Risk factors for acquiring Strongyloides stercoralis infection among patients attending a tertiary hospital in south India

Coinfection with Strongyloides and SARS-CoV-2: A Systematic Review

BACKGROUND

Treatments for COVID-19, including steroids, might exacerbate Strongyloides disease in patients with coinfection. We aimed to systematically review clinical and laboratory features of SARS-CoV-2 and Strongyloides coinfection, investigate possible interventions, assess outcomes, and identify research gaps requiring further attention.

METHODS

We searched two electronic databases, LitCOVID and WHO, up to August 2022, including SARS-CoV-2 and Strongyloides coinfection studies. We adapted the World Health Organization-Uppsala Monitoring Centre (WHO-UMC) system for standardized case causality assessment to evaluate if using corticosteroids or other immunosuppressive drugs in COVID-19 patients determined acute manifestations of strongyloidiasis.

RESULTS

We included 16 studies reporting 25 cases of Strongyloides and SARS-CoV-2 coinfection: 4 with hyperinfection syndrome; 2 with disseminated strongyloidiasis; 3 with cutaneous reactivation of strongyloidiasis; 3 with isolated digestive symptoms; and 2 with solely eosinophilia, without clinical manifestations. Eleven patients were asymptomatic regarding strongyloidiasis. Eosinopenia or normal eosinophil count was reported in 58.3% of patients with Strongyloides reactivation. Steroids were given to 18/21 (85.7%) cases. A total of 4 patients (19.1%) received tocilizumab and/or Anakirna in addition to steroids. Moreover, 2 patients (9.5%) did not receive any COVID-19 treatment. The causal relationship between Strongyloides reactivation and COVID-19 treatments was considered certain (4% of cases), probable (20% of patients), and possible (20% of patients). For 8% of cases, it was considered unlikely that COVID-19 treatment was associated with strongyloidiasis reactivations; the relationship between the Strongyloides infection and administration of COVID-19 treatment was unassessable/unclassifiable in 48% of cases. Of 13 assessable cases, 11 (84.6%) were considered to be causally associated with Strongyloides, ranging from certain to possible.

CONCLUSIONS

Further research is needed to assess the frequency and risk of Strongyloides reactivation in SARS-CoV-2 infection. Our limited data using causality assessment supports recommendations that clinicians should screen and treat for Strongyloides infection in patients with coinfection who receive immunosuppressive COVID-19 therapies. In addition, the male gender and older age (over 50 years) may be predisposing factors for Strongyloides reactivation. Standardized guidelines should be developed for reporting future research.

The Association between Diabetes and Human T-Cell Leukaemia Virus Type-1 (HTLV-1) with Strongyloides stercoralis: Results of a Community-Based, Cross-Sectional Survey in Central Australia

In central Australia, an area that is endemic for the human T-cell leukaemia virus type-1 (HTLV-1), the prevalence of Strongyloides stercoralis and its association with other health conditions are unknown. A cross-sectional community-based survey was conducted in seven remote Aboriginal communities in central Australia, from 2014 to 2018. All residents aged ≥10 years were invited to complete a health survey and to provide blood for Strongyloides serology, HTLV-1 serology and HTLV-1 proviral load (PVL). Risk factors for Strongyloides seropositivity and associations with specific health conditions including diabetes and HTLV-1 were determined using logistic regression. Overall Strongyloides seroprevalence was 27% (156/576) (children, 22% (9/40); adults (≥15 years), 27% (147/536), varied widely between communities (5–42%) and was not associated with an increased risk of gastrointestinal, respiratory or dermatological symptoms. Increasing age, lower HTLV-1 PVL (<1000 copies per 105 peripheral blood leucocytes) compared to the HTLV-1 uninfected group and community of residence were significant risk factors for Strongyloides seropositivity in an adjusted model. A modest reduction in the odds of diabetes among Strongyloides seropositive participants was found (aOR 0.58, 95% CI 0.35, 1.00; p = 0.049); however, this was lost when body mass index was included in the adjusted model (aOR 0.48, 95% CI 0.48, 1.47; p = 0.542). Strongyloides seropositivity had no relationship with anaemia. Exploring social and environmental practices in communities with low Strongyloides seroprevalence may provide useful lessons for similar settings.

A fatal combination of disseminated strongyloidiasis with two bacterial infections in an immunocompromised host

Introduction

Strongyloides stercoralis is an intestinal nematode that is endemic in tropical countries. It can have a variable presentation ranging from asymptomatic eosinophilia in immunocompetent hosts to disseminated disease with sepsis in immunocompromised hosts.

Case report

We report a case of chronic diarrhoea and decreased appetite in a 53-year-old man. He was a chronic alcoholic with diabetes, hypertension and dyslipidaemia and had earlier been treated for pulmonary tuberculosis. He was treated symptomatically for loose stools at a primary health care facility without relief. Following referral to our tertiary care centre, microscopic examination of the stool showed numerous larvae and a few eggs of Strongyloides stercoralis. Additionally, Aeromonas sobria was isolated from stool culture. The patient was discharged following improvement with a combination therapy of ivermectin, albendazole and ciprofloxacin. However, within 3 days, he was readmitted and succumbed to Escherichia coli sepsis.

Conclusion

Strongyloidiasis can be diagnosed easily using a very simple but often neglected investigation, namely stool microscopy. This provides an early diagnosis, based on which prompt treatment with the appropriate antihelminthics can be started, thereby reducing the probability of disseminated infection. Disseminated strongyloidiasis is a medical emergency with a poor prognosis, especially in an immunocompromised state. Such patients should be treated aggressively with antihelminthics. They must be monitored for sufficient duration in the hospital for early signs of complication. Their discharge from hospital should be planned based on a negative stool microscopy report in addition to clinical improvement, so as to decrease the mortality reported for both untreated and treated individuals.

Infectious Complications of Biological and Small Molecule Targeted Immunomodulatory Therapies

The past 2 decades have seen a revolution in our approach to therapeutic immunosuppression. We have moved from relying on broadly active traditional medications, such as prednisolone or methotrexate, toward more specific agents that often target a single receptor, cytokine, or cell type, using monoclonal antibodies, fusion proteins, or targeted small molecules. This change has transformed the treatment of many conditions, including rheumatoid arthritis, cancers, asthma, and inflammatory bowel disease, but along with the benefits have come risks. Contrary to the hope that these more specific agents would have minimal and predictable infectious sequelae, infectious complications have emerged as a major stumbling block for many of these agents. Furthermore, the growing number and complexity of available biologic agents makes it difficult for clinicians to maintain current knowledge, and most review articles focus on a particular target disease or class of agent. In this article, we review the current state of knowledge about infectious complications of biologic and small molecule immunomodulatory agents, aiming to create a single resource relevant to a broad range of clinicians and researchers. For each of 19 classes of agent, we discuss the mechanism of action, the risk and types of infectious complications, and recommendations for prevention of infection.

Imported strongyloidiasis: Data from 1245 cases registered in the +REDIVI Spanish Collaborative Network (2009-2017)

BACKGROUND

Imported strongyloidiasis is increasingly being diagnosed in non-endemic areas. The aim of this study was to describe the epidemiological, clinical and microbiological characteristics of patients with imported strongyloidiasis in Spain.

METHODOLOGY

This is an observational retrospective study that included all patients diagnosed of strongyloidiasis registered in the +REDIVI Collaborative Network from 2009 to 2017. Demographic, epidemiological and clinical information was collected from the +REDIVI database, and extra information regarding microbiological techniques, treatment and follow-up was requested to participant centers.

FINDINGS

Overall, 1245 cases were included. Most of them were immigrants (66.9%), and South America was the most frequent area of origin. Detection of larvae in stool samples was observed in 21.9% of the patients, and serological tests allowed making the diagnosis in the rest of the cases. Eosinophilia was present in 82.2% of cases. Treatment with ivermectin (compared with albendazole) was the most strongly associated factor to achieve the cure (OR 2.34).

CONCLUSIONS

Given the long latency of the infection and the risk of developing a severe presentation, screening of S. stercoralis infection should be mandatory in patients coming from or had traveling to endemic areas, especially in those with immunosuppressant conditions.

Strongyloidosis Hyperinfection Syndrome in an HIV-Infected Patient: A Rare Manifestation of Immune Reconstitution Inflammatory Syndrome

Parasitic infections such as Strongyloides stercoralis and HIV have been reported to coexist, particularly in resource-limited settings such as India. In an immunocompromised host, S. stercoralis can progress to strongyloidiasis hyperinfection syndrome (SHS). However, SHS is not common in patients with advanced HIV disease. Immune reconstitution inflammatory syndrome (IRIS) developing after initiation of antiretroviral therapy (ART) can target multiple pathogens including S. stercoralis. The authors present here a 46-year-old HIV-infected female who was recently diagnosed with HIV-1 infection, started ART, and developed SHS. Her upper GI endoscopy revealed severe gastroduodenitis, and X-ray chest showed extensive bilateral pneumonitis. We could identify S. stercoralis in induced sputum and duodenal biopsy. We could also identify gut inflammation to restrict invading parasites. After receiving antihelminthic therapy, she showed improvement, a course of events that fit the diagnosis of unmasking S. stercoralis IRIS.

Eosinophilia in Advanced HIV Infection with Hyperinfection Syndrome: A Case Report

Strongyloides stercoralis is a soil-transmitted helminth that occurs almost worldwide, yet estimates about its prevalence are not well documented. The spectrum of clinical manifestations of strongyloidiasis is wide, ranging from asymptomatic disease to hyperinfection or dissemination of larvae involving multiple organ systems. Immunosuppression can increase the risk of hyperinfection syndrome in patients with strongyloidiasis. Strongyloidiasis continues to remain a neglected tropical disease, the diagnosis of which is often overlooked by clinicians and diagnosticians alike. The paucity of published literature from India further accentuates this problem. We hereby present a case report with the aim of elucidating this relatively underreported infection.

Tropical Parasitic Infections in Individuals Infected with HIV

PURPOSE OF REVIEW

Neglected tropical diseases share both geographic and socio-behavioral epidemiological risk factors with HIV infection. In this literature review, we describe interactions between parasitic diseases and HIV infection, with a focus on the impact of parasitic infections on HIV infection risk and disease progression, and the impact of HIV infection on clinical characteristics of tropical parasitic infections. We limit our review to tropical parasitic infections of the greatest public health burden, and exclude discussion of classic HIV-associated opportunistic infections that have been well reviewed elsewhere.

RECENT FINDINGS

Tropical parasitic infections, HIV-infection, and treatment with antiretroviral therapy alter host immunity, which can impact susceptibility, transmissibility, diagnosis, and severity of both HIV and parasitic infections. These relationships have a broad range of consequences, from putatively increasing susceptibility to HIV acquisition, as in the case of schistosomiasis, to decreasing risk of protozoal infections through pharmacokinetic interactions between antiretroviral therapy and antiparasitic agents, as in the case of malaria. However, despite this intimate interplay in pathophysiology and a broad overlap in epidemiology, there is a general paucity of data on the interactions between HIV and tropical parasitic infections, particularly in the era of widespread antiretroviral therapy availability.

SUMMARY

Additional data are needed to motivate clinical recommendations for detection and management of parasitic infections in HIV-infected individuals, and to consider the implications of and potential opportunity granted by HIV treatment programs on parasitic disease control.

Does Strongyloides stercoralis infection protect against type 2 diabetes in humans? Evidence from Australian Aboriginal adults

OBJECTIVE

To explore the relationship between infection with Strongyloides stercoralis and the likelihood of having type 2 diabetes mellitus (T2DM).

METHODS

Cross-sectional survey of 259 Aboriginal adults living in a remote community in northern Australia during 2013. Prior infection with S. stercoralis was determined by ELISA testing on serum. Main outcomes were eosinophil count, T2DM diagnosis, HbA1c, BMI, fasting lipids, Hb, blood pressure.

FINDINGS

Ninety two participants (36%) had prior infection with S. stercoralis and 131 (51%) had T2DM. Those with previous S. stercoralis infection (ELISA titre ≥0.3) were 61% less likely to have a diagnosis of T2DM than those uninfected, adjusted for age, triglycerides, blood pressure and BMI using propensity score (adjusted OR=0.39, 0.23-0.67, P=0.001).

INTERPRETATION

In this remote community where prevalence of both S. stercoralis and T2DM is very high, infection with S. stercoralis appears to be associated with a significantly reduced risk of T2DM in adults. A plausible immunological mechanism has been identified in animal models. If confirmed, this result may have practical implications for the prevention of T2DM and associated metabolic disorders in humans. This finding should be explored further with larger longitudinal studies in transitional populations where the risk of both conditions is high.

FUNDING

No external funding was required for this study.

Prevalence and risk factors of acquiring Strongyloides stercoralis infection among patients attending a tertiary hospital in Thailand

OBJECTIVES

We aimed to determine the prevalence and risk factors for Strongyloides stercoralis infection in adult patients attending Siriraj Hospital, a tertiary hospital in Thailand.

METHODS

A case-control study was carried out between July 2008 and April 2010. Case and control were identified from 6022 patients for whom results of faecal examination were available. A case was a patient who had S. stercoralis larva detected from faecal examination. Control was randomly selected from patients without S. stercoralis larvae detected in three consecutive faecal examinations. The proportion of control to case was 2 : 1. Demographic and clinical data for the day of diagnosis and retrospectively up to 15 days preceding the date of faecal examination were reviewed from their medical records.

RESULTS

Overall, 149 (2.47%) patients had S. stercoralis larvae positive. There were 105 males (70.5%), with the mean (SD) age of 53.9 (17.2) years. A total of 300 controls were selected. Male gender (odds ratio (OR)  =  2.79, 95% confidence interval (CI) 1.78-4.27)), human immunodeficiency virus (HIV) infection (OR  =  3.23, 95% CI 1.43-7.29), and eosinophilia (OR  =  1.81, 95% CI 1.33-2.47) were found to be independent risk factors associated with S. stercoralis infection in this setting. Corticosteroid or other immunosuppressive treatment, and other concomitant illnesses were not associated with increased risk of S. stercoralis infection.

CONCLUSION

In this setting, strongyloidiasis was seen more often in male patients with eosinophilia and with HIV infection. Prevention of fatal complication caused by S. stercoralis by regular faecal examination, or serology for early detection and treatment of undiagnosed S. stercoralis infection, is warranted in these high-risk patients.

Co-infection with Nocardia asteroides complex and Strongyloides stercoralis in a patient with autoimmune hemolytic anemia

We describe an unusual case of pulmonary nocardiosis co-existing with Strongyloides stercoralis hyperinfection syndrome in a patient with autoimmune hemolytic anemia who was being treated with corticosteroids. This case highlights the importance of being aware of the possibility that infections can co-exist in immunosuppressed patients. To the best of our knowledge, this is the first report of co-infection with Nocardia asteroides and S. stercoralis.