Tropical Parasitology

: 2020  |  Volume : 10  |  Issue : 1  |  Page : 56--58

Coinfection with Hymenolepis nana and Hymenolepis diminuta infection in a child from North India: A rare case report

Charu Singh1, Bhawna Sharma1, Aradhana Aneja2, Sadhna B Lal2, Sumeeta Khurana1,  
1 Department of Medical Parasitology, PGIMER, Chandigarh, India
2 Department of Paediatric Gastroenterology, PGIMER, Chandigarh, India

Correspondence Address:
Sumeeta Khurana
Department of Medical Parasitology, PGIMER, Chandigarh


Hymenolepiasis is considered the most common tapeworm infection throughout the world infecting 50–75 million people. Hymenolepis diminuta infection is not commonly reported in human beings as compared to Hymenolepis nana because it is primarily a parasite of rats and mice. There are few case reports of H. diminuta in the Indian population. To the best of our knowledge, not a single case of coinfection with H. nana and H. diminuta has been reported from India. We present here a rare case report of coinfection of H. nana and H. diminuta in a 4-year-old male child from a semirural area of India who presented with acute and severe colitis.

How to cite this article:
Singh C, Sharma B, Aneja A, Lal SB, Khurana S. Coinfection with Hymenolepis nana and Hymenolepis diminuta infection in a child from North India: A rare case report.Trop Parasitol 2020;10:56-58

How to cite this URL:
Singh C, Sharma B, Aneja A, Lal SB, Khurana S. Coinfection with Hymenolepis nana and Hymenolepis diminuta infection in a child from North India: A rare case report. Trop Parasitol [serial online] 2020 [cited 2020 Jul 14 ];10:56-58
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Full Text


Infection caused by the cestodes belonging to the genus Hymenolepis is called as hymenolepiasis. Hymenolepis nana (dwarf tapeworm) mostly causes human infections, whereas Hymenolepis diminuta <i>(rat tapeworm) exclusively infects rats and rarely humans. The carrier rate of H. nana is estimated to be 50,000,000–75,000,000.[1] The source of infection is contaminated food and fecal exposure.

H. diminuta infection is acquired by the accidental ingestion of infected intermediate hosts such as arthropods containing cysticercoid larvae. It is prevalent in areas infested with rodents and where large amounts of grain and dry food products are stored. Heavy infection causes abdominal pain, diarrhea, headache, dizziness, nausea, vomiting, urticarial skin eruptions, and phlyctenular conjunctivitis.[2],[3]

Here, we present a rare case of coinfection of H. nana and H. diminuta in a 4-year-old child.

 Case Report

A school-going 4-year-old child (youngest of three siblings), from a semirural area of Punjab, was referred by a government hospital in Punjab to the pediatric emergency department of Postgraduate Institute of Medical Education and Research, Chandigarh, with a 3-day history of passage of blood in stools and headache. There was a history of fever and loose stools (6–7 times/day) admixed with mucus for 10 days, but in the past 3 days, the passage of bright red blood (50–60 ml) and blood clots was also observed. There was a history of loss of appetite and weight loss of 5 kg in a span of 15 days with a history of rectal prolapse. No history of vomiting, enuresis, fits, passing of worms, redness, swelling or watering of eyes, lesions/nodules on the skin, joint swelling, or pain was documented. There was a history of pica for the past 2 years. There was no history of rodent infestation in the house; however, the father gave a history of getting their wheat grains from a nearby flour mill that was heavily infested with rats. Physical examination revealed pallor, 102°F fever, high respiratory rate, and tenderness in the hypogastrium region which improved on passing stools. Other family members and neighbors were healthy, showing no signs of similar illness.

The stool specimen of the child was sent to the Medical Parasitology Laboratory of PGIMER which was pale colored, watery with flakes of mucus seen macroscopically. Both saline and iodine mounts of unconcentrated and concentrated (Mini Parasep SF kit, Apacor Limited, UK) stool were examined microscopically. Numerous spherical eggs (7–10/hpf) which were variable in size ranging from 30 to 80 μm and having a thick shell with striated outer membrane and thin inner membrane containing six hooklets were observed. The eggs were of two kinds [Figure 1]. The smaller ones (30–50 μm) had polar thickenings on each end with polar filaments suggestive of H. nana. The larger eggs (70–80 μm) with oncospheres containing six hooklets and two distinct embryonic sheaths but devoid of polar thickenings and filaments were identified as H. diminuta. The eggs were counted by Kato–Katz technique which came out to be 120 eggs per gram of stool. The stool samples of the other four family members examined were negative for Hymenolepis, but the mother was found to excrete Giardia lamblia cysts.{Figure 1}

Routine laboratory investigations revealed an elevated absolute eosinophil count (470 cells/μl) and peripheral eosinophilia (6%). The patient was anemic (hemoglobin – 9.1 g/dl) with normal platelet count (2.14 × 10[5]/μl) and total leukocyte count (6200/μl). Abdominal ultrasonography showed multiple submesenteric lymph nodes, with largest being 6 mm in diameter with no sign of obstruction or intussusception.

Based on these observations, a diagnosis of mixed infection of both H. nana and H. diminuta was made. Following this, the child was given a single dose of praziquantel (20 mg/kg), and a second parasitological examination of stool was carried out 7 days following the treatment which was negative, and the child became asymptomatic. The stool was examined fortnightly for 1 month which yielded the negative results. Health education regarding the proper sanitation was given to the family.


Hymenolepiasis diagnosis is based on the demonstration of the cestode eggs by stool microscopy. H. nana eggs differ from those of H. diminuta in terms of size, polar thickenings, and polar filaments.[4] The infection with H. nana is much more common than H. diminuta because its transmission does not need any intermediate host in its direct life cycle. In direct life cycle, human or rodents are the only hosts and there is no intermediate host. In indirect cycle, human is a definitive host and insects act as intermediate hosts such as beetles. Humans acquire the infection of H. diminuta rarely by the accidental ingestion of insects containing the cysticercoid larva. Adult worms are found in the small intestine of human beings and it passes eggs in the stools.

H. diminuta (rat tapeworm) is a rodent parasite, which rarely infects humans (accidental host) and requires an arthropod (rat flea) as an intermediate host. Rodents become infected by ingesting arthropod containing cysticercoid larva. Foods such as cereals contaminated with infected insects are reported as chief sources of infection.[5]

The overall prevalence of H. nana ranges from 0% to 4% throughout the world with a higher prevalence in children, i.e., 16%.[6] Cases of H. diminuta infection, though rarely reported, seem to be on a rise. About 500 cases of H. diminuta infection had been reported worldwide, and survey reports from different populations have shown an incidence of 0.001%–5.5% of H. diminuta parasitism.[7] In India, almost a century ago, a survey of 10,000 stool samples was done by Chandler, in which 23 cases of H. diminuta infection were reported.[8] In addition, there are few case reports from Tamil Nadu, Odisha, and Haryana.[5] In our case, there is no history of a rat infestation in the house, thus opening a possibility of some other indirect mode of transmission, but there was a history of obtaining food grains from rat-infested mill and intake of untreated drinking water. Coinfection of H. nana and H. diminuta is a very rare finding. Pérez-Chacón et <ial. from Venezuela reported such a case in an HIV patient.[9] To the best of our knowledge, there is no case report of coinfection of H. nana and H. diminuta from India. The symptomatic profile of these cestodes is almost similar. The patient is usually asymptomatic in both of these infections, but when the worm burden exceeds to >1000 worms, patients develop symptoms such as anorexia, abdominal pain, diarrhea, and other extraintestinal manifestations such as pruritis, irritation, and eosinophilia.[10] Schulte et<i>al. have suggested that eosinophilia is characteristic of tissue invasive stage.[11] Rare symptoms include increased appetite, vomiting, nausea, bloody diarrhea, headache, dizziness, and behavioral symptoms. Headache and bloody diarrhea were present in our patient. Our case also had a high eosinophil count and characteristic gastrointestinal symptoms which are suggestive of high worm load.

Praziquantel is the drug of choice for both H. diminuta and H. nana. Our patient received praziquantel (10 mg/kg) single dose and he responded to the therapy. Subsequent stool samples were negative for the eggs of Hymenolepis.

We report this case because of the rarity of the coinfection of H. nana and H. diminuta. Such infections can be prevented by health education regarding the proper sanitation, hygiene, and intake of treated water.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent from the patient's parents. Written consent from the parents was duly obtained (as the patient is minor) regarding the publishing of clinical details in the journal. The patient's parents understand that the child's name and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


1Craig P, Ito A. Intestinal cestodes. Curr Opin Infect Dis 2007;20:524-32.
2Syadaf HS, Khan SS, Kanwal N, Tasawer BM, Ajmal SM. Review on diarrhea causing hymenolepis nana-dwarf tapeworm. Int Res J Pharm 2013;4:32-5.
3Kim BJ, Song KS, Kong HH, Cha HJ, Ock M. Heavy hymenolepis nana infection possibly through organic foods: Report of a case. Korean J Parasitol 2014;52:85-7.
4Devera R, Blanco Y, Amaya I, Requena I, Tedesco RM, Alevante C, et al. Prevalence of intestinal parasites in residents from a rural community in the state of Bolivar, Venezuela. Gen 2012;66:243-9.
5Kalaivani R, Nandhini L, Seetha KS. Hymenolepis diminuta infection in a school-going child: A rare case report. Australas Med J 2014;7:379-81.
6Bogitsh BJ, Carter CE, Oeltmann TN. Intestinal Tapeworms. Human Parasitology. 5th ed. London, UK: Elsevier; 2013.p. 237-49.
7Tesjaroen S, Chareonlarp K, Yoolek A, Mai-iam W, Lertlaituan P. Fifth and sixth discoveries of Hymenolepis diminuta infections in Thai people. J Med Assoc Thai 1987;70:49-50.
8Chandler AC. The distribution of H. diminuta infections in India and discussion of its epidemiological significance. Indian J Med Res 1927;14:973.
9Pérez-Chacón G, Pocaterra LA, Rojas E, Hernán A, Jiménez JC, Núñez L. Coinfection with Hymenolepis nana, Hymenolepis diminuta, Giardia intestinalis, and human immunodeficiency virus: A case report with complex immunologic interactions. Am J Trop Med Hyg 2017;96:1094-6.
10Baily GC. Intestinal cestodes. In: Cook G C, editor. Manson's Tropical Diseases. 10th ed. Galveston (TX): W.B. Saunders Company, Ltd.; 1996. p. 1477-85.
11Schulte C, Krebs B, Jelinek T, Nothdurft HD, von Sonnenburg F, Löscher T. Diagnostic significance of blood eosinophilia in returning travelers. Clin Infect Dis 2002;34:407-11.