Eosinophils mediate SIgA production triggered by TLR2 and TLR4 to control Ascaris suum infection in mice.

Human ascariasis is the most prevalent but neglected tropical disease in the world, affecting approximately 450 million people. The initial phase of Ascaris infection is marked by larval migration from the host's organs, causing mechanical injuries followed by an intense local inflammatory response, which is characterized mainly by neutrophil and eosinophil infiltration, especially in the lungs. During the pulmonary phase, the lesions induced by larval migration and excessive immune responses contribute to tissue remodeling marked by fibrosis and lung dysfunction. In this study, we investigated the relationship between SIgA levels and eosinophils. We found that TLR2 and TLR4 signaling induces eosinophils and promotes SIgA production during Ascaris suum infection. Therefore, control of parasite burden during the pulmonary phase of ascariasis involves eosinophil influx and subsequent promotion of SIgA levels. In addition, we also demonstrate that eosinophils also participate in the process of tissue remodeling after lung injury caused by larval migration, contributing to pulmonary fibrosis and dysfunction in re-infected mice. In conclusion, we postulate that eosinophils play a central role in mediating host innate and humoral immune responses by controlling parasite burden, tissue inflammation, and remodeling during Ascaris suum infection. Furthermore, we suggest that the use of probiotics can induce eosinophilia and SIgA production and contribute to controlling parasite burden and morbidity of helminthic diseases with pulmonary cycles.

Lectin-Mediated Bacterial Modulation by the Intestinal Nematode Ascaris suum.

Ascariasis is a global health problem for humans and animals. Adult Ascaris nematodes are long-lived in the host intestine where they interact with host cells as well as members of the microbiota resulting in chronic infections. Nematode interactions with host cells and the microbial environment are prominently mediated by parasite-secreted proteins and peptides possessing immunomodulatory and antimicrobial activities. Previously, we discovered the C-type lectin protein AsCTL-42 in the secreted products of adult Ascaris worms. Here we tested recombinant AsCTL-42 for its ability to interact with bacterial and host cells. We found that AsCTL-42 lacks bactericidal activity but neutralized bacterial cells without killing them. Treatment of bacterial cells with AsCTL-42 reduced invasion of intestinal epithelial cells by Salmonella. Furthermore, AsCTL-42 interacted with host myeloid C-type lectin receptors. Thus, AsCTL-42 is a parasite protein involved in the triad relationship between Ascaris, host cells, and the microbiota.

Oxfendazole kinetics in pigs: In vivo assessment of its pattern of accumulation in Ascaris suum.

Ascaris suum is a widespread parasitic nematode that causes infection in pigs with high prevalence rates. Oxfendazole (OFZ) is effective against A. suum when used at a single high oral dose of 30 mg/kg. The aim of this study was to assess the pattern of distribution/accumulation of OFZ and its metabolites, in bloodstream (plasma), mucosal tissue and contents from small and large intestine and adult specimens of A. suum collected from infected and treated pigs. The activity of glutathione-S-transferases (GSTs) in A. suum was also investigated. Infected pigs were orally treated with OFZ (30 mg/kg) and sacrificed at 0, 3, 6 and 12 h after treatment. Samples of blood, mucosa and contents from both small and large intestine as well as adult worms were obtained and processed for quantification of OFZ/metabolites by HPLC. OFZ was the main analyte measured in all of the evaluated matrixes. The highest drug concentrations were determined in small (AUC0-t 718.7 ±â€¯283.5 µg h/g) and large (399.6 ±â€¯110.5 µg h/g) intestinal content. Concentrations ranging from 1.35 to 2.60 µg/g (OFZ) were measured in adult A. suum. GSTs activity was higher after exposure to OFZ both in vivo and ex vivo. The data obtained here suggest that the pattern of OFZ accumulation in A. suum would be more related to the concentration achieved in the fluid and mucosa of the small intestine than in other tissues/fluids. It is expected that increments in the amount of drug attained in the tissues/fluids of parasite location will correlate with increased drug concentration within the target parasite, and therefore with the resultant treatment efficacy. The results are particularly relevant considering the potential of OFZ to be used for soil transmitted helminths (STH) control programs and the advantages of pigs as a model to assess drug treatment to be implemented in humans.

Differential changes in expression of intestinal antimicrobial peptide genes during Ascaris lumbricoides infection in Zambian adults do not respond to helminth eradication.

BACKGROUND: Intestinal helminthiasis modulates immune responses to vaccines and environmental allergens. To explore the impact on intestinal host defense, we assessed expression of antimicrobial peptide genes, together with T cell subset markers and cytokines, in patients with ascariasis before and after treatment. METHODS: Case patients (n = 27) and control subjects (n = 44) underwent enteroscopy for collection of jejunal biopsy specimens, which were used in quantitative, real-time reverse-transcription polymerase chain reaction for a range of host defense genes; blood samples were also analyzed simultaneously. RESULTS: The level of gene expression (mRNA) of HD5, hBD1, and LL-37 was lower in case patients than in control subjects, and the level of expression of HD6 was increased. However, after successful eradication, there was no trend to values seen in control subjects. Helminthiasis was associated with increased intestinal expression of the Th1 genes T-bet and interferon-γ. In peripheral blood mononuclear cells (PBMCs), a mixed profile of T cell markers and cytokines was increased. Ascaris-induced down-regulation of HD5 was observed in individuals with higher RORγt expression in PBMCs, but we found no evidence that this was mediated by circulating interleukin-22. CONCLUSIONS: Human ascariasis was associated with changes in antimicrobial peptide gene expression and immunological markers. Such changes may have implications for susceptibility to infectious disease and responsiveness to oral vaccines in tropical populations.

2-Methyl-pentanoyl-carnitine (2-MPC): a urine biomarker for patent Ascaris lumbricoides infection.

Infections with intestinal worms, such as Ascaris lumbricoides, affect hundreds of millions of people in all tropical and subtropical regions of the world. Through large-scale deworming programs, World Health Organization aims to reduce moderate-to-heavy intensity infections below 1%. Current diagnosis and monitoring of these control programs are solely based on the detection of worm eggs in stool. Here we describe how metabolome analysis was used to identify the A. lumbricoides-specific urine biomarker 2-methyl pentanoyl carnitine (2-MPC). This biomarker was found to be 85.7% accurate in determining infection and 90.5% accurate in determining a moderate-to-heavy infection. Our results also demonstrate that there is a correlation between 2-MPC levels in urine and A. lumbricoides DNA detected in stool. Furthermore, the levels of 2-MPC in urine were shown to rapidly and strongly decrease upon administration of a standard treatment (single oral dose of 400 mg albendazole). In an Ascaris suum infection model in pigs, it was found that, although 2-MPC levels were much lower compared to humans, there was a significant association between urinary 2-MPC levels and both worm counts (p = 0.023) and the number of eggs per gram (epg) counts (p < 0.001). This report demonstrates that urinary 2-MPC can be considered an A. lumbricoides-specific biomarker that can be used to monitor infection intensity.

Shared expression of mucin12 in Ascaris lumbricoides and the human small intestine.

This study focuses on the host-parasite relationship of human Ascaris lumbricoides, which is a parasite of the small intestine and is also one of the commonest parasites worldwide. As part of this investigation, we examined the host-parasite relationship assuming that there is a common antigenicity, shared protein between A. lumbricoides and human small intestinal mucosa, using molecular techniques. We obtained three DNA clones from human colon cDNA library by screening for anti-A. lumbricoides polyclonal antibodies. The transmembrane mucin12 gene was identified after sequencing analysis of these clones. Specific signals of immunostaining with polyclonal anti-mucin12 antibodies were observed in the mucous secretory organs, epidermis, and intestinal canal of A. lumbricoides. These signals disappeared when immunohistochemistry was performed using pre-absorbed polyclonal antibodies with a specific peptide. These results suggest that mucin12 is localized in the mucous secretory organs in the epidermis of A. lumbricoides. Furthermore, we examined the site of mucin12 localization in the host; specific mucin12 signals were observed on the mucosal epithelia present around intestinal crypts and villi of the small intestine. Therefore, we suggest that mucin12 is a protein that shows common antigenicity in both A. lumbricoides and its host. It is presumed that adult A. lumbricoides live in their preferred environment, which is the small intestine, by secreting mucin12 to avoid being attacked by the host immune system.

Bifidobacterium animalis subspecies lactis modulates the local immune response and glucose uptake in the small intestine of juvenile pigs infected with the parasitic nematode Ascaris suum.

An evaluation of a localized intestinal allergic type-2 response concomitant with consumption of probiotic bacteria is not well documented. This study investigated the effect of feeding probiotic Bifidobacterium animalis subspecies lactis (Bb12) or a placebo in weaned pigs that were also inoculated with Ascaris suum (A. suum) eggs to induce a strong Th2-dependent allergic type 2 immune response. Sections of jejunal mucosa were mounted in Ussing chambers to determine changes in permeability and glucose absorption, intestine and liver samples were collected for analysis of type-2 related gene expression, jejunum examined histologically, and sera and intestinal fluid were assayed for parasite antigen specific antibody. The prototypical parasite-induced secretory response to histamine and reduced absorption of glucose in the jejunum were attenuated by feeding Bb12 without a change in mucosal resistance. Parasite antigen-specific IgA response in the serum and IgG1 and IgG2 response in the ileal fluid were significantly increased in A. suum-infected pigs treated with Bb12 compared to infected pigs given the placebo. Ascaris suum-induced eosinophilia in the small intestinal mucosa was inhibited by Bb12 treatment without affecting the normal expulsion of A. suum 4th stage larvae (L4) or the morphometry of the intestine. Expression of genes associated with Th1/Th2 cells, Treg cells, mast cells, and physiological function in the intestine were modulated in A. suum infected-pigs treated with Bb12. These results suggested that Bb12 can alter local immune responses and improve intestinal function during a nematode infection by reducing components of a strong allergenic type-2 response in the pig without compromising normal parasite expulsion.

Cognitive Performance and Iron Status are Negatively Associated with Hookworm Infection in Cambodian Schoolchildren.

Soil-transmitted helminth (STH) infection has been associated with lower cognitive performance of schoolchildren. To identify pathways through which STH infection might affect school performance, baseline data from a large rice-fortification trial in Cambodian schoolchildren were used to investigate associations between STH infection, micronutrient status, anemia, and cognitive performance. Complete data on anthropometry, cognitive performance, and micronutrient status were available for 1,760 schoolchildren, 6-16 years of age. STH infection was identified using Kato-Katz, whereas cognitive performance was assessed using Raven's Colored Progressive Matrices (RCPM), block design, and picture completion. STH infection was found in 18% of the children; almost exclusively hookwork infection. After adjusting for age and gender, raw cognitive test scores were significantly lower in hookworm-infected children (-0.65; -0.78; -2.03 points for picture completion, RCPM, and block design, respectively; P < 0.05 for all). Hookworm infection was associated with iron status (total body iron), but not with vitamin A and zinc status, nor with inflammation or anthropometry. Body iron was negatively associated with increased intensity of hookworm infection (R = 0.22, P < 0.001). Hookworm infection in Cambodian schoolchildren was associated with lower cognitive performance, an effect most likely mediated through lower body iron. Interventions that are more effective against hookworm infection are needed to contribute to better health and improvement of cognitive performance.

Absorption of macronutrients from a rice-vegetable diet before and after treatment of ascariasis in children.

The apparent absorption of nitrogen (N), fat, and total energy from a rice and vegetable diet was measured in 13 children of similar nutritional status but infected with varying loads of Ascaris lumbricoides. Apparent N absorption was modestly decreased initially in subjects with heavy infections as compared to those with light infections (57.2% of intake versus 64.1% of intake, 0.05 < P < 0.1). After antihelminthic therapy there ws a significant improvement in apparent N absorption (P < 0.02), apparent N retention (P < 0.05), and apparent fat absorption (P < 0.05) for the group as a whole, particularly for those with heavy infections. Total energy absorption improved slightly, but not significantly, after treatment, and there was no change in xylose excretion tests. Treatment of ascariasis may be nutritionally advantageous for children with heavy worm burdens and marginal protein availability.

Malabsorption of water miscible vitamin A in children with giardiasis and ascariasis.

Vitamin A absorption was studied using a water-miscible oral preparation of vitamin A in 19 children ages 1 1/2 to 9 years old with giardiasis and/or ascariasis, both before and after their eradication with appropriate therapy, and in three children without parasites. Marked impairment of vitamin A absorption was noted when administered in a water miscible form in children with 1) combined infection with Giardia lamblia and Ascaris lumbricoides, 2) giardiasis alone, and 3) in a proportion of children with ascariasis alone. In children with both giardiasis and ascarasis eradication of the infections promptly lead to a significant improvement in vitamin A absorption and restored it to normal. Children with giardiasis alone also showed improved vitamin A absorption after therapy. In children with ascariasis alone successful therpay did not lead to a statistically significant improvement.

Ascariasis and malnutrition. A study in urban Ethiopian children.

Treatment of 13 urban Ethiopian children with mild ascariasis did not produce any evidence of improved intestinal morphology and absorption or nutritional status. Ascariasis treatment had no impact on anthropometric measures in an additional study group of 84 children. A review of the literature reveals that the nutritional consequences of ascariasis are uncertain.

PIP: Ascariasis, highly prevalent among children in developing countries, is thought to cause widespread and important morbidity. The role of ascariasis as a contributory factor in the etiology of childhood malnutrition has been illustrated by clinical observation of patients with massive infection; however, systematic evidence and objective information are scanty. The prevalence of ascariasis among Ethiopian children is about 10% in infants, 28% in children 1-2 years old, and 62% in children over 3 years. 2 clinical trials were conducted to determine the effect of the infection on childhood nutrition and to assess the desirability of allocating scarce resources to treatment and control. In a double blind trial, 13 boys with the infection were given piperazine citrate or a placebo syrup. Stool analyses for worm load, fat and nitrogen excretion, and anthropometric measurements, tests for xylose absorption, and jejunal biopsies were conducted. 24 hour dietary recalls were obtained from the mothers. In the 2nd trial, complete information including anthropometric measurements and incidence of morbidity was obtained on 44 infected and 40 uninfected children between the ages of 1-4 as part of a community study. A double blind system of allocating treatment and placebo to underweight infected and noninfected children and normal weight infected and uninfected children was implemented. The results showed that the individual wormload in the children was low. Initial treatment did not result in complete deworming. The nutritional status of the children was unaffected by treatment, although in the community study, a somewhat lower rate of acute morbidity was noted in treated children. The results of other metabolic and functional studies are inconsistent; in some studies, a treatment effect was noted. However, the results of these studies are questionable because intervening factors, such as the presence of infection in the study groups, were not adequately controlled. The results of other community studies are also inconsistent. So far little clear cut epidemiological evidence exists regarding the relative importance of ascariasis in the causation of malnutrition in communities suffering from concommitant infection and other ills of poverty. Clinical evidence suggests that massive infection may result in malnutrition, and treatment of symptomatic ascariasis is justified. At the community level, deworming programs do not have a clear beneficial nutrition effect.

Vitamin A absorption in ascariasis.

Vitamin A absorption was studied in a group of 28 adult patients with ascariasis and 12 healthy adult controls, using a simplified vitamin A absorption test. In over 70% of the patients with ascariasis malabsorption of vitamin A was demonstrated. Stool egg counts for ascaris were not related to the degree of vitamin A malabsorption. Of the 23 patients in whom a D-xylose absorption test was performed, seven showed excretion less than 20% in 5 hr. Immediately after expulsion of the worms, vitamin A absorption improved in 13 out of 14 patients tested (in nine to normal level). The results of this study suggest that ascariasis in populations on marginal intakes of vitamin A and its precursors is an important contributing factor in producing clinical vitamin A deficiency.

Malabsorption syndrome in ascariasis.

PIP: This group of researchers recently reported findings on the overall effect of Ascaris lumbricoides infection on human nutrition. On the basis of available data, it was suggested that intestinal malabsorption is a potential cause of nutritional impairment in children infected with Ascaris lumbricoides. The purpose of this discussion is to present additional data on the effect of Ascaris infection on small bowel function and structure in children. 5 children with heavy Ascaris infection without any evidence of clinical malnutrition were admitted to a metabolic unit. On admission, each child was placed on a constant diet consisting of 82-95 kcal and approximately 1 g protein/kg body weight/day. The amount of dietary fat varied from 55-60 g; the levels of vitamins and minerals in the diet were adjusted to meet the recommended dietary allowances. After an adjustment period of 4-6 days, fecal samples were collected during 2 periods of 4 days each for nitrogen and fat analysis. Peroral jejunal biopsies were obtained using an 8 mm Crosby-Kugler biopsy capsule. The samples were processed and stained according to standard techniques. The children then received deworming treatment consisting of 75 mg piperazine/kg body weight daily for 5 consecutive days. In 4 of 5 children there was reduced fecal nitrogen excretion; the mean reduction represented 6.5% of dietary nitrogen. Steatorrhea was present in 4 children; deworming resulted in a reduction of fecal fat from 9.9-2.3% of dietary fat. 3 children demonstrated an impairment in D-xylose excretion. It returned to normal following deworming in only 1 child. The jejunal morphology was found to be abnormal in all children. In each case a significant improvement was noted soon after deworming. The study results strongly suggest that there is a cause and effect relationship between Ascaris infection and intestinal lesions in children.^ieng

Effects of Ascaris infection on human nutrition.

PIP: The role of Ascaris lumbricoides infection in human nutrition was investigated in 12 children 5-10 years of age. Daily levels of dietary protein intake varied from 1-2.8 g/kg body weight but were kept constant for each child as was caloric intake. Nitrogen, fat balance, and d-xylose absorption determinations were done before and after deworming. A mean reduction in fecal nitrogen excretion of 230 mg/day was noted after worm removal. In 7 children harboring 48 or more parasites, the reduction in fecal nitrogen amounted to 7.2% of the dietary nitrogen. In 3 children receiving 1 g of protein/kg body weight, the improved nitrogen absorption after deworming led to an increased nitrogen retention. In 8 children the infection was associated with moderate steatorrhea (13.4% of dietary fat) and impairment of d-xylose absorption; the former was markedly reduced, and the latter was partially improved following treatment. It is concluded that Ascaris infection in children can lead to marked nutritional impairment when a high parasite load is associated with a low protein intake.^ieng

Influence of intestinal parasitism on lactose absorption in well-nourished African children.

Hydrogen breath tests were performed in Gabon (Central Africa) after a loading dose of lactose in 67 well-nourished African children (50 with intestinal parasites and 17 unparasitized) and in 18 unparasitized young adults. All had normal nutritional status, and none had diarrhea or digestive symptoms. Parasites that were found included Ascaris lumbricoides in 76% of the parasitized children, Trichuris trichiura in 58%, Giardia in 24%, Entamoeba histolytica in 20%, Schistosoma intercalatum in 16%, and Necator Americanus in 14%. A similar proportion of parasitized (64%) or unparasitized (62.8%) subjects were lactose malabsorbers. Giardia infection was associated with a higher, but not significantly different, proportion of lactose intolerance (10 of 12, 83.3%). The presence of infection with A. lumbricoides or T. trichiura did not increase the percentage of lactose malabsorption. These data indicate that a decrease of lactase activity in well-nourished African children is not related to the presence or the importance of Ascaris or other intestinal parasites if the nutritional status is normal.

Plasma albumin concentrations and intestinal permeability in Bangladeshi children infected with Ascaris lumbricoides.

Plasma albumin concentration and intestinal permeability have been investigated in Bangladeshi children before and 9-14 d after successful treatment for ascariasis. Children infected with A. lumbricoides had lower plasma albumin concentrations than counterparts not harbouring this worm and values increased with successful treatment. Intestinal permeability tests indicated that the children had impaired gastrointestinal function and some loss of mucosal integrity; these factors had not improved 9-14 d after A. lumbricoides expulsion. The lowered nitrogen nutritional status implied by the reduced plasma albumin values in infected children, and the improvement following treatment, are in keeping with previous reports that A. lumbricoides impairs protein digestion or absorption. This may be the basis of the better growth rates of dewormed children in this area.

Effect of intestinal helminthiasis on intestinal permeability of early primary schoolchildren.

Intestinal permeability of 246 early primary schoolchildren at 2 schools (106 of whom were infected with intestinal helminths) was assessed by using the lactulose/mannitol differential absorption test. The ratio of the urinary recoveries of lactulose and mannitol was determined after oral administration of a standard solution of the 2 sugars. Assessment of intestinal permeability was repeated on 100 infected children after treatment and on a cohort of 68 uninfected children. Infected and uninfected groups were compared with respect to baseline lactulose/mannitol ratio (L/M1) and change in lactulose/mannitol ratio between assessments (delta L/M). The correlations between baseline intensity of infection and L/M1, and between fall in intensity and delta L/M, were evaluated. Based on a crude index of socioeconomic status, each child was assigned to one of 3 socioeconomic groups; all but 3 children belonged to either groups 2 or 3. Trichuris trichiura and Ascaris lumbricoides were the 2 predominant infections; the hookworm infection rate was relatively low. The results suggested that helminthiasis exerted only a marginal effect on intestinal permeability, the impact of which in children from lower socioeconomic backgrounds was negligible in comparison with the cumulative effects of other factors.

Inhibitory activity of soluble material from sheep eosinophils for sheep complement.

Soluble material from frozen and thawed sheep eosinophils and sonicated extracts of eosinophils or their granules inhibited the alternative activation pathway dependent action of sheep complement for human erythrocytes sensitized by sheep antibody. Sephadex G-50 fractions of the sonicated eosinophil and granule extracts showed that inhibitory activity was associated with the void volume fraction, the fraction possessing the eosinophil peroxidase activity.

Increase in serum beta-carotene following dark green leafy vegetable supplementation in Mebendazole-treated school children in Bangladesh.

OBJECTIVE: To study the effect of consumption of dark green leafy vegetables (DGLV) and sweet pumpkin on serum beta-carotene and retinol concentrations in children treated for Ascaris lumbricoides. DESIGN: Experimental study with a randomised design. SUBJECTS: A total of 110 primary school children aged 8-12 y in northwestern Bangladesh. INTERVENTIONS: All children were de-wormed and 2 weeks later randomly assigned to one of three groups to receive for 6 days per week, for 6 weeks, one complete meal containing either: (1) 4.4 mg beta-carotene from DGLV (n=37, after 18 dropouts); (2) 1.5 mg beta-carotene from sweet pumpkin (n=36, 18 dropouts); or (3) vegetables containing virtually no beta-carotene (control) (n = 37, 18 dropouts). RESULTS: Significant increases (P < 0.001) in mean serum beta-carotene concentrations were seen in all three study groups, with a statistically higher increase (micromol/l) in the DGLV group (0.44; 95% confidence interval (CI) 0.32, 0.55) compared to the control group (0.20; 95% CI 0.14, 0.26; P = 0.002). The increase in serum retinol (micromol/l) was statistically significant (P=0.04) only in the DGLV group (mean 0.066; 95% CI 0.002, 0.13), but this increase was not different from the increase in the control group. CONCLUSION: In children successfully treated for Ascaris lumbricoides, a substantial increase in serum beta-carotene was seen after feeding with a moderately high cumulative dose of DGLV for 6 weeks.

Serum malondialdehyde level in patients infected with Ascaris lumbricoides.

AIM: The aim of the study was to investigate the changes of serum malondialdehyde level, i.e; the oxidative stress hypothesis in patients infected with Ascaris lumbricoides. METHODS: Serum malondialdehyde activity was measured in 43 patients who were positive for intestinal parasite of Ascaris lumbricoides. Scores were obtained for the positives and their age-and sex-matched 60 Ascaris lumbricoides negative healthy controls. RESULTS: The difference between malondialdehyde levels of patients infected with Ascaris lumbricoides and control group was statistically significant both for females (P<0.05) and for males (P<0.05). In the patient and control groups, no correlation was found between age and malondialdehyde levels (P>0.05) both in females and in males. In addition, no significant correlation could be found between malondialdehyde levels of both females and males for patients and control groups (P>0.05). CONCLUSION: Malondialdehyde levels clearly increase in patients infected with Ascaris lumbricoides.