is an intestinal nematode of humans. Although most infected individuals are asymptomatic,19
,20 S. stercoralis
is capable of causing a fulminant illness that is often fatal if not recognized and treated. This is seen in certain conditions associated with a decrease in host immunity, including immunosuppressive therapy (particularly the use of glucocorticoids), hematological malignancies, bone marrow and renal transplants, human T-cell lymphotropic virus type 1 infection, human immunodeficiency virus infection, hypogammaglobulinemia, and malnutrition.5
Although various immunocompromising conditions have been associated with hyperinfection, steroids and human T-cell lymphotropic virus type 1 infection are the most consistent. In these conditions S. stercoralis
The patient discussed had a S. stercoralis
hyperinfection following renal transplant. Of interest is that the majority of cases of hyperinfection with S. stercoralis
that have occurred following organ transplant were seen in patients following renal transplant and most of these cases seem to have been precipitated by increased glucocorticoid doses in response to rejection.8
The authors’ patient did not show signs of rejection, but he was on glucocorticoid therapy and this probably contributed to the development of superinfection. Given the increasing numbers of immunocompromised patients throughout the world, this calls for a closer evaluation and observation of all conditions under which S. stercoralis
infection becomes dangerous. This is of paramount importance to physicians caring for these patients, as early identification and treatment of those at risk is likely to decrease the morbidity and mortality associated with S. stercoralis
commonly causes gastrointestinal symptoms that are nonspecific and easily attributed to other diseases. This was the case in the patient discussed, who was complaining of nausea and vomiting only; the striking and alarming feature was the sudden and significant weight loss. This called for further investigation including colonoscopy, which showed features suggestive of inflammatory bowel disease. The diagnosis of S. stercoralis
infection was made on colonic biopsy and subsequently on fecal examination. The definitive diagnosis of S. stercoralis
infection depends on the demonstration of larvae in the feces or duodenal fluid. In uncomplicated cases, the intestinal worm load is low and larval output is minimal. A single fecal examination thus fails to detect larvae in up to 70% of cases.21
Repeated fecal examinations increase the sensitivity of detection of S. stercoralis
In immunocompromised patients, the autoinfective cycle of S. stercoralis
can become amplified into a potentially fatal hyperinfection syndrome, characterized by increased numbers of infective filariform larvae in the feces.
Strongyloidiasis is a curable disease and early diagnosis and appropriate therapy with anthelmintics can reduce morbidity and mortality.23
Ivermectin, when compared with albendazole and thiabendazole, shows similar or better rates of larval clearance from feces with similar side effects but is much better tolerated and has become the treatment of choice. An important point which must be considered is the fact that hyperinfections are often complicated by infections caused by gut flora that gain access to extra-intestinal sites, presumably through gut ulcers induced by the filariform larvae. Gut flora can include Escherichia coli
, Klebsiella pneumoniae
, Proteus mirabilis
spp, Enterococcus faecalis
, coagulase-negative staphylococci, Streptococcus bovis
, and Streptococcus pneumoniae.
Patients on immunosuppressive therapy may also develop systemic candidemia in addition to enteric Gram-negative infections.