Online First

2023 : Volume 1, Issue 1

Incidental Detection of Hookworm in The Stomach During Upper Gastrointestinal Endoscopy

Author(s) : Prabhat Pradhan 1 and Birendra Pradhan 2

1 Department of Surgery , Jigme Dorji Wangchuck National Referral Hospital (JDWNRH) , Bhutan

2 Department of Laboratory Medicine , Jigme Dorji Wangchuck National Referral Hospital (JDWNRH) , Bhutan

J Med Clin Case Rep

Article Type : Case Reports



Upper gastrointestinal endoscopy (UGIE) is performed routinely for upper gastrointestinal (GI) related symptoms. Occasionally there are incidental discoveries contrary to intended objectives. Helminth infestation to human is diagnosed commonly by stool examination with presence of its eggs or parasites. But sometime it is encountered during endoscopy performed for different intentions. Few literatures have reported it’s detection while performing endoscopy from other countries but not yet reported from Bhutan, although it may have been detected. In this paper we report a 59 years old female who had two adult live hookworms in the stomach during upper GI endoscopy done for anemia and pain abdomen. The diagnosis was established by microscopic examination. The patient was treated with anthelmintic therapy. Her symptoms improved with the treatment.

Keywords: Hookworm Infestation; Stomach; Upper Gastrointestinal Endoscopy




Upper gastrointestinal endoscopy (UGIE) is performed routinely for upper gastrointestinal (GI) related symptoms; like pain or reflux, indigestion, bleeding or malena (blood in stool), reduced weight or appetite, and screening for gastric cancer. Occasionally there are incidental discoveries contrary to intended objectives. Helminth infestation to human is diagnosed commonly by stool examination with presence of its eggs or parasites. But sometimes it is encountered during endoscopy performed for different intentions.

Human hookworm disease is a common helminth infection worldwide. It is acquired through skin exposure to larvae in the soil contaminated by human feces, and direct feco-oral transmission. Worldwide, it is estimated that about 576-740 million people are infected by hookworm [1]. Most individuals affected by hookworm remain asymptomatic [2], but some experience iron deficiency anemia (IDA), malnutrition, abdominal pain and other complications [3]. Infection is most prevalent in tropical and subtropical zones. The disease flourishes in rural communities with moist shaded soil and inadequate latrines. Agricultural laborers have traditionally been at high risk. Diagnosis of hookworm infection is made with direct microscopic analysis of patient’s stool for presence of ova and parasites. In some individuals the worms may be detected in the stomach through endoscopy when the adult worms are regurgitated into the stomach. Herein, we present a case of hookworm infection diagnosed in a 59 years old lady while performing upper GI endoscopy for abdominal pain and weakness.

Figure 1: Two adult hookworms in the lower part of stomach detected by endoscopy.

Figure 2: Microscopic images of the hookworm.


Hookworm disease is one of the most widely distributed parasitic diseases in the world. An estimated 576-740 million people in the world are infected with hookworm. It is more common in low and middle-income countries with higher concentration of cases in Southeast Asia, followed by Sub-Saharan Africa. It tends to be more prevalent in rural areas, where there is favorable tropical or subtropical ecologies in addition to poverty and weak sanitary infrastructures. A study conducted in western Bhutan in 2003 found the prevalence of soil-transmitted helminth (STH) infections to be 16.5% [4]. Few, earlier studies conducted in 1985, 1986 and 1989 reported even higher prevalence between 20% to 70%4. After establishing a successful school deworming program recommended by WHO in 1988, the infection prevalence saw a steep decline (1.4%) [5].

There are number of case reports of endoscopy being used for detection of worms in patients with GI symptoms in the literatures [6-8]. In these reoports the hookworms were detected in small intestine and stomach by upper GI endoscopy, but two studies reported detection by colonoscopy [9] and capsule endoscopy as well [10]. These studies highligthed the important role of endoscopy as a tool to evaluate the cause for IDA when all other causes have been ruled out. Moreover, sometimes it is difficult to detect eggs in the faces. The sensitivity and specificity of hookworm egg detection by stool examination are 65.2% and 94.4% for one stool sample respectively, [11] which is slightly lower than for Ascaris lumbricoids and Trichuris trichiura infection. This could be due to rapid degeneration of delicate hookworm eggs with time.

Hookworms are soil-transmitted nematode parasites that can reside for many years in the small intestine of their human hosts. The hookworm larvae enter the blood stream by penetrating the skin or mucous membrane. Through the blood it reaches the lungs via the right heart. It then destroys the capillaries of lungs, enter the aveoli, travel along the bronchi to the pharynx. By swallowing, the larvae enter the digestive tract and reach to the small intestine where they develop into adults [12]. The other route of entry is by direct feco-oral transmission. The adult worms are usually not seen in stomach. It is discovered during endoscopy when the worms are regurgitated into the stomach.

The adult worms remain attached to the intestinal mucosa from where they derive nutrition. It causes iron-deficiency anemia, malnutrition, indigestion, bleeding, abdominal pain, obstruction of intestine and distension, and even jaundice. The symptom severity depends on parasite load. Infection may go undetected or unsuspected since there are no specific symptoms. The clinicians should consider this parasite as a cause for IDA, especially in elderly patients who have the history of walking/working barefoot. Fecal examination and endoscopy are suggested for anemia evaluation. It is important to thoroughly check every folds of stomach and duodenum carefully during endoscopy, since the worms can be easily missed which remain buried into the mucosal folds or in the gastric secretion. The endoscopist should be aware of this fact, especially in the endemic areas when patient presents with anemia of unknown cause.

Dedinite diagnosis of hookworm infection is made primarily by repeated stool examination for its eggs. Some may give the history of skin exposure to contaminated soil which produces skin itching. Our patient is a housewife whose main occupation is farming. She is exposed to the risk of transmission from the soil. Due to her illness many active labor days were lost as she was mostly weak and fatigue during work. After the treatment with antihelminth (Tablet Albendazole) her symptoms improved and hemoglobin returned to normal (11.6 gm%). Stool examination after treatment was negative for eggs. All her family members were also treated. Awareness on prevention of infection were also given. The health staffs at the respective health center were instructed to strengthen the deworming program at that community.

The treatment of choice for elimination of hookworm infection from the intestine is a benzimidazole anthelmintic, either albendazole (400 mg once orally) or mebendazole (100 mg orally twice a day for 3 days or 500 mg once).


Infection by hookworm to humans have been known for a very long time, seriously endangering human health if not diagnosed and treated on time. They are easily missed and misdiagnosed due to overlapping signs and symptoms with other illnesses. In this case it would have been difficult to establish the cause of anemia had she not have the chance to undergo endoscopy. Possibility of hookworm infection was also difficult to predict in her. Our patient received timely diagnosis and treatment through the endoscopy. This has reduced the gradual continuous damage to her body by the hookworm.

Hookworm infection is a treatable disease and results in complete recovery. Every endoscopists should keep in mind the possibility of STH infections while performing endoscopy in areas where the prevalence rate is significant. Lastly, the deworming program, hygiene and sanitation in the community should be strengthened. Awareness program on STH transmission and prevention should also be given to the heath staffs working in the community which is lacking at present.



Conflicts of Interest


Ethical Approval

Not needed. Informed consents were routinely obtained from patients attending endoscopy. Consent was also taken from this patient for any type of publication.


We would like to acknowledge Dr. Trisha Sharma, DMO of Gomtu hospital for the treatment and the followup of our patient.Also would like to thank the endoscopist nurses: Ms. Nima Chunda and Mr Zangla for their role in carrying out the endoscopy to our patient. We would als acknowledge Dr Gyan Prasad Bajgai for his continuous support and guide to publish this paper.


  1. Global Health, Division of Parasitic Diseases and Malaria. Hookworm. Centers for Disease Control and Prevention, 2020.
  2. Mason L, Tribolet L, Simon A, et al. Probing the Equatorial Groove of The Hookworm Protein and Vaccine Candidate Antigen, Na-ASP-2. Int J Biochem Cell Biol. 2014;50:146-155.
  3. Global Health, Division of Parasitic Diseases and Malaria. Hookworm (Intestinal). DPDx-Laboratory Identification of Parasites of Public Health Concern. 2019.
  4. Allen H, Sithey G, Padmasiri EA, et al. Epidemiology of Soil-Transmitted Helminths in The Western Region of Bhutan. Southeast Asian J Trop Med Public Health. 2004; 35:777-779.
  5. Dukpa T, Dorji N, Thinley S, et al. Soil-Transmitted Helmnth Infections Reduction in Bhutan: A Report of 29 Years of Deworming. PLoS ONE.2020;15: e0227273.
  6. Chen YY, Soon MS. Endoscopic Diagnosis of Hookworm Infection That Caused Intestinal Bleeding. Gastrointest Endosc. 2005;62:142.
  7. Boopathy V, Balasubramanian P, Phansalkar M, et al. Endoscopic (video) Demonstration of Hookworm Infestation of The Stomach. BMJ Case Rep 2014.
  8. Kato T, Kamoi R, Lida M, et al. Endoscopic Diagnosis of Hookworm Disease of The Duodemum. J Clin Gastroenterol. 1997; 24:100-102.
  9. Lin CK, Liao CH, Su KE, et al. Colonoscopic Diagnosis of Ancylostoma Ceylanicum Infection: Report of A Case. Gastroenterol J Taiwan. 2009;26:21-26.
  10. Wu IC, Lu CY, Wu DC. Acute Hookworm Infection Revealed by Capsule Endoscopy. Endoscopy. 2007;39:e306.
  11. Tarafder MR, et al. Estimating the Sensitivity and Specificy of Kato-Katz Stool Examination Technique For Detection of Hookworms, Ascaris lumbricoides and Trichuris trichiura Infections In Humans In The Absence of A ‘Gold Standard’. Int J Parasitol. 2010;40:399-404.
  12. Lanjuan Li, Hong Ren. Infectious Diseases[M]. BeiJing: People’s Medical Publishing House. 2013:322-325.

Correspondence & Copyright

Corresponding author: Prabhat Pradhan, Department of Surgery, Jigme Dorji Wangchuck National Referral Hospital, Bhutan.

Copyright: © 2023 All copyrights are reserved by Prabhat Pradhan, published by Coalesce Research Group. This This work is licensed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution and reproduction in any medium, provided the original author and source are credited.

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