Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “STRONGYLOIDES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 415 records · Page 23Linked to original sources
PubMed2006

A microarray analysis of gene expression in the free-living stages of the parasitic nematode Strongyloides ratti.

BACKGROUND: The nematode Strongyloides ratti has two adult phases in its lifecycle: one obligate, female and parasitic and one facultative, dioecious and free-living. The molecular control of the development of this free-living generation remains to be elucidated. RESULTS: We have constructed an S. ratti cDNA microarray and used it to interrogate changes in gene expression during the free-living phase of the S. ratti life-cycle. We have found very extensive differences in gene expression between first-stage larvae (L1) passed in faeces and infective L3s preparing to infect hosts. In L1 stages there was comparatively greater expression of genes involved in growth. We have also compared gene expression in L2 stages destined to develop directly into infective L3s with those destined to develop indirectly into free-living adults. This revealed relatively small differences in gene expression. We find little evidence for the conservation of transcription profiles between S. ratti and S. stercoralis or C. elegans. CONCLUSION: This is the first multi-gene study of gene expression in S. ratti. This has shown that robust data can be generated, with consistent measures of expression within computationally determined clusters and contigs. We find inconsistencies between EST representation data and microarray hybridization data in the identification of genes with stage-specific expression and highly expressed genes. Many of the genes whose expression is significantly different between L1 and iL3s stages are unknown beyond alignments to predicted genes. This highlights the forthcoming challenge in actually determining the role of these genes in the life of S. ratti.

Animals↗
PubMed2005

Comparison of albendazole regimen for prophylaxis of strongyloides hyperinfection in nephrotic syndrome patients on long-term steroids in Cambodia.

Nephrotic syndrome patients on long-term steroids face the risk of having heavy uncomplicated strongyloidiasis or death from its extreme form, the strongyloides hyperinfection. The risk can be minimized if we eradicate the parasite first. We compare a once daily and twice daily albendazole regimen in preventing this potentially fatal complication in 122 patients with nephrotic syndrome.

Adolescent↗
PubMed1993

Protein analysis of Strongyloides venezuelensis by two-dimensional polyacrylamide gel electrophoresis.

Infective larvae, larvae in the lung and adult-stage worms in the small intestine of Strongyloides venezuelensis were analysed for protein by two-dimensional gel electrophoresis. The infective larvae were differentiated from the other two stages of parasite with 13 stage-specific spots, whereas the larvae in the lung and the adult-stage worms were identical to each other in spot patterns except for 6 spots.

Animals↗
PubMed1994

Wasting condition under normal cardiac rhythms in rabbits following Strongyloides papillosus infection.

Pathogenicity of Strongyloides papillosus to rabbits was investigated by monitoring of food intake, body weight and electrocardiogram. No abnormalities were observed in rabbits infected with 10(4) infective larvae (L3)/kg. Rabbits given 10(5) L3/kg exhibited anorexia after the establishment of patent infections. Four of them died on Days 19-33 having lost 32-44% of initial body weight. The other one animal regained appetite and body weight as fecal egg output decreased. Cardiac rhythms remained normal even in the emaciation state. In lethal cases, cardiac activities finally disappeared through escape beats preceded by sinus arrhythmia as in a fasted control. These results suggest that heavy S. papillosus infection produces a wasting condition in rabbits resulting from anorexia under normal cardiac functions.

Animals↗
PubMed1994

Parasitic females of Strongyloides papillosus as a pathogenetic stage for sudden cardiac death in infected lambs.

The present study was aimed at elucidating the responsibility of parasitic females for sudden cardiac death following Strongyloides papillosus infection in calves. A preliminary experiment demonstrated a percutaneous infection with S. papillosus infective larvae to cause sudden cardiac death in lambs as in calves, indicating lambs could serve as a model to study fatal stronglyloidiasis in calves. Parasitic females of S. papillosus were inoculated into the duodenum of lambs. Lambs given live worms developed continuous sinus tachycardia immediately after inoculation, and died of sudden cardiac arrest by ventricular fibrillation through a phase of the disease identical to the case of percutaneous larval infection. The lambs had high fecal egg counts at the time of death. Inoculation of homogenized worms did not produce fatal arrhythmias. These results demonstrate that live parasitic females of S. papillosus in the small intestine are responsible for cardiac dysfunction regardless of the presence or absence of migratory larvae.

Animals↗
PubMed1995

Massive experimental infection with Strongyloides venezuelensis in rats and absence of sudden death.

Ten rats were divided into five groups, A - E, to determine the larval dose-effect of infection with Strongyloides venezuelensis (SVZ). The rat groups were exposed to SVZ infective larvae as follow: (A) 100, (B) 1,000, (C) 10,000, (D) 100,000 and (E) 1,000,000. The eight rats in Groups A - D survived the infection. Rats exposed to the higher doses of larvae had the higher egg per gram counts (EPG), but more rapid reduction in EPG counts. The four rats in Groups C and D had EPG counts greater than 10,000 EPG during days 7 - 21 after infection. Maximum EPG values in Group C were 85,400 and 106,600; those in Group D were 134,000 and 346,000. The two rats in Group E showed severe itching and bleeding on their digital pads at the time of infection. They became listless thereafter and died with hemorrhagic pneumonia at 4 days after infection. The sudden death that has been demonstrated in calves infected with massive doses of S. papillosus was not observed in SVZ-infected rats.

Animals↗
PubMed2002

Enhanced protection against the migratory phase, but defective protection against the intestinal phase of Strongyloides venezuelensis infection in cotton rats, Sigmodon hispidus.

The protective capacity of the cotton rat, Sigmodon hispidus, against the migratory and intestinal phases of Strongyloides venezuelensis infection was examined. After subcutaneous infection with infective larvae (L(3)), adult worm recovery rates from male and female animals on Day 71 were only 0.10% and 0.06% of initial dose, respectively. To determine whether this enhanced protection was expressed during the migratory phase or the intestinal phase, larval recovery from the lungs of cotton rat was evaluated 3 days after subcutaneous L(3) infection. The larval recovery rate was only 0.5% of initial dose and about 40-fold lower than that from control mice. Protection in the intestine was also evaluated after intraduodenal implantation of adult worms. About 30% of implanted worms became established and worm burden remained constant until Day 28. Despite a high worm burden on Day 28, EPG was about 25-fold lower than the peak count. To evaluate expulsive capacity and monitor the cellular responses in the intestine of cotton rats, adult Nippostrongylus brasiliensis worms were implanted in addition to S. venezuelensis. Cotton rats were unable to expel adult S. venezuelensis worms, even after 21 days of observation. Although the number of mucosal mast cells increased significantly, the intraepithelial migration of mast cells was not observed. In contrast, N. brasiliensis was expelled by Day 6 in association with goblet cell hyperplasia. These results suggest that in cotton rats, the defective intestinal protection against adult S. venezuelensis worms results from dysfunction of mucosal mast cells.

Animals↗
PubMed2002

Androgen- and estrogen-dependent sex differences in host resistance to Strongyloides venezuelensis infection in Wistar rats.

The effects of male and female sex hormones on the protective capacity of Wistar rats against infection with Strongyloides venezuelensis were investigated. Male rats were more susceptible than females in terms of worm recovery from the lungs. Orchidectomy of male animals significantly reduced the plasma testosterone concentration and increased host resistance to the migratory stages of S. venezuelensis larvae. In contrast, ovariectomy of female animals significantly decreased host resistance in association with a significant reduction of estrogen levels. To examine the direct effect of sex hormones, exogenous testosterone and estrogen were implanted into animals. Susceptibility significantly increased or decreased in ovariectomized females given testosterone or estrogen, respectively. These results suggest that male and female sex hormones are important in the down- and up-regulation of host resistance against S. venezuelensis in Wistar rats.

Animals↗
PubMed2002

Age- and sex-related changes in susceptibility of Wistar rats to Strongyloides venezuelensis infection.

The effects of host age and sex on susceptibility to Strongyloides venezuelensis in Wistar rats were examined by counting larvae recovered from the lungs of animals 3 days after infection. The susceptibility of female rats to S. venezuelensis rapidly decreased with age and elevated estrogen. Resistance in female rats inoculated at 6 and 10 weeks of age was nine and twenty-fold higher, respectively than that in the youngest group (3 weeks). In contrast, the susceptibility of male animals was lowest in the youngest group, then increased with age and elevated testosterone. Sex differences in susceptibility were not evident in the youngest group, but became apparent with age.

Age Factors↗
PubMed2003

Migration of Strongyloides venezuelensis in rats after oral inoculation of free-living infective larvae.

Strongyloides venezuelensis (SVZ) infection was chronologically monitored in 85 Sprague-Dawley rats (SDR), which were orally inoculated with approximately 1,000 infective larvae. In order to describe the characteristics of migrating larvae (MLS) in various visceral organs (the liver, lung, cardiac blood, and small intestine), 5 SDR were sacrificed at 20 min, 45 min, 1 hr, 2 hr, 3 hr, 4 hr, 8 hr, 12 hr, 16 hr, 48 hr, 72 hr, 96 hr, 120 hr, 144 hr, 168 hr and 192 hr post inoculation (PI). MLS were recovered from the liver and blood 20 and 45 min PI and measured 788 +/- 26 microm and 846 +/- 40 microm in length, respectively. MLS were first observed in the lung tissue 45 min PI and measured 925 +/- 38 microm on the average. In the trachea, MLS measuring 849 +/- 75 microm appeared 3 to 96 hrs PI. Adult worms (AWS) measuring 1,926 +/- 521 microm to 2,956 +/- 159 microm in length were observed in the small intestine from 120 hr PI. The worms appeared to mature more than 168 hr PI and attained the average maximum length of 2,420 +/- 532 microm. At 3 hr PI focal hyperemic and necrotic lesions were evidently observed in the liver and lung, together with eosinophilic infiltration in the stomach, liver, and lung. The parasites were histologically detectable in the lung tissues but were very difficult to find in the liver and the epithelial layer of small intestine. These data demonstrate that SVZ parasites take 20 min to reach the liver via the stomach and only three hours to reach the trachea through the same route. The development from eggs to adults takes 168 hr in the SDR model.

Animals↗
PubMed1993

Disseminated Strongyloides stercoralis in human immunodeficiency virus-infected patients. Treatment failure and a review of the literature.

We describe a North American human immunodeficiency virus (HIV)-positive patient with Strongyloides stercoralis infection of the gastrointestinal tract, who required repeated "standard" courses of thiabendazole. Pulmonary infection with numerous roundworms developed, as suspected by bronchoalveolar lavage, and while he was receiving therapy, dissemination occurred. On autopsy, S stercoralis was recovered in the gastrointestinal tract, liver, lung, and heart. After a literature review, we conclude that HIV-positive patients have a higher risk of dissemination and "standard" treatment failure. This may occur without elevation of IgE or eosinophilia. Those patients may require prolonged courses of thiabendazole or alternatively ivermectin therapy.

Animals↗
PubMed1990

Pulmonary hyperinfection syndrome with Strongyloides stercoralis.

A 65-year-old man with steroid-dependent chronic airflow obstruction presented with progressive dyspnea and weight loss. Travel history included a military tour in southeast Asia. A chest roentgenogram revealed hyperexpanded lung fields with diffusely increased interstitial markings. The Papanicolaou stain of expectorated sputum demonstrated the rhabditiform larvae of Strongyloides stercoralis. Endemic areas of infection include the southeastern United States, Puerto Rico, Central America, the Pacific basin, and central Africa. In recent immigrant groups and veterans of the Vietnam conflict, rates of infection are as high as 6 percent. The hyperinfection syndrome occurs in immunocompromised hosts and is associated with glucocorticoid steroid therapy. This allows massive proliferation of larval forms. Clinical clues include an appropriate travel history (even in the remote past), gastrointestinal symptoms, cutaneous symptoms, eosinophilia, or thrombocytosis. Our patient demonstrated a classic presentation of the hyperinfection syndrome, and the condition responded well to thiabendazole.

Aged↗
PubMedDate not supplied

[The evaluation of antigenic preparations of Strongyloides stercoralis for the immunodiagnosis of strongyloidiasis].

Aqueous-soluble (AS) antigens from larvae of Strongyloides stercoralis, extracted with phosphate-buffered saline, are traditionally used for serodiagnosis of strongyloidiasis. To identify sources of antigens for use in serodiagnosis, residual particulates from parasite larvae after aqueous extraction were solubilized with Tris-buffered 8M urea, yielding a urea-soluble (US) antigen fraction. Both AS and US antigens from S. stercoralis were evaluated by an enzyme-linked immunosorbent assay. No significative differences were observed between AS and US antigens from the parasite regarding specific antigenic activity and cross-reactivity. Immunoassays are highly dependent on the antigen for sensitivity and specificity. Crude extracts from S. stercoralis should be further studied, mainly in relation to antigenic fractions which could provide even more sensitive and specific results. Studies of fractionation of S. stercoralis must take into account the antigen yield of both the crude extract and fractions, since larvae of parasite are normally difficult to obtain. Considering this aspect, the results from this study are very useful, since the extraction with urea substantially increased the amounts of antigenic materials normally obtained with the classical aqueous extraction.

Animals↗
PubMedDate not supplied

[The treatment of rats experimentally infected with Strongyloides venezuelensis by orally administered ivermectin].

Strongyloides venezuelensis experimental infection in rats was treated by two different oral preparations of ivermectin, 0.2 mg/kg. One was a human formula used by WHO in the treatment of onchocerciasis; the other was a veterinary preparation. Adult worms and larvae were evaluated. The human formulation cleared both forms in 59.3% (adult worms) and 73.0% (larvae), whereas the veterinary one cleared 98.0% and 84.2%, respectively. The antilarval action is very useful when treating systemic strongyloidiasis.

Administration, Oral↗
PubMedDate not supplied

Strongyloides stercoralis and other enteroparasites in children at Uberlândia city, state of Minas Gerais, Brazil.

To evaluate the rate of infection by Strongyloides stercoralis and other enteroparasites a survey was conducted in the city of Uberlândia, State of Minas Gerais, Brazil. A total of 900 stool samples from 300 children aging from four months to seven years, randomly selected in ten nursery schools from September 1994 to December 1995, were examined, both by the Baermann-Moraes and Lutz methods. Thirty nine children (13%) were found to be infected by S. stercoralis, 64.1% were boys and 35.9% were girls. Taking all the enteroparasites as a whole the results of the survey pointed out that 265 (88.4%0 of the 300 children were infected by the following: Giardia lamblia, 78.3%; Ascaris lumbricoides, 15.3%; S. stercoralis, 13%; Hymenolepis nana, 6.7%; hookworms, 6%; Enterobius vermicularis, 4%; Hymenolepis diminuta, 4% and Trichuris trichiura, 0.7%. From 265 infected children 64.5% were mono-infected, 27.2% were infected by two parasites and 8.3% had a poly-specific parasite burden. It was concluded that strongyloidiasis is hyperendemic in this area.

Analysis of Variance↗
PubMedDate not supplied

Coinfection by Strongyloides stercoralis in blood donors infected with human T-cell leukemia/lymphoma virus type 1 in São Paulo City, Brazil.

The frequency of coinfection with Strongyloides stercoralis and human T-cell leukemia/lymphoma virus type 1 (HTML-1) was determined in 91 blood donors examined at the blood bank of a large hospital in São Paulo city, Brazil. As control group 61 individuals, not infected by HTLV-1, were submitted to the same techniques for the diagnosis of S. stercoralis infection. In HTLV-1 infected patients the frequency of S. stercoralis infection was 12.1%; on the other hand, the control group showed a frequency significantly lower of S. stercoralis infection (1.6%), suggesting that HTLV-1 patients should be considered as a high risk group for strongyloidiasis in São Paulo city.

Animals↗
PubMed2002

Frequency of Strongyloides stercoralis infection in alcoholics.

Several studies have shown that chronic alcoholics have increased susceptibility to infections due to higher exposure to infectious agents as well as breakdown in their immune defenses. As Strongyloides stercoralis infection is usually more relevant in immunocompromised patients, the aim of this study was to evaluate the frequency of S. stercoralis infection in alcoholics. Thus, coproparasitological examination was carried out in 145 subjects, from which 45 were chronic alcoholics (mean age of 45.7 +/- 11.0 years), 10 were nonalcoholic cirrhotic patients (mean age of 50.2 +/- 13.1 years), and 90 were asymptomatic nonalcoholic subjects (mean age of 46.7 +/- 10.1 years), which served as controls. From the alcoholics, 9 had hepatic cirrhosis, 9 had chronic pancreatitis and 27 had neither cirrhosis nor pancreatitis. For the diagnosis of strongyloidiasis, the Baermann-Moraes and Lutz methods were used in three fecal samples from each subject. Samples were collected at alternated days, and three slides of each sample were analyzed for each method, thus totalizing 2,610 slides examined. The frequency of strongloidiasis in the total alcoholic group (33.3%) and in the subgroups of alcoholics, i.e., patients with hepatic cirrhosis (44.4%), with chronic pancreatitis (33.3%), and those with no cirrhosis or pancreatitis (29.6%) was statistically higher than that found in the control group (5.5%). None of the individuals with nonalcoholic hepatic cirrhosis had S. stercoralis infection. Our results showed that the chronic alcoholism itself is an important factor that predisposes to strongyloidiasis.

Alcoholism↗