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Strongyloides hyperinfection in a renal transplant recipient receiving cyclosporine: possible Strongyloides stercoralis transmission by kidney transplant.

Strongyloides hyperinfection and dissemination are recognized complications in kidney allograft recipients; however, the development of strongyloidiasis in renal transplant recipients receiving cyclosporine A (CyA) has not been described, nor has the development of strongyloidiasis in other organ transplant recipients. The former observation has been attributed to the antiparasitic activity of CyA seen in animal studies; the latter has no explanation yet. We report the first case of Strongyloides hyperinfection in a renal transplant patient occurring immediately after CyA was discontinued. From the unique characteristics of this case, it appears that the anti-Strongyloides activity of CyA in animals may also be found in humans.

Animals↗

Species-specific differences in heterogonic development of serially transferred free-living generations of Strongyloides planiceps and Strongyloides stercoralis.

The direction of free-living development (homogonic vs. heterogonic) in Strongyloides stercoralis and Strongyloides planiceps was examined by successive transplantation of the uterine eggs of free-living females into a test tube culture system containing fresh feces. The eggs from the first-generation free-living females of S. stercoralis did not develop into second-generation free-living adult worms, but all developed into filariform larvae. However, the majority of S. planiceps eggs from the first-generation free-living females developed into second-generation free-living adults. By successive transfer of uterine eggs of each generation, 9 generations developed, and in every cycle more adult worms developed than filariform larvae. However, the number of free-living generations was not infinite; in experiments repeated twice, the number of worms developing from the eggs of eighth or ninth generations was too small to continue further culture. These findings indicate that the pattern of free-living development is different between the 2 species.

Animals↗

Cryo-microtome sections of coproculture larvae of Strongyloides stercoralis and Strongyloides ratti as antigen sources for the immunodiagnosis of human strongyloidiasis.

Cryo-microtome sections of larvae of Strongyloides stercoralis and S. ratti respectively obtained from human and rat feces cultures, were used as antigens. Fluoresceinate conjugates against human IgG were employed at the ideal titer of 10 for S. stercoralis and 100 for S. ratti. The sensitivity of the indirect immunofluorescence reaction (IIF) was 94.4% and 92.5% and the specificity 94.2% and 97.1% for the two specific larval antigens, respectively. Sera from 123 persons (54 from carriers of S. stercoralis infections and 69 from controls) were submitted to the reaction. The titers of different sera varied from 20 to 2560. There was a significant linear correlation (r = 0.85 p < or = 0.001) between the antibodies from the two species of larval antigens. We conclude that both antigens may be used in the IIF reaction for the diagnosis of human strongyloidiasis. Due to the feasibility of safe and low-cost mass production of S. ratti larvae in the laboratory with a considerable economy of conjugate, their utilization in the serum diagnosis of human strongyloidiasis is recommended.

Animals↗

No association found between Strongyloides infestation and asthma.

It has been postulated that infestation with Strongyloides stercoralis is associated with asthma. We conducted a case-control study to determine whether the presence of parasites is associated with asthma. We undertook a retrospective analysis of 15,856 stool specimens received by our Parasitology Laboratory from January 1989 to December 1992. The diagnosis of asthma was secured by a chart review or a review of the computer diagnosis coding system. An association between asthma and Strongyloides was tested by calculating an odds ratio, as well as a Fisher's Exact Test to estimate the strength of the relationship. We also prospectively collected stool specimens for Strongyloides in asthmatics hospitalized for acute exacerbations of asthma from January 1992 to January 1993. Of 60 subjects with evidence of Strongyloides in a stool specimen, 6 were asthmatic. Of 203 stool-negative controls matched for age, sex, and ethnicity, 13 were asthmatic (odds ratio, 1:62; 95% confidence interval, 0.6-4.4; Fisher's Exact two-tailed, p = 0.39). Of 443 subjects admitted for acute exacerbations of asthma, stool specimens were analyzed for the presence of Strongyloides from 161, of which two were parasitized. These data suggest no statistically significant difference in prevalence of asthma among patients with Strongyloides infestation compared to those without parasitic infection. These results do not support the hypothesis that there is an association, either causal or protective, between Strongyloides infestation and asthma.

Acute Disease↗

Strongyloides fuelleborni kellyi and other intestinal helminths in children from Papua New Guinea: associations with nutritional status and socioeconomic factors.

This survey examined the prevalence and intensity of Strongyloides fuelleborni kellyi and other intestinal helminths in children 5 years of age or under living near Kanabea, Papua New Guinea. Of 179 samples, 27% of the children tested positive for Strongyloides, with 81% of these children being a year or less in age. Overall, 68% of the children had one or more infections including Ascaris lumbricoides and hookworm (Necator americanus) as well as Strongyloides. Egg counts in the stools ranged from 100 to 98,300 eggs/ml for Strongyloides, 100 to 59,200 eggs/ml for Ascaris and 100 to 3400 eggs/ml for hookworm. There were significant associations between Strongyloides intensity and weight for age and weight for height such that children with higher intensities had, on average, lower z-scores. Relationships between the prevalence of helminth infections and socioeconomic factors were also observed. Logistic regression models showed that children living farther away from Kanabea (more than 2 hours' walking distance), in smaller households (5 or less people) and with uneducated mothers best predict children with Strongyloides. Two of these variables also predicted the presence of hookworm: maternal education and household size. However, in contrast to Strongyloides, a larger household size (6 or more people) was significantly associated with the presence of hookworm. House type was associated with the prevalence of Ascaris, with children living in houses with tin roofs being less likely to have Ascaris than those living in traditional houses. In addition, maternal education was associated with Ascaris intensity in those children with infection, such that the mean intensities were greater in children of uneducated mothers.

Animals↗

Molecular phylogenetic analysis of the genus Strongyloides and related nematodes.

Strongyloides spp., parasitic nematodes of humans and many other terrestrial vertebrates, display an unusual heterogonic lifecycle involving alternating parasitic and free-living adult reproductive stages. A number of other genera have similar lifecycles, but their relationships to Strongyloides have not been clarified. We have inferred a phylogeny of 12 species of Strongyloides, Parastrongyloides, Rhabdias and Rhabditophanes using small subunit ribosomal RNA gene (SSU rDNA) sequences. The lineage leading to Strongyloides appears to have arisen within parasites of terrestrial invertebrates. Inferred lifecycle evolution was particularly dynamic within these nematodes. Importantly, the free-living Rhabditophanes sp. KR3021 is placed within a clade of parasitic taxa, suggesting that this species may represent a reversion to a non-parasitic lifecycle. Species within the genus Strongyloides are very closely related, despite the disparity of host species parasitised. The highly pathogenic human parasite Strongyloides fuelleborni kelleyi is not supported as a subspecies of the primate parasite S. fuelleborni fuelleborni, but is most likely derived from a local zoonotic source.

Animals↗

Opportunistic infections with Strongyloides stercoralis in renal transplantation.

Opportunistic infections with the nematode Strongyloides stercoralis occur most often in patients with impaired T lymphocyte function, including recipients of renal allografts. Occult intestinal infection can remain quiescent for more than 30 years, becoming apparent only after the initiation of immunosuppression. Pulmonary and gastrointestinal symptoms predominant as initial clinical manifestations in patients with strongyloides hyperinfection or dissemination. Although thiabendazole remains the treatment of choice for all forms of strongyloidiasis, the duration of therapy must be individualized on the basis of frequent examinations of both stool and sputum. Transplantation centers drawing patients from areas with endemic Strongyloides should evaluate potential recipients closely for occult strongyloides infection prior to initiating immunosuppressive therapy. Empiric therapy with thiabendazole should be considered for renal allograft recipients with unexplained eosinophilia and a history of travel or residence in an area with endemic Strongyloides. Prophylactic monthly administration of thiabendazole in immunocompromised patients who have survived strongyloides hyperinfection or dissemination can prevent reinfection.

Adult↗

Epidemiological and clinical interaction between HTLV-1 and Strongyloides stercoralis.

Strongyloides stercoralis is the most common human parasitic nematode that is able to complete a life cycle and proliferate within its host. The majority of patients with strongyloidiasis have an asymptomatic infection or mild disease. However, when autoinfection occurs, a high number of infecting larvae can gain access to the bloodstream by penetrating the colonic mucosa leading to a severe hyperinfection and the development of disseminated strongyloidiasis. The human T cell lymphotropic virus type 1 (HTLV-1) predominantly infects T cells and induces spontaneous lymphocyte proliferation and secretion of high levels of type 1 cytokines. Strongyloides stercoralis patients with HTLV-1 co-infection have a modified immunological responses against parasite antigens and co-infection has clinical implications for strongyloidiasis. The high production of IFN-gamma observed in patients co-infected with HTLV-1 and Strongyloides stercoralis decreases the production of IL-4, IL-5, IL-13 and IgE, molecules that participate in the host defence mechanism against helminths. Moreover, there is a decrease in the efficacy of treatment of Strongyloides stercoralis in patients co-infected with HTLV-1. Alterations in the immune response against Strongyloides stercoralis and the decrease in the efficacy of anti-parasitic drugs are responsible for the increased prevalence of Strongyloides stercoralis among HTLV-1 infected subjects and make HTLV-1 infection the most important risk factor for disseminated strongyloidiasis.

Animals↗

[Prevalence of Strongyloides spp. infection in household dogs].

A total of 1,505 household dogs were investigated for the prevalence of Strongyloides spp. infection by fecal examination in relation to their fecal conditions, rearing environments, origins, age, sex and breed. Strongyloides spp. infection was demonstrated in 29 of 1,505 (1.93%) dogs. Strongyloides stercoralis was detected in 28 dogs, and Strongyloides planiceps was detected in one dog. The rate of Strongyloides spp. infection was higher in dogs reared indoors, originated from pet shops/breeding kennels and aged 1-6 months. The infected rate was higher in dogs excreting soft feces. No significant sex-related difference was observed in Strongyloides spp. infection. The rate was high in Pomeranians and low in mongrels. The detection of S. stercolaris in dogs reared indoors will involve a serious problem in public health, because the parasite has zoonoitic potential. It suggests that a positive sanitary instruction against a dog's owner and a worker in pet shops/breeding kennels seems necessary for prevention of transmission from dogs to humans. Furthermore, the reliable treatment for dogs infected with S. stercoralis seems to be important.

Age Factors↗

Strongyloides hyperinfection presenting as acute respiratory failure and gram-negative sepsis.

STUDY OBJECTIVES: Disseminated strongyloides is a rarely reported phenomenon and occurs in immunosuppressed patients with chronic Strongyloides stercoralis infection. Typically, patients present with pulmonary symptoms but subsequently acquire Gram-negative sepsis. Several cases have been noted in Minnesota, and their presentation, diagnostic evaluation, and clinical outcomes were reviewed. DESIGN: A retrospective chart review was conducted of complicated strongyloides infections from 1993 to 2002 in Minneapolis and St. Paul, MN. Cases were identified by reviewing hospital microbiology databases. SETTING: Metropolitan hospitals with large immigrant populations. RESULTS: Nine patients, all of Southeast Asian heritage, were identified. Eight patients immigrated to the United States > or = 3 years prior to acute presentation. All patients were receiving antecedent corticosteroids; in five patients, therapy was for presumed asthma. Absolute eosinophil counts > 500/microL occurred in only two patients prior to steroid initiation. Eight patients presented with respiratory distress, and Gram-negative sepsis developed in four patients. Four patients had evidence of right-heart strain on ECG or echocardiography at the time of presentation. Three patients died; all had eosinophil counts of < 400/microL. CONCLUSIONS: Serious complications, including death, may occur in patients with chronic strongyloides infection treated with corticosteroids. Strongyloides hyperinfection usually presents as acute respiratory failure and may initially mimic an asthma exacerbation or pulmonary embolism. Southeast Asian patients presenting with new-onset "asthma," acute respiratory distress, and/or Gram-negative sepsis should undergo evaluation to exclude strongyloides infection.

Acute Disease↗

Correlation between human T cell lymphotropic virus type-1 and Strongyloides stercoralis infections and serum immunoglobulin E responses in residents of Okinawa, Japan.

To clarify the relationship between Strongyloides stercoralis, infection with human T cell lymphotropic virus type-1 (HTLV-1), and serum immunoglobulin E (IgE) levels, epidemiologic investigations of these two infections were conducted in inhabitants of Okinawa, a subtropical zone in Japan. Blood and feces samples were taken from 1,347 healthy inhabitants (554 males and 793 females). Antibody to HTLV-1 was measured by particle agglutination, enzyme-linked immunosorbent assay, and Western blotting. The presence of Strongyloides was determined by direct detection of rhabditiform larvae in fresh stool on agar-plate cultures. Serum IgE levels in 127 inhabitants were measured by a fluoroenzyme immunoassay. Antibody to HTLV-1 was detected in 23.0% of the blood samples and was more frequent in females (25.1%) than in males (20.0%) (P < 0.05). Strongyloides were detected in 21.9% of the feces samples and were more frequent in males (31.9%) than in females (14.9%) (P < 0.001). The prevalence of both infections increased with age, especially in persons 50 years of age and older: The prevalence of Strongyloides infection was significantly higher in HTLV-1 carriers (31.6%) than in those without HTLV-1 infection (P < 0.001). The level of IgE was low in HTLV-1 carriers, and significantly lower in HTLV-1 carriers than in noncarriers among inhabitants with Strongyloides infection. Both HTLV-1 and Strongyloides infections are endemic in the area studied.

Adult↗

Strongyloides stercoralis hyperinfection associated with human T cell lymphotropic virus type-1 infection in Peru.

A study was conducted in Lima, Peru to determine if patients with Strongyloides hyperinfection had human T cell lymphotropic virus type-1 (HTLV-I) infection. The study included patients with Strongyloides hyperinfection and a control group consisted of sex- and age-matched asymptomatic healthy individuals whose stools were negative for Strongyloides. A third group included patients with intestinal strongyloidiasis. Sera from each study subject were tested for HTLV-1/2I by an ELISA and Western blot. The HLTV-1 infection rates (85.7%, 18 of 21) were significantly (P < 0.001) associated with Strongyloides hyperinfection compared with the control group (4.7%, 1 of 21). The HTLV-1 rate (10%, 6 of 62) for patients with intestinal strongyloidiasis was significantly (P < 0.001) lower than patients with Strongyloides hyperinfection, but did not differ significantly (P > 0.05) from the control group. The association of HTLV-1 infection was observed among 17 of 19 patients more than 20 years of age and one of two younger patients. None had HTLV-2 infection. In conclusion, Strongyloides hyperinfection among Peruvian patients was highly associated with HTLV-1 infection.

Adult↗

Disseminated Strongyloides stercoralis Infection in an AIDS Patient: The Role of Suppressive Therapy.

Patients with AIDS are prone to develop infections caused by opportunistic pathogens. Unusual agents, such as Strongyloides stercoralis, are being described in this syndrome, resulting in disseminated disease which is always severe and, in some cases, fatal. We describe a case of a patient with AIDS and Strongyloides stercoralis infection involving the gastrointestinal tract and the lungs. Therapy with thiabendazole for ten days led to resolution of the acute episode. Preventive therapy with 3g of thiabendazole once a week was then prescribed, and repeated fecal examinations were negative for larvae. Following discontinuation of treatment, however, the patient again had a positive fecal examination for Strongyloides stercoralis larvae, even though reinfection was considered to be very unlikely. The patient was retreated with a shorter course of therapy and once per week preventive therapy was reintroduced. After four months of follow-up, repeated fecal examinations were negative. When the treatment was changed to thiabendazole given once every two weeks, however, pulmonary Strongyloides stercoralis recurred. Subsequently, because of intolerance to thiabendazole, the patient was treated with cambendazole. The patient died three months later due to Pseudomonas aeruginosa pneumonia. Prolonged therapy for Strongyloides stercoralis infection may be necessary. Although further evaluation is needed, 3g of thiabendazole once a week may be adequate for this purpose. Cambendazole may be a useful alternative for disseminated Strongyloides stercoralis.

Journal Article↗

Not your typical strongyloides infection: a literature review and case study.

Strongyloides hyperinfection syndrome is one of several clinical manifestations of strongyloidiasis and has a mortality rate exceeding 85%. The syndrome is characterized by a high organism burden owing to autoinfection and is most common in immunocom-promised hosts. The recovery of multiple pathogens is likely due to a piggyback phenomenon that occurs when enteric pathogens are transferred to the bloodstream attached to Strongyloides larvae. Herein, we describe a case of Strongyloides hyperinfection syndrome with a novel feature in a 69-year-old Venezuelan man. To our knowledge, this is the first case of Strongyloides hyperinfection syndrome and Pneumocystis jiroveci pneumonia occurring simultaneously. Owing to its extremely high mortality rate, Strongyloides hyperinfection syndrome must be considered early in the differential diagnosis for respiratory failure when multiple pathogens are recovered in patients from endemic areas.

Aged↗