LeprosyLepra – formerly also called "leprosy" – is a bacterial infectious disease, which was already described in writings of antiquity. Today, it occurs mainly in India, South America and Southeast Asia. Although the number of cases has declined worldwide and leprosy is curable, severe cases still occur. Affected persons are still ostracized because of leprosy-related skin changes.
At a glance
– Leprosy is a chronic infectious disease caused by bacteria (Mycobacterium leprae). – The disease is still prevalent in India, South America and Southeast Asia. – Leprosy is treated with a combination of different antibiotics, making it curable. – Early treatment is important to prevent leprosy-related disabilities. – If left untreated, the disease can lead to severe physical disabilities and severe skin, eye and nerve damage. – Leprosy patients still experience social rejection in many societies.
What is leprosy?
Leprosy is a chronic infectious disease caused by bacteria called Mycobacterium leprae. The pathogens of tuberculosis (Mycobacterium tuberculosis) also belong to the mycobacteria.
The word leprosy comes from the Greek-Latin and means something like "scaly" or "rough": This points to the disease-conditioned changes of the skin. Nerve damage, which can lead to paralysis and sensory disturbances, is also one of the characteristic symptoms of leprosy.
In Germany, the disease used to be called leprosy. The name probably comes from the fact that people with leprosy were exposed outside human settlements. Even today, leprosy patients are still marginalized and stigmatized.
Although the worldwide number of cases has been successfully contained, the goal of the World Health Organization (WHO) to completely eradicate leprosy has not yet been achieved. Therefore, WHO efforts are directed at further reducing the number of new cases, preventing leprosy-related disabilities as best as possible, and counteracting discrimination against those with the disease.
What are the symptoms of leprosy?
Leprosy leads to visible changes in the skin and to damage of nerves, associated with a loss of pain sensation. Mucous membranes, respiratory tract and the eyes can also be affected. Two to 20 years or even more can pass before the first symptoms appear after infection with the pathogen (incubation period).
There are four types of leprosy: indeterminate leprosy, tuberculoid leprosy, severe leprosy (leprosy lepromatosa), and transitional leprosy (borderline leprosy). The severity of leprosy and the symptoms depend on the immune response and the bacterial load.
Leprosy indeterminata
Leprosy indeterminata manifests itself with isolated small and uncharacteristic skin lesions, which may appear lighter than the rest of the skin. In about three quarters of those affected, the skin lesions heal spontaneously. However, if leprosy indeterminata does not heal, it progresses to one of the following forms of progression.
Tuberculoid leprosy
This form of leprosy develops with a basically functioning immune system: Since the immune defense actively fights the pathogens, tuberculoid leprosy is less severe than leprosy lepromatosa. Few asymmetrical, sharply limited skin lesions occur, which often also have a raised edge. On darker skin, the lesions appear lighter than the surrounding skin, sometimes – especially on lighter skin – they appear reddened. In addition, tuberculoid leprosy causes visible nerve swelling and nerve damage, which can severely impair the sensation of pain and sweat production.
Severe leprosy (leprosy lepromatosa)
In the absence of an immune response, i.e. poorly functioning defenses, reddish skin lesions form symmetrically distributed over the entire body, which sometimes appear light on dark skin. Without treatment, this rash penetrates deep into the skin. This happens mainly in the face. May lead to loss of eyebrows. Swelling and lumps can give the face a lion-like appearance over time, known as "facies leontina" in technical language. Nerve damage leads to pronounced sensory disturbances, including loss of pain and temperature sensation. Ulcers, wounds, deformities and mutilations of limbs are among the possible consequences of the sensory disturbance in leprosy lepromatosa, which often lead to the exclusion of the diseased.
Borderline leprosy
Borderline leprosy refers to gradations or mixed forms between tuberculoid and lepromatous leprosy. Symptoms of both the one and the other form can occur here.
What causes leprosy?
The infection occurs from person to person. Probably leprosy is transmitted mainly by droplets, which are produced and distributed during sneezing. Whether transmission can also occur via skin contact has not yet been clarified. Leprosy is not highly contagious, only prolonged and close contact can lead to a disease-causing infection. Since the bacterium Mycobacterium leprae multiplies very slowly, signs of the disease often do not appear until several years after infection.
What are the known risk factors for leprosy??
Since leprosy is only a moderately contagious infectious disease, the living conditions and the general condition play an important role for the infection. An infection is particularly promoted by malnutrition and a weakened immune system. The climate plays rather a subordinate role.
Where and how often does leprosy occur??
Every year, about 200 people worldwide contract leprosy.000 people. Leprosy occurs particularly in certain areas within Southeast Asia and South America. Men are more often affected than women.
Incidence of leprosy worldwide
Based on the year 2018, there were the most cases in India (120.334), followed by Brazil (28.660) and Indonesia (17.017). But progress is being made in the fight against leprosy: more and more people are being diagnosed and treated before they become disabled. In addition, the number of children suffering from the disease has decreased by 24 percent between 2012 and 2018, compared to only nine percent among adults.
Leprosy in Germany
One case of leprosy was reported in Germany in 2019. Cases of the disease in tourists returning to Germany from South America or Southeast Asia, for example, are rare.
What is the course of leprosy?
There are mild, but also very severe forms of progression. For more information, see the section on symptoms. The course of the disease depends strongly on the immune system of an infected person: The weaker the immune defense, the more unhindered the pathogens can multiply in the body and drive a severe course of the disease.
If left untreated, severe leprosy can lead to mutilation of the hands and feet, serious infections and blindness. These consequences of the disease still lead to social rejection of sufferers in many places today.
How to prevent leprosy?
Currently, there is no approved vaccine for leprosy. However, a first clinical trial to develop a vaccine (LepVax) against leprosy was successfully completed in the USA in 2019. The vaccine has been shown to be very safe and to cause no serious side effects. Since the summer of 2020, a further study has been underway in Brazil in female patients with leprosy. Patients with early leprosy disease carried out.
Some protection against tuberculoid leprosy is offered by the tuberculosis vaccine.
How leprosy is diagnosed?
Initial indications are provided by the symptoms. If leprosy is suspected, the pathogens must be detected. In the so-called skin smears method, the skin is scratched at certain points with a scalpel in order to obtain some lymphatic fluid. In 70 percent of patients, however, this examination does not reveal a bacterial load that is as high as would be required for proof of the disease.
More reliable results are obtained by testing tie samples. A biopsy is necessary for this purpose: That is, a small piece of skin is taken and examined histologically in the laboratory.
How is leprosy treated?
Leprosy can be cured. Early treatment is important to avoid leprosy-related disabilities.
The disease is treated with several drugs at the same time so that resistance does not develop: that is, the bacteria become insensitive to the drugs used. Therapy lasts at least six months.
Agents that can be used in combination include:
Which of these agents a patient receives depends on the form of leprosy diagnosed.
Therapy should be carried out in specialized centers, because inflammatory reactions can occur during the course of treatment, to which doctors must react quickly and in a targeted manner.
Patients do not generally have to be isolated. This is only necessary if open wounds exist.
Sources
– Robert Koch Institute (RKI). Epidemiological bulletin 5/2007: Leprosy – the new global strategy. Retrieved on 12.11.2020. – Robert Koch Institute (RKI). Epidemiological bulletin 4/2020: World Leprosy Day: Leprosy, not what you think. Retrieved on 12.11.2020. – World Health Organization (WHO). Guidelines for the diagnosis, treatment and prevention of leprosy. 10.2018. Retrieved on 12.11.2020. – World Health Organization (WHO). Leprosy (Hansens's disease). Retrieved on 12.11.2020.