key: cord-0736602-9heqyx6a
authors: Barkati, Sapha; Greenaway, Christina; Libman, Michael D
title: Strongyloidiasis in immunocompromised migrants to non-endemic countries in the era of COVID-19: What is the role for presumptive ivermectin?
date: 2021-09-28
journal: J Travel Med
DOI: 10.1093/jtm/taab155
sha: 07487b97c8af4d634d9d89a583430145d56a9951
doc_id: 736602
cord_uid: 9heqyx6a

The COVID-19 pandemic has led to widespread use of dexamethasone. Corticosteroid therapy is an important risk factor for Strongyloides hyperinfection. Challenges associated with the performance of Strongyloides tests, and the poor availability of high quality and timely diagnostic testing, makes the use of presumptive ivermectin reasonable in selected situations.

The COVID-19 pandemic has led to widespread use of dexamethasone. Corticosteroid therapy is an important risk factor for Strongyloides hyperinfection. Challenges associated with the performance of Strongyloides tests, and the poor availability of high quality and timely diagnostic testing, makes the use of presumptive ivermectin reasonable in selected situations. Strongyloides hyperinfection was also initially missed in a 69-year-old migrant from Colombia presenting with abdominal pain and vomiting who developed progressive shortness of breath with diffuse bilateral infiltrates on imaging. 8 He was receiving immunosuppressive therapy as part of a clinical trial for stage IV prostate cancer with bone metastases. He was initially treated with broad-spectrum antibiotics, followed by methylprednisolone and gancyclovir for a suspicion of drug-induced toxicity and CMV viremia respectively. A diagnostic bronchoscopy was performed and microscopic examination of the bronchoalveolar lavage fluid revealed Strongyloides larvae. These cases reflect the lack of awareness of this neglected tropical disease and raise questions related to the best strategy to prevent severe strongyloidiasis in the migrant immunocompromised patients: systematic screening or presumptive ivermectin treatment have both been employed.

A recent systematic review provided indirect evidence supporting screening for strongyloidiasis in migrants from endemic areas and particularly in those who are, or are anticipated to become immunosuppressed because of the increased risk of HS/DS. 9 The most

cost-effective strategy to decrease morbidity and mortality due to strongyloidiasis in migrant is unclear. A recent cost-effectiveness analysis has showed that presumptive treatment of all immunosuppressed migrants from Strongyloides endemic areas to the European Union would generate cost savings to the health system. 10 Currently, screening for strongyloidiasis in migrants from endemic region who are immunocompromised, will undergo iatrogenic immunosuppression or have HTLV-1 infection is recommended. 1,11

Despite the recommendations for screening, the diagnostic approach to strongyloidiasis is challenging and testing is not widely available, often requiring referral to a reference laboratory. The sensitivity of stool-based parasitological and biomolecular methods is low hence, infection can easily be missed. Serologic testing is the most sensitive modality and is the routine diagnostic method of choice, although specificity is difficult to define in the absence of a diagnostic gold standard. In immunosuppressed patients the sensitivity of serology may be reduced.

Ivermectin is the drug of choice for Strongyloides treatment. Limited availability and slow turnaround of diagnostic tests means that, in selected circumstances, it is reasonable to consider presumptive treatment in high-risk immunosuppressed patients prescribed additional urgent immunosuppression such as corticosteroids for SARS-CoV-2. Ivermectin has a very good safety profile and could be administered as a single dose for presumptive treatment. Presumptive treatment was recently recommended for patients with COVID-19 at moderate to high-risk for strongyloidiasis and who may become candidates for dexamethasone. 12 Ivermectin has been widely used in the context of SARS-CoV-2 pandemic given the reported inhibitory effect on viral replication in vitro, despite the absence of supporting clinical data. As a result, drug shortages have been widely reported with limited quantities available; targeting individuals at highest risk of Strongyloides infection for empiric treatment will be necessary. A simple and targeted presumptive treatment strategy for asymptomatic strongyloidiasis among COVID-19 positive patients or those with other conditions for which urgent corticosteroids need to be administered is proposed in Figure 1 . For immunocompromised migrants from high and moderate-risk regions

who will be receiving urgent corticosteroids, presumptive ivermectin treatment should be given.

Presumptive ivermectin should be considered in previously immunocompetent patients receiving tocilizumab with dexamethasone for the treatment of COVID-19. Currently, 200 micrograms/kg daily for one to two days is commonly recommended. 12 In the absence of symptoms, it is presumed that the burden of larvae in an infected patient is likely to be low, and 

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