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PubMed1981

Prevalence and treatment of intestinal helminthic infections among children in orphanages in Jakarta, Indonesia.

A survey was carried out in three orphanages in Jakarta for intestinal helminthic infections. Stool samples and anal swabs of 158 children were examined. The prevalences of intestinal helminthic infections in the Putra Utama, Muslimin and Van der Steur orphanages were respectively as follows: a lumbricoides 70.0%, 76.6% and 50.8%, T. trichiura 78.0% 93.6% and 70.5%, hookworm 20.0%, 12.7% and 3.2% and E. vermicularis 34.0% 29.8%, 59.0%. Treatment with Trivexan (100 mg of pyrantel pamoate and 150 mg of mebendazole), one tablet as a single daily dose for 3 consecutive days resulted in cure rates for A. lumbricoides 96.0%, 100% for T. trichiura 78.0%, 80.9% and 86.9% for hookworm 98.0%, 100% and 100% and for E. vermicularis 82.3% 92.9% and 97.2%. No side effects were observed, except in one child who complained of nausea.

Adolescent↗
PubMed2004

The role of parasites in genetic susceptibility to allergy: IgE, helminthic infection and allergy, and the evolution of the human immune system.

There have been numerous studies in the mouse illustrating the dichotomy of T cell responses, with the common classification orchestrated around Th1 vs. Th2 responses. This classification is now widely applied to human disease as well and the generic conclusion is that the Th1 responses are more likely to occur secondary to specific microbiologic insult but also inflammatory responses. In contrast, the Th2 response is the prevalent response in subjects with atopy and allergic disease but is also the mechanism for protection against helminthic infections. Unfortunately, the paradigm of Th1 vs. Th2 is not as clear in the human as it is in mouse models. Even so, the immunological mechanisms responsible for IgE production that are protective in helminthic infections, i.e. Schistosoma, are similar to those for the production of specific IgE against allergens. In fact, there also appear to be associations in the memory T cell subpopulation CD4+CD45RO+ and the elicitation of IgE against both parasites and allergens. In this review, we present the overall contemporary scheme on the role of parasites in genetic susceptibility to allergic IgE, helminthic infections with specific discussion of its implications for the evolution of the human immune system.

Animals↗
PubMed1966

[Experimental studies on the effects in helminthic infection, with special reference to the gonadectomy of the host]

INTRODUCTION: Concerning the influences of the host's hormone in helminthic infection, Solomon(1963) reported that castrated hamsters were less susceptible to Nippostrongylus brasiliensis infection than the sham-operated or normal control groups, and Addis(1946) demonstrated that testosterone in the male host was necessary for normal growth of Hymenolepis diminuta and the egg productive ability was also effected by the hormone. Beck(1950, 1952) noted a significant reduction in egg production in castrated rats infected by a single worm. Egg production of a single worm in gonadectomized or thyroidectomized hamsters was found to be lower than the control group (Landt 1954, 1955). Dobson(1964) reported that male lambs were more susceptible to Oesophagostomum columbianum infection, harbouring more and larger worms and producing fewer nodules than females, but gonadectomy removed these differences by increasing the susceptibility and worm growth in the female lambs. Thyroidectomy did not affect host resistance, as measured by nodule numbers, but did increase adult worm survial, partcularly in female host. Solomon(1964) found that the mean recovery of adult worms from gonadectomized or normal hamsters given 20 mg testosterone propionate intramuscularly at 8 and 16 hour prior to infection and necropsied on the 9th day of infection, was nearly 50% that from sham or normal animals was apporximately 10%; and that from gonadectomized animals was only 3%. Campbell and Melcher(1940), Haam and Rosenfeld(1942), Sadun(1948, 1951), Haley (1958 a, b), Mathies(1959 a, b) and Dobson(1961 a, b), noted that estrogen increased the resistnace of the host against helminthic infection, while testosterone had a little or no effect. There were many studies on the effects of parasite infection in cases of host sex hormone imbalance but there are many unknown points as yet. In the present study, the author studied the infectiousness of helminths in castrated or in sex hormone-administrated hosts. MATERIALS AND METHODS: 1) 51 mature rats and 30 immature rats were divided into 10 groups for the former and 6 groups for the latter. 51,000 of hookworm(Ancylostoma caninum) filariform larvae were given to 51 gonadectomized rats by subcutaneous injection. The rats were sacrifeced 7 days after the infection and the larvae which had migrated to muscle, liver and lung were collected by Baermann's method. Thirty rats, given sex hormone, were infected with 100 filariform larvae of Ancylostoma caninum for each rat orally and the larvae were collected from the liver, muscle, lung and small intestine 72 hours after the infection. After calculation of the number of larvae a statistical method was applied for the singnificance of the difference. 2) Gonadectomized rats and control rats inoculated with Capillaria hepatica were sacrificed 5 weeks after infection. The adult worms were collected from the liver and were calculated. Four dogs, including one with oophorectomy, one castrated and two controls, were sacrificed 7 days after infection with 100 filariform larvae of Ancylostoma caninum to each and calculation of the number of larvae from the small intestines was carried out. 3) A castrated adult dog and one control dog(sham-operation) were infected orally with 500 A.caninum larvae each and the other two dogs were given 1,000 larvae each orally. The egg productivity was checked every five days by Stoll's egg counting method from three weeks after the infection was initated. A certain number of the hormones influenced adult worm from the castrated host were placed in vitro for the extensive examination fo egg productivity. RESULT: 1)No significant difference was noted in canine hookworm infection due to hormone influence between the control group and the gonadectomized rats which were sacrificed 17 days after gonadectomy and 7 days after the infection. However in the rats which were infected 20 days after oophorectomy a significant difference was thought to be present in this group(176 +/- 12.9 larvae/rat) compared with the control group (138 +/- 21.2 larvae/rat). On /rat). On the other hand, in the castrated group the number of larvae (138 ± 37.1 larvae/rat) was less than that in the control group (208 ± 43.4 larvae/rat). In the estrogen-injected male and female groups, there were no difference compared to the control, but the testosterone-injected groups of males and females showed more susceptibility to infection by A. caninum than in the control group. 2)The Capillaria hepatica infection to the castracted host showed no significant difference between the gonadectomized and the control group. (oophorectomy; 214 ± 28.0), castration; 250 ± 36.5 and control; 191 ± 58.2 and 270 ± 30.1 adults/rat). 3)Concerning the influence of the host's sex hormone on egg production of canine hookworm, there was a significantly decreased egg production in castrated dogs(6,578 ± 664.0 egg per gram) compared to the control dogs(9,711 ± 1,322.3 egg per gram). The same results were observed in vitro test. CONCLUSION: 1)In the host, the susceptibility to hookworm infection was reduced in castrated rats, while oophorectomy group had a little or no effect. 2)In the favorable or unfavorable hosts, testosterone gave the tendency of increasing susceptibility of the host to infection, while estrogen did a little or no effect.

Journal Article↗
PubMed2001

School enrollment in Zanzibar linked to children's age and helminth infections.

UNLABELLED: School health programmes have been identified as a cost-effective strategy to reduce morbidity due to soil-transmitted helminths in the school-age population, but the low rate of school enrollment in developing countries is a major factor limiting their success. OBJECTIVE: The present study was conducted to identify reasons for non-enrollment and to evaluate differences in the occurrence of helminth infection between enrolled and non-enrolled children in Zanzibar, United Republic of Tanzania. METHOD: A questionnaire was submitted to 520 households to obtain information about enrollment and other socio-economic indicators. In addition, one school-age child was randomly selected in each household and investigated for soil-transmitted helminth infection. RESULTS: Overall, 71% of school-age children were enrolled. Enrollment increased with age. Only 41% of children under 9 years of age were enrolled compared to 91% in children older than 12 years. Enrollment is delayed because of an insufficient number of schools. Among non-enrolled school-age children, the proportion of heavy intensity infections was twice that of enrolled school-age children. CONCLUSIONS: Most of the non-enrolled school-age children live together with enrolled siblings in the same household, thereby representing an important opportunity for effective outreach activities. The effectiveness of the school-based helminth control programme in reducing the intensity of infection was confirmed. The significant gains achieved by enrolled school-age children in this study must be viewed as an attainable goal for the important numbers of non-enrolled school-age children in endemic areas. Decision-makers must ensure that outreach activities are included in helminth control programmes targeted to school-age children.

Adolescent↗
PubMed1994

Does helminth infection affect mental processing and educational achievement?

In this article, Catherine Nokes and Donald Bundy reexamine the evidence linking intestinal helminth infection to impaired cognitive function and educational outcomes. They consider first the evidence that implies a connection between intellectual dysfunction and the sequelae of infection, then the significance of correlations between infection and poor mental status, and finally the evidence from case-control and double-blind intervention studies. The article is not intended as a comprehensive summary of all the research on helminth infection and mental function - indeed the majority of research undertaken in the early part of this century is not included - but rather as a thought provoking article to highlight the difficulties with interpreting existing data and to stimulate new interest in this field.

Journal Article↗
PubMed2000

The role of eosinophils in parasitic helminth infections: insights from genetically modified mice.

Eosinophilia - an increase in the number of eosinophils in the blood or tissues - has historically been recognized as a distinctive feature of helminth infections in mammals. Yet the precise functions of these cells are still poorly understood. Many scientists consider that their primary function is protection against parasites, although there is little unequivocal in vivo evidence to prove this. Eosinophils are also responsible for considerable pathology in mammals because they are inevitably present in large numbers in inflammatory lesions associated with helminth infections or allergic conditions. In this review, Carolyn Behm and Karen Ovington outline some of the cellular and biological properties of eosinophils and evaluate the evidence for their role(s) in parasitic infections.

Animals↗
PubMed2002

Chronic helminth infection induces alternatively activated macrophages expressing high levels of CCR5 with low interleukin-12 production and Th2-biasing ability.

Helminth infections induce Th2-type biased immune responses. Although the mechanisms involved in this phenomenon are not yet clearly defined, antigen-presenting cells (APC) could play an important role in this process. Here, we have used peritoneal macrophages (F4/80+) recruited at different times after challenge with Taenia crassiceps as APC and tested their ability to regulate Th1/Th2 differentiation. Macrophages from acute infections produced high levels of interleukin-12 (IL-12) and nitric oxide (NO), paralleled with low levels of IL-6 and prostaglandin E(2) (PGE(2)) and with the ability to induce strong antigen-specific CD4+ T-cell proliferation in response to nonrelated antigens. In contrast, macrophages from chronic infections produced higher levels of IL-6 and PGE(2) and had suppressed production of IL-12 and NO, associated with a poor ability to induce antigen-specific proliferation in CD4+ T cells. Failure to induce proliferation was not due to a deficient expression of accessory molecules, since major histocompatibility complex class II, CD40, and B7-2 were up-regulated, together with CD23 and CCR5 as infection progressed. These macrophages from chronic infections were able to bias CD4+ T cells to produce IL-4 but not gamma interferon (IFN-gamma), contrary to macrophages from acute infections. Blockade of B7-2 and IL-6 and inhibition of PGE(2) failed to restore the proliferative response in CD4+ T cells. Furthermore, studies using STAT6(-/-) mice revealed that STAT6-mediated signaling was essential for the expansion of these alternatively activated macrophages. These data demonstrate that helminth infections can induce different macrophage populations that have Th2-biasing properties.

Animals↗
PubMed2004

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

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

Age Factors↗
PubMed2004

Epidemiology of gastrointestinal helminths infections in Dorper sheep in a semi-arid area of Kenya.

A survey on the prevalence and intensity of infection with gastrointestinal helminths of Dorper sheep in relation to age and weather factors was carried out on a ranch in Kajiado district, a semi-arid area of Kenya for a period of 13 months (May 1999 to May 2000). Faecal samples from lambs (3 months to 1 year), yearlings (1-2 years) and adult breeding ewes (2-4 years) were examined for helminth egg output and helminth genus composition at 3-week intervals. The results indicated that the prevalence of strongyle and tapeworms infections were highest for lambs, followed by the adult breeding ewes and then for the yearlings. In all age groups the proportions of infected animals were higher during the wet season than in the dry season for both nematodes and tapeworms. The mean strongyle egg counts were higher during the dry season for lambs, but were higher during the wet season for the other age groups. Mixed strongyle infections were detected, with Trichostrongylus (55 %), Haemonchus (28 %), Cooperia (10.5 %) and Oesophagostomum (6.5 %) being the most frequently encountered genera throughout the study period. The trends in strongyle faecal egg counts indicated the occurrence of hypobiosis, with resumption of development towards the end of the dry season and at the onset of the short rains in October and November. Self-cure was also observed in September and November in all age groups, although less frequently in lactating ewes. The prevalence and intensities of infection with gastrointestinal helminths in this area appeared to be influenced by the age of the host and weather factors.

Age Factors↗
PubMedDate not supplied

Comparative helminth infections of man in two rural communities of the Niger Delta, Nigeria.

The intestinal parasitic helminth infections of man in Bonny and Isiokpo communities were studied between May 1992 and March 1994. Of the 2008 stool samples examined from Bonny community, 503 (25.0%) were infected. 305 (26.7%) of these infections were males while 198 (22.9%) were females. Ascaris lumbricoides (24.1%) occurred most frequently, followed by Hookworms (18.0%), Trichuris trichiura (17.3%,) Strongyloides stercoralis (10.1%) and Enterobius vermicularis (0.1%). Peak infection (41.7%) was recorded for the males in (10-14) years age bracket. The use of bush as a toilet facility had the highest parasitic infection (38.3%), followed by that of shoreline (35.3%), pit (33.3%), Bucket (27.8%) and of water closet (7.5%). Degree of infection relative to source of drinking water showed that well water was associated with highest infection (43.3%) while the pipe borne water was the lowest (18.0%). From Isiokpo community 2,462 stool samples were examined for intestinal parasites 1,633 (66.3%) people were infected consisting of 862 (64.8%) males and 771 (68.2%) females. Higher parasitic infection of females in this community was attributed to the cultural and occupational factors. Frequency of occurrence of individual helminth was as follows: A-lumbricoides (64.5%), T. trichiura (59.4%), Hookworms (58.8%), S. stercoralis (25.1%), Hymenolepsis nana (2.9%) and E. vermicularis (0.3%). Prevalence of infection was significantly higher in Isiokpo than in Bonny because the climatic and edaphic factors were conducive to larval development and infectivity. On the contrary, the saline soil and surface water of Bonny community constituted harsh environmental conditions inimical to larval development and infectivity. Observations on parasitic infections in relation to toilet facilities and source of drinking water were similar to those made in Bonny. The study therefore demonstrated that the provision of pipe borne water and water closet facilities in rural Niger Delta communities could reduce helminth infections of man.

Adolescent↗
PubMed1996

Helminth infections, morbidity indicators and schistosomiasis treatment history in three villages, Dongting Lake region, PR China.

In order to estimate the public health impact of helminth infections, and to provide baseline data for interventions, parasitological and morbidity surveys were conducted among inhabitants of three villages in Dongting Lake region, Hunan Province, China. Ascaris lumbricoides was found to be the most common helminth infection, followed by Trichuris trichiura and Schistosoma japonicum. Left liver enlargement was the most common indicator of morbidity. Observed numbers of multiple species infections closely correlated with expected figures generated from a simple probabilistic model. Heterogeneity was observed in age and sex-standardized infection and morbidity prevalences among the villages and occupations. Males had higher levels of infection, were more likely to suffer morbidity, and were more likely to have been treated for schistosomiasis than women. The prevalence of each morbidity indicator was positively correlated with the number of times of treatment for schistosomiasis, and negatively correlated with number of years since last treatment. The results imply that treatment history for S. japonicum infection may be a good indicator of current morbidity risk.

Adolescent↗
PubMed2000

Prenatal immune priming with helminth infections: parasite-specific cellular reactivity and Th1 and Th2 cytokine responses in neonates.

The present investigation aimed to determine to what extent maternal helminth infection primes parasite-specific cellular responsiveness in neonates. Umbilical cord mononuclear blood cells (UCBC) and peripheral blood mononuclear cells (PBMC) from mothers proliferated in response to mitogenic stimulation with concanavalin A, as well as to bacterial Streptococcus pyogenes-derived (streptolysin O) and helminth-specific antigens of Necator americanus and Onchocerca volvulus. Cellular responses to Echinococcus multilocularis (Em) and Oesophagostomum bifurcum (Oes), helminth parasites not endemic in the study area, were absent (for Em) or very low (for Oes due to antigenic cross-reactivity). Cellular responsiveness to mitogen and antigens was higher in mothers than in their neonates. Several Th1-type (IL-2, IL-12, and IFN-gamma) and Th2-type (IL-5 and IL-10) cytokines were produced by UCBC from neonates and PBMC from mothers. Low levels of IFN-gamma were elicited by UCBC in response to helminth and bacterial antigens, while secretion of IL-2 was pronounced and similarly high in neonates and their mothers. Amounts of IL-5 produced by UCBC in response to bacterial SL-O and mitogenic stimulation (PHA) were low, but equivalent levels of IL-5 were induced by intestinal helminth and filaria-derived antigens in neonates and mothers. A pronounced production of IL-10 and IL-12 by UCBC was observed--spontaneous IL-10 and IL-12 secretion by UCBC was higher in neonates than by PBMC from mothers. Net amounts of IL-10 elicited by helminth antigens were similar, while net IL-12 in response to mitogen, and bacterial and helminth antigens was significantly higher in mothers than their offspring. Our results indicate that human maternal helminth infection does sensitize in utero for parasite-specific cellular responsiveness in offspring, and also activates specific production of several cytokines, and such children do not present a dominant expression of immunity of either Th1 or Th2.

Adolescent↗
PubMed1995

The ecology of endoparasitic helminth infections of brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss) in Scotland.

Two hundred and forty brown trout (Salmo trutta) and 49 rainbow trout (Oncorhynchus mykiss), obtained from 21 locations in Central Scotland between October 1990 and August 1993, were examined for endoparasitic helminth infections. Crepidostomum farionis (Digenea) was the most widely distributed helminth species, followed by Eubothrium crassum (Cestoda), Diphyllobothrium dendriticum and D. ditremum (Cestoda), Neoechinorhynchus rutili (Acanthocephala), Echinorhynchus truttae (Acanthocephala), Eustrongylides sp. (Nematoda), Capillaria salvelini (Nematoda), Cyathocephalus truncatus (Cestoda), Raphidascaris acus (Nematoda) and Cystidicola farionis (Nematoda), in that order. The prevalences and intensities of each helminth infection were recorded. No evidence was found to indicate that even fish with the highest worm burdens (e.g. 339 plerocercoids of Diphyllobothrium spp.) were experiencing any obvious morbidity. An analysis of pairs of associations between species of helminths revealed a significantly positive association between N. rutili and C. farionis (P < 0.01). The results are discussed in terms of patterns in helminth communities in freshwater fish.

Acanthocephala↗
PubMed1997

A school-based approach to the control of urinary schistosomiasis and intestinal helminth infections in children in Matuga, Kenya: impact of a two-year chemotherapy programme on prevalence and intensity of infections.

A school- and chemotherapy-based urinary schistosomiasis and intestinal helminth infection control programme was conducted in Matuga Division, Kwale District, Coast Province with teachers taking care of diagnosis, treatment and health education. More than 12,000 children in 36 primary schools were included in the 2-year programme. Results for 20 evaluation schools are presented. Children with haematuria were treated with praziquantel (40 mg/kg) once a year. Within 2 years, the prevalence of haematuria in the schools was reduced from 28% (range 8-68%) to 11.4% (range 3-23%). More than 80% of the schoolchildren were infected with one or more intestinal helminths at baseline. After one year with levamisole mass chemotherapy, single dose (2.5 mg/kg) three times a year (once per school term), the prevalence of Ascaris infection was reduced by 83% from 18% to 3%, but there was no change in pretreatment prevalences of hookworm (57%) and Trichuris (56%) infections. In the second year of the programme, albendazole 600 mg once every six months was administered to the children in 10 randomly selected schools. This resulted in 52% and 23% reductions in prevalences of hookworm and Trichuris infections, respectively, in these schools and a reduction in mean intensity of infection of 52.8% and 50.3%, respectively.

Adolescent↗
PubMed2006

Inhibition of autoimmune type 1 diabetes by gastrointestinal helminth infection.

Gastrointestinal nematode infections are prevalent worldwide and are potent inducers of T helper 2 responses with the capacity to modulate the immune response to heterologous antigens. Parasitic helminth infection has even been shown to modulate the immune response associated with autoimmune diseases. Nonobese diabetic (NOD) mice provide a model for studying human autoimmune diabetes; as in humans, the development of diabetes in NOD mice has been linked to the loss of self-tolerance to beta cell autoantigens. Previous studies with the NOD mouse have shown that helminth and bacterial infection appears to inhibit type 1 diabetes by disrupting the pathways leading to the Th1-mediated destruction of insulin-producing beta cells. The aim of our study was to examine whether infection with the gastrointestinal helminths Trichinella spiralis or Heligmosomoides polygyrus could inhibit the development of autoimmune diabetes in NOD mice and to analyze the mechanisms involved in protection and the role of Th2 responses. Protection from diabetes was afforded by helminth infection, appeared to inhibit autoimmune diabetes by disrupting pathways leading to the destruction of beta cells, and was mediated by seemingly independent mechanisms depending on the parasite but which may be to be related to the capacity of the host to mount a Th2 response.

Animals↗
PubMed2001

Th2 responses without atopy: immunoregulation in chronic helminth infections and reduced allergic disease.

The immune response to helminth infections has long been known to share key features with the allergic response. In particular, both are typified by enhanced T helper 2 (Th2) responses with high levels of interleukin-4 (IL-4), IL-5 and IL-13, accompanied by eosinophilia and abundant IgE production. Paradoxically, the geographical distribution of helminth parasitism and allergic disease is complementary rather than coincident. Thus, the question arises does the Th2 response to parasites protect or pre-empt the host from developing Th2-linked allergic manifestations? It is suggested that downregulatory immune mechanisms, which dampen the anti-parasite response, might benefit the host by blocking progression to atopic reactions. This is of relevance in explaining how the "hygiene hypothesis" might operate immunologically and in the design of therapeutics.

Animals↗
PubMed2005

Effect of age, sex and season on the prevalence and intensity of helminth infections in domestic pigeons (Columba livia) from Bursa Province, Turkey.

The one-year study reported in this paper was carried out from April 2002 to March 2003 in domestic pigeons (Columba livia) of Bursa Province (Turkey) to determine the occurrence of helminth species and to evaluate the effect of host age, sex and season on their prevalence and intensity. A total of 100 (31 young and 69 adult) domestic pigeons were necropsied and examined. The results of necropsies revealed that 74 pigeons harboured helminth infections. Three helminth species were identified: Baruscapillaria obsignata (63%), Ascaridia columbae (42%) and Raillietina echinobothrida (1%). There were no significant differences in the prevalence of B. obsignata and A. columbae by host age and sex. Significantly the highest prevalence rate of A. columbae was observed in the autumn months, but there was no significant difference in the seasonal prevalence of B. obsignata. The mean intensity of B. obsignata and A. columbae was higher in adults than in young pigeons but it did not differ significantly between the two sexes. The highest mean intensity rate of B. obsignata was observed in the autumn, while there was no significant difference for A. columbae with regard to season. From the data obtained in this study it can be concluded that in regions with similar climatic conditions as those in the present study area, pigeon breeders should be cautioned especially of B. obsignata and A. columbae infections of adult pigeons in the autumn months.

Aging↗