Severe and treatment resistant strongyloidiasis--indicator of HTLV-I infection.

The association between severe and persistent strongyloidiasis with human T cell lymphotropic virus type I (HTLV-1) infection is well documented in reports from HTLV-1 endemic regions like Japan and Jamaica. But there are no reports from non-endemic areas like India. We report a case of severe intestinal strongyloidiasis in a 45-year old Keralite man, living in Sikkim. Despite standard treatment with many courses of albendazole, his stool persistently showed Strongyloides stercoralis larvae. In the absence of other immunosuppressive conditions, human T cell lymphotropic virus type I infection was considered and determined positive. Subsequently, treatment with 2 courses of ivermectin achieved eradication of the infection. On follow-up, 3 years later, his stools again revealed Strongyloides stercoralis larvae.     

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.     

Impairment of host immune response against strongyloides stercoralis by human T cell lymphotropic virus type 1 infection

A large-scale study was undertaken to clarify the prevalence rate of strongyloidiasis in Okinawa, Japan and to evaluate the relationship between strongyloidiasis and infection with human T cell lymphotropic virus type 1 (HTLV-1). The prevalence rate of Strongyloides stercoralis and HTLV-1 infection were 6.3% and 14.0%, respectively. Among 2,185 patients more than 50 years of age, the rate of S. stercoralis infection was significantly higher in patients with HTLV-1 infection compared with patients without HTLV-1 infection. In 252 patients treated with ivermectin, serum IgE levels and peripheral eosinophil counts were significantly lower in HTLV-1 co-infected patients compared with patients without HTLV-1 infection. In addition, the anthelmintic effect was significantly lower in patients with HTLV-1 infection compared with patients without HTLV-1 infection. Our prospective study demonstrated a prevalence rate for strongyloidiasis and HTLV-1 infections, and clearly demonstrated that co-infection with HTLV-1 impaired the immune response against S. stercoralis.     

Endoscopic and histopathological study on the duodenum of Strongyloides stercoralis hyperinfection

AIM： To investigate endoscopic and histopathological findings in the duodenum of patients with Strongyloides stercoralis （S. stercoralis） hyperinfection. METHODS： Over a period of 23 years （1984-2006）, we investigated 25 patients with S. stercoralis hyperinfection who had had an esophagogastroduodenoscopy before undergoing treatment for strongyloidiasis. The clinical and endoscopic findings were analyzed retrospectively. RESULTS： Twenty-four （96%） of the patients investigated were under immunocompromised condition which was mainly due to a human T lymphotropic virus type 1 （HTLV-1） infection. The abnormal endoscopic findings, mainly edematous mucosa, white villi and erythematous mucosa, were observed in 23 （92%） patients. The degree of duodenitis including villous atrophy/destruction and inflammatory cell infiltration corresponded to the severity of the endoscopic findings. The histopathologic yield for identifying larvae was 71.4% by duodenal biopsy. The endoscopic findings of duodenitis were more severe in patients whose biopsies were positive for larvae than those whose biopsies were negative （Endoscopic severity score： 4.86 ± 2.47 vs 2.71 ±1.38, P 〈 0.05）. CONCLUSION： Our study clearly demonstrates that, in addition to stool analysis, endoscopic observation and biopsies are very important. We also emphasize that S. stercoralis and HTLV-1 infections should be ruled out before immunosuppressive therapy is administered in endemic regions.     

Pulmonary strongyloidiasis in a patient receiving prednisolone therapy

Strongyloidiasis is widely distributed in tropical and subtropical areas. Disseminated strongyloidiasis may develop in patients with immunodeficiencies. In the absence of early diagnosis and treatment, the prognosis of disseminated strongyloidiasis is extremely poor. We report a case of pulmonary strongyloidiasis that was successfully treated. The patient was an 83-year-old woman who had been receiving long-term oral prednisolone therapy for uveitis. The patient visited our emergency department complaining of breathing difficulties and diarrhea. A chest X-ray revealed a diffuse enhancement of interstitial shadows. A bronchoalveolar lavage (BAL) was performed, and both Gram staining and Grocott's staining revealed the presence of multiple filariform larvae of Strongyloides stercoralis in the bronchoalveolar lavage fluid (BALF). A stool examination performed at the same time also yielded S. stercoralis. The patient was diagnosed as having pulmonary strongyloidiasis and was treated with thiabendazole and ivermectin, in addition to antimicrobial agents; her respiratory symptoms and diarrhea improved, and S. stercoralis was not detected in subsequent follow-up examinations thereafter. In endemic areas of S. stercoralis, pulmonary strongyloidiasis should be considered as part of a differential diagnosis if chest imaging findings like alveolar and interstitial shadow patterns or lobar pneumonia are seen in patients with immunodeficiencies.     

Chronic diarrhoea due to strongyloidiasis in a Nigerian with chronic renal failure: a case report.

A case of chronic diarrhoea due to infection with Strongyloides stercoralis in a Nigerian patient with chronic renal failure is presented. Due to the potential for fatal outcome in this infection, strongyloidiasis should be kept in mind as a cause of chronic diarrhoea in chronic renal failure patients in endemic areas.     

Human T-cell lymphotropic virus-I in Latin America

HTLV-1 infection is endemic in several Latin American countries. HTLV-1-associated myelophathy/tropical spastic paraparesis (HAM/TSP) and adult T-cell leukemia lymphoma (ATLL) are emerging diseases in the region. Documented risk factors for acquiring the virus include breast-feeding, contaminated blood transfusion, and sexual intercourse, all of which are amenable to prevention efforts. Strongyloides stercoralis hyperinfection syndrome and therapeutic failure in apparently healthy patients with nondisseminated strongyloidiasis may be markers of HTLV-1 infection. HTLV-1 co-infection may adversely effect the clinical course of scabies and HIV disease. The new enzyme-linked immunosorbent assays (ELISA) are sensitive and specific, and Western blot technology is reliable for differentiating HTLV-1 from less common HTLV-2. HTLV-1 screening of blood donors and individuals with any disorder that suggests infection has become a necessity in Latin America to prevent the spread of this important emerging pathogen.     

Biliary obstruction resulting from Strongyloides stercoralis infection. Report of a case.

Hepatobiliary manifestations of strongyloidiasis are rare. A case is described of biliary obstruction associated with the presence of Strongyloides stercoralis in the duodenal mucosa and 250 microns rhabditiform larvae in bile. Biliary obstruction resulted from papillary stenosis, which resolved after treatment with thiabendazole. It is proposed that papillary stenosis may be responsible for obstructive jaundice associated with Strongyloides stercoralis infection, and that strongyloidiasis should be added to the causes of papillary stenosis.     

A rare cause of asthma exacerbation: systemic anguilluliasis

Strongyloides is an helminthic infection that may induce bronchospasm during systemic migration of larvae. We report a case of a 60 years old man originating from Caribbean who had corti-codependent asthma since 30 years. He was hospitalized for severe exacerbation that worsen when steroid dosage was increase. Sputum examination revealed the presence in great number of Larvae of Strongyloides stercoralis. A good clinical evolution was achieved after specific anti-helminthic treatment. Later on, it was even possible to stop completely steroid treatment. This clinical case demonstrates the interest to look for Strongyloides superinfection in asthmatic patients that worsen when receiving increasing dose of steroids. This is particularly important for patients who have resided, even many years earlier, in areas where intestinal helminthic infection are endemic.     

Severe strongyloidiasis during interferon plus ribavirin therapy for chronic HCV infection

Ribavirin is a nucleoside analogue, recently introduced in hepatitis C virus (HCV) therapy, that has postulated immunomodulatory and immunosuppressive action. Strongyloidiasis is an helmintic infection caused by Strongyloides stercoralis, endemic in tropical countries. Severe strongyloidiasis has been demonstrated after immunosuppression by corticosteroids evolving some fatal cases. Here, we describe two cases of severe strongyloidiasis coincident with ribavirin plus interferon therapy for treating HCV infection. The review of our monotherapy protocol with interferon did not disclose any case of symptomatic strongyloidiasis pointing to a possible role of ribavirin in modifying immune response to S. stercoralis. We propose a careful screening for S. stercoralis before initiating ribavirin therapy or even empiric antihelmintic treatment.     

HTLV-1 decreases Th2 type of immune response in patients with strongyloidiasis

Eosinophils, immunoglobulin (Ig)E and cytokines have important roles in defence mechanisms against helminths. In this study, the influence of HTLV-1 infection, characterized by a Th1 type of immune response, was evaluated on the cytokine pattern and parasitic specific IgE response in patients with strongyloidiasis. Patients were divided into four groups: strongyloidiasis without HTLV-1 infection, strongyloidiasis with HTLV-1, HTLV-1 without strongyloidiasis and controls without either helminth infection or HTLV-1. The cytokine profile was determined in supernatants of mononuclear cells stimulated with Strongyloides stercoralis crude antigen and the parasite specific IgE was measured by ELISA. Patients coinfected with HTLV-1 had higher levels of interferon (IFN)-gamma and interleukin (IL)-10 (P < 0.05) and lower levels of IL-5 and IgE (P < 0.05) than patients with strongyloidiasis without HTLV-1. There was an inverse relationship between IFN-gamma and IL-5 (P = 0.01; rs = - 0.37) and between IFN-gamma and parasite specific IgE (P = 0.01; rs = - 0.39), and a direct relationship between IFN-gamma and IL-10 (P = 0.04; rs = 0.35). These data show that coinfection with HTLV-1 decreases IL-5 and IgE responses in patients with strongyloidiasis consistent with a relative switch from Th2 to Th1 response. Immunological responses such as these are important in the control of this helminthic 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.     

Pulmonary strongyloidiasis presenting as chronic bronchitis leading to interlobular septal fibrosis and cured by treatment

Two patients presented with long-standing chronic bronchitis and exertional dyspnoea of 5 and 3 months' duration, respectively, and had interlobular septal fibrosis on chest high resolution CT. In the past both had lived in areas in which Strongyloides stercoralis was known to be endemic. Serological tests confirmed the diagnosis of pulmonary strongyloidiasis, and both patients were treated with anti-helminthic medications, including albendazole and ivermectin. Following this there was complete resolution of both symptomatic and radiological manifestations of their disease. An awareness of the possibility of Strongyloides infection presenting with respiratory symptoms in patients exposed to this parasite is important in the management of such patients.     

Interrelation of strongyloidiasis and tuberculosis.

A 31 year old man from Gambia, resident in the United Kingdom for two years, presented with a two month history of unproductive cough, malaise, weight loss, non-specific abdominal pain, and episodic diarrhoea. Acid alcohol fast bacilli were identified in his sputum, together with Strongyloides stercoralis larvae and Giardia lamblia cysts in his stools. This case illustrates that latent strongyloidiasis can become overt in the presence of tuberculosis, and the diagnosis of strongyloidiasis must be borne in mind in patients who have previously resided in endemic regions.     

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.     

Strongyloides stercoralis hyperinfection in systemic lupus erythematosus and the antiphospholipid syndrome

OBJECTIVE: The Strongyloides stercoralis hyperinfection syndrome (SHS) may develop in individuals with asymptomatic infection receiving immunosuppressive treatment. This report summarizes current knowledge regarding SHS in patients with systemic lupus erythematosus (SLE) and associated antiphospholipid syndrome (APS). METHODS: Two patients with active SLE and associated APS presenting with SHS are reported. Additional cases of strongyloidiasis in SLE were identified and reviewed. RESULTS: Patient 1: A 34-year-old woman with SLE and APS characterized by active glomerulonephritis, stroke, and several hospital-acquired infections presented with vomiting and diffuse abdominal pain. Intestinal vasculitis was suspected, and treatment with methylprednisolone and cyclophosphamide was given. Response was partial. A gastric biopsy revealed S. stercoralis larvae. She received ivermectin and eventually recovered. Patient 2: A 37-year-old man with active glomerulonephritis and APS with recurrent thrombosis presented with digital necrosis. Necrotizing vasculitis was suspected and treated with immunosupressants. He suddenly developed respiratory failure secondary to alveolar hemorrhage and bronchoalveolar lavage was performed. The patient developed Gram-negative septic shock and died. The postmortem result of bronchoalveolar lavage yielded Strongyloides larvae. Nine cases of strongyloidiasis and the SHS in SLE patients reported in the literature were identified and reviewed. Five of these patients died; none had associated APS. CONCLUSIONS: These cases suggest that the SHS can exacerbate SLE and APS, predisposing to Gram-negative sepsis and death. Immunocompromised patients need an early diagnosis and specific treatment of parasitic diseases and their complications. The SHS should be considered in the differential diagnosis of lupus complications in patients from endemic areas.     

粪类圆线虫及粪类圆线虫病研究概况

粪类圆线虫是一种机会性致病寄生线虫,幼虫可侵入肺、脑、肝、肾等组织器官引起粪类圆线虫病。随着居民生活水平的提高、生活方式的改变、饲养宠物的家庭日益增多,导致粪类圆线虫病的感染机会增加。迄今为止国内有关粪类圆线虫病的研究多局限在病例报告和流行病学调查,而其生物学特性、免疫现象及免疫保护等方面的研究涉及甚少。本文对粪类圆线虫的形态学、生活史、致病性、流行病学、免疫学、实验诊断及防治进行了综述。     

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.     

Strongyloides stercoralis hyperinfection in a patient with the acquired immune deficiency syndrome

Severe infections with Strongyloides stercoralis occur in immunocompromised patients. Strongyloides hyperinfection syndrome complicated by gram-negative bacteremia and meningitis in a bisexual man with the acquired immune deficiency syndrome (AIDS) is described. Increased awareness of this infection, which may also be sexually transmitted, is recommended when caring for patients with AIDS who are homosexual, or have resided in areas endemic for strongyloidiasis. Multiple stool examinations should be performed routinely for such patients. Examination of sputum for the parasite is recommended if pneumonia is present. Prompt diagnosis and therapy are essential for prevention of fatal dissemination.     

Chronic relapsing colitis due to Strongyloides stercoralis

The small intestine is the usual site of chronic infection with Strongyloides stercoralis. Colonic involvement has generally been seen in the hyperinfection syndrome in immunosuppressed individuals. We describe an immunologically competent female who underwent multiple abdominal operations over a 5-year period for hematochezia and diffuse abdominal pain of obscure etiology. Eosinophilia had been present but never investigated until 1981, at which time stool examination revealed S. stercoralis larvae. Pathological specimens from operations in 1977 and 1981 demonstrated extensive colonic wall invasion with filariform larvae consistent with S. stercoralis. Involvement of other organs was never documented. We believe this case is consistent with chronic colitis due to strongyloidiasis. This entity has not been previously described, and expands the spectrum of this disease.