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Year : 2021  |  Volume : 64  |  Issue : 1  |  Page : 165-167
Strongyloidiasis duodenum: A histopathological study

Department of Pathology, Vivekananda Polyclinic and Institute of Medical Sciences, Lucknow, Uttar Pradesh, India

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Date of Submission04-May-2019
Date of Decision11-Dec-2019
Date of Acceptance02-Jan-2020
Date of Web Publication8-Jan-2021


Strongyloides stercoralis is an intestinal nematode that infects humans, percutaneously and has a complex life cycle. We report a case of a thirty year old male presenting with chief complaints of profuse watery diarrhoea, abdominal fullness, loss of appetite, creepy abdominal pain and low-grade fever for the last one month. He was on corticosteroids for systemic sclerosis. Endoscopy showed thickened and oedematous duodenal folds with pinpoint areas of bleeding and multiple ulcerations on the duodenal mucosa. Histopathologial examination of duodenal biopsy revealed infestation by Strongyloides stercoralis in the duodenum, the duodenal mucosal glands were occupied by various parts of parasite. The patient was successfully treated and had uneventful recovery.

Keywords: Histomorphology of Strongyloides stercoralis, immunosuppression and strongyloidiasis, scleroderma with strongyloidiasis

How to cite this article:
Pandey R, Agarwal PK, Katiyar P. Strongyloidiasis duodenum: A histopathological study. Indian J Pathol Microbiol 2021;64:165-7

How to cite this URL:
Pandey R, Agarwal PK, Katiyar P. Strongyloidiasis duodenum: A histopathological study. Indian J Pathol Microbiol [serial online] 2021 [cited 2022 Jan 20];64:165-7. Available from: https://www.ijpmonline.org/text.asp?2021/64/1/165/306510

   Introduction Top

Strongyloidiasis is an intestinal nematode that infects humans, endemic in both tropical and temperate countries and has a worldwide distribution. It usually causes a mild or asymptomatic infection. However, hyperinfection syndrome can cause significant morbidity and mortality in immunocompromised states such as malignancy, HIV infection or immunosuppressive agent administration.[1] It has a complex life cycle including a direct, an auto-infective and a nonparasitic free-living developmental cycle. The filariform larvae (infective form) penetrates the skin on coming in contact with the contaminated soil to enter the circulation, reaches the lungs from where they get coughed up and swallowed into the intestine to develop into mature adult worms. This is a usual route of transmission of this parasite. Female parasites are embedded in the submucosa of the duodenum and produce dozens of embryonated eggs a day. These eggs hatch in the gut lumen of the host and release the first-stage larvae (rhabditiform larvae), which are passed out in feces. Then they develop into infective third-stage larvae (filariform larvae) or into free-living adult males and females. Alternatively, larvae may develop to the third stage (filariform larvae) within the gastrointestinal tract and penetrate the intestinal mucosa or perianal skin, restarting a new infection cycle without ever leaving their host. Autoinfection is the major characteristic feature that separates Strongyloides stercoralis from other parasitic infections.

   Case History Top

30-year-old male, a worker in the textile industry, Surat was admitted to the male medical ward, at a tertiary care hospital with the chief complaints of profuse watery diarrhea, abdominal fullness, loss of appetite, creepy abdominal pain, and low-grade fever since last 1 month. On physical examination, he was febrile, had pallor and pedal edema. Systemic examination showed tenderness in the epigastric region, whereas the rest of the systemic examination was within normal limits. The routine laboratory investigations, including blood and stool examination, were non-contributory to the diagnosis. The total and differential leucocyte count was within the normal range (absolute eosinophil count [AEC] = 245 cells/cumm). Though clinically he was looking pale, his hemoglobin was 12.7 g%. All the viral serological markers (HBsAg, HCV, and HIV) were also negative.

He did not respond to conventional medical treatment for his gastrointestinal symptoms, hence, endoscopic examination of the upper gastrointestinal tract was carried out which showed thickened and edematous folds of the duodenum [Figure 1]a with pinpoint areas of bleeding [Figure 1]b and multiple ulcerations on the duodenal mucosa [Figure 1]c.
Figure 1: Endoscopy findings: (a) Thickened and edematous folds of the duodenum. (b) Pinpoint areas of bleeding and hemorrhages. (c) Multiple ulcers and hemorrhages on the duodenal mucosa

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Histopathological examination

Endoscopic biopsies were taken from representative areas of the duodenum and were submitted for histopathological examination. Serial paraffin sections were studied which revealed that the duodenal mucosa was ulcerated and infiltrated by chronic inflammatory cells [Figure 2]a. The mucosal glands were loaded with various parts and developmental stages of a parasite, suggestive of S. stercoralis. Longitudinal and transversely cut parts of the parasite were seen on serial sections. Thorough screening of the sections showed almost all the stages of the parasite development, that is, eggs, filariform larvae and rhabditiform larvae and adult worms. Filariform larvae had a notched tail end [Figure 2]b which helped in differentiating it from the rhabditiform larvae [Figure 2]c. The adult worm showed a body covered by a cuticle [Figure 2]d. Proximal end showed a buccal capsule and mid area showed esophagus and genital tract, which was identified by the presence of ovaries embedded in the wall [Figure 2]e. Eggs of Strongyloides showed characteristic eight-stage embryonic cleavage [Figure 2]f. Hence, the final diagnosis was given Strongyloidiasis duodenum.
Figure 2: Histopathology findings: (a) Ulceration and infiltration by chronic inflammatory cells in the duodenal mucosa (H: E ×10). (b) Filariform larvae with a notched tail end (arrow) (H: E ×40). (c) Rhabditiform larvae (H: E ×40). (d) Adult worm body showing proximal end covered by buccal capsule and mid area of esophagus (H: E ×40). (e) Adult female worm, body covered by cuticle showing ovaries (arrowhead) embedded in the wall (H: E ×100). (f) Eggs of Strongyloides with characteristic eight-stage embryonic cleavage (H: E ×100)

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Past history revealed that the patient was a diagnosed case of systemic sclerosis and was on corticosteroids for the same for 18 months. Subsequently, skin biopsy was performed which revealed thinned out epidermis. Dermis showed an increase in fibro collagenous tissue, the sparse inflammatory reaction by plasma cells and few lymphocytes along with the adnexal structures. The final impression of the skin biopsy was given as scleroderma.

He was managed with antihelminthic therapy (praziquantel) along with the concurrent reduction of immunosuppression. The patient had uneventful recovery after the treatment for about a year.

   Discussion Top

Strongyloidiasis is an intestinal parasite remains endemic in all the tropical and subtropical countries worldwide, particularly in countries with developing infrastructure but also in developed nations.[2]

S. stercoralis has a complex life cycle, including a direct, an auto-infective and a nonparasitic free-living developmental cycle. The larva penetrates the skin to enter the circulation, reaches the lungs from where they get coughed up and swallowed into the intestine to develop into mature adult worms.[3],[4] This is a usual route of transmission of this parasite.

The parasite usually resides in the duodenum, rarely in the colon or stomach and is asymptomatic in healthy individuals, thus allowing the infection to remain undiagnosed and untreated for years. Hence, the parasite can persist in the host and increases the risk of infection among the community. The common manifestations include severe cramping, abdominal pain, watery diarrhea, weight loss, nausea, vomiting, and occasionally gastrointestinal bleeding and small bowel obstruction.[5] The present case presented with creepy abdominal pain, diarrhea, and fever, which was not responding to conventional treatment.

Strongyloides have the tendency to develop the severe disease in immunocompromised patients and is a major public health concern. The immunocompromised population includes those undergoing steroid therapy or chemotherapy, and those with hematologic malignancy, kidney transplants, bone marrow transplants, human T-lymphotropic virus type 1 infection, and hypogammaglobulinemia.[6]

The present case was receiving corticosteroids for the treatment of scleroderma for more than a year and a half. The transformation of chronic infection to hyper-infection in the duodenum may have been caused by the use of steroids in this case. Blood counts in chronic parasitic infections often show eosinophilia, but the eosinophilia is often absent in hyperinfection syndrome as reported in a study by Newberry et al. in 2005. In their series, 3 out of 7 patients with Strongyloides hyperinfection had absolute eosinophil counts <400/cumm.[7] The present case also had an absolute eosinophil count of 245/cumm, which was within the normal range at the time of admission, probably because he was on corticosteroid therapy for scleroderma, which leads him to immunosuppression.

However, Strongyloidiasis is difficult to diagnose only on stool examination, as the parasitic load is low and the larval output is irregular in the majority of the patients.[8] Even after three stool examinations, positivity does not exceed 46% cases.[9] In the present case, also the repeated stool examination was inconclusive initially and was negative even after a histopathological diagnosis of the disease.

The endoscopic examination has been recognized to be an important tool for the diagnosis of Strongyloides, as the adult worms, larvae, and eggs colonize in the duodenum.[4] This procedure is the most sensitive diagnostic technique for Stronyloidiasis, with a false negative frequency of less than 10%.[10] The present case was successfully treated with praziquantel.

   Conclusion Top

Strongyloidiasis is a curable disease. Early diagnosis and appropriate therapy can reduce the mortality and morbidity. Unless severely infected, the clinical signs and symptoms are generally not severe and frequently nonspecific. The possibility of S. stercoralis infection should be considered as a causative agent of diarrhea particularly in an immunocompromised patient. Even in the asymptomatic state, Strongyloidiasis must be treated to avoid the risk of subsequent fatal hyperinfection. Timely initiation of appropriate therapy before the development of significant complications would be life-saving. The present case report therefore, strongly emphasizes the need for extensive investigations including endoscopic study, followed by detailed histopathological examination of the biopsy specimen, with suspicion of Strongyloidiasis, particularly in immunocompromised hosts.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.


The authors are grateful to Mr. S. K. Shukla, of the Pathology Department for his technical assistance.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

Pukhrambam PD, Rebachandra H, Singh NB, Singh TN. Opportunistic Strongyloides stercoralis infection in an immunocompromised patient. Ind Med Gaz 2012:497-500.  Back to cited text no. 1
Beknazarova M, Whiley H, Ross K. Strongyloidiasis: A disease of socioeconomic disadvantage. Int J Environ Res Public Health 2016;13:517.  Back to cited text no. 2
Thompson BF, Fry LC, Wells CD, Olmos M, Lee DH, Lazenby AJ, et al. The spectrum of GI strongyloidiasis: An endoscopic pathologic study. Gastrointest Endosc 2004;59:906-10.  Back to cited text no. 3
Kishimoto K, Hokama A, Hirata T, Ihama Y, Nakamoto M, Kinjo N et al. Endoscopic and histopathological study on the duodenum of Strongyloides stercoralis hyperinfection. World J Gastroenterol 2008;14:1768-73.  Back to cited text no. 4
Keiser PB, Nutman TB. Strongyloides stercoralis in the Immunocompromised Population. Clin Microbiol Rev 2004;17:208-17.  Back to cited text no. 5
Liu HC, Hsu JY, Chang KM. Strongyloides stercoralis hyperinfection presenting with symptoms mimicking acute exacerbation of chronic obstructive pulmonary disease. J Chin Med Assoc 2009;72:442-5.  Back to cited text no. 6
Newberry AM, Williams DN, Stauffer WM, Boulware DR, Hendel-Paterson BR, Walker PF. Strongyloides hyperinfection presenting as acute respiratory failure and Gram-negative sepsis. Chest 2005;128:3681-4.  Back to cited text no. 7
Ardic N. An oversight of Strongyloides stercoralis and its infections. Mikrobiyol Bul 2009;43:169-71.  Back to cited text no. 8
Martin-Davila P, Fortun J, Lopez-Velez R, Norman F, Montes de Oca M, Zamarron P, et al. Transmission of tropical and geographically restricted infections during solid-organ transplantation. Clin Microbiol 2008;21:60-96.  Back to cited text no. 9
Ganesh S, Cruz RJ. Strongyloidiasis: A multifaceted disease. Gastroenterol Hepatol 2011;7:194-6.  Back to cited text no. 10

Correspondence Address:
Rimi Pandey
Agarwal Pathology Centre, A.15, Nirala Nagar, Lucnow - 226 020, Uttar Pradesh
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/IJPM.IJPM_359_19

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