Is there an association between positive Strongyloides stercoralis serology and diabetes mellitus?

The purpose of this study was to determine the frequency of association between positive Strongyloides stercoralis serology and diabetes mellitus. A total of 78 diabetic patients and 42 controls were evaluated. For a parasitological diagnosis, Baermann and Hoffman et al.'s methods were applied. The immunological diagnosis involved the indirect fluorescence antibody test, ELISA and Western blotting to detect IgG antibodies. The frequency of positive S. stercoralis serology in diabetics was 23% versus 7.1% in the control group (P<0.05). The odds ratio for diabetics was 3.9 (CI, 1.6-15.9, P<0.05). Diabetic patients with HbA(1c)< or =7 had a greater chance of testing negatively for S. stercoralis infection (OR: 1.5, P>0.05). Provided there are related cases of disseminated strongyloidiasis in diabetics and there is a higher frequency of asymptomaticity of the infection in this group, the immunological screening of these patients at risk could prevent severe and fatal outcomes of the disease.     

Parasitological and immunological diagnoses of strongyloidiasis in immunocompromised and non-immunocompromised children at Uberlândia, State of Minas Gerais, Brazil

Parasitological and immunological diagnoses were part of a study conducted among 151 children, 83 immunocompromised (IC) and 68 non-immunocompromised (non-IC) aged from zero to 12, seen at the University Hospital, Universidade Federal de Uberlandia, State of Minas Gerais, Brazil, from February, 1996, to June, 1998. Three fecal samples from each child were analyzed for the parasitological diagnosis by Baermann-Moraes and Lutz methods. The immunological diagnosis to detect IgG and IgM antibodies was carried out by the indirect immunofluorescence antibody test (IFAT) with cryo-microtome sections of Strongyloides stercoralis and Strongyloides ratti larvae as antigens and by the ELISA test with an alkaline extract of S. ratti as the antigens. Of the 151 children 5 (3.31%) were infected with larvae of S. stercoralis (2 cases IC, 2.41%, and 3 cases non-IC, 4.41%). The IFAT-IgG detected 7 (8.43%) serum samples positive among IC, and 2 (2.94%) cases among non-IC. The ELISA-IgG test detected 10 (12.05%) serum samples positive among IC, and 1 (1.47%) case among non-IC. The IFAT-IgM detected 6 (7.22%) positive cases among IC, and 3 (4.41%) cases among non-IC. ELISA-IgM test detected 10 (12.05%) positive cases among IC, and 3 (4.41%) cases among non-IC. It was concluded that the immunological tests can help in the diagnosis of strongyloidiasis in immunocompromised children.     

Prevalence of Strongyloides stercoralis infection among HIV-positive immigrants attending two Italian hospitals, from 2000 to 2009

In patients with Strongyloides stercoralis infection, a dysregulation of host immunity can lead to hyperinfection syndrome (HS) and disseminated strongyloidiasis (DS), characterized by high fatality rate. HS has been reported in HIV-positive patients following use of corticosteroids or during immune reconstitution inflammatory syndrome (IRIS). A retrospective study was conducted to estimate the prevalence of S. stercoralis infection among HIV-positive immigrants, attending two Italian hospitals. From January 2000 to August 2009, 138 HIV-positive immigrants were systematically screened for strongyloidiasis, as a part of their routine care, with an indirect immunofluorescent antibody test (IFAT) developed at the Centre for Tropical Diseases, Sacro Cuore Hospital of Negrar, Verona. The majority were also submitted to stool examination. Fifteen (11%) resulted infected by S. stercoralis, of whom four (27%) had a negative serology (diagnosis made with stool examination). A higher eosinophil count (0·94 versus 0·24×10(9)/l, P<0·01) and more frequent gastrointestinal and cutaneous symptoms (odds ratio: 4·8 and 5·8, respectively) were found in patients with strongyloidiasis compared with controls. The IFAT is more sensitive than direct parasitological methods. The proportion of false negative results was higher than expected based on the theoretical test sensitivity. Considering the high prevalence detected and the apparent, lower sensitivity of serology, we propose a systematic screening for Strongyloides infection, with both serology and stool culture, for all HIV-positive immigrants coming from endemic areas.     

Biology and immunology of human strongyloidiasis

Strongyloidiasis is an important human parasitic infection primarily because of its potential for serious and even lethal disease in immunosuppressed patients. Certain features of the biology of Strongyloides stercoralis, such as the ability to autoinfect the host, help explain why the parasite is dangerous. Characteristics of the parasite can also be exploited in parasitological diagnosis of infection with the Baermann concentration procedure and by culture. Use of filariform larval antigens in ELISA or immunofluorescent-antibody tests now provide reliable serological tests for diagnosis, and, in most patients, antibody levels decline one to two years after successful treatment. Immediate hypersensitivity is a prominent component of the immune response to strongyloides infection and may play a role in the pathogenesis of disease as well as in protection. An IgE-mediated skin test appears to be useful in diagnosis. Animal models used for immunologic studies of other intestinal helminths have lacked relevance to human strongyloidiasis. Features of the human disease, however, including hyperinfection syndrome, can be produced by S. stercoralis in the Patas monkey and in dogs.     

An inverse relationship between autoimmune liver diseases and Strongyloides stercoralis infection

A case-control study was undertaken to describe the prevalence of Strongyloides stercoralis infection among patients with autoimmune liver diseases, such as primary biliary cirrhosis (PBC), autoimmune hepatitis (AIH), and primary sclerosing cholangitis (PSC). This study covered 4,117 patients who were admitted to hospitals in Okinawa, Japan, between 1988 and 2006. During this period, 538 patients had the following chronic liver diseases: PBC, AIH, PSC, chronic viral hepatitis group, and alcoholic liver disease. The other 3,579 patients who were hospitalized and underwent parasitologic tests served as controls. The frequency of S. stercoralis infection in the autoimmune liver diseases group (1.0%) was lower than that found in the control group (7.0%; P = 0.0063). None of the female patients with PBC born before 1955 had S. stercoralis infection, which was also statistically significant (P = 0.045). We hypothesized that immunomodulation by S. stercoralis infection may lower the incidence of autoimmune liver disease.     

An epidemiological survey on intestinal parasite infection in Khammouane Province, Lao PDR, with special reference to Strongyloides infection

To estimate the current prevalence of intestinal helminth infection in Lao PDR, a parasitological survey was conducted in three villages in Khammouane Province in December 1996, with special reference to Strongyloides infection. A total of 669 fecal samples were collected in the villages and examined by agar-plate culture method and Kato-Katz thick smear method. Intestinal helminths were demonstrated in 82% of the samples as follows: Ascaris lumbricoides (30.5%), Trichuris trichiura (23.7%), hookworm (28.8%), Strongyloides stercoralis (19.0%), Enterobius vermicuralis (3.4%), Opisthorchis viverrini (56.7%) and Taenia sp (3.0%). The infection rates of S. stercoralis were 27.5% and 18.4% in two rural villages, but only 9.4% in an urban village. The highest prevalence rate of Strongyloides infection was obtained in the age group from 20 to 29 years old, although the infection rate already reached 10% in the age group under 10 years old. The prevalence was consistently higher in male subject than females in almost all age groups.     

Bronchial nodules produced by Strongyloides stercoralis as the cause of bronchial obstruction

Infection by Strongyloides stercoralis can cause asthma-like symptoms through mechanisms that have not yet been clarified. A 55-year-old male farm worker with a 2-year history of illness diagnosed as asthma and treated unsuccessfully with bronchodilators and corticosteroids was referred to our hospital with severe dyspnea. The initial chest radiograph showed mild air trapping, and pulmonary function tests detected airway obstruction that did not respond to salbutamol. Bronchoscopy revealed multiple nodules protruding into the airway lumen. S. stercoralis larvae were detected in bronchoalveolar lavage fluid and stool samples. Although treatment with albendazole was initiated, the patient's condition worsened over the next 3 days, hemoptysis presented, and the process ended in death. Autopsy demonstrated Strongyloides larvae in the bronchial nodules. Infection by S. stercoralis should be considered in the differential diagnosis of asthmatic-like symptoms refractory to treatment. In such cases nodules may be responsible for obstruction.     

Eosinophilia in Southeast Asian refugees: evaluation at a referral center

We determined the cause of persistent eosinophilia in 128 Indochinese refugees for whom initial comprehensive routine screening had failed to yield an explanation. Intestinal parasitism with one or multiple organisms was the cause of eosinophilia in all but six of these patients. Hookworm and Strongyloides stercoralis were among the potentially pathogenic organisms most frequently implicated (55% and 38%, respectively). There was no correlation between the age or sex of the patients and the type of infecting organism. We also confirmed the usefulness of a previously described serological test for diagnosing infection with Strongyloides stercoralis and examined the test's ability to distinguish between infected and noninfected individuals and to determine parasitological cure.     

Strongyloidiasis: challenges in diagnosis and management in non-endemic Kuwait

Among immunocompromised individuals, hyper-infection with Strongyloides stercoralis may occur and lead to fatal strongyloidiasis. To clinicians and laboratory diagnosticians in non-endemic countries such as Kuwait, this severe infection poses a particular problem. The clinical histories and signs and symptoms of four Kuwaiti cases of S. stercoralis hyper-infection were reviewed. Each of the four was found not only to have lived in an area where S. stercoralis was endemic but also to have been treated with immunosuppressive steroids (for medical problems unrelated to the nematode infection). When they presented with undiagnosed hyper-infections their clinical features were confusing. Three of the cases, all with low eosinophil counts, died but the other, who was treated with thiabendazole, survived. In the light of these observations, healthy medical examinees who had recently moved from endemic zones were checked for asymptomatic S. stercoralis infection, both by stool examination and ELISA-based serology. Of 381 stool samples investigated over a 3-month period, 183 (48%) were found positive for helminths, 7% for S. stercoralis. Of 198 individuals from endemic zones who were screened after another medical examination, 71 (35.8%) were found positive for intestinal helminth parasites, including one (1.45%) infected with S. stercoralis. Although ELISA appear reliable in making a presumptive diagnosis of strongylodiasis, the results of such assays are not very specific and are best interpreted in conjunction with the patient's clinical status. The concurrent administration of anthelminthics to patients prescribed steroids who, because they live or have lived in an area where S. stercoralis is endemic, are at risk of infection with the nematode, should be considered.     

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.     

Comparative sensitivity and specificity of ELISA and IHA for serodiagnosis of strongyloidiasis with larval antigens

Sera from 68 patients with parasitologically proven strongyloidiasis were tested by the ELISA and IHA tests using larval antigens prepared from Strongyloides stercoralis and Strongyloides ratti. The ELISA using the S. stercoralis antigen detected the greatest number of sero-reactors (83.8%), whereas the IHA using the S. ratti antigen detected the fewest (55.9%). In addition, the S. stercoralis antigen had higher geometric mean titers than the S. ratti antigen in both the ELISA and the IHA tests. Sera from 37 presumed normal individuals also were tested by IHA and ELISA and nonspecific reactions were seen only with the IHA test. When sera from patients with parasitic infections other than strongyloidiasis were tested, the only consistent cross-reactions were with those sera from patients who had occult filariasis and acute schistosomiasis.     

A luciferase immunoprecipitation systems assay enhances the sensitivity and specificity of diagnosis of Strongyloides stercoralis infection

BACKGROUND: We investigated whether luciferase immunoprecipitation systems (LIPS) can be the basis for a more rapid, specific, and standardized assay for the diagnosis of Strongyloides stercoralis infection. METHODS: A LIPS assay was developed based on immunoglobulin (Ig) G or IgG4 antibody to a recombinant Strongyloides antigen (NIE) and was compared with an NIE enzyme-linked immunosorbent assay (ELISA). A second antigen, S. stercoralis immunoreactive antigen (SsIR), was tested alone and in combination with NIE. The assays were tested using serum samples from patients with parasitologically proven S. stercoralis or filarial infections and from healthy, uninfected control subjects. RESULTS: The NIE LIPS assay based on IgG antibody easily differentiated between S. stercoralis-infected and uninfected patients (P< .0001) and demonstrated improved specificity compared with the NIE ELISA (100% vs. 95%). Serum from filaria-infected patients did not cross-react when tested with the NIE LIPS assay. When SsIR was used in combination with NIE in the LIPS format, sensitivity and specificity improved to 100%, with a 7-fold difference between positive and negative values. No advantage was found in using a LIPS assay based on IgG4. At posttreatment follow-up, a significant decline in antibody titers was detected using the NIE ELISA (P< .0017) and the NIE LIPS assay (P< .0001). CONCLUSIONS: LIPS addresses several limitations of current ELISAs and represents a major advance in the diagnosis of S. stercoralis infection.     

Risk factors for strongyloidiasis. A case-control study

Although infection with Strongyloides stercoralis is usually only mildly symptomatic, it can persist for many years and occasionally progress to the hyperinfection syndrome, with a resultant high mortality rate. We studied factors associated with S stercoralis infection by comparing 28 domestic cases of S stercoralis infection with 76 controls with negative stool samples for ova and parasites. The relative risk (RR) of S stercoralis infection was increased for white patients (RR = 5.6), men (RR = 3.9), and patients who had recently used corticosteroids (RR = 3.3), had a hematologic malignancy (RR = 5.28) or had prior gastric surgery (RR = 11.5). These risk factors might be for initial infection, persistence of infection, or both. Although they are not necessarily causal, knowledge of them may lead to earlier recognition of this dangerous and treatable disease.     

Case Report: Real-Time Polymerase Chain Reaction in Stool Detects Transmission of Strongyloides stercoralis from an Infected Donor to Solid Organ Transplant Recipients

Solid organ transplant recipients can acquire Strongyloides stercoralis from an infected donor. The diagnosis of S. stercoralis in immunocompromised individuals may be challenging due to a lower sensitivity of available parasitological and serological methods, compared with immunocompetent individuals. Recently, a real-time polymerase chain reaction (RT-PCR) in stool has been developed for S. stercoralis diagnosis. We report two cases of S. stercoralis infection transmitted by a donor to two solid organ transplant recipients, who were diagnosed with RT-PCR in stool. This test could play an important role in S. stercoralis diagnosis in immunosuppressed patients, facilitating rapid treatment initiation and reducing the risk of severe strongyloidiasis. Adherence to current recommendations of screening among donors and recipients from endemic areas is also urgently needed.     

Strongyloidiasis im Moscow region

The paper presents two cases of infection with Strongyloides stercoralis (in a 13-year-old boy and in a 93-year-old female), occurred in the Moscow Region, which is indicative of the resurgence of stronglyoidiasis in the Moscow Region. Although the likelihood of this infection in this region is little, nevertheless, strongyloidiasis should be borne in mind in examining patients who are not leaving for well-known endemic areas if they have an allergic reaction of unclear etiology, eosinophilia, and digestive disorders. In these cases, the syndromic-and-empiric approach to justifying and performing chemotherapy is recommended due to the inadequate efficiency of parasitological methods for diagnosing strongyloidiasis at the low rate of invasion. These cases are indicative of the rather low virulence of Moscow strains, but at the same time of their capacity for autoinvasion and accordingly for the long-term infection of patients without recurrent infections.     

Detection of opportunistic and non-opportunistic intestinal parasites and liver flukes in HIV-positive and HIV-negative subjects

We assessed the frequency and distribution of infection with opportunistic and non-opportunistic intestinal parasites and the liver fluke, Opisthorchis viverrini, in HIV-seropositive and HIV-seronegative subjects. Age- and sex-matched HIV-seropositive (n = 78) and HIV-seronegative patients (n = 78) from two hospitals in Khon Kaen Province, Thailand, participated in this study from November 1998 to August 2000. These subjects were divided according to the presence of diarrhea and CD4 counts. A single stool sample was obtained and analyzed by using specific techniques. Opisthorchis viverrini, was the most common parasite (19.2%) in each group. The prevalence rates of Cryptosporidium spp (11.5%) and Strongyloides stercoralis (17.9%) in the HIV-seropositive group were significantly (p < 0.05) higher than those in the HIV-seronegative group (1.0% for Cryptosporidium spp and 7.7% for S. stercoralis infections). The prevalences of these two parasites were 28% for Cryptosporidium spp and 20% for S. stercoralis in HIV-seropositives with diarrhea and CD4 counts lower than 100 cells/mm3, and were higher compared with patients without diarrhea or with high CD4 counts. These results suggest that infection with these parasites increases during HIV infection. The epidemiological distribution of Cryptosporidium and S. stercoralis may have implications for AIDS-related diseases.     

Strongyloides stercoralis infection in a patient with rheumatoid arthritis and type 2 diabetes mellitus: a case-based review

Clinical Rheumatology - Strongyloides stercoralis (S. stercoralis), a human intestinal nematode, can lead to hyper/disseminated (HD) infection in patients treated with corticosteroids. Here, we...     

Recurrent Massive Upper Gastrointestinal Hemorrhage Due to Strongyloides stercoralis Infection

A 29-yr-old black male immigrant from Africa presented with recurrent life-threatening upper gastrointestinal bleeding due to massive duodenal infection by Strongyloides stercoralis. The diagnosis was missed by repeated examinations of fresh stool specimens for ova and parasites and by an initial esophagogastroduodenoscopy. The diagnosis was made by pathologic examination of a duodenal biopsy and of a duodenal aspirate obtained at a second esophagogastroduodenoscopy. This has been previously reported as a cause of massive upper gastrointestinal hemorrhage in four cases. Patients with obscure gastrointestinal bleeding who have travelled or lived in an endemic area should have a duodenal aspiration performed at esophagogastroduodenoscopy.     

Strongyloidiasis:A case with acute pancreatitis and a literature review

Strongyloides stercoralis,a soil transmitted helminth infection,affects millions with varying prevalence worldwide.A large number of affected hosts are asymptomatic.Symptoms pertaining to pulmonary and gastrointestinal involvement may be present.Manifestations of involvement beyond lung and intestine can be seen with dissemination of infection and lethal hyperinfection.Immunosuppression secondary to use of steroids or other immunosuppressants and coexistence of human T-lymphotropic virus type-1 are the known risk factors for dissemination and hyperinfection.Diagnostic modalities comprise stool examination,serology and molecular testing.Stool tests are inexpensive but are limited by low sensitivity,whereas serologic and molecular tests are more precise but at the expense of higher cost.Treatment with Ivermectin or Albendazole as an alternative is safe and efficacious.We present a rare case of acute pancreatitis secondary to Strongyloides.High index of suspicion in patients specifically from endemic countries of origin and lack of other common etiologies of acute pancreatitis may help in early diagnosis and prompt treatment of this potentially fatal infection.     

Strongyloides stercoralis hyperinfection in hematopoietic stem cell transplantation

Abstract: Strongyloides stercoralis is endemic in tropical, subtropical, and even temperate regions, and infects up to 100 million people worldwide. The diagnosis of strongyloidiasis can be difficult because of intermittent larval output in stool and nonspecific symptoms with mild peripheral eosinophilia. In this case report, a patient with acute myelogenous leukemia underwent peripheral blood hematopoietic stem cell transplantation (HSCT) and was subsequently diagnosed with strongyloidiasis. Strongyloidiasis should be considered in immunocompromised patients from endemic areas who have unexplained peripheral eosinophilia. If screening tests are positive for S. stercoralis or if a patient has unexplained eosinophilia with even a remote history of travel to or residence in endemic areas, then ivermectin should be given before HSCT to prevent often fatal hyperinfection syndrome from occurring after HSCT.