Schistosoma japonicum and occult blood loss in endemic villages in Leyte, the Philippines. (1/6)

Schistosoma japonicum has been related to anemia, but the mechanisms mediating this relationship remain unresolved. The primary objective of this study was to assess the role of occult blood loss in mediating S. japonicum-associated anemia after adjusting for age, sex, socioeconomic status (SES), and other helminth infections. The secondary objective was to identify intensity categories of risk for occult blood loss for Trichuris and hookworm after adjustment for the presence of other helminth infections. The role of occult blood loss in mediating S. japonicum-associated anemia was studied cross-sectionally in 729 individuals 8-30 years old in Leyte, The Philippines. Three stool specimens were examined in duplicate for helminth eggs. Hemoglobin, fecal occult blood loss, and anemia were measured and related to the presence and intensity of helminths. Multivariate models were made to adjust for confounding by other helminths and SES. In multivariate models, hemoglobin significantly decreased with increasing infection intensity of S. japonicum, hookworm, and T. trichuria (P < 0.0031, P < 0.0001, and P < 0.0001, respectively). Individuals with higher intensities S. japonicum and T. trichuria were significantly more likely to be fecal occult positive (odds ratio [OR] = 3.54; P = 0.008 and OR = 2.68; P = 0.013, respectively), although this was not true for individuals with hookworm. Additionally, individuals with higher intensities of S. japonicum, hookworm, and T. trichuria were all more likely to be anemic (OR = 3.7, P = 0.0002; OR = 5.3, P = 0.0003; and OR = 1.6, P = 0.021, respectively). It is likely that occult blood loss plays a role only at heavier intensity S. japonicum infections and some other mechanism, such as anemia of inflammation, may be contributing to anemia.  (+info)

Dose-ranging study for trials of therapeutic infection with Necator americanus in humans. (2/6)

Epidemiological studies suggest that a hookworm infection producing 50 eggs/gram of feces may protect against asthma. We conducted a dose-ranging study to identify the dose of hookworm larvae necessary to achieve 50 eggs/gram of feces for therapeutic trials of asthma. Ten healthy subjects without asthma or airway hyperresponsiveness to inhaled methacholine received 10, 25, 50, or 100 Necator americanus larvae administered double blind to an area of skin on the arm. Subjects were seen weekly for 12 weeks and were then treated with mebendazole. Skin itching at the entry site and gastrointestinal symptoms were common at higher doses. Lung function did not change. Levels of blood eosinophils and IgE increased transiently, and levels of IgG increased progressively. All doses resulted in at least 50 eggs/gram of feces in the eight subjects who completed the study. Infection with 10 N. americanus larvae is well tolerated, elicits a modest host eosinophil response, and is potentially suitable for use in preliminary clinical therapeutic trials.  (+info)

Rapid detection and identification of human hookworm infections through high resolution melting (HRM) analysis. (3/6)

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Parasite detection efficiencies of five stool concentration systems. (4/6)

Fresh fecal material that was free of ova and parasites was pooled with 10% Formalin in a 1:4 ratio to prepare a standard specimen. Portions of 100 ml of this specimen were individually seeded with Cryptosporidium oocysts, Entamoeba coli, Entamoeba histolytica, and Giardia lamblia cysts; ova of Necator americanus; and Strongyloides larvae. Appropriate volumes of each parasite suspension were used to evaluate the Fecal Concentrator Kit (Remel, Lenexa, Kans.), Fecal Parasite Concentrator (Evergreen Scientific, Los Angeles, Calif.), Para-Pak Macro-Con (Meridian Diagnostics, Inc., Cincinnati, Ohio), and Trend FeKal CON-Trate (Trend Scientific, Inc., St. Paul, Minn.). A standardized gauze filtration method was used as the reference procedure. Tests were performed in triplicate with each individual parasite-concentrator combination, with three slides examined from each sediment. All of the systems effectively concentrated parasites compared with direct examination of unconcentrated fecal material. The Fecal Concentrator Kit provided the best overall performance. Clarity of sediment, lack of debris, and uniformity of background material were found to be important considerations for microscopic detection of parasites in concentrated specimens.  (+info)

Distribution of Necator americanus and Ancylostoma duodenale in Liberia. (5/6)

In the first country-wide survey of hookworm infection in Liberia, diagnosis by test-tube filter-paper cultivation revealed a prevalence of more than 90%. This sensitive technique also permitted differential species determination. Necator americanus was found to occur in all regions and in a high proportion of the persons examined. Ancylostoma duodenale was mainly confined to a narrow coastal belt, and usually parasitized individuals harbouring N. americanus as well. The average number of eggs per gram of faeces (EPG) of infected individuals was lowest in the population of the hinterland. During the latter part of the studies a modified test-tube filter-paper cultivation technique was used in combination with dilution counting to obtain data on intensity of infection separately for the 2 species. For N. americanus there was little regional difference in the intensity of infection, but the EPG for A. duodenale was much higher in people living in the coastal area.  (+info)

Pyrantel embonate in treatment of hookworm infestation. (6/6)

The efficacy of pyrantel embonate (1,4,5,6-tetrahydro-1-methyl-2-(trans-2-(2-thienyl)-vinyl)-pyrimidine embonic acid salt; Combantrin) was evaluated in 60 cases of hookworm infestation. They were divided into six groups of 10 cases. Pyrantel embonate was administered orally, in dosage schedules (randomized) of 100, 75, 50, 20, 15, and 10 mg/kg of body weight. The stool examination for hookworm ova and coproculture were positive in each case. The predominant species was Ancylostoma duodenale (in 58 patients). After treatment with pyrantel embonate the stool examination for hookworm ova and coproculture were negative on the 10th and 15th days in each group. The blood levels of the drug were significantly higher in patients receiving 100 and 75 mg/kg body weight. In groups A and B one patient experienced nausea and vomiting on the day of administration of drug. There were no abnormal changes in liver function tests or blood urea levels in any of the groups. Hence the optimum single dose of the drug effective against hookworm infestation is 10 mg/kg body weight, and further studies are required to evaluate the minimum effective dose of pyrantel embonate.  (+info)