|Year : 2015 | Volume
| Issue : 1 | Page : 179-180
Diagnostic dilemma in hookworm infection: An unusual case report
B Sharma, S Mohapatra, AM Kumar, M Deb
Department of Microbiology, Vardhaman Mahavir Medical College and Safdarjung Hospital, New Delhi, India
|Date of Submission||07-Nov-2013|
|Date of Acceptance||27-Mar-2014|
|Date of Web Publication||5-Jan-2015|
Department of Microbiology, Vardhaman Mahavir Medical College and Safdarjung Hospital, New Delhi
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Sharma B, Mohapatra S, Kumar A M, Deb M. Diagnostic dilemma in hookworm infection: An unusual case report. Indian J Med Microbiol 2015;33:179-80
|How to cite this URL:|
Sharma B, Mohapatra S, Kumar A M, Deb M. Diagnostic dilemma in hookworm infection: An unusual case report. Indian J Med Microbiol [serial online] 2015 [cited 2020 Jun 4];33:179-80. Available from: http://www.ijmm.org/text.asp?2015/33/1/179/148418
Hookworm infection is a common public health problem, caused by Ancylostoma duodenale and Neactor americanus. Approximately one billion people are affected in the underdeveloped countries and characterised by iron deficiency anaemia and hypoalbuminaemia.  The diagnosis is based on the identification of characteristic ova in the stool. 
A 17-year-old male was admitted to the medicine ward with chief complaints of generalised swelling, passage of black-coloured stool and fever for 3 month. On physical examination, the patient was febrile, anaemic with bilateral pedal pitting oedema. The complete blood count report reveals haemoglobin 6.6 g/dL, WBC 12,000/L. Peripheral blood film showed microcytic hypochromic anaemia with no malaria parasite. Liver function test showed reversal of albumin globulin ratio (albumin: Globulin 2.2:3.9). Blood and urine were found sterile. On routine examination, the stool sample was found to be black in colour, semisolid in consistency, and foul smelling without any segments or adult worm. On wet mount examination, non-bile-stained ova (60-65 μm in length, 40-45 μm in width) with transparent hyaline shell membrane containing different developing stages i.e. motile larvae (15-20/cover slip), developing granulated larva (2-5/cover slip) and blastomeres (3-4/cover slip) were observed [Figure 1]. For further confirmation of larval forms and to exclude the probability of mixed infection with Strongyloides stercoralis, the modified Harada Mori nematode larval culture method was performed. The suggestive diagnosis was communicated to the clinician on the same day and HIV test was suggested, which was later found to be negative. Similar findings were observed in the repeat stool sample.
|Figure 1: Wet mount showing different stages of egg of hookworm (a) immature and mature form, (b) granulated developing larva, (c) fully developed larva|
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Hookworm infection is acquired by penetration of the 3 rd stage larvae (L3) through the skin. L3 migrates through the body, entered to the lungs and later swallowed to reach the intestine where it grows to adult form. The disease is manifested as iron deficiency anaemia with reduced haemoglobin, serum ferritin, which is in direct co-relation with the number of parasite (as measured by quantitative egg count).  In the present case, although presence of blastomere was highly suggestive of hookworm, the larval forms may create confusion between the identification of the hookworm and Strongyloides stercoralis infection. Srongyloides stercoralis is viviparous and only larval forms are excreted in stool. The large number of eggs containing larvae as seen in the present case was unusual. Modified Harada Mori larval culture method helped in confirmation of identification of larvae. In the present case, the characteristics morphological features were noted and compared with the Srongyloides stercoralis larva (laboratory preserved stool sample). The long mouth part of the larvae in the test sample was distinctive [Figure 2]. Moreover, genital primordium and double bulb oesophagus were more prominent in the larvae of S. stercoralis.  Hence, the above case was confirmed as hookworm infection. The patient was treated with Albendazole (400 mg OD ×3 days).
|Figure 2: Rhabditiform larva of hookworm showing (a) long slit in the mouth part, (b) less prominent double bulb oesophagus|
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Confirmation of diagnosis in intestinal nematodes is very important in the view of therapeutic approach. Although Albendazole and Iverrnectin are the drug of choice for hookworm infection and S. stercoralis infection, respectively; but vice-versa they are ineffective. The larvae of hookworm resemble S. stercoralis and create confusion in diagnosis. The differential diagnosis in such a situation is essential. Modified Harada Mori nematode larval culture method is rapid, cost-effective, and would be useful for the confirmation of the diagnosis and for the therapeutic benefits of the patients.
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[Figure 1], [Figure 2]