Epidemiological studies on gastro-intestinal nematode parasites of sheep. The control of infection in lambs on contaminated pasture.
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Abomasum↗
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Epidemiological studies on gastro-intestinal nematode parasites of sheep. Infection patterns on clean and summer-contaminated pasture.
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Abomasum↗
[Intestinal parasitosis in children admitted to the Pediatric Teaching Hospital of Cerro, Havana City, Cuba].
A study on intestinal parasitism was conducted among 401 children admitted in the Pediatric Teaching Hospital of Cerro, from May to June, 1999. To this end, a representative, randomized and stratified sample by service was taken. 3 samples of feces per child were collected, preserved in formaldehyde, and processed by 3 parasitological methods. There was an intestinal parasitism prevalence of 15% at the hospital and there were no differences between the stratum of children admitted in Gastroenterology and the rest of the services as regards commensals and parasites in general (p > 0.05); however, commensals predominated in the second group (p < 0.01) The intestinal coccidia, Cryptosporidium parvum and Cyclospora cayetanensis prevailed in the Gastroenterology service over the rest of the services (p < 0.01). The age group over 4 (school children) was the most affected, both by protozoa and commensals (p < 0.01), excepting Cryptosporidium parvum that affected the infants more (p < 0.05). The analysis of some epidemiological antecedents showed that those children eating fruit without peeling and washing them, having vegetables withouth washing them first and walking barefooted were more prone to infection (RR > 1). A higher frequency of infection due to intestinal parasites was found among those living in rural areas, drinking well or river water, and defecating in latrines or in the open air (RR > 1). These results suggested that in spite of the existing knowledge of the epidemiological and risk factors, the intestinal parasites continue affecting the child population
Child, Preschool↗
Prevalence of intestinal parasitosis within three population groups in La Plata, Argentina.
The prevalence of intestinal parasites was studied as a function of socioeconomic conditions within La Plata, Argentina. Age, sex, and environmental factors were considered. Thus, from each of three areas within the city - the first a 'marginal' zone, the second a lower-income suburb, the third a middle-income urban district - 100,101, and 91 children up to 14 years old, respectively, were examined for intestinal parasites. Giardia lamblia was the most frequent species found. The respective prevalences of intestinal parasites overall (73, 54.4, and 35.1%), of polyparasitism (61.6, 27.2, and 12.5%), and of helminthic infection (32, 10.9, and 0.0%) were the highest within the population group having significantly inferior sanitary and environmental conditions. A positive statistical association between the prevalence of intestinal parasitosis and age was observed in all three of the neighborhoods. We also noted a correspondence between the frequency of such infections and school attendance in the two suburban districts. Management practices in accordance with the specific characteristics of an urban environmental and sociocultural ecosystem are thus important for the control of intestinal-parasite infection within municipal populations.
Adolescent↗
Efficacy of ivermectin and pyrantel pamoate combined in a chewable formulation against heartworm, hookworm, and ascarid infections in dogs.
Eight trials were conducted in dogs to document the efficacy of ivermectin (6 micrograms/kg of body weight) and pyrantel pamoate (5 mg of active pyrantel/kg) in a beef-based chewable formulation against Dirofilaria immitis, Ancylostoma caninum, Uncinaria stenocephala, Toxocara canis, and Toxascaris leonina. Three studies involved induced infection with D immitis, and 5 studies involved induced or natural infection with hookworms and ascarids. In 3 intestinal parasite trials, the efficacy of the combination chewable tablet was compared with each of its components. Results indicated that 1 component did not interfere with the activity of the other. In 1 heartworm and 2 intestinal parasite trials, the efficacy of pyrantel, ivermectin/pyrantel combination, or ivermectin with pyrantel dosage of 10 mg/kg was evaluated. The ivermectin/pyrantel combination was 100% effective in preventing development of D immitis larvae. Efficacy of the combined product against T canis, Toxascaris leonina, A caninum, and U stenocephala was 90.1, 99.2, 98.5, and 98.7%, respectively. In the intestinal parasite trials, each individual component was found not to interfere with the anthelmintic action of the other. Increasing the dosage of pyrantel to 10 mg/kg (2 x that in the combination) did not interfere with the efficacy of ivermectin against heartworm or increase the activity of pyrantel against intestinal parasites.
Administration, Oral↗
Intestinal helminth parasite community in wolves (Canis lupus) in Italy.
From 1987 to 1993, 89 wolves (Canis lupus) collected throughout the whole Italian range were examined for intestinal helminth parasites. Twelve species were found, including 5 nematodes (Uncinaria stenocephala, Toxocara canis, Ancylostoma caninum, Trichuris vulpis and Toxascaris leonina) and 7 cestodes (Echinococcus granulosus, Taenia hydatigena, T. multiceps, T. pisiformis, T. ovis, Mesocestoides lineatus and Dipylidium caninum). No significant differences were detected between sexes. T. canis showed higher prevalence and numbers in youngs, while E. granulosus and T. vulpis in adults. Interference between U. stenocephala and A. caninum was detected. Parasite biocenosis was stable in respect to geographical and ecological variables.
Animals↗
Parasitological survey in Gorontalo North Sulawesi, Indonesia.
A survey for blood and intestinal parasites was carried out in the municipality of Gorontalo on the Minahasa peninsula of North Sulawesi. A total of 156 stool specimens were obtained from 83 males and 73 females. Trichuris trichiura, Ascaris lumbricoides, hookworm, unidentified dicrocoeliid-like ova and Entamoeba coli, in that order, were the most common intestinal parasites detected. Other intestinal parasites found less frequently were Entamoeba histolytica, Iodamoeba bütschlii, Endolimax nana, Giardia lamblia, Enterobius vermicularis and Chilomastix mesnili. Brugia malayi microfilaremiar were detected in 6% and Plasmodium falciparum in less than 1% of the population sampled.
Adolescent↗
Memory Th2 effector cells can develop in the absence of B7-1/B7-2, CD28 interactions, and effector Th cells after priming with an intestinal nematode parasite.
B7-1/B7-2 interactions are required for many Th2-cell mediated primary immune responses including the response that follows infection with the intestinal nematode parasite, Heligmosomoides polygyrus. However, few studies have examined the role of B7-1/B7-2/CD28 interactions in the development of a Th2 memory immune response. We examined the development of the memory Th2 response to H. polygyrus in BALB/c mice deficient in both B7-1 and B7-2 (B7-1/B7-2(-/-)) and in BALB/c mice deficient in CD28 (CD28(-/-)). Following primary inoculation with H. polygyrus, adult worms in the gut were cleared with an anti-helminthic drug and mice were subsequently challenge-inoculated with H. polygyrus larvae. The memory Th2 response is readily distinguished by its inhibitory effect on adult worm maturation, resulting in marked reductions in adult worm egg production that are not observed during the primary immune response. Following H. polygyrus challenge inoculation, comparable decreases in egg production and similar increases in mesenteric lymph node cell IL-4 production were observed in B7-1/B7-2(-/-) and B7-1/B7-2(+/+) mice. However, elevations in total serum IgG1 and IgE were reduced, while increases in serum Ag-specific IgG1 and IgE and germinal center formation were blocked in H. polygyrus-challenged B7-1/B7-2(-/-) mice. In contrast, in H. polygyrus-challenged CD28(-/-) mice, marked elevations in Ag-specific IgG1 and IgE and increased germinal center formation were observed. The results of these studies demonstrate that effector Th2 memory cells that produce IL-4 and mediate host defense can develop when B7-1/B7-2 interactions, and associated effector Th2 cell development, are blocked during priming. However, humoral immunity is impaired and differentially affected in B7-1/B7-2(-/-) mice and CD28(-/-) mice following H. polygyrus challenge.
Animals↗
[Bacteriological quality of human drinking water in high-margination zones in Chiapas].
OBJECTIVE: To analyze the bacteriological quality of drinking water (BQDW) and its association with diarrhoea and intestinal parasites in children 1 to 14 years old, in areas of high levels of poverty in Chiapas, Mexico. MATERIAL AND METHODS: From March to September 1998, drinking water was collected from a random sample of 99 households in the Border Region of Chiapas, Mexico; data on diarrhoeal disease (in the past 15 days) were collected and stool testing for intestinal parasites was performed in children 1 to 14 years old (n = 322). The BQDW was determined by the filtration membrane technique. Intestinal parasitic infections were determined by the Faust Method. The chi 2 statistic was used to analyse factors associated with BQDW. RESULTS: Only 31% of the water samples were adequate for human consumption. The BQDW and the presence of diarrhoea (informed by the mothers of the children) showed no association. Children living in households with inadequate BQDW had a higher prevalence of Entamoeba histolytica and a greater tendency to have intestinal parasites. CONCLUSIONS: It is necessary to develop programs that improve BQDW and to develop education efforts aimed at increasing the use of boiled water and the adequate management and care of community water storage sites.
Adolescent↗
PCR-mediated recombination between Cryptosporidium spp. of lizards and snakes.
The presence or absence of genetic recombination has often been used as one of the criteria for Cryptosporidium species designation and population structure delineation. During a recent study of cryptosporidiosis in reptiles that were housed in the same room, 4 lizards were found to have concurrent infections of C. serpentis (a gastric parasite) and C. saurophilum (an intestinal parasite), and 6 snakes were concurrently infected with C. serpentis, C. saurophilum and a new Cryptosporidium as indicated by PCR-RFLP analysis of the SSU rRNA gene. DNA sequence analysis of cloned PCR products confirmed the diagnosis of mixed infections. Surprisingly, it appeared that 11 of the 22 clones (8 and 14 clones from a lizard and a snake, respectively) had chimeric sequences of two Cryptosporidium spp. BootScan analysis indicated the existence of recombinants among the cloned sequences and detection of the informative sites confirmed the BootScan results. Because the probability for genetic recombination between gastric and intestinal parasites is small, these hybrid sequences were likely results of PCR artifacts due to the presence of multiple templates. This was confirmed by PCR-sequencing analysis of single-copy templates using diluted DNA samples. Direct sequencing of 69 PCR products from 100- to 1,000-fold diluted DNAs from the same snake and lizard produced only sequences of C. serpentis, C. saurophilum and the unnamed Cryptosporidium sp. Thus, care should be taken to eliminate PCR artifacts when determining the presence of genetic recombination or interpreting results of population genetic studies.
Animals↗
Antibody-independent effector mechanisms in resistance to the intestinal nematode parasite Trichuris muris.
The development of a strong Th2-type immune response is essential in resistance to the intestinal nematode parasite Trichuris muris. Although the underlying cell-regulatory mechanisms important in protective immunity are well defined, the actual Th2-controlled effector mechanisms culminating in worm expulsion are uncharacterized. Using methodology involving the selective reconstitution of severe combined immunodeficiency mice with highly pure populations of CD4+ T cells from immune BALB/c donors, we show here that antibody is not an essential component in resistance to T. muris. Thus, CD4+ T cells purified from BALB/c donor mice at a time point when Th2 cells are in dominance (days 19 to 21 postinfection) confer resistance to infection on recipient severe combined immunodeficiency mice in the complete absence of an antibody response.
Animals↗
High levels of protection induced by a 40-mer synthetic peptide vaccine against the intestinal nematode parasite Trichinella spiralis.
Parenteral vaccination, using a 40-mer synthetic peptide from a 43,000 MW immunodominant glycoprotein secreted by the intestinal nematode parasite Trichinella spiralis, induced high levels of protection against a subsequent challenge infection in mice. The expulsion of adult worms from the gut was accelerated following vaccination with peptide 40-80, but peptides 81-120 and 121-160 were not protective. Mesenteric lymph node cells taken from T. spiralis-infected mice showed some proliferation in response to in vitro stimulation with peptide 40-80, but were unaffected by peptide 81-120. As expulsion of T. spiralis is known to be brought about by T-cell-mediated inflammatory events in the intestine, the ability of the 40-80 sequence to promote accelerated worm expulsion upon challenge infection may reflect induction of a specific and appropriate T-cell response. To our knowledge, this is the first report of a protective synthetic peptide vaccine against an intestinal nematode.
Amino Acid Sequence↗
Abomasal lymph node responses to Haemonchus contortus intestinal antigens established in kid goats by infection or immunization with intestinal antigens.
Immune responses to Haemonchus contortus intestinal antigens were evaluated using abomasal lymph node (ALN) lymphocytes from kid goats protected against challenge infection by immunization with parasite intestinal antigen, and from kids that were challenged after immunization with ovalbumin. ALN lymphocytes from the intestinal antigen-immunized group produced significantly higher antibody levels against intestinal antigens than the ovalbumin group, supporting the theory that immunization contributed to that ALN response. In contrast, intestinal lysates and membrane enriched preparations from intestinal cells stimulated significant proliferation of ALN lymphocytes in both groups. The proliferation was antigen-dependent, since intestinal antigens failed to stimulate proliferation in ALN lymphocytes from unimmunized and uninfected kids. For both the intestinal antigen and ovalbumin immunized groups, CD4+ T lymphocytes predominated in ALN lymphocytes that were stimulated to proliferate by intestinal antigens. The results indicate that H. contortus infection alone can induce ALN lymphocyte responses to intestinal antigens. In contrast to ALN lymphocyte responses, serum antibody against intestinal antigens was generally low to undetectable in ovalbumin-immunized kids following infection. Abomasal mucus from an H. contortus infected lamb was probed with a monoclonal antibody that binds to a periodate sensitive determinant on numerous H. contortus intestinal membrane and secreted proteins. Numerous bands of reactivity were detected, indicating that multiple parasite intestinal antigens were released into abomasal mucus during infection. The results, challenge the general concept that H. contortus intestinal antigens are 'hidden' from the host immune system during an infection. On the contrary, parasite intestinal proteins may be relatively abundant antigens presented to the host during infection. In addition, ALN T lymphocytes appear to provide a more sensitive measure than serum antibody to detect presentation of these antigens to the host immune system.
Abomasum↗
[Prevalence of iron-deficiency anemia in schoolchildren and adolescents, Medellín, Colombia, 1999].
OBJECTIVE: This research had two objectives: (1) to determine the prevalence of iron-deficiency anemia and describe iron consumption in the diet of schoolchildren and adolescents enrolled in public and private schools of the urban area of the city of Medellín, Colombia, in the 1999-2000 school year and (2) to explore the associations that age group, sex, socioeconomic class, and intestinal parasitism show with iron-deficiency anemia and iron deficiency. METHODS: A cross-sectional study was carried out among 960 students from 6 to 18 years old who were selected by simple random sampling after stratified multistage sampling and clustering in public and private schools in districts of Medellín. Body iron content was evaluated by determining ferritin and hemoglobin levels, average corpuscular volume, and amplitude of the erythrocyte distribution; the presence of intestinal parasites was evaluated through stool analysis; nutritional status was evaluated by means of anthropometric measurements; and consumption of iron and vitamin C was evaluated using a semiquantitative questionnaire on food intake. In order to define the cases of iron-deficiency anemia and of iron deficiency we used the standard definitions of the World Health Organization, based on ferritin and hemoglobin values. We used nonparametric tests, with a significance level of 0.05, to examine the associations between age group, sex, socioeconomic class, and the presence of intestinal parasites on the one hand and the presence of anemia on the other hand. RESULTS: The prevalence of iron deficiency was 4.9%, and the prevalence of iron-deficiency anemia was 0.6%. The prevalence of both was higher among adolescent women (P < 0.05) than in the rest of the sample studied. No significant association was found between the presence of intestinal parasites and the presence of anemia. The average daily consumption of iron (+/- standard deviation) was 5.5 mg (+/- 2.3 mg) (32% +/- 15% of the recommended dietary intake for the studied age group); the average contribution of serum iron in the diet was 0.7 mg (+/- 0.7 mg). Comparing the children who did and who did not have anemia, there were no significant differences in iron consumption and the type of iron consumed. The anthropometric parameter that showed the greatest association with the presence of anemia was height for age. CONCLUSIONS: The prevalences of iron deficiency and of iron-deficiency anemia found in the population studied were low, according to the parameters for hemoglobin and ferritin as defined by the World Health Organization as being normal for these population groups. The low prevalence of blood-sucking parasites, adequate consumption of vitamin C, and the refined mechanisms with which the body regulates iron homeostasis may have contributed to these results. Adequate iron content in the diet of adolescents should be maintained, and education campaigns should be implemented to help prevent iron deficiency in this population group.
Adolescent↗
Prevalence of parasitism among students of the Karen hill-tribe in Mae Chame district, Chiang Mai province, Thailand.
Infection caused by intestinal parasites is still a common health problem in a poor-hygiene population especially for children in developing countries. A cross-sectional study was conducted among 781 Karen students (age: 3 to 19, males: 325, females: 456) to determine the current status of intestinal parasitic infections in a mountainous area in the North of Thailand. The study was drawn from three schools in the Doi Inthanon region, in Mae Chame district of Chiang Mai province, from December 2002 to June 2003. The techniques used for the diagnosis were: stool concentration by using the 'formalin-ether' technique and perianal region examination by using the 'Scotch-tape' technique. The average rate of intestinal parasites for the group tested using the stool concentration technique was 42.06% (male: 46.87%, females: 38.82%); and 22.66% (males: 28.92%, females: 18.20%) when using the Scotch-tape technique.Among helminth-infected individuals, enterobiasis was found at the highest prevalence (15.49%). Other common infections were ascariasis (9.78%), trichuriasis (5.90%) and hookworm infection (2.20%). Strongyloildiasis was found only in 0.92%. For protozoa infection, the major cause is the non-pathogenic species "Entamoeba coli" (27.68%). The other non-pathogenic protozoa (Endolimax nana, Chilomastix meslini and Iodamoeba butschlii) had a low prevalence from ranged 0.18%-4.79%. The prevalence of pathogenic Giardia lamblia infection was 2.21%. Entamoeba histolytica infection was found in only one case. Based on the two techniques used, the results from the Scotch-tape provided a higher sensitivity for the detection of Taenia spp. and Enterobius vermicularis eggs. Drug treatment was given to all the infected students. School-based health education should be implemented in order to prevent and control the infections.
Child↗
[Intestinal parasitosis in French West Indies: endemic evolution from 1991 to 2003 in the University Hospital of Pointe-a-Pitre, Guadeloupe].
Guadeloupe is one of the French West Indies, where, until 1960, intestinal parasitic infections were endemic. In the microbiological laboratory of the university hospital of the island, we carried out a retrospective study of the 17,660 stool examinations received from 1991 to 2003. All the stool specimens were examined using at least a wet mount preparation and a concentration method (Bailenger). Specific techniques such as Ziehl-Neelsen modified acid fast stain, chromotrope staining procedure or Baermann's technique were used when indicated. A parasite considered as really pathogenic is detected in only 5.6% of the cases of the 17,660 stool examinations. The intestinal protozoa count for 10.8% of them, G. intestinalis (60%) is the most common, followed by Cryptosporidium sp (26%) and Isospora belli in AIDS patients while Entamoeba histolytica/dispar rarely appears (2.3%). Among the parasitic intestinal helminths, Strongyloïdes stercoralis is seen as the most prevalent (82%) whereas hookworms and Trichuris trichuria count respectively for 9.8% and 5.6%. Schistosoma mansoni appears as an exception. This epidemiological change for intestinal parasitic infections results from the improvement of socio-economic and sanitary way of living of the population. However the persistence of the strongyloidiasis constitutes the outstanding fact in a area of strong prevalence of the HTLV1 infection.
Endemic Diseases↗
Diagnosis of intestinal amebiasis using salivary IgA antibody detection.
Attempts were made to use soluble antigen extract of strain HK-9 of Entamoeba histolytica to detect salivary IgA antibodies in intestinal amebiasis patients by using ELISA. Total salivary samples of 109 individuals were divided into four groups. Group I comprised 32 patients whose stools were positive only for E. histolytica cysts and/or trophozoites. Group II comprised 12 individuals whose stools were positive for E. histolytica and other intestinal parasites. Group III comprised 36 individuals whose stools were negative for E. histolytica but contained other intestinal parasites such as E. coli, E. nana, Blastocystis hominis, Trichomonas hominis, Giardia lamblia, Opisthorchis viverrini, and hookworm. Group IV comprised 29 healthy individuals whose stools were free from any intestinal parasitic infections. Based on the mean optical density, OD + 2SD of the results from 29 parasitologically negative healthy individuals, the cut-off OD value for salivary IgA antibodies was 1.265. Therefore, the assays were positive in 14 out of 32 (43.75%) of group I and 2 out of 12 (16.6%) of group II. The assays were positive in 16 out of 36 (44.44%) for group III whereas 2 out of 29 (6.90%) for group IV were positive. The overall sensitivity and specificity of the assays were 36% and 72%, respectively. The false positive rate was 28% and the false negative rate was 64%. The predictive values of positive and negative results were 47% and 63%, respectively. The diagnostic accuracy of ELISA for the presence of salivary IgA antibodies was 58%.
Animals↗
Impact of a filariasis control program on intestinal helminthic infections; a pilot study in Narathiwat Province, Thailand.
This study was conducted in 9 villages located in endemic areas for brugian filariasis in Narathiwat Province, Thailand. Parasitological and anthropometric examinations were cross-sectionally performed to assess the prevalence of intestinal parasitic infections of 539 villagers. Paired stool samples were collected before and after mass treatment for the filariasis control program in 150 participants in order to study the impact of the filariasis control program on intestinal helminthiasis. The results found that 50.3% of the villagers were infected with one or more types of intestinal parasites. Double and triple infections were found in 10.9% and 1.6% of infected individuals respectively. The prevalence of intestinal parasitic infections peaked in the 1-10 year old age-group, which are pre-school and young school-age children. A significant reduction of intestinal helminthic infections in the post-treatment stool sample was observed in the 150 participants who were examined six months after mass treatment. Integrating an intestinal helminthic control program alongside the existing filariasis control program would be an appropriate and cost-effective strategy in the control of intestinal helminths. However, reinfection of parasites was observed.
Adolescent↗