Case Report: Strongyloides stercoralis Hyperinfection in a Patient with HTLV-1: An Infection with Filariform and Rhabditiform Larvae, Eggs, and Free-Living Adult Females Output

Abstract

Strongyloides stercoralis is the main etiological agent of human strongyloidiasis. Severe strongyloidiasis is commonly associated to alcoholism, corticostereoid use, and human T cell lymphotropic virus type 1 (HTLV-1) coinfection. Herein, we report a case of a 13-year-old boy coinfected with S. stercoralis and HTLV-1, excreting several parasitic forms in the stool. The parasitological examination of his feces showed a large amount of filariform (about 3,000 larvae per gram of feces) and rhabditiform larvae (about 2,000 larvae per gram of feces). In addition, free-living adult females (about 50 parasites per gram of feces) and eggs (about 60 eggs per gram of feces) were detected. The main laboratory findings pointed to high immunoglobulin E (IgE) levels (228 UI/mL) and eosinophila (11.6%). The patient was treated with three courses of ivermectin (200 μg/kg twice, 2 weeks apart), achieving the parasitological cure. An increase of about 19 times in interleucin (IL)-17 level was observed following the parasitological cure, in addition to a decrease in the white blood cell, eosinophil counts, and IgE levels. This is the first case report, to our knowledge, in which an S. stercoralis adult free-living female was described in human feces and where an increase in IL-17 levels after Strongyloides treatment in a HTLV-1 coinfected individual was observed. This finding raises the need for further studies about IL-17 immunomodulation in S. stercoralis and HTLV-1 coinfected patients.

Prevalência de Strongyloides stercoralis em portadores do Vírus Linfotrópico-T Humano (HTLV) atendidos no Núcleo de Medicina Tropical da Universidade Federal do Pará

“…Portanto, é evidente que existe uma alta frequência de portadores com HTLV-1 dentre os indivíduos portadores de HTLV, podendo os mesmos estar com coinfecção pelo Strongyloides stercoralis (Souza et al, 2018). Apesar da alta frequência de indivíduos com HTLV no presente estudo, não se sabe ao certo a quantidade exata de infectados na população, uma vez que se trata de um patógeno que normalmente não causa sintomas clínicos evidentes, dificultando o diagnóstico precoce e as possíveis medidas de intervenção (Romanelli et al, 2010).…”

Human T-cell Leukemia Virus Type 1 and Strongyloides stercoralis: Partners in Pathogenesis

“…In one case, intestinal obstruction induced by S. stercoralis was observed in a pregnant woman following corticosteroid treatment, and it was subsequently determined that she was an HTLV-1 carrier [18]. Another report described a household in rural Brazil, in which the entire family was HTLV-1 positive, and the 13-year-old son exhibited eosinophilia and very large numbers of S. stercoralis worms, larvae, and eggs [19].…”

“…IL-2 receptor expression has also been observed in these patients [26]. Recently, a patient with concurrent HTLV-1 and S. stercoralis infection was determined to have elevated IL-17 levels following ivermectin treatment [19]. More studies are needed to determine if IL-17 modulates the consequences of co-infection.…”

Strongyloides stercoralis larvae or egg: Which came first?

“…Hyperinfection due to SS is a well‐documented clinical condition in immunosuppressed patients, and SS can be a potential morbidity/mortality agent due to their ability to cross the intestinal wall leading to septicemia due to bacterial translocation . On the other hand, SS eggs are rarely reported during routine stool analysis because they typically hatch within the wall of the intestine and release rhabditiform larvae.…”