Causes of leprosy
Leprosy is one of the oldest recorded diseases. It's caused by the bacteria Mycobacterium leprae, a very slow-growing bacteria similar to that which causes tuberculosis.There are three types of the disease. The generalised form - the lepromatous form - attacks peripheral nerves, the skin, the hands and feet, the mucous membranes (such as the lining of the nose) and the eyes. In contrast, the tuberculoid form is localised, so its effects are less widespread across the body. The third type is known as borderline or dimorphous leprosy, and is has characteristics of both other forms.
Leprosy is passed from person to person by droplets from the nose and mouth of untreated patients with severe disease. However it's not highly infectious.
According to the World Health Organization (WHO) there has been a dramatic decrease in cases in recent decades from 5.2 million cases in 1985 to 805,000 in 1995 and 213,036 cases at the end of 2008. However, more than 200,000 new cases are still reported each year, and it's most prevalent in poverty-stricken areas of in Asia, Africa and Latin America.
Symptoms of leprosy
Leprosy is a chronic infectious disease that attacks the nervous system, particularly the nerves of the hands, feet and face. Sufferers may feel no pain in these areas and are thus likely to injure themselves without realising it.Lepromatous leprosy symptoms are a chronically stuffy nose and many skin lesions and nodules on the front and back of the body. Sensation loss starts at the fingers and toes and may only affect a small patch of skin to begin with. The loss of sensation can lead to unnoticed injuries, which may in turn become infected. In advanced cases, gangrene may set in with loss of body tissues. With time there may be significant damage to the body, and those disfigured by leprosy used to be widely shunned by their communities.
Tuberculoid leprosy symptoms usually consist of a few well-defined skin lesions that are numb. Sensation loss may only affect a small patch of skin. Again, the loss of sensation can lead to unnoticed injuries, infection and tissue damage.
Dimorphous leprosy creates skin lesions characteristic of the lepromatous and tuberculoid forms.
Treatments for leprosy
Leprosy is curable, but the effectiveness of the treatment is dependant on an early diagnosis (before tissue damage occurs). Diagnosis these days is very simple.Since 1982, the WHO has recommended a 6-12 month course of multidrug therapy (MDT), which it provides free throughout the world. Patients are given a cocktail of 3 strong antibiotics (dapsone, rifampicin and clofazimine) which can completely cure the tuberculoid form of the disease within six months and the more infectious lepromatous form within two years. A combination of drugs must be used because the leprosy bacteria can develop resistance to antibiotics given individually as single treatments. MDT is highly effective, has few side effects and no known drug resistance.
If treatment is started early, deformities and disabilities can be prevented. MDT also makes the few highly infectious patients non-infectious very quickly, which helps prevent the spread of leprosy.
To date more than eight million patients have been totally cured of leprosy. However, because most cases of the disease occur in difficult to reach places, many of them are not treated early enough.
Vaccines for leprosy are being tested but aren't yet in general use.
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