|Year : 2013 | Volume
| Issue : 1 | Page : 82-84
Dipylidium caninum infection in a child: A rare case report
MV Narasimham, P Panda, I Mohanty, S Sahu, S Padhi, M Dash
Department of Microbiology, MKCG Medical College Berhampur, Odisha, India
|Date of Submission||26-Jun-2012|
|Date of Acceptance||28-Oct-2012|
|Date of Web Publication||15-Mar-2013|
M V Narasimham
Department of Microbiology, MKCG Medical College Berhampur, Odisha
Source of Support: None, Conflict of Interest: None
Dipylidiasis is a zoonotic parasitic infestation caused by the dog tapeworm Dipylidium caninum. Human dipylidiasis has been rarely reported in English literature. Young children are mostly at risk of acquiring the infection due to their close association with dogs and cats. We report a rare case of Dipylidium caninum infection in a 4 year old male child. The diagnosis was based on microscopic examination of stool. Confirmation of the proglottid segments was done by histopathological examination. To the best of our knowledge this is the first human case of Dipylidium caninum reported from this part of the country.
Keywords: Dipylidium caninum, dog tapeworm, proglottids
|How to cite this article:|
Narasimham M V, Panda P, Mohanty I, Sahu S, Padhi S, Dash M. Dipylidium caninum infection in a child: A rare case report. Indian J Med Microbiol 2013;31:82-4
|How to cite this URL:|
Narasimham M V, Panda P, Mohanty I, Sahu S, Padhi S, Dash M. Dipylidium caninum infection in a child: A rare case report. Indian J Med Microbiol [serial online] 2013 [cited 2020 Apr 5];31:82-4. Available from: http://www.ijmm.org/text.asp?2013/31/1/82/108738
| ~ Introduction|| |
Dipylidium caninum, also called the cucumber tapeworm or the double pore tapeworm, has been rarely implicated in human infection.  Linnaeus first described a disease caused by it in humans in 1758. This disease is prevalent worldwide and about 120 human cases have been reported until date.  The definitive hosts are usually dogs and cats, while humans are the accidental hosts. Dog flea (Ctenocephalides canis) and cat flea (Ctenocephalides felis) act as intermediate hosts.  The infection usually presents with non-specific systemic manifestations in many cases but no pathological changes. Due to this, it is rarely diagnosed and reported. We report a rare case of human dipyliadiasis in a young child from Odisha.
| ~ Case Report|| |
An anxious mother of a 4-year-old male reported to the Pediatrics outpatient department of MKCG Medical College, Berhampur in Odisha with complaints of the child suffering from anal itching and passage of small structures resembling rice grains in stool for the past 6 months. The child had developed diarrhea for the past 2 days. There was no history of vomiting, fever, or poor feeding. The child often complained of recurrent abdominal pain. The mother also mentioned that the child was frequently handling pet cats and street dogs.
The child was previously treated for pinworm (Enterobiasis) infection by a practitioner 4 months back. At that time, he had presented with similar complaints, for which a single deworming dose of albendazole along with some antihistaminics was prescribed. Despite this treatment, the child did not recover completely and the same symptoms persisted, for which he was referred to the Pediatrics outpatient department of this hospital.
On a general examination, the child was of a moderate built, weighing 15 kg. He had mild pallor and a protruding abdomen. The child was afebrile with respiration rate of 20/min and blood pressure of 90/60 mm Hg. No icterus, puffy face, or pedal edema was noted. The laboratory findings revealed 9.1 gm/dl hemoglobin level, hematocrit reduced to 27.9%, and ESR as 15 mm/1 st hour. Other hematological profile was normal. Urine microscopic examination was also normal.
The stool sample was examined microbiologically and was found to be yellowish on gross appearance, watery in consistency, and not foul smelling. Small ivory colored structures resembling cucumber seeds or rice grains were also observed in the stool sample [Figure 1].
|Figure 1: Naked eye examination of stool sample showing the ivory colored cucumber seed like proglottid segments|
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These structures when observed under the hand lens resembled proglottids of tapeworm. Each proglottid segment were about 0.5-1.0-cm long and 0.1-0.2-cm thick.
A wet mount of the stool sample revealed eggs in clusters [Figure 2]. For further confirmation, the proglottid segments were crushed and examined by normal saline mount. Crushed proglottid segment showing eggs in packets containing 8-15 eggs in clusters surrounded by a thin membrane were observed under ×10 magnification [Figure 3]. The eggs showed the characteristic envelope, an embryophore surrounding the oncosphere, which was hexacanth along with 2 pairs of hooklets under ×40 magnification [Figure 4].Subsequent stool samples collected on successive 3 days also showed rice grain like proglottids and eggs on wet mount examination.
|Figure 2: Direct wet mount examination of stool showing eggs (×10 magnification)|
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|Figure 3: Crushed proglottid segment showing eggs in packets containing 8-15 eggs in clusters surrounded by a thin membrane (×10 magnification)|
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|Figure 4: Eggs showing the characteristic envelope, embryophore surrounding the oncosphere, inner hexacanth along with 2 pair of hooklets (×40 magnification)|
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The proglottid segments were processed by paraffin embedment and stained with hemotoxylin-eosin. These sections showed body wall with tegument and smooth muscle fibers and internal compartmentalization of eggs in packets, when observed under ×10 magnification [Figure 5]. Stool culture did not reveal any pathogenic bacteria.
|Figure 5: Hemotoxylin– eosin staining of proglottid sections revealed body wall (tegument and smooth muscle fibers) and internal compartmentalization of eggs in packets with similar morphology (×10 magnification)|
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With a history of contact with pet cats and street dogs, microscopic examination of feces and histopathological examination of the proglottid segments, a diagnosis of dipylidiasis due to Dipylidium caninum was made.
The child was treated with praziquantel palmoate (10 mg/kg bodyweight) single dose. Stool samples' examination was followed up after 1 month and 3 months. There was no evidence of the segments of the parasite or eggs.
| ~ Discussion|| |
Dipylidiasis infection occurs throughout the world and has a natural infection cycle in members of the dog and cat family. It is a cyclophyllid cestode that infects organisms afflicted with fleas including canids, felids, and pet owners, especially children. Occasional human infections have been reported in literature.  Young children and toddlers are at greater risk of infection due to accidental ingestion of infected fleas or contact with saliva of pet animals while playing with them. Human cases are either asymptomatic or are under reported. This may be due to non-specific clinical manifestations. 
Diagnosis of Dipylidium caninum in children relies on the accurate history given by the parents or caretaker of the child. Failure to examine a sample of stool may lead to an error in clinical diagnosis. Often this is infection is misdiagnosed as threadworm (Enterobius vermicularis) infection. , Accurate diagnosis can be made on finding proglottids or egg packets in stool. The eggs are found occasionally in fresh stool specimens and disintegrate rapidly.
The proglottids are pumpkin or cucumber seed shaped when freshly passed in stool and often resemble rice grains when dried. The adult worms may rarely be passed in the stool. They resemble long flat ribbon like tapeworms that inhabit the intestines. The body of Dipylidium caninum is composed of a scolex with 4 suckers, a neck, and proglottids.
Each proglottid segment has two pores and maybe immature, mature, or gravid.  The proglottid segments which we examined were mostly gravid in nature where the organs and structural morphology was lost. The segments showed body wall with tegument, smooth muscle fibres with the eggs completely filling these segment spaces.
Though Dipylidium caninum in humans is rare, there have been some reports of dipylidiasis mostly in children worldwide. ,,, To the best of our knowledge, no documented cases of human dipylidiasis have been reported from Odisha. Till date, 120 human cases of dipylidiasis have been reported with only two human cases from India, one from Kolkata (West Bengal,)  and another from Karimnagar, Andhra Pradesh. 
Although humans are not the natural hosts, there have been growing reports of dipylidiasis in humans recently. A human case of dipylidiasis in a 2-year-old child was reported from Chile by Neira et al.  In another study, it was found that the patients were mainly children,30% of whom were aged <6 months and 85% were aged <8 years. 
A case of Dipylidium caninum was reported in a 9-year-old child from Karimnagar by Ramana et al. They reported the finding of adult worm and eggs in clusters from the stool specimen similar to those in the present report. However, the study did not mention about histopathological confirmation as in our study.
Microscopic examination for ova and parasites may not be helpful in the diagnosis of dipylidiasis unless proglottids are demonstrated. The gravid segments do not release eggs within the intestine of the host. It has been speculated that infants may develop resistance, which may explain the paucity of cases in older children and adults. Lack of direct exposure to infected animals and personal hygiene may also be the contributing factors to infrequent diagnosis in adults. 
Appropriate treatment of Dipylidium caninum infection includes praziquantel palmoate and niclosamide. , The infection is preventable by keeping pet dogs and cats free of tapeworm infestation and colonization by fleas.
Though many cases are asymptomatic, the clinical microbiologists and pediatricians must recognize the significance of dipylidiasis in children with abdominal complaints. Microscopic examination of stool helps in resolving many diagnostic dilemma.
| ~ References|| |
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]
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