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 About
the Disease
Leprosy is a chronic infectious disease caused by
Mycobacterium leprae. It usually affects the skin
and peripheral nerves, but has a wide range of clinical manifestations. The
disease is classified as paucibacillary or multibacillary, depending on the bacillary load. Paucibacillary leprosy is a milder disease characterized
by few (up to five) hypopigmented, anaesthetic skin lesions (pale or reddish). Multibacillary leprosy is associated with multiple (more
than five) skin lesions, nodules, plaques, thickened dermis or skin
infiltration, and in some instances, involvement of the nasal mucosa,
resulting in nasal congestion and epistaxis.
Involvement of certain peripheral nerves may also be noted, sometimes
resulting in the characteristic patterns of disabilities. In most cases of
both paucibacillary and multibacillary
disease, the diagnosis is straightforward, but in a small proportion of
cases, suspects without anaesthetic patches require
examination by a specialist to look for other cardinal signs of the disease,
including nerve involvement and a positive laboratory test (the slit skin
smear).
Among communicable diseases, leprosy is a leading cause of
permanent physical disabilities. Timely diagnosis and treatment of cases,
before nerve damage has occurred, is the most effective way of preventing
disabilities due to leprosy; effective management of leprosy complications,
including reactions and neuritis, can prevent or minimize the development of
further disabilities. The disease and its associated deformities are
responsible for social stigma and discrimination against patients and their
families in many societies.
The mode of transmission of the leprosy bacillus remains
uncertain, but most investigators believe that M. leprae
is spread from person to person, primarily as a nasal droplet infection. The
incubation period is unusually long for a bacterial disease, generally 5-7
years. The peak age of onset is young adulthood, usually 20-30 years of age;
disease is rarely seen in children less than five years old. While humans are
considered to be the major host and reservoir of M. leprae,
other animal sources, including the armadillo, have been incriminated as
reservoirs of infection. The epidemiological significance of these findings
is unknown, but is likely to be very limited, except perhaps in North America. Unlike tuberculosis, there is no
evidence to suggest that an association exists between HIV infection and
leprosy. BCG vaccination is known to have some protective effect against the
disease. 
Achievements
The enormous success in global leprosy control is due to a
combination of three elements: a clear objective, an effective technology and
an explicit implementation strategy. The remarkable achievement in reducing
the global burden of leprosy over the last two decades can be traced to two
important events in the history of the fight against leprosy. The first took
place in 1981, when a WHO Study Group on Chemotherapy of Leprosy recommended the use of multidrug therapy as the standard treatment for leprosy.[1] The success of
multidrug therapy led to the second event in 1991, when the Forty-fourth World Health Assembly adopted resolution WHA44.9,[2]
declaring its commitment to eliminating leprosy as a public health problem by
the end of 2000 – i.e. achieving a prevalence of less than one case per
10 000 population. The following are some of the notable achievements
since MDT was first introduced:
Between 1985 and the beginning of 2008, close to
15 million persons affected by leprosy were diagnosed and cured with
multidrug therapy, with very few relapses reported.
There has been improvement in coverage of leprosy
services, particularly in previously inaccessible areas and in underserved
population groups, especially in countries recovering from prolonged armed
conflicts and civil unrest in the African and Eastern Mediterranean Regions.
Timely case-finding and treatment with MDT has prevented
disabilities due to leprosy among an estimated one to two million
individuals.
There is higher level of awareness and political
commitment in
leprosy endemic countries, with renewed emphasis on human
rights’ issues related to stigma and discrimination faced by persons affected
by leprosy and their families.
One of the favourable features
has been the integration of leprosy control activities into the general
health services. This has been implemented as a policy in the majority of
leprosy endemic countries.
Since 1995, drugs required for multidrug therapy have been
available free of charge in all endemic countries through WHO and this
arrangement is likely to continue for the foreseeable future.
Much progress has been made in developing effective
partnerships with national and international agencies, which has resulted in
improved collaboration among all partners to achieve an agreed common goal.
Objectives
The goal of the Enhanced Global Strategy is to further
reduce the disease burden due to leprosy and sustain provision of
high-quality leprosy services for all affected communities, ensuring that the
principles of equity and social justice are followed
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