Leprosy: Factfile

Leprosy is a chronic infectious disease caused by Mycobacterium leprae. The Norwegian physician, Dr. Gerhard Armauer Hansen, discovered it in 1873. It is also known as Hansen' disease. Leprosy can either be Paucibacillary leprosy or Multibacillary leprosy. It is classified on the basis of clinical signs and skin smear results.

In classification based on skin smears, patients showing negative smears at all sites are classified as having Paucibacillary leprosy, while those showing positive smears at all sites are grouped as having Multibacillary.

In clinical classification, those with one to five skin lesions are grouped as Paucibacillary and those with five to 10 lesions as Multibacillary.

Leprosy elimination aims to reduce Prevalence Rates (PR) in any given endemic area to less than one case per 10,000 population. Multi-drug therapy (MDT), available free of cost, is the best way to deal with leprosy. It interrupts the transmission chain and cures the disease, preventing mutilation and deformation. More than 12 million cases have been treated and cured by the beginning of the year 2002.

The number of countries showing prevalence rates above one per 10,000 population has come down from 122 in 1985 to 14 at the end of 2001.

India, Brazil, Madagascar, Mozambique, Myanmar and Nepal represent 90 per cent of the global burden. Bihar, Madhya Pradesh, Orissa, Uttar Pradesh and West Bengal are the worst affected States in India.Punjab, Nagaland and Haryana have prevalence rate of less than one per 10,000 population.

Leprosy is completely curable at any stage with MDT, if taken regularly.

It is not hereditary or caused by immoral behaviour. Not more than 2 to 5 per cent of the population develops leprosy in any endemic community, as 95 per cent of the population is immune to it. Only about 20 per cent of the cases are infectious.

Paucibacillary leprosy is relatively harmless.

The most frequent form, it accounts for 70 to 80 per cent of the cases. Wire touch with an infectious patient does not spread leprosy. Only prolonged contact with an untreated infectious case can spread it. Early signs of leprosy could be discoloured patches on skin, with partial or complete loss of sensation to light touch and prick over the patch. It could also be numbness in hand and feet. Or, multiple, smooth, ill-defined red spots or patches on the face, buttocks, back or other parts with or without loss of sensation.

The inhalation of bacilli-laden dust particles is thought to be the most likely path of its transmission.

Environment factors such as unhygienic and crowded living conditions contribute to the spread of the disease.

Malnutrition and weak immune system favour infection.

New cases will continue to crop up for some more years not because of continued transmission of infection but as a result of infection acquired years earlier.

Leprosy has a long incubation period, which is believed to last up to 40 years.

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