Prospective study of strongyloidosis in patients with hematologic malignancies

Methotrexate exposure and risk of strongyloidiasis

OBJECTIVE

Rheumatologic disease patients receiving immunomodulating drugs such as methotrexate (MTX) have increased infection rates. Strongyloides, a global endemic intestinal parasite, can cause significant or fatal disease in immunocompromised patients. The risk of serious Strongyloides infection with MTX dosed for rheumatologic disease is unknown.

METHODS

We performed a systematic literature review searching EMBASE, Medline and Web of Science databases. All studies reporting humans exposed to MTX and tested for Strongyloides were reviewed. Exclusion criteria were bone marrow transplantation, intrathecal route and MTX exposure completed >1 year prior to clinically apparent Strongyloides disease.

RESULTS

After excluding duplicates, 294 articles were reviewed. Of these, 29 cases were described in 27 papers. Twenty cases (69%) had an underlying rheumatologic or dermatologic disease, the rest had a haematologic disease. Hyperinfection or dissemination was found in 59% of cases (52% low-dose MTX; 75% high-dose MTX). Death occurred in 34% of cases (19% low-dose MTX; 75% high-dose MTX, P < 0.01). All eight patients on high-dose MTX received other immunosuppressants. Corticosteroids were taken in 18/21 patients on low-dose MTX. One of the three patients on MTX monotherapy had hyperinfection syndrome. None had disseminated Strongyloides.

CONCLUSIONS

Serious Strongyloides infection can occur with low-dose MTX particularly when given with other immunosuppression. Global travel and greater awareness of rheumatologic conditions in low- to middle-income countries will increase the exposure of individuals prescribed MTX (with or without corticosteroids) to Strongyloides. Strongyloides screening and treatment should be considered for individuals receiving low-dose MTX therapy, particularly if combined with additional immunosuppression.

Imported Disease Screening Prior to Chemotherapy and Bone Marrow Transplantation for Oncohematological Malignancies

Reactivation of latent imported infections has been periodically reported in migrant patients undergoing immunosuppression. We performed a prospective study at Vall d'Hebron University Hospital (Barcelona, Spain). Migrant patients over 16 years with the diagnosis of any oncohematologic disease were included. Patients were tested for soil-transmitted helminths, hepatitis virus, and human immunodeficiency virus, Treponema pallidum, human T-cell lymphotropic virus, latent tuberculosis infection, Toxoplasma spp., Plasmodium infection, Schistosoma spp., Trypanosoma cruzi infection, Leishmania spp., and dimorphic fungi. Patients were treated and followed for 1 year to assess reactivation. A total of 42 patients were included in this study. Median age was 39 (31-51) years. Twenty-five (59.5%) patients were women. More than half of the patients were of Latin American origin. Sixteen patients (38.1%) underwent hematopoietic stem cell transplantation. Of the patients, 71.4% had at least one imported infection. Patients with at least one positive result in the screening did not show any statistically significant association with the studied variables. We did not find any reactivation of the treated latent infections. After specific treatment we did not observe any reactivation. Screening of latent imported infections previous to an immunosuppressive treatment is easy to perform and it may be lifesaving.

Prevalence of strongyloidiasis in Latin America: a systematic review of the literature

Strongyloides stercoralis is rarely recognized as a major public health issue, probably because its burden is largely underestimated. We reviewed the literature (both PubMed and 'grey' literature) about the prevalence of strongyloidiasis in Latin America, an area of presumable high endemicity. There were finally 88 papers involved in the analysis, covering the period between 1981 and 2011. Studies were heterogeneous in several aspects, such as the populations screened and the diagnostic methods used. Most of the studies relied on direct coproparasitological examination, which has low sensitivity for the detection of S. stercoralis larvae. The following countries presented areas of high prevalence (>20%): Argentina, Ecuador, Venezuela, Peru and Brazil. Globally, for most of the included countries it was not possible to define reliable data because of paucity and/or inadequacy of studies. S. stercoralis requires specific diagnostic methods for its detection; therefore, surveys should be specifically designed in order to avoid underestimation of the infection.

Epidemiological aspects of strongyloidiasis in Brazil

The objective of this review was to outline an epidemiological profile of Strongyloides stercoralis by parasitological and serological diagnosis in inhabitants, and to associate this profile with different immunosupression situations, in Brazil, over 20 years (1990-2009). The occurrence of S. stercoralis using parasitological methods was 5·5%, being 4·8% in rural and 5·0% in urban areas, characterizing the country as hyperendemic. There was a diversity of techniques used as a diagnostic tool and only 39·1% of the studies presented results based on at least 1 specific method. The occurrence increased with age, being 12·1%, for those over 60 that suggests an epidemiological condition of concern for the elderly population. Of the seroepidemiological studies in the general population the mean positivity in serum samples was 21·7% and 29·2%, using an immunofluorescence antibody test and enzyme-linked immunosorbent assay (ELISA), respectively. The occurrence of strongyloidiasis in immunosuppressed individuals was 11·8% by parasitological methods and 19·5% using immunological methods. Considering that Brazil is a tropical country and that the character of chronicity and autoinfection of the parasite that can result in severe forms of hyperinfection or dissemination makes strongyloidiasis an important medically and socially neglected problem.

Parasitological and immunological diagnosis of Strongyloides stercoralis in patients with gastrointestinal cancer

This study examined the frequency of Strongyloides stercoralis infection in patients with gastrointestinal cancer through parasitological and immunological tests. A total of 77 patients were evaluated, 33 with gastrointestinal cancer and 44 controls with other types of cancers. All the patients were undergoing chemotherapy and 14 (18.2%) were receiving concomitant radiotherapy. For a parasitological diagnosis, we applied the Baermann and Lutz methods. The immunological diagnosis involved the indirect fluorescence antibody test (IFAT) and enzyme linked immunosorbent assay (ELISA) to detect IgG antibodies using Strongyloides ratti antigens. The frequency of positive S. stercoralis in gastrointestinal cancer diagnosed by parasitological methods was 3 cases (9.1%), by serology it was 8 cases (24.2%). In the control group 1 case (2.3%) of S. stercoralis was diagnosed by parasitological methods and 2 cases (4.5%) by immunological tests (p<0.05). Patients with gastrointestinal cancer had a 6.7-fold greater chance of testing positive for S. stercoralis infection. Our data highlight the importance of parasitological and immunological diagnosis for S. stercoralis in patients with gastrointestinal cancer living in endemic areas of strongyloidiasis, since they have a higher risk of becoming infected with S. stercoralis than patients with other types of cancer.

Strongyloidiasis in patients at a comprehensive cancer center in the United States

BACKGROUND

The frequency of Strongyloides stercoralis infestation and complication in patients with cancer in the United States is unknown.

METHODS

The authors performed a retrospective analysis of S. stercoralis infection in patients who were undergoing cancer treatment at The University of Texas M. D. Anderson Cancer Center (Houston, TX).

RESULTS

The overall S. stercoralis infection frequency was approximately 1.0 per 10,000 new cancer cases between 1971 and 2003. Twenty-two of 25 patients (88%) were U.S. residents (19 from Texas; 1 each from Mississippi, Tennessee, and Puerto Rico), and the remaining 3 (13%) were from Latin America. Thirteen (52%) had solid-organ malignancies, whereas 12 (48%) had hematologic malignancies (lymphoma or multiple myeloma, n=8; leukemia, n=3; aplastic anemia, n=1). Twelve patients (48%) received systemic corticosteroids, 9 (36%) received antineoplastic therapy, and 2 underwent hematopoietic stem cell transplantation (HSCT). Diarrhea was reported in 13 patients (57%), and eosinophilia was observed in 11 patients (48%); 4 patients (16%) had probable hyperinfection syndrome (in 3 cases of polymicrobial gram-negative bacteremia, 1 patient had Klebsiella pneumoniae pneumonia, whereas 1 patient presented with K. pneumoniae lung infection alone). Evidence of definite pulmonary hyperinfection syndrome was observed in 2 HSCT recipients (8%). Fourteen (74%) of 19 patients responded to thiabendazole therapy. Two patients with definite pulmonary hyperinfection syndrome developed fatal S. stercoralis hemorrhagic alveolitis despite receiving high-dose thiabendazole plus ivermectin therapy.

CONCLUSIONS

In the current study, strongyloidiasis was uncommon in patients with cancer and remained localized in individuals with solid-organ malignancies. Definite pulmonary accelerated autoinfections were observed only in HSCT recipients. Therefore, pre-HSCT S. stercoralis screening in individuals from endemic regions of the United States warrants further study.

Strongyloidiasis associated with amebiasis and giardiaisis in an immunocompetent boy presented with acute abdomen

Strongyloides stercoralis (SS) is an intestinal nematode that is mainly endemic in tropical and subtropical regions and sporadic in temperate zones. SS infection frequently occurs in people who have hematologic malignancies, HIV infection and in individuals undergoing immunosuppressive therapy. In this study, we report a 12- year-old immunocompetent boy who was admitted to our hospital with acute abdomen. Laboratory evaluation showed strongyloidiasis, amebiasis and giardiasis. Clinical and laboratory findings immediately improved with albendazole therapy. Therefore, when diarrhea with signs of acute abdomen is observed, stool examinations should be done for enteroparasitosis. This approach will prevent misdiagnosis as acute abdomen. Complete clinical improvement is possible by medical therapy without surgical intervention.

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 Uberlândia, 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.