides and Trichuris trichiura were negligible (< 1%). Anaemia and stunting were highly prevalent and widespread. Hookworm and S. mansoni occurred more frequently in multiple infections with other helminths than as single-species infections, but triple-species infection was rare. Analysis of the frequency distribution of infection amongst schools showed that prevalences of S. haematobium and hookworm tended to be normally distributed, with medians 75% and 45%, respectively, while the distribution of S. mansoni was markedly skewed such that only 17% schools had a prevalence greater than 20%. An inverse association between S. mansoni and S. haematobium was observed. Geographical information system (GIS) analysis indicated that S. mansoni infection was highly prevalent only along the shore of Lake Victoria, whilst S. haematobium was homogeneously prevalent everywhere except the lakeshore. This pattern appears to reflect the distribution of schistosome species-specific snail intermediate hosts. The results imply that joint treatment for hookworm infection and schistosomiasis would be beneficial throughout the district.

Background School-based deworming programmes have been promoted as a cost-effective strategy for control of nematode infection in developing countries. While numerous efficacy studies have been conducted, there is little information on actual programme effectiveness in areas of intense transmission. Methods A randomized trial of a school-based deworming programme was conducted in 12 primary schools on Pemba Island, Zanzibar. Four schools each were randomized to control, twice a year deworming with single dose mebendazole or three times a year deworming. Baseline and 12-month follow-up data on helminth infection using the Kato-Katz technique, demographic information and nutritional status were collected on 3028 children from March 1994 to May 1995. Results Intensity of infection measured as eggs per gram of faeces (epg) declined significantly for Ascaris lumbricoides, Trichuris trichiura and hookworm infections in both treatment groups. A. lumbricoides infection intensity declined 63.1% and 96.7% in the twice and three times per year treatment groups compared to the controls. T. trichiura infection intensity declined 40.4% and 75.9% respectively and hookworm intensity declined 35.3% and 57.2% respectively compared to control schools. Conclusions These results suggest that school-based programmes can be a cost-effective approach for controlling the intensity of intestinal helminth infection even in environments where transmission is high.

Intestinal nematode infections are recognized as a major public health problem, and helminth control is currently being directed towards school-aged children who are known to harbour the heaviest infections and are most likely to suffer from associated morbidity. However, few data are available for the epidemiology of intestinal nematodes in pre-school children in Africa, and the contribution of hookworm infection to the aetiology and severity of anaemia among pre-school children remains poorly understood. This paper investigates the epidemiology of parasitic infections in 460 pre-school children who were part of a larger case-control study of severe malaria in Kilifi on the Kenyan coast. Almost one-third (28.7%) were infected with hookworm, 20.2% with Ascaris lumbricoides and 15.0% with Trichuris trichiura. Infection prevalence of each species rose with age, and the prevalence of heavy infection with hookworm and mean intensity of hookworm were markedly age-dependent. One-third (34.3%) of children had malaria. Overall, 76.3% of children were anaemic (haemoglobin < 110 g/L), with the prevalence decreasing with age. Anaemia was significantly worst in children with heavy hookworm infection (> 200 eggs per gram). This relationship held for all ages, both sexes, and was independent of socioeconomic factors. The application of attributable morbidity methods confirmed the contribution of hookworm infection to anaemia.

A cross-sectional study of 729 children and adults in western Kenya investigated the impact of infection with hookworm, Ascaris lumbricoides, Trichuris trichiura, Schistosoma mansoni and malaria on iron status. In bivariate analyses, hookworm intensities as low as 300 eggs/g of faeces were negatively related to levels of haemoglobin (Hb) and serum ferritin (SF). Malaria parasitaemia was negatively related to Hb and positively related to SF, while S. mansoni intensities were negatively related to SF. Multivariate regression analysis was done to identify predictors of Hb and SF levels. In children, age (in years) was the only predictor for Hb (B = 1.7 g/L) and only malaria parasitaemia (negative, light, moderate, heavy) was retained in the model for log10 SF (B = 0.097 microgram/L). In adults, hookworm infection and malaria parasitaemia together with age, sex, pregnancy, SF levels < 12 micrograms/L and elevated body temperature were significant predictors of low Hb. The regression coefficient for hookworm egg count (for increments of 100 eggs/g) was -1.3 g/L. Significant interactions between sex and age and between sex and malaria parasitaemia were revealed. Age and malaria parasitaemia were significant predictors only among females, with a regression coefficient for malaria parasitaemia of -6.9 g/L. The regression coefficient for hookworm did not change when SF < 12 micrograms/L was taken out of the model, indicating that the effect of hookworm cannot be explained by low iron stores alone. Using SF as the dependent variable, hookworm and S. mansoni intensities together with age and sex were retained in the model. The regression coefficients for hookworm egg count (increments of 100 eggs/g) and S. mansoni egg count (increments of 10 eggs/g) were -0.011 microgram/L and -0.012 microgram/L, respectively. Iron deficiency was a problem in this population and hookworm infections contributed significantly to this situation.

A study of helminth infections was undertaken among 3244 schoolchildren from 28 schools in Morogoro Rural District, Tanzania. Schistosoma haematobium was the most common infection, followed by hookworms, Ascaris lumbricoides, S. mansoni, and Trichuris trichiura. Infection prevalence of each species varied among schools and age groups, but not between sexes. There was no relationship between the prevalences of different infections among schools, except for a strong negative correlation between the prevalence of hookworm and S. mansoni infections. Within each age group, there was little excess overlap in the distribution of each infection; thus the number of multiple infections was low whereas the number of individuals harbouring at least one infection was relatively high. More children than expected carried infections of A. lumbricoides and S. mansoni, and the clustering effect increased with age. Only 2 schools had high overall infection prevalences of both geohelminths and schistosomes. Logistic regression analysis of morbidity and parasitological data indicated that individuals with multiple species infections were not at increased risk of morbidity (on a multiplicative scale) compared to individuals with single species infections. This was attributed in part to the low egg counts observed for each parasite species. The results implied little interaction between schistosome and geohelminth infections in the region, both in parasitological terms and in the context of their combined effects on health. Implications for the feasibility and benefits of combined control of geohelminths and schistosomes are discussed.

Texto completo: acesso restrito. p.66-68 Submitted by Edileide Reis (leyde-landy@hotmail.com) on 2013-09-04T10:35:56Z No. of bitstreams: 1 66.full.pdf: 110685 bytes, checksum: 1fe83ac2115043ec4fd62e183f7a6e7e (MD5) Approved for entry into archive by Rodrigo Meirelles (rodrigomei@ufba.br) on 2013-11-01T11:55:03Z (GMT) No. of bitstreams: 1 66.full.pdf: 110685 bytes, checksum: 1fe83ac2115043ec4fd62e183f7a6e7e (MD5) Made available in DSpace on 2013-11-01T11:55:03Z (GMT). No. of bitstreams: 1 66.full.pdf: 110685 bytes, checksum: 1fe83ac2115043ec4fd62e183f7a6e7e (MD5) Previous issue date: 2006 The differential diagnosis of chronic diarrhea is extensive and requires the investigation of several diseases, such as celiac disease, inflammatory bowel disease and irritable bowel syndrome. A few patients infected by Trichuris trichiura may present a chronic dysentery-like syndrome in the context of a massive infestation of the colon leading to anemia and growth retardation, but the rarity of that finding demands a high level of suspicion. Herein we report the case of an 8-year-old boy from the rural zone who had suffered diarrhea without blood or mucus for 4 years and was taken to our Service because his mother had noticed the presence of blood on the feces on the 3 previous months. The diagnosis of a massive Trichuris trichiura infestation as the cause of the process was only reached by colonoscopy. We stress that Trichuris trichiura infection can mimic other forms of inflammatory bowel disease and lead to physical growth retardation and that prolonged regimens of albendazole may be required to the effective treatment of massive infestations.

The present study was the first to investigate the potential of saliva in community diagnosis of the major human intestinal nematode infections, Trichuris trichiura, Ascaris lumbricoides, and the hookworms. Immunoglobulin G (IgG) antibodies specific to parasite antigens were quantified in saliva samples of 187 individuals (all ages) from a St Lucian community, and 120 school-aged children from Tanga region, Tanzania, and relationships with current infection status (determined by numbers of parasite eggs in stool) were examined. For T. trichiura infection, the age relationships of parasite-specific salivary IgG antibodies mirrored those of infection intensity at the community level. Within both areas, children with current T. trichiura infection exhibited significantly higher anti-T. trichiura salivary IgG responses than uninfected children. Similar trends were apparent for A. lumbricoides and hookworm infections, though not to a level of statistical significance. Comparison of mean T. trichiura infection levels and antibody responses in age-matched children from St Lucia and Tanzania suggested that measurement of parasite-specific salivary IgG may have potential as a marker of transmission intensity at the community level.

The comparative efficacy of albendazole and mebendazole in the treatment of intestinal nematode infections were compared 3 weeks after treatment in a randomized trial among schoolchildren on Pemba Island, Tanzania. Egg counts were compared 3 weeks, 4 months and 6 months after treatment of 731 children seen on each occasion. Differences in the efficacies were apparent with some nematodes 21 d after treatment, but these were no longer apparent 4 months after treatment, and by 6 months intensities of infection were similar to pre-treatment levels. These findings suggest that treatment of schoolchildren every 4 months may be necessary in this highly endemic area in order to have an impact on the intensity of intestinal nematode infections sufficient to be likely to reduce morbidity.

We investigated the risk of severe inflammatory diarrhoea associated with geohelminth parasites in 1746 children attending a rural hospital in Ecuador from December 2000 to July 2002. Infections with geohelminths were strongly protective against the risk of severe inflammatory diarrhoea. Our findings suggest that geohelminth infections have important protective effects against enteroinvasive infections in young children.

Enteric helminths are among the most prevalent parasites of humankind, yet only scanty information exists about their effects on the gastrointestinal tract of their hosts. Specifically, there is little agreement on which worms definitely cause diarrhea. The available evidence suggests that five helminthic parasites are associated with human diarrheal disease: Trichinella spiralis (early phases of infection), Trichuris trichiura, Strongyloides stercoralis, Capillaria philippinensis, and Schistosoma (particularly Schistosoma mansoni). All these parasites have an invasive phase during which adult worms, their eggs, or their larvae establish intimate contact with the host's intestinal mucosa and elicit strong local inflammatory responses resulting in various structural and functional alterations of the gut. In contrast, strictly intraluminal worms do not seem to interfere with their hosts' intestinal structure and function to a degree sufficient to cause diarrhea.

The rational design of helminth control programmes for endemic areas requires that the limited resources be focused on the communities in greatest need. The process of locality-targetting would be facilitated by a simple, inexpensive method of assessing morbidity at the community level. This paper describes how a simple model of the distribution of infection in human populations can use infection prevalence data to predict the proportion of heavy, and potentially clinically significant, infections in a community. Analysis of observed data for Ascaris lumbricoides indicates that the risk of clinical ascariasis increases non-linearly with the prevalence of infection. The predicted prevalence of morbidity is low up to approximately 60% prevalence of infection, but increases very rapidly thereafter. Analyses of data for Trichuris trichiura, Schistosoma mansoni, S. haematobium and the hookworms suggests qualitatively similar patterns. The application of the model in predicting resource requirements for control is illustrated using infection prevalence data for A. lumbricoides in Brazil.

This study used a method of retrieving eggs from soil to examine the spatial and temporal dynamics of soil contamination with geohelminth eggs. The level of soil contamination in two children's homes in Jamaica was determined before and after further soil contamination was prevented by chemotherapy. The home which had higher human infection levels also had a higher prevalence and density of eggs in soil. The spatial distribution of the eggs in soil was overdispersed in the home with higher levels of infection, and underdispersed in the other, perhaps due to the low density of eggs. At both localities, the proportion of soil samples containing eggs and the density of eggs in soil declined over a two-month period. The results suggest that geohelminth eggs are rapidly depleted from die surface of tropical soils in the absence of continuing sources of contamination.

This study describes the age-targeted chemotherapeutic control of geohelminthiasis in the total population (n = 11,500) of the island of Montserrat, West Indies. The intervention programme involved the treatment with single dose albendazole of all children aged 2-15 years (approximately 2500) in 4 sequential cycles at intervals of 4 months. Infection status was monitored by an initial coprological survey of an age-stratified sample (11.5%) of the population, and by surveys of smaller samples (4-5%) after 2 and 4 cycles of treatment (7 and 15 months respectively). The programme delivered treatment to greater than 90% of the target population in each cycle, and reduced the prevalence and intensity of Ascaris lumbricoides and Trichuris trichiura infection in the target age-class. A decline in infection was also observed in the 16-25 year age-class, even though less than 4% of adults received treatment. The study demonstrates that chemotherapy targeted only at children can be implemented within an existing health infrastructure, and can achieve an overall reduction in the prevalence and intensity of geohelminth infection.

A study to evaluate the efficacy and safety of nitazoxanide as a single agent for the treatment of a broad spectrum of mixed parasitic infections, both protozoa and helminths, was conducted at a primary school in San Pedro Tolimán, Querétaro, Mexico. Three faecal samples from 1824 adults and children were screened for the presence of oocysts, cysts, trophozoites, eggs or larvae of intestinal protozoa or helminths. Two hundred and forty-six adults and children infected with at least one protozoan and 2 helminths were given 7.5 mg/kg of nitazoxanide (500 mg to adults and 200 mg to children less than 12 years old) every 12 h for 3 consecutive days. Faecal samples were examined on days 6, 7, 8, 13, 14 and 15 (+/- 1) following initiation of treatment, using formalin-ether concentration and Kato-Katz egg counting. Treatment with nitazoxanide was 71-100% effective in eliminating evidence of infection with Entamoeba histolytica/E. dispar, Giardia duodenalis, Blastocystis hominis, Isospora belli, Enterobius vermicularis, Ascaris lumbricoides, Trichuris trichiura and Hymenolepis nana. Haematology and clinical chemistry values obtained before and after treatment remained unaffected by nitazoxanide. The drug was well tolerated, with only 15 patients (6.1%) reporting mild abdominal pain that lasted less than 24 h.

A high incidence (28 per 100 000 admissions) of liver abscesses is reported in children from the Western Cape Province of South Africa. Of a total of 84 childhood hepatic abscesses over a 10-year period, 51 per cent (43 patients) were primary pyogenic, 30 per cent (25 patients) amoebic, 2 per cent (two patients) Ascaris, and 17 per cent (14 patients) were culture negative. Protein calorie malnutrition was evident in 56 per cent of cases. Amoebic abscesses originated in patients from rural areas, whereas pyogenic abscesses occurred in patients from urban and periurban environments. Staphylococcus aureus was cultured in 85 per cent of pyogenic liver abscesses. Gram negative organisms were identified in four cases of amoebic hepatic abscess where secondary infection occurred. Co-existing parasites of Ascaris lumbricoides and Trichuris trichiura were identified in the stools of 31 per cent of patients. A low (4.8 per cent) mortality is reported for this series.

Diagnosis: Capillariasis associated with tubular narrowing of multiple small-bowel loops with fold effacement. The clinical and radiographic presentations of these cases are representative of Capillaria philippinensis infection. Infection with C. philippinensis is primarily acquired by ingestion of raw, undercooked, small, fresh- or brackish-water fish [1]. Capillaria philippinensis, first discovered in the Philippines, has subsequently been detected in Thailand, Japan, Iran, Egypt, and Taiwan, with major outbreaks reported in Thailand and the Philippines [2]. Typically, patients present with signs and symptoms of malabsorption inclusive of chronic diarrhea, edema, muscle wasting, and abdominal pain; laboratory data reveal low serum albumin and potassium [3–4]. The diagnosis of C. philippinensis is usually based on the detection of eggs (Figure 1), larva, and/or adult worms with or without egg in stool specimens (Figure 1), although excretion can be sporadic, necessitating multiple repeated stool examinations, with small intestinal aspiration or biopsy to confirm the diagnosis in some cases [1–2]. Notably, mortality has been reported in patients with C. philippinensis who did not have capillaria eggs or larva recovered from stool specimens [2–3]. The detection of the parasite’s stichosome (the posterior glandular esophagus) and stichocytes (large glandular cells) by hematoxylin and eosin stain are not diagnostic, as these can also be identified in biopsies of patients with Trichinella spiralis and Trichuris trichiura infection. The clinical presentations and locations of lesions can readily help in the differentiation and case detection of these 3 parasitic infections [5]. Whereas patients with C. philippinensis typically present with clinical manifestations of chronic watery diarrhea and malabsorption, those with T. trichiura usually present with prolonged diarrhea, blood-streaked stool, anemia, colitis, proctitis, and rectal prolapse (in patients with heavy infestation). Cases with T. spiralis usually have biphasic presentations that begin with clinical manifestations of nausea, vomiting, and diarrhea (intestinal phase) followed by intense myalgias and periorbital edema (muscular phase) [5]. Additionally, C. philippinensis typically involves the distal jejunum and proximal ileum, T. trichiura tends to cause lesions limited to the large bowel, and T. spiralis is typically associated with encysted larva that migrated to specific organ tissues (eg, muscle, myocardium, and brain). In each of our 4 reported cases, the initial stool specimen was negative for C. philippinensis. Subsequent stool specimens were positive for C. philippinensis in 2 patients, and all 4 had small-bowel biopsies remarkable for severe villous blunting, inflammatory cell infiltration, and visualization of nematodes in longitudinal sections with the identification of stichocytes

The significance of parasite-specific serum and secretory immunoglobulin (Ig) isotype responses as determinants of Trichuris trichiura infection intensity in endemic communities is discussed. Comparison of age-dependent isotype responses and the age profiles of infection intensity in 2 endemic communities with markedly different levels of T. trichiura transmission suggest that serum IgA responses may reflect the accumulated past experience of infection and thus may be relevant in acquired immunity to T. trichiura and contribute to the age-convexity of infection intensity in areas of intense transmission. Preliminary analysis of data from a second community-based study shows that parasite-specific secretory IgA in saliva increases with age and correlates negatively with infection intensity, suggesting that secretory IgA may also be implicated in acquired immunity to this gut-dwelling nematode.

This study examines the persistence of familial aggregation and familial predisposition to Ascaris lumbricoides and Trichuris trichiura infection over 2 periods of treatment and reinfection, in an urban community in Kuala Lumpur, Malaysia. Both parasite species were shown to be aggregated (assessed by the variance to mean ratio) within families at all 3 interventions, although no consistent trend in aggregation was observed over the period of the study. Associations between mean A. lumbricoides and T. trichiura infection levels of families, at all 3 interventions, were highly significant (P < 0·0001), suggesting persistent predisposition at the family level.

The blood haemoglobin concentrations and intestinal helminth infections were surveyed in 658 children aged between 6 and 12 years attending 4 primary schools in Coclé Province, Panama, in November 1987. 147 (22.3%) of the children were judged to have haemoglobin concentrations indicative of iron-deficiency anaemia. Blood haemoglobin concentrations were significantly lower in children with heavier Trichuris trichiura infections (5000 eggs/g) (P = 0.014), and in children with dual infections of both hookworm and T. trichiura (P = 0.005). Children with concomitant T. trichiura and hookworm infections were also significantly more likely to have blood haemoglobin levels indicative of anaemia than children who were uninfected or had single infections with either of these helminths (P0.005). In a longitudinal study involving 171 children selected from the original 658, blood haemoglobin concentrations were measured again in November 1988. Children who were considered to show an improvement in both hookworm and T. trichiura infections over this 12 month period showed a significantly greater increase in blood haemoglobin concentrations than children who had remained uninfected with either of these helminths throughout the study period (P0.05).

A helminthological study of stool and urine samples collected from 1, 037 people from four rural communities in Gumau District of Bauchi State, Nigeria was carried out using formo-ether concentration and direct centrifugation methods respective ly. The study is the first parasitological survey to be carried out in the district. Thirty-nine per cent of examined persons were infected. Ova of Ascaris lumbricoides, Schis-tosoma haematobium, Schistosoma mansoni and Trichuris trichiura were most common. Hookworm, tapeworm and Strongyloides stercoralis were also encountered, 17.9% and 10. 8% of examined persons had S. haematobium and S. mansoni infections respectively. Water demand index (number of persons per well) for each community was calculated as a ratio of the total population to the number of safe water sources available in that community. A significant relationship was found between water demand index and S. haematobium (r = 0.95) on one hand, and S. mansoni (r = 0.88) on the other (P < 0.01). Such relationship was not found in soil borne helminth infections. A similarly significant association was found between distance from river and prevalence of S. haematobium (r = 0.94) on one hand and S. mansoni (r = 0.95) on the other (P < 0.01) but not found in soil-borne helminth infections. These findings seem to suggest that water demand index may be an important factor in the epidemiology of Schistosome infections in rural communities. Water demand index may also be a useful field technique for estimating and comparing the rates of water associated helminth infections in rural communities with comparable environmental conditions.

In this prospective study, we examined stool specimens from children with cancer receiving chemotherapy who were admitted for fever to the Universiti Sains Malaysia Hospital in Kota Baru, Kelantan. Stool specimens were examined for ova and cysts of parasites. Over a period of 15 months, there were 129 febrile episodes in 50 children with cancer and, in all, 237 stool specimens were examined. Sixty-six per cent of febrile episodes were associated with neutropenia and 9 per cent were associated with diarrhoea. Stool parasites were found in 42 per cent of children. The most common were helminths, followed by protozoa. Trichuris trichiura was the most common parasite (24 per cent), followed by Ascaris lumbricoides (22 per cent). Hookworm was found in 2 per cent. Giardia lamblia was found in 6 per cent of children, Blastocystis hominis in 4 per cent, and Cryptosporidium parvum in 2 per cent.

Stool examination of 249 early primary schoolchildren at 2 schools in north-eastern peninsular Malaysia revealed that 73 were infected with Ascaris lumbricoides, 103 with Trichuris trichiura,. and 18 with hookworms. Infected children were treated with a single dose of 400 mg of albendazole. The school attendance records during a 60 d period before treatment and 2 consecutive 60 d periods after treatment were examined. The absenteeism rate did not improve more among infected children after treatment than it did among the uninfected control children. The correlation between worm intensity and the number of lost school-days was poor. There was no evidence that intestinal helminthiasis caused school absenteeism among this group of children.

A 'sandwich' enzyme-linked immunosorbent assay was established to detect circulating antigens of Trichinella spiralis in human sera, its sensitivity and specificity was evaluated using 4 antigens (Trichinella spiralis, Trichuris trichiura, Dirofilaria immitis and Ascaris suum), and it was found to be sensitive and specific for T. spiralis antigen. Samples of 347 individuals with suspected trichinellosis, who had eaten incompletely cooked bear meat containing larvae of T. spiralis, were examined. Among individuals showing clinical symptoms, circulating antigens were detected in 29.9%, and the prevalence of antibodies was 18.9%. Among individuals lacking clinical symptoms, antigens were detected in 21.4% and antibodies in 5.0%. It was concluded that detection of circulating antigens was more useful for making diagnoses than measurement of specific antibodies.