Indian Journal of Health Sciences and Biomedical Research KLEU

: 2015  |  Volume : 8  |  Issue : 2  |  Page : 153--155

Incidental demonstration of filaria saved a child from pyrexia of unknown origin: Report of an interesting case

Anindya Adhikari1, Palash Kumar Mandal2, Krishnendu Haldar1, Sanjay Sengupta1,  
1 Department of Pathology, Bankura Sammilani Medical College, Bankura, India
2 Department of Pathology, North Bengal Medical College, Siliguri, Darjeeling, West Bengal, India

Correspondence Address:
Anindya Adhikari
Vil-Basudevpur, P.O. Banipur, P.S. - Sankrail, Howrah, West Bengal


Filariasis is endemic in tropical countries. Though commonly affects lymphatic system, the majority are asymptomatic and even amicrofilaremic, i.e. may not show microfilariae in blood. Uncommonly, filaria may affect other body tissues. Herein, we report a case where a 10-year-old boy form Orissa presented with pyrexia of unknown origin for 6 months. He had a moderate degree of pallor and lymphadenopathy. Blood examination showed moderate anemia and mild pancytopenia. Other blood tests, fine needle aspiration cytology of lymph node including radiological investigations were inconclusive. Bone marrow examination incidentally demonstrated microfilaria and adult worm was detected in lymph node biopsy. The boy recovered fully with antifilarial drug and hematinic.

How to cite this article:
Adhikari A, Mandal PK, Haldar K, Sengupta S. Incidental demonstration of filaria saved a child from pyrexia of unknown origin: Report of an interesting case.Indian J Health Sci Biomed Res 2015;8:153-155

How to cite this URL:
Adhikari A, Mandal PK, Haldar K, Sengupta S. Incidental demonstration of filaria saved a child from pyrexia of unknown origin: Report of an interesting case. Indian J Health Sci Biomed Res [serial online] 2015 [cited 2022 Dec 4 ];8:153-155
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Full Text


Lymphatic filariasis caused by mosquito-borne nematodes Wuchereria bancrofti is one of the major health problems in tropical countries. India is among the worst affected countries with 45 million disease burden and 6 million new cases per year. W. bancrofti is responsible for 98% of the cases of filariasis in India. The highest number of cases in this country is reported from coastal areas and banks of big rivers. [1],[2] Adult worms of W. bancrofti reside in the lymph node or lymphatic channels. However, microfilariae even in asymptomatic cases can reach various tissue spaces. [3] Diagnosis of filariasis mainly depends on the demonstration of microfilariae in blood or occasionally in body fluids and other tissues. Adult worms also have been shown in few cases. [4] Our case was diagnosed by demonstration of microfilaria in bone marrow aspirate and adult worm in lymph node biopsy. The case is unique because marrow involvement by filaria is very rare and exact incidence is not found in any literature as it is always an incidental finding.

 Case Report

A 10-year-old boy from Orissa (a coastal state of India) presented with weakness and irregular fever for 6 months. He had only moderate pallor and a large nontender left axillary lymph node of about 2.5 cm in diameter and few small discrete nodes in the right axillary region and both sides of the neck. Investigations revealed hemoglobin 8.5 g/dl, raised erythrocyte sedimentation rate, mild pancytopenia. No hemoparasite was detected. Fine needle aspiration cytology of left axillary lymph node showed features of reactive hyperplasia. After treatment with hematinics, antibiotics, and antihelminthic there was no significant improvement. Then bone marrow examination and axillary lymph node biopsy were done. Bone marrow aspirate revealed four microfilariae [Figure 1]. Histopathological examination of the lymph node showed the presence of adult filarial worm of W. bancrofti [Figure 2]. On treatment with antifilarial drugs and hematinics, the patient recovered completely.{Figure 1}{Figure 2}


Lymphatic filariasis, a chronic disorder whose common manifestations are prolonged fever, lymphangitis or lymphadenitis, lymphedema of extremities, breast, or scrotum. However, majority particularly in endemic areas usually remain asymptomatic or may have vague symptoms not usually linked to filariasis. Many cases may not show microfilariae in blood even after proper collection (amicrofilaremic case). This is again commonly observed in endemic areas with high rate of disease transmission. [5] This may be the reason for our failure to demonstrate microfilariae in blood in the present case. The diagnosis of these atypical amicrofilaremic cases is really challenging. In few of these cases, incidental demonstration of microfilariae or rarely adult worm in various tissue samples may lead to correct diagnosis. [6-9] Though there are many sophisticated tools available such as filarial antigen detection [10],[11] [(by ELISA, immunochromatography, polymerase chain reaction) and even ultrasonography of lymph nodes (filarial dance sign) [12],[13] most of these cannot be afforded by people of lower socioeconomic strata. In the index case, we were able to demonstrate both adult worms and larval forms in amicrofilaremic patient. Microfilaria possibly reached the bone marrow due to lymphatic obstruction and subsequent extravasation. [5] Adult worms are slender, thread-like with tapering ends without any cuticular appendages. Confirmation of species is often impossible. [3] Microfilariae in bone marrow aspirate were identified by their thin elongated structure, wide head end, and pointed tail end. Microfilariae of W. bancrofti were differentiated from larval forms of other sheathed nematodes (Brugia malayi, Loa loa) by their pointed tail and the absence of nucleus toward the end. [2],[3],[4] Pradhan et al. reported seven cases of microfilarial infestation of the bone marrow. [7] Five out of 6 cases reported by Shenoi et al. were found to have aplastic anemia. [8] However, in none of the previously reported cases cause-effect relationship was established between microfilarial infestation and bone marrow aplasia. Our patient had features of mild pancytopenia.

Financial support and sponsorship

Department of Pathology, Bankura Sammilani Medical College, Bankura, West Bengal, India.

Conflicts of interest

There are no conflicts of interest.


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