key: cord-0861995-04hhm2um
authors: De Wilton A, Angus; Nabarro, Laura E.; Godbole, Gauri S.; Chiodini, Peter L.; Boyd, Aileen; Woods, Katherine
title: Risk of Strongyloides Hyperinfection Syndrome when prescribing Dexamethasone in Severe COVID-19
date: 2021-01-31
journal: Travel Med Infect Dis
DOI: 10.1016/j.tmaid.2021.101981
sha: 31c56fd4f719734b582dbf116435c8d8c4ff36df
doc_id: 861995
cord_uid: 04hhm2um

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Dear Editor, Dexamethasone reduces mortality in patients hospitalized with moderate and severe COVID-19 infection [1] . In this context there is a need to consider asymptomatic Strongyloides infection in patients undergoing immunosuppression with dexamethasone, to avoid precipitating Strongyloides Hyperinfection Syndrome (SHS). There are now two published case reports of SHS in COVID-19 patients immunosuppressed with dexamethasone and tocilizumab [2, 3] but this is likely to underestimate the incidence of this event.

Strongyloides stercoralis, a parasitic nematode infection endemic in tropical and subtropical regions, is estimated to infect 30 to 100 million people worldwide. There are also foci of Strongyloides endemicity in temperate regions including Japan, Italy, Australia and the USA. In high income countries, high risk populations include migrants, refugees, travellers and exprisoners of war. Strongyloides infection occurs when soil-dwelling filariform larvae penetrate the skin and migrate to the small intestine. There they mature to adulthood, embed in the submucosa, and produce eggs by parthenogenesis. Rhabditiform larvae, released from eggs, are passed in the stool, but can also develop into infective filariform larvae whilst still within the gut, resulting in autoinfection. It is this unusual property that allows infection to persist for decades and cause overwhelming infection if people become immunosuppressed later in life.

Strongyloidiasis is often asymptomatic in immunocompetent adults, but may present with mild gastrointestinal or respiratory symptoms, or with larva currens, a rapidly moving pruritic linear skin eruption. In patients proven to have strongyloidiasis by microscopy or culture, 77% of patients have eosinophilia and 81% have positive serology [4] . However, microscopy and culture are frequently negative in asymptomatic infection. If these patients become To prevent this, we propose a risk assessment and screening algorithm for Strongyloides, in COVID-19 patients with risk exposures (Figure 1 ). Patients deemed at high risk (migrants with high risk exposure) may need empirical treatment with ivermectin, which has an efficacy of 85% as a single dose [5] . Those at potential, but not high risk, should be monitored and if deteriorating on immunosuppression, urgent screening with microscopy of stool, respiratory secretions, and charcoal culture for Strongyloides larvae should be undertaken. Serology should also be performed, but results are not usually available within 24 hours.

Stauffer et al recently proposed a screening and treatment protocol for Strongyloides in COVID-19 patients [6] . We welcome their proposal but suggest more focused screening and treatment for those at the highest risk of Strongyloides infection and SHS. The proposed broad screening

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