Infection and Hyperinfection with Strongyloides stercoralis: Clinical Presentation, Etiology of Disease, and Treatment Options

Corticosteroids in Covid-19 pandemic have the potential to unearth hidden burden of strongyloidiasis

COVID-19 pandemic has posed formidable public health and clinical challenges to the entire humanity. A significant proportion of the COVID-19 patients have been provided immunosuppressive agents, particularly corticosteroids, as a part of management of moderate to severe COVID-19 disease. This has the drawback of development of strongyloides hyperinfection to disseminated infection in latent strongyloides infection patients. We are reporting the case of strongyloidiasis hyperinfection in a COVID-19 patient from a developing country, who initially received corticosteroid therapy for management of COVID-19, but later presented to hospital with non-specific, strongyloides related symptoms.

Strongyloides stercoralis larvae or egg: Which came first?

Strongyloides stercoralis (SS) hyperinfection is a well-documented condition. However, SS eggs in stool samples are not commonly observed during routine analysis. Here, we report a case on SS hyperinfection where both larvae and eggs were observed in the stool sample of an immunossupressed liver allograft transplanted patient.

Neoplastic patients' knowledge about intestinal parasitoses in southern Brazil

Since oncologic patients have been considered an important risk group for parasitic infections, it is fundamental to find out what they know about intestinal parasites. This study aimed at evaluating knowledge that the adult oncologic patients undergoing chemotherapy in the main centers of treatment for cancer in the city of Pelotas, Brazil, has about intestinal parasites. A semi-structured questionnaire was used for collecting data from two hundred oncologic patients who were undergoing chemotherapy. Results showed that 69.5% know what intestinal parasites are and cited Ascaris lumbricoides and Taenia sp. as being the most known ones. The statistical comparison between the group that knows intestinal parasites and the one that does not know about them - associated with socioeconomic variables -, showed that factors that significantly influenced their knowledge were their place of residence, schooling and household income (p≤0.05). Only 36% stated that they know when they are infected with parasites and misdescribed some signs and symptoms. Regarding prevention, 52% mentioned that they do not know how to avoid parasitism. The population under study showed that there are some gaps in its knowledge of the theme under investigation. Therefore, it is important to implement socioeducational measures in hospitals and clinics that treat cancer patients.

Strongyloides stercoralis infection after the use of emergency corticosteroids: a case report on hyperinfection syndrome

BACKGROUND

In clinical practice, identification of a case of severe asthma exacerbation prompts initiation of corticosteroids. However, not all that wheezes is asthma.

CASE PRESENTATION

A 61-year-old man from the Peruvian Amazon presented with progressive dyspnea, abdominal pain, and cough for the past week. His medical history was remarkable for asthma since childhood; he was treated with beta-agonists, ipratropium, and orally administered corticosteroids. On evaluation, he was febrile and ill-appearing. His chest examination revealed diffuse wheezing and bilateral crackles. He was diagnosed as having community-acquired pneumonia and asthma exacerbation and was started on empiric antibiotics, nebulized beta-agonists, and orally administered corticosteroids. His clinical status continued deteriorating and he became critically ill despite broad-spectrum antibiotics and antifungals. Considering the epidemiological background of our patient, bronchoalveolar and fecal samples were obtained to investigate soil-transmitted helminths. Larvae of Strongyloides stercoralis were found in both specimens. Ivermectin was initiated and corticosteroids were discontinued. He experienced remarkable improvement of clinical condition over the next weeks. The literature on this topic was reviewed.

CONCLUSION

Cases of severe asthma exacerbation warrant careful evaluation before the initiation of corticosteroids, especially in patients at risk for parasitic infections. A high index of suspicion is critical. Alternative etiologies of respiratory decompensation should be considered in patients who fail to improve with broad-spectrum antibiotics and antifungals.

Strongyloides stercoralis hyperinfection syndrome: a deeper understanding of a neglected disease

Strongyloides stercoralis hyperinfection syndrome (SHS) is a life-threatening condition that warrants early detection and management. We describe the pathogenesis, organ-specific clinical manifestations, and risk factors associated to this condition. A comprehensive review of the literature was conducted in PubMed, LILACS, EBSCO and SciELO by using the keywords: "hyperinfection syndrome"; "Strongyloides stercoralis"; "disseminated strongyloidiasis"; "systemic strongyloidiasis", "pathogenesis" and "pathophysiology". Relevant articles on this topic were evaluated and included by consensus. Also, a secondary search of the literature was performed. Articles in English and Spanish language were included. SHS has been described in tropical and sub-tropical regions. However, there is growing evidence of cases detected in developed countries favored by increasing migration and the advance in immunosuppressive therapies for oncologic and inflammatory diseases. SHS is characterized by massive multiplication of larvae, typically in immunocompromised hosts. Clinical manifestations vary according to the organ involved and include diarrhea, intestinal bleeding, alveolar hemorrhages, heart failure, jaundice, bacteremia among others. Despite advances in the understanding of this condition, fatality rates are near 90%. Clinicians should consider SHS in the differential diagnosis of acutely ill patients with multiple organ damage and epidemiological risk factors. Adverse outcomes are common, especially with delayed anti-parasitic treatment.

Methylprednisolone acetate induces, and Δ7-dafachronic acid suppresses, Strongyloides stercoralis hyperinfection in NSG mice

Strongyloides stercoralis hyperinfection causes high mortality rates in humans, and, while hyperinfection can be induced by immunosuppressive glucocorticoids, the pathogenesis remains unknown. Since immunocompetent mice are resistant to infection with S. stercoralis, we hypothesized that NSG mice, which have a reduced innate immune response and lack adaptive immunity, would be susceptible to the infection and develop hyperinfection. Interestingly, despite the presence of large numbers of adult and first-stage larvae in S. stercoralis-infected NSG mice, no hyperinfection was observed even when the mice were treated with a monoclonal antibody to eliminate residual granulocyte activity. NSG mice were then infected with third-stage larvae and treated for 6 wk with methylprednisolone acetate (MPA), a synthetic glucocorticoid. MPA treatment of infected mice resulted in 50% mortality and caused a significant >10-fold increase in the number of parasitic female worms compared with infected untreated mice. In addition, autoinfective third-stage larvae, which initiate hyperinfection, were found in high numbers in MPA-treated, but not untreated, mice. Remarkably, treatment with Δ7-dafachronic acid, an agonist of the parasite nuclear receptor Ss-DAF-12, significantly reduced the worm burden in MPA-treated mice undergoing hyperinfection with S. stercoralis Overall, this study provides a useful mouse model for S. stercoralis autoinfection and suggests a therapeutic strategy for treating lethal hyperinfection.

Intestinal parasites in cancer patients in the South of Brazil

Abstract Intestinal parasitic infections in immunocompromised patients can lead to serious complications when not diagnosed and treated early. This study aimed to investigate the frequency of intestinal parasites in cancer patients undergoing chemotherapy in the South of Brazil. Three fecal samples collected from each patient (73 individuals) were processed by Ritchie and Faust techniques and submitted to specific staining methods for intestinal protozoa. A 61.6% parasite and/or commensal positivity was found. Helminths identified were Ascaris lumbricoides (33.3%), Taenia spp. (6.6%), Strongyloides stercoralis (4.4%) and Trichuris trichiura (2.2%). Among protozoans, Giardia lamblia (26.6%), Cryptosporidium spp. (13.3%) and Cystoisospora belli (4.4%) were identified. The presence of Entamoeba coli, Endolimax nana and Entamoeba hartmanni was also recorded. The results obtained warn of the importance of fecal parasitological diagnosis and the use of specific staining methods for the detection of intestinal parasites in cancer patients. These exams should be regularly requested at the patient’s first clinic visit, given the high prevalence found in this study and the possible severity of such conditions for these individuals.

Evaluation of gastrointestinal transit after infection with different loads of Strongyloides venezuelensis in rats

The aim was to correlate the gastrointestinal transit profile in rats, evaluated by a biomagnetic technique, in response to infection with different loads of Strongyloides venezuelensis. Eggs per gram, intestinal number of worms and fecundity, and also gastric emptying time, cecum arrival time, small intestinal transit time and stool weight were determined. Assessments occurred at 0 (control), 3, 6, 9, 12, 15, 18 and 21 days post infection (dpi) with three infective loads (400, 2000, and 10,000 L). Gastric emptying was faster (p=0.0001) and the intestinal transit was significantly slower (p=0.001) during the infection time course. Also, linear mixed-effects models showed significantly changes in small intestinal transit after three parasite load over time. Cecum arrival was not influenced by infection time course or parasite load. As indirect effect, stool weight decreased accompanied a strong oviposition peak at 9 dpi in 400 L and 2000 L. In several motor function instances, neuromuscular dysfunction persists after mucosal inflammation has decreased. Our approach could be very helpful to evaluate gastrointestinal motor abnormalities in vivo after parasite infection. Despite parasitological data progressively decreased after 15 dpi, small intestinal transit worse over time and according to burden.