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Year : 2022  |  Volume : 67  |  Issue : 5  |  Page : 624
Patterns and trends of tribal leprosy: An overview from a tertiary care leprosy clinic of Choto Nagpur Plateau of Eastern India

1 Department of Dermatology, B. S. Medical College, Bankura, West Bengal, India
2 Department of Dermatology, Burdwan Medical College, Burdwan, West Bengal, India

Date of Web Publication29-Dec-2022

Correspondence Address:
Somenath Sarkar
Barsul, Burdwan - 713 124, West Bengal
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijd.ijd_227_22

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Background: Leprosy is a chronic granulomatous disease mainly affecting the peripheral nerves and skin. Any communities including the tribals are susceptible to leprosy. Very few studies on clinico-epidemiological patterns of leprosy have been reported in the tribal population, especially in the Choto Nagpur plateau. Aims: To observe clinical types of newly diagnosed leprosy cases among the tribal population and demonstrate bacteriological index, frequency of deformity, and lepra reaction at presentation. Methods: An institution-based cross-sectional study was conducted with consecutive newly diagnosed tribal leprosy patients attending the leprosy clinic of a tribal-based tertiary care center of Choto Nagpur plateau of eastern India, from January 2015 to December 2019. Thorough history taking and clinical examination were done. A slit skin smear for AFB was performed to demonstrate the bacteriological index. Results: There was a steady rise in total leprosy cases from 2015 to 2019. Borderline tuberculoid (BT) was the commonest form of leprosy (64.83%). Pure neuritic leprosy was not uncommon (16.26%). Multibacillary leprosy was noted in 74.72% of cases and childhood leprosy was observed in 6.70% of cases. The commonest nerve involved was the ulnar nerve. Garde II deformity was noted in around 20% of cases. AFB positivity was observed in 13.73% of cases. A high bacteriological index (BI ≥3) was noted in 10.65% of cases. Lepra reaction was observed in 25.38% of cases. Conclusion: BT leprosy, pure neuritic leprosy, childhood leprosy, grade II deformity, and higher AFB positivity were prevalent in this study. The tribal population required special attention and care for the prevention of leprosy amongst them.

Keywords: Choto Nagpur plateau, leprosy, tribal

How to cite this article:
Sarkar S, Sarkar T, Patra AC, Ghosh A, Gorai H, Mondal S. Patterns and trends of tribal leprosy: An overview from a tertiary care leprosy clinic of Choto Nagpur Plateau of Eastern India. Indian J Dermatol 2022;67:624

How to cite this URL:
Sarkar S, Sarkar T, Patra AC, Ghosh A, Gorai H, Mondal S. Patterns and trends of tribal leprosy: An overview from a tertiary care leprosy clinic of Choto Nagpur Plateau of Eastern India. Indian J Dermatol [serial online] 2022 [cited 2023 Feb 7];67:624. Available from:

   Introduction Top

Leprosy (Hansen's disease) is a chronic infectious disease caused by Mycobacterium leprae. It is essentially a disease of the peripheral nerves but can affect the skin, muscles, eyes, bones, and other internal organs. Leprosy is clinically characterized by hypopigmented patches, partial or total loss of cutaneous sensation of the affected area, and thickened peripheral nerves. The signs of advanced disease are the presence of nodules and lumps, especially on the face and ears, loss of digits, claw hand, planter ulcers, foot drop, claw toes, depression of nose, and other deformities.

The disease manifests itself in two polar forms, namely tuberculoid and lepromatous leprosy. In between the two polar types, borderline and intermediate form of leprosy occurs, depending on the cell-mediated immune response (CMI) of the host to the bacteria. Indian leprologists classified leprosy mainly depending upon the clinical features into five types, namely, tuberculoid type, borderline type, lepromatous type, pure neuritic type, and intermediate type.[1] According to the clinical, immunological, histopathological, and bacteriological aspects, leprosy had been classified by Ridley and Jopling into five types. They are tuberculoid (TT), borderline tuberculoid (BT), mid borderline (BB), borderline lepromatous (BL), and lepromatous (LL).[2] The WHO has classified leprosy simply into two types for the field workers, that is, multibacillary (MB) and paucibacillary (PB).[3] The global prevalence of leprosy in 1985 was 12 per 10,000. Since then, there has been a consistent decline in leprosy cases and it has come down to <1 per 10,000 by 2008. But still India has the major burden of leprosy cases worldwide. In 2007–2008, the prevalence was 0.72 per 10,000 populations. Also, 554 districts (81.29%) out of 682 districts in India achieved leprosy elimination by March 2007. Amongst the Indian states, Chhattisgarh, Jharkhand, Bihar, and West Bengal had a higher prevalence of leprosy.

Our leprosy center is located in the western part of West Bengal, within the Chota Nagpur plateau. It is inhabited by various tribes, such as santal, cole, vill, munda, and others since a very long. In spite of cultural admixture, they are still socially backward in many ways. Demographic diversity, social non-acceptance, inaccessibility, scarcity of health care facilities, and difficulties in implementing national programs made them susceptible to many diseases including leprosy. Hence, the present study was undertaken to observe the patterns and trends of newly diagnosed leprosy cases among the tribal population of Choto Nagpur plateau of eastern India, who attended the Leprosy Outpatient Department (OPD) of a rural and tribal-based tertiary care center and demonstrate the bacteriological index in them. The study was also subjected to determine the frequency of deformities and lepra reaction at the time of presentation.

   Materials and Methods Top

This institution-based cross-sectional study done with consecutive newly diagnosed cases of leprosy belongs to the tribal population, irrespective of their age and sexes who attended the leprosy OPD of a tribal-based tertiary care leprosy center of Choto Nagpur plateau of eastern India, between 15 January and 19 December. The only exclusion criteria were those patients or parents (in the case of minors) who refused to give consent. The study was approved by Institutional Ethics Committee. Tribal patients were identified by taking appropriate history about their ethnicity and also by considering their surnames. After taking proper consent, demographic data were collected by history taking and a thorough clinical examination was performed. Slit skin smear for AFB was performed in all patients and the smears were stained using the Ziehl–Neelsen technique,[4] and the bacteriological index was determined according to the Ridley scale.[5] Histopathological examination and Fite's staining were done when it was found to be necessary. The occurrence of deformity and lepra reaction was observed. All data were collected in a pre-structured case data sheet and analyzed accordingly using appropriate statistical software (Medcalc version by Acacialaan 22, B-8400, Ostend, Belgium).

   Results Top

The overall dermatology OPD attendance from January 2015 to December 2019 was 733,437, amongst them, the number of newly diagnosed leprosy patients in the tribal population was 918. The proportion of new leprosy patients per 1000 increased from 1.09 in 2015 to 1.39 in 2019. Year-wise total OPD attendees, number of new leprosy patients in tribals, and the proportion of new leprosy cases amongst them are summarized in [Table 1]. Eight patients out of 918 denied to give consent; hence 910 patients were included in the study. The ages of the patients ranged from 7 to 72 years with a mean of 35.8 ± 12.52 years. More than half of the patients were between 21 and 40 years of age [Vide [Table 2]]. Most patients were male, with a female-to-male ratio of 1:2.05. Borderline tuberculoid (BT) leprosy was the commonest (63.04%) form of leprosy found in the study, followed by pure neuritic leprosy (16.26%), borderline lepromatous (8.35%), and lepromatous leprosy (5.05%) [Vide [Table 3]]. Histoid leprosy was observed in 1.20% of cases. According to the WHO classification, PB leprosy was noted in 25.27% of cases and MB leprosy in 74.72% of cases. Childhood leprosy was observed in 6.70% of cases. There was a consistent rise in the total number of leprosy cases from 2015 to 2019 in the study population. MB cases showed a steady rise, whereas PB cases showed a slight decline [Figure 1].
Table 1: Year-wise distribution of dermatology OPD attendees and newly diagnosed tribal leprosy patients

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Table 2: Age distribution (n=910)

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Table 3: Types of leprosy (n=910)

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Figure 1: Year-wise distribution of PB and MB cases

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The majority of the patients (around 82%) presented with skin lesions. Anesthesia or hypoesthesia was noted in 674 patients (74.06%). Occurrences of other presenting symptoms, such as pain, fever, swelling of legs, tingling sensation, numbness, trophic ulcers, and deformity, are summarized in [Table 4].
Table 4: Presenting complaints (n=910)

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Most patients presented with macules (48.57%), followed by plaques (38.57%), ulcers (6.37%), nodules (5.71%), and papules (2.19%). Dry skin lesions and loss of hair were noted in 46.7% and 48.51%, respectively. Glistening skin surface was observed in 96 (10.54%) cases, and all of them were having lepromatous spectrum. Sensory impairment was noted among 674 (74.06%) patients. The upper limb (48.46%) was the commonest site of involvement followed by the lower limb (32.74%), trunk (14.72%), and face (4.94%). Overall, the most common nerve involved was the ulnar nerve (36.48%). Other nerves involved in the upper extremities were the radial nerve (6.70%) and the median nerve (6.04%). The common nerves involved in the lower limbs were the common peroneal (29.01%), posterior tibial nerve (8.79%), and anterior tibial nerve (7.14%). In the head-neck region, the commonest nerve involved was the great auricular nerve (3.51%). Feeding nerve to the lesion was demonstrated in 13.62% of cases [Vide [Table 5]].
Table 5: Nerve involvement (n=910)

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In this study, a slit skin smear for AFB was positive in 13.73% of cases. All smear-positive cases were within the lepromatous spectrum. Only a few cases of the lepromatous spectrum showed AFB negativity. AFB was demonstrated by doing Fite's staining on histology. BI ≥3 was noted among 10.65% (97 out of 910) of cases [vide [Table 6]]. At presentation, lepra reaction was present in 231 (25.38%) cases, of these, 16.70% had type 1 reaction and 8.68% had type II reaction.
Table 6: Bacteriological index (n=910)

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Grade II deformity was noted in 20.10% of cases in the present study. Among the pure neuritic patients, grade II deformity was observed in 95.94% of cases [vide [Table 7]]. The commonest deformity was a claw hand (7.19%). Trophic ulcer, foot drop, and claw toe were noted in 6.37%, 4.83%, and 2.195% of cases, respectively.
Table 7: Grade II deformity

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   Discussion Top

Leprosy is probably the oldest disease known to mankind. It is often called a social disease.[6] There are numerous factors that favor the spread of leprosy in the community, such as poor housing, overcrowding, lack of personal hygiene, and education. Amongst the communicable diseases, leprosy is a major cause of permanent physical disability. Due to the involvement of peripheral nerves, there is a loss of sensation in the hands, feet, and eyes and muscular weakness leading to ulceration and deformity. Social stigma and discrimination associated with leprosy are primarily due to ulceration and disability caused by the disease. Early diagnosis and proper treatment (including lepra reaction) before nerve damage are of utmost importance to prevent disability. With proper treatment and care, a leprosy patient can lead a productive life. To plan health care activities in a community, we need to know the prevalence of that disease, its types, and complications thoroughly. This study enlightens the clinical types and consequences of leprosy in the tribal population of the Choto Nagpur plateau for epidemiological purposes.

Multidrug therapy came into wide use in India since 1982. National Leprosy Eradication Programme (NLEP) was launched by the Ministry of Health and Family Welfare, Government of India, in 1983 with the objective to reduce the disease burden in the country. Due to their tremendous efforts, India has brought down the national prevalence of leprosy from 57.8/10,000 in 1983 to “elimination as a public health problem” (i.e. less than 1/10,000) in December 2005 and even further down to 0.66/10,000 in 2016.[7] The NLEP data showed a new case detection rate of 9.71/100,000 population in 2015–2016. The childhood new case detection rate was 0.89/100,000 population. Affection among the tribal population was 18.79%. MB leprosy was predominant (51.27%) and grade II deformity was present among 4.60% of cases. The NLEP data of West Bengal of the same year showed the prevalence was <1/100,000 populations. The numbers of new cases detected were 9,054, among which 13.86% were tribals. MB Hansen was noted in 69.3% of cases. Childhood MB Hansen was observed in 3.51% of cases. Grade II deformity was obtained in 4.61% of cases.[8]

Borderline tuberculoid (near 65%) was the commonest form of leprosy in this study, borderline lepromatous, and mid borderline leprosy were observed in around 8% and 1%, respectively. So, as a whole, the borderline spectrum of leprosy was noted in around 74% of cases. These data were more or less comparable with those of the study conducted in Jammu in 2008,[9] and in Surat in 2008,[10] Greece during 1988–2000.[11] The proportion of MB leprosy in the study population (74.72%) was much higher than the national prevalence of MB leprosy (51.27%) and it is slightly higher than the occurrence of MB leprosy in West Bengal (69.3%) in 2015–2016.[8] The proportion of childhood leprosy (6.70%) in our study was slightly higher than that occurred in pan west Bengal acceding to the NLEP data of 2015–2016.[8] Data from the WHO showed that 208,619 new cases of leprosy were reported in 2018 from 127 countries, including all priority endemic countries, compared with 211,009 cases in 2017, indicating a slight global decrease of cases by 1.2%. India reported a decline in the number of new cases in 2017–2018, nearly 15,000 cases (135,485 in 2016 to 120,334 in 2017–2018).[12] The present study demonstrates there is a consistent rise in the total number of leprosy cases in the tribal population. Amongst the types of leprosy, MB cases showed a steady rise, whereas a slight decline was noted for PB cases, indicating the need for special attention for this population.

The proportion of pure neuritic leprosy was around 16% in the present study, which was much higher than the studies such as the study done Mahajan et al. (4.6%)[13] and the study done in Oman (6.2%)[14] So, like borderline leprosy, pure neuritic leprosy was quite high among the tribal population. Nerve thickening was noted in around 80% of cases, which was lower than the study done in Ethiopia (>90%)[15] but it is still much higher than different studies from India.[9],[10] The nerves involved were the ulnar nerve (around 36%), common peroneal nerve (around 29%), posterior tibial nerve (near to 9%), and anterior tibial nerve (around 7%). Involvement of the nerves is more or less similar to the study done in Ethiopia[15] and India.[11] Thickened feeding nerve was observed in around 13% of cases, which was quite higher than the Indian study done by Kumar et al.[16]

The WHO launched a 5-year “Global Leprosy Strategy 2016–2020 in April 2016 titled 'accelerating towards a leprosy-free world'.[17] This was based on the earlier 5-year (2011–2015) strategy that emphasized early leprosy detection to reduce deformities and disabilities. Grade II deformity was observed in around 20% of cases in the present study. The caseload of grade II deformity was much higher than that of the NLEP data of 2015–2016 (4.60%).[10] Among the pure neuritic leprosy patients, grade II limb deformity was noted in 95.94% of cases which was nearly double in the study done at Poona (48.6%).[13] This clearly denotes that the burden of deformity of leprosy is still very much high in the tribal population.

The proportion of lepra reactions documented in the present study was around 25%. Of them, around 16% showed type I reaction and the rest are type II reaction. This is quite higher than the occurrence of lepra reaction in a study done at Jodhpur in 1995.[18] It can be appreciated from the data that lepra reaction is much more prevalent among the tribal community.

The latest update from the WHO titled “Global leprosy update, 2016: accelerating reduction of disease burden: states that – although there has been a significant reduction in the prevalence of the disease worldwide since the mid-1980s to elimination levels, new cases continue to arise indicating continued transmission.[19] In our study, AFB positivity was noted in around 13% of cases. Most smear-positive cases were within lepromatous spectrum, which was consistent with the study done at Wardha by Naik et al.[20] In their study, BI ≥3 was noted among 9.23% of cases but in our study, BI ≥3 was noted among 10.65% of cases. This clearly denotes higher BI among the AFB-positive patients, indicating a higher possibility of the spread of leprosy among the tribals.

   Conclusion Top

The present study demonstrates a higher proportion of borderline tuberculoid leprosy in the tribal population of the Choto Nagpur plateau, indicating a higher degree of CMI in them. Pure neuritic leprosy, childhood leprosy, grade II deformity, and lepra reaction are quite high among them. A high bacillary index in study subjects indicates a higher possibility of spread. This study concludes that the tribal population needs much more attention for the prevention of deformity as well as the intercommunity and intra-community spread of leprosy.


It is not a community-based study; it is very difficult to predict the exact burden of leprosy and its consequences in the concerned population. For this, a community-based study with a door-to-door survey is needed.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names 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.

   References Top

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Ridley DS, Jopling WH. Classification of leprosy according to immunity. A five group sustem. Int J Lepr other Mycobact Dis 1966;34:255-73.  Back to cited text no. 2
WHO Expert Committee on Leprosy. Seventh report. Technical Report Series No. 874. Geneva: World Health Organization; 1998.  Back to cited text no. 3
Collee JG, Duguid JP, Fraser AG, Marmion BP. Practical Medical Microbiology. 13th ed. Edinburg: Churchill Livingstone; 1989. p. 46.  Back to cited text no. 4
Ridley DS. Bacterial indices. In: Cochrane RG, Davey TF, editors. Leprosy in Theory and Practice. Bristol: John Wright and Sons; 1964. p. 620-2.  Back to cited text no. 5
Willims HW. Leprosy- A social disease. Can Med Assoc J 1977;116:834-5.  Back to cited text no. 6
Rao PN, Suneetha S. Current situation of leprosy in India and its future implications. Indian Dermatol Online J 2018;9:83.9.  Back to cited text no. 7
NLEP Annual Report 2015-2016. Central Leprosy Division, Directorate General of Health Services, Ministry of Health and Family Welfare Government of India, Nirman Bhavan, New Delhi.  Back to cited text no. 8
Sharma A, Sharma RK, Goswami KC, Bardwaj S. Clinicohistopathological correlation in leprosy. Ind J Dermatol Venereol Leprol 2008;10:120-3.  Back to cited text no. 9
Pandya AN, Tailor HJ. Clinicohistopathological correlation of leprosy. Indian J Dermatol Venereol Leprol 2008;74:174-6.  Back to cited text no. 10
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Leprosy New data showed steady decline of new cases. Geneva: World Health Organization; 2018. Avilable from: [Last accessed on 2018 Jun].  Back to cited text no. 12
Mahajan PM, Jogaikar DG, Mehta JM. A study of pure neuritic leprosy: Clinical experience. Indian J Leprol 1996;68:137-41.  Back to cited text no. 13
Al-Suwaid AR, Venkatram MN, Banodkar DD. Study of pure neuritic leprosy in Oman. Gulf J Dermatol 1994;1: 25-7.  Back to cited text no. 14
The Diagnosis and Classification of Leprosy. Int J Lepr other Mycobact Dis 2002;70 (1 Suppl):S25.  Back to cited text no. 15
Kumar B, Kour I, Dogra S, Kumaran MS. Pure neuritic leprosy in India: An appraisal. Int J Lepr other Mycobact Dis 2004;72:284-90.  Back to cited text no. 16
Global leprosy strategy 2016–2020: Accelerating towards a Leprosy-Free World. New Delhi, World Health Organization, Regional Office for South-East Asia; 2016.  Back to cited text no. 17
Soladkar AD, Kalla G. A clinico-epidemiological study of leprosy in arid north-west Rajasthan, Jodhpur. Indian J Lepr 1995;67:161-6.  Back to cited text no. 18
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Naik VB, Naik UB, More S, Rao VP. Evaluation of significance of skin smears in leprosy for diagnosis, follow-up, assessment of treatment outcome and relapse. Asiatic J Biotechnolol Resources 2011;2:547-552.  Back to cited text no. 20


  [Figure 1]

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7]


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