The half-life of Ascaris lumbricoides prevalence in Japanese school children.

In the present study, we examined the dynamic of school-health-based parasite control and the related socio-economic influences. This is an ecological study based on data from 46 prefectures in Japan. The exponential decay of Ascaris lumbricoides prevalence was calculated by iterative least-squares method. Pearson's correlation and multiple linear regression model analysis were performed to assess the associations between the prevalence of Ascaris lumbricoides in Japanese school children and socio-economic variables such as the prefecture income per capita, the percentage of primary industry, the population density per 1 km2, the diffusion rate of population under water supply, and the percentage of upper secondary school enrollment. The results indicated that the parasite carrier rate was higher in younger students. The half-life of Ascaris lumbricoides prevalence was approximately 3 years with significant variation among prefectures. Multiple regression analyses showed that the decrease of infection in elementary and lower secondary school children had a significant positive association with primary industry and a significant negative association with prefecture income per capita. The school-health-based parasite intervention differs by prefecture and has changed over time according to the respective prefectural stage of economic development.

Antibody responses and resistance against Ascaris lumbricoides infection among Venezuelan rural children: the influence of ethnicity.

We studied the production of anti parasite antibodies and the resistance against A. lumbricoides infection among the school population of three different Venezuelan ethnic groups: Warao Amerindians, Afro- Americans and white 'Creole' descendents. The prevalence and intensity of A. lumbricoides were determined before and after 1 year of anthelminthic treatment. Parasitic loads were associated to pre-treatment serum levels of anti A. lumbricoides IgE and IgG4 antibodies. The intensity of the infection and the proportion of re-infected children were significantly lower (p < 0.0001) among the Warao Amerindians, exhibiting higher levels of IgE (p < 0.0001) and lower levels of IgG4 (p < 0.0001) compared to their non-Amerindian counterparts. IgE levels correlated inversely with the proportion of re-infected children, whereas the levels of IgG4 were positively associated. These results suggest that ethnicity may influence the balance of IgE/IgG4 levels, modulating the intensity of A. lumbricoides and the resistance to the infection.

[Antibody response to Ascaris lumbricoides among the children population in the Ustí Region]. / Protilátková odpoved' na Ascaris lumbricoides v populaci detí Usteckého kraje.

A group of 156 children aged between 10 and 12 years were screened for IgG and IgE antibodies to Ascaris lumbricoides. The study subjects were 64 children of Romany origin and 92 children from the majority population. IgG antibodies to Ascaris lumbricoides were detected in 112 (71.8%) children. No difference in the prevalence of IgG antibodies was found between Romany children and those from the majority population. As many as 34.1% of the study subjects had IgE antibodies to Ascaris lumbricoides, again with no difference between the two ethnic groups. Children with IgG antibodies to Ascaris lumbricoides had significantly higher total IgE levels compared to those who had tested IgG negative. To demonstrate induction of a non-specific IgE response was one of the study objectives. The high prevalence rates of IgG and IgE antibodies to Ascaris lumbricoides are suggestive of a high frequency of cross- and non-specific reactions. Possible effect of cross-reactivity to other antigens on the specific IgG and IgE antibody response to Ascaris lumbricoides is discussed.

Modes of transmission for Ascaris lumbricoides and Trichuris trichiura among Chinese children in Macao City.

To obtain more information on the transmission of Ascaris lumbricoides and Trichuris trichiura in Macao City, 308 Chinese children were surveyed. The infection rates of A. lumbricoides and T. trichiura were 14.9 and 6.8%, respectively. There was no association between the infections. A. lumbricoides infection was associated with age and T. trichiura with new immigrants from China. No association was found between the infections and family socio-economic factors. The results suggest that the modes of transmission for A. lumbricoides and T. trichiura may be different in highly urbanized areas.

Prevalence of intestinal parasitic infestation in schoolchildren in the northeastern part of Kathmandu Valley, Nepal.

This paper presents the status of intestinal parasitosis in public schoolchildren (1 to 10 classes) in a rural area of the Kathmandu Valley, Nepal. A total of 533 schoolchildren (269 girls and 264 boys, aged 4 to 19 years) were included in this study. A questionnaire was filled out regarding hygienic and other habits, including factors predisposing to parasitic infections. Fecal samples from the children were examined by formol-ether concentration technique. The overall prevalence of parasitosis was 66.6% (395/533) with no significant difference between boys and girls (p> 0.05). Tibeto-Burman children had a non-significant higher prevalence, compared with Indo-Aryan and Dalit children (p>0.05). Half (53.8%; 191/355) of the children had multiple parasitic infections. Altogether, nine types of parasites were recovered. The recovery rate of helminths was higher (76.9%) than protozoa (23.1%). Trichuris trichiura was the most common helminth detected, followed by hookworm, Ascaris lumbricoides and others. Entamoeba coli was the most common protozoan parasite, followed by E. histolytica, Giardia lamblia and others.

Intestinal parasitic infestation among different population groups of Andaman and Nicobar islands.

A survey was carried out among the rural and urban settlers and two tribal groups viz. Nicobarese and Onges, of Andaman and Nicobar islands. The survey covered preschool school aged children and adults. Out of the total 1,384 stool samples examined, 652 (47.1%) showed ova or cysts of one or more intestinal parasites. Among the preschool children, Nicobarese showed the highest overall prevalence rate (80.5%) followed by urban (46.7%) and rural (38.6%) preschool children. Ascaris lumbricoides was the commonest form of parasite encountered in all the groups of preschool children, followed by Trichuris trichura. While ascariasis and trichuriasis were more common among the urban children than in rural children, giardiasis was more common among the rural preschool children. The school age children among rural settlers showed an overall prevalence rate of 61.1% which was significantly higher than that among the rural preschool children. Among the school age children also, ascariasis was the commonest form of parasitosis followed by trichuriasis. The Nicobarese and Onge adults showed significantly higher overall prevalence rates (72.2%) and 71.1% vs 48.6%) compared to rural adults. In all the groups studied ascariasis was the commonest form of parasitosis except in Onges among whom trichuriasis and giardiasis were more common than ascariasis. Change in prevalence rates over age was studied among the rural settlers. While ascariasis and trichuriasis showed peak prevalence rates in school age children prevalence of giardiasis declined with increase in age from a peak in the preschool age group and prevalence rates of hook worm infestation continued increasing beyond school age.

Determining the prevalence of intestinal parasites in three Orang Asli (Aborigines) communities in Perak, Malaysia.

This study was conducted to determine the prevalence of intestinal parasites among children and adult Orang Aslis (Aborigines) from different locations in Perak. Faecal samples were collected and analyzed using the direct smear and formal ether sedimentation technique. Some of the faecal samples were stained using the Modified Acid fast stain for Cryptosporidium. Nail clippings of the respondents and the soil around their habitat were also analyzed. Of the 77 stool samples examined, 39 (50.6%) were positive for at least one intestinal parasite. The most common parasite detected was Trichuris trichiura (39.0%) followed by Ascaris lumbricoides (26.9%), Entamoeba coli (5.2%), Giardia lamblia (5.2%), Blastocystis hominis (3.9%), hookworm (3.9%), Entamoeba histolytica (1.3%), Iodamoeba butschlii (1.3%) and Cryptosporidium sp. (1.3%) respectively. Some respondents had single parasites (24.7%), some with two parasites (18.2%). Some with three parasites (6.5%) and one had four parasites species (1.3%). The parasites were slightly more common in females (54.7%) than males ((41.7%). The parasites were more common in the 13-20 year age group (90.9%) followed by 1-12 years (69.6%), 21-40 year age group (34.8%) and least in the 41-60 year age group (27.8%). Nail examinations of the respondents did not show any evidence of parasites. One had a mite, three had pollen grains and one had yeast cells isolated from the finger nails. Soil samples taken around their houses showed only one sample with a nematode ova and one with oocyst which was of a non human origin.

Localization of multiple quantitative trait loci influencing susceptibility to infection with Ascaris lumbricoides.

A linkage-based genome scan of 1,258 members of a single pedigree of the Jirel population of Nepal localized 6 potential quantitative trait loci (QTLs) influencing susceptibility to infection with Ascaris lumbricoides, the most common soil-transmitted intestinal helminth. Three QTLs exhibited genomewide significance, including QTLs on chromosomes 13 (logarithm of the odds ratio [LOD] score, 3.37; genomewide P = .013, 8 (LOD score, 3.03; genomewide P = .031), and 11 (LOD score, 3.19; genomewide P = .020). Another QTL on chromosome 1 approached significance (LOD score, 2.72; genomewide P = .067). There was suggestive evidence of linkage for 2 additional loci on chromosomes 1 and 13.

Anaemia and iron deficiency anaemia among aboriginal schoolchildren in rural Peninsular Malaysia: an update on a continuing problem.

A cross-sectional study to determine the current prevalence of anaemia and iron deficiency anaemia (IDA) and to investigate the possible risk factors for IDA was carried out on 241 aboriginal schoolchildren (120 boys, 121 girls) aged 7-12 years and living in remote areas in Pos Betau, Pahang, Malaysia. Haemoglobin (Hb) level was measured and serum iron status was assessed by serum ferritin (SF), serum iron (SI) and total iron binding capacity measurements. Socioeconomic data were collected using pre-tested questionnaires. All children were screened for intestinal parasitic infections. Overall, 48.5% (95% CI 42.3-54.8) of children were anaemic (Hb<12 g/dl). The prevalence of IDA was 34% (95% CI 28.3-40.2), which accounted for 70.1% of the anaemia cases. The prevalence of IDA was significantly higher in females than males. Low levels of mothers' education and low household income were identified as risk factors for IDA. Severe trichuriasis also found to be associated with low SF and SI. Logistic regression confirmed low levels of mothers' education and gender as significant risk factors for IDA. Improvement of socioeconomic status and health education together with periodic mass deworming should be included in public health strategies for the control and prevention of anaemia and IDA in this population.

Helminthiasis and cultural change in the Peruvian rainforest.

The objective of this study was to identify the impact of cultural and ecological change on intestinal helminth infections in traditional indigenous communities in the Peruvian rainforest and to identify the ways of transmission of helminth eggs. A remote indigenous settlement was compared with a more developed mestizo town. Stool specimens as well as soil, dust, air and water were examined for Ascaris and Trichuris eggs. A significantly lower infection intensity of Ascaris and Trichuris could be demonstrated for the traditional Indian community. Here the hygienic conditions were found to be better than in the town. The mestizo teacher and his family, who had come from the town to the Indian settlement, showed poorer hygienic standards and higher levels of Ascaris and Trichuris egg excretion than the Indian dwellers. The distribution of Ascaris and Trichuris eggs in the soil, house dust and in the air suggests that the contaminated dust from defaecation sites was distributed through the whole community by feet, animals (chickens) and wind. It was observed that many traditional habits that contributed to the good hygiene of the native population were being abandoned in the process of cultural change.

Pancreatitis due to Ascaris lumbricoides: second occurrence after 2 years.

Pancreatitis is a common disease in the United States, with the most likely etiologies being biliary tract disease and alcohol use. Infections with parasites such as Ascaris lumbricoides comprise a small percentage of pancreatitis cases in the United States, but they are a common etiology in developing countries. In the United States, the incidence of pancreatic and biliary ascariasis has been increasing because of the migration of people from endemic countries, as well as increased travel by Americans to such countries. Patients treated for this roundworm can have reinvasion for the same reasons. We report the case of a patient with two episodes of pancreatitis due to A. lumbricoides 2 years apart.