Human infection withStrongyloides stercoralisand other related Strongyloides species

Abstract

SUMMARY The majority of the 30–100 million people infected with Strongyloides stercoralis, a soil transmitted intestinal nematode, have subclinical (or asymptomatic) infections. These infections are commonly chronic and longstanding because of the autoinfective process associated with its unique life cycle. A change in immune status can increase parasite numbers, leading to hyperinfection syndrome, dissemination, and death if unrecognized. Corticosteroid use and HTLV-1 infection are most commonly associated with the hyperinfection syndrome. Strongyloides adult parasites reside in the small intestine and induce immune responses both local and systemic that remain poorly characterized. Definitive diagnosis of S. stercoralis infection is based on stool examinations for larvae, but newer diagnostics – including new immunoassays and molecular tests – will assume primacy in the next few years. Although good treatment options exist for infection and control of this infection might be possible, S. stercoralis remains largely neglected.

Strongyloides Stercoralis Hyperinfection Syndrome: An Uncommon Mimicker

“…Transmission usually occurs through skin penetration by direct contact with infected environment harboring the parasite [4]. Inoculation following solid organ transplantation has also been described [4].…”

“…It then passes through alveoli to the upper respiratory tract and is swallowed [4]. In the intestine, it matures in an adult worm that produces eggs [4]. Most of non-infective (rhabdiform) larvae are cleared through feces [4].…”

“…In the intestine, it matures in an adult worm that produces eggs [4]. Most of non-infective (rhabdiform) larvae are cleared through feces [4]. Some of rhabdiform larvae could mature into filariform form and re-infect the host through GI mucosa or perianal skin [4].…”

Severe Anemia and Lung Nodule in an Immunocompetent Adopted Girl with Strongyloides stercoralis Infection

“…[2][3][4] In fact, S. stercoralis is characterized by a peculiar autoinfective cycle that permits the infection to become chronic. 5 Only sporadic cases of possible current transmission have been reported in Europe. 6 In immunocompetent hosts, chronic strongyloidiasis tends to have subclinical, unspecific manifestations involving the abdomen, the respiratory tract, and the skin.…”

“…In hyperinfection, larvae are generally easily detected by stool (and also other body fluids) microscopy, because of their increased number. 5 Other diagnostic tests, such as serology, stool culture (including agar plate culture [APC]), and real-time polymerase chain reaction (PCR) (quantitative PCR [qPCR], currently available in a few referral centers), demonstrated higher sensitivity than stool microscopy, so they are useful to achieve the diagnosis during the chronic phase. 7 However, a high index of suspicion is the first fundamental step leading to the diagnosis.…”