2. Leprosy is also called Hansen’s disease after the
discovery of bacteria (Mycobacterium leprae) by
Dr Gerhard Armauer Hansen, in 1873.
3. Can leprosy be cured?
- Yes, leprosy can definitely be cured.
- Highly effective and safe drugs available for the
treatment of leprosy.
4. How is leprosy spread?
-The disease spreads through droplets from the nose or
mouth of a patient to the skin and respiratory tract of
another person.
- The bacteria multiply very slowly and therefore
leprosy is not highly infectious.
- About 95% of people have natural immunity against
leprosy.
5. Different TYPES of leprosy?
- It is classified on the basis of individual’s resistance
to the disease, not the type of bacteria.
-There is only one type of causative agent
(Mycobacterium leprae), but people react to it in
different ways......
6. Classification type-I:
- Leprosy can be classified as
Paucibacillary (PB) leprosy
Multibacillary (MB) leprosy
depending on 3 criterias like
- no. of lesion, - peripheral nerve involvement & - skin smear test.
7. Sl no Paucibacillary (PB) leprosy Multibacillary (MB) leprosy
1 Lesion 1-5 lesions >5 lesions
2 Peripheral
nerve
involvement
0 or 1 nerve involved > 1 nerve involved
3 Skin smear All smears from lesions
should be negative
Even 1 lesion is found to be
positive it is multibacillary
While classifying leprosy, it is particularly important to ensure
that patients with multibacillary disease are not treated with the
regimen for the paucibacillary form of the disease.
8. Classification type-II:
- In 1966, Redley & Jopling developed a classification
system for leprosy based on low & high resistance given by
the body against the bacteria.
- They are
1) Lepromatous type - represents low resistance
- Border line Lepromatous (BL)
- Lepromatous Leprosy (LL)
2) Tuberculoid type - represents high resistance
- Borderline Tuberculoid (BT)
- Tuberculoid Type (TT)
9. Lepromatous type Tuberculoid type
Body’s resistance low high
Severity More severe Less severe
No of lesions More skin lesions Less skin lesions (slow)
Growth of bacteria Significant bacterial
growth
Slow bacterial growth
Infectivity more infectious (spread)
compared to tuberculoid
Less infective to others
10. How humans react when exposed to mycobacterium
leprae?
- Most people resist leprosy so well, so that they will
never develop clinical signs even if exposed to active
cases for long periods.
11. What is the incubation period?
- This ranges from 9 months to 20 years.
- The average is about 4–5 years for tuberculoid leprosy,
and 12 years for lepromatous leprosy.
Incubation period: the period between exposure to an infection and the
appearance of the first symptoms.
12. How is the clinical diagnosis of leprosy made?
- Clinical diagnosis is based on complete skin
examination.
What is the laboratory criterion for diagnosis of
leprosy?
- Scrap-incision method.
13. What is the definition for leprosy by WHO?
- A case of leprosy is a person with one or more of the following
clinical features, and who is yet to complete a full course of
treatment:
● reddish skin lesion(s) with definite loss of sensation
● involvement of the peripheral nerves (definite loss of sensation).
● skin smears positive for bacilli.
14. What other diseases have similar symptoms?
- Many skin diseases which cause patches may
resemble lepromatous leprosy.
- Several skin conditions including fungal infections
which cause discolouration or scars may resemble
tuberculoid leprosy.
15. Do fingers and toes fall off when someone gets leprosy?
- No.
Can leprosy be passed on from parents to children?
- No, leprosy is not a hereditary disease.
16. What is the treatment for leprosy?
- The treatment for leprosy is called
Multi Drug Therapy (MDT).
- It is a combination of drugs depending upon the type
of leprosy.
17. Can BCG immunization also protect against leprosy?
- Yes. Studies show that BCG immunization protects
against leprosy in addition to tuberculosis.
- It is therefore important that every child be
immunized with BCG (Bacille Calmette Guerin).
18. Is leprosy treatment life-long?
- No.
- The treatment lasts between 6–12 months, depending
on the type of disease.
20. Leprosy is a disease caused by a type of bacteria called
Mycobacterium leprae.....
21. These bacteria attack nerves in the hands, feet and face,
causing numbness and loss of sensation to those parts
of the body.
It can also affect the nose and the eyes....
22. It is moderately contagious bacteria and its
transmission requires prolonged direct contact with an
affected individual.
Inoculation through respiratory tract is believed to be a
potential mode of transmission of infection.
24. The causative agent of leprosy is the bacillus,
Mycobacterium leprae.
Target for M.laprae
It is an intra cytoplasmic parasite of
- macrophages ( a phagocytic WBC cell found in stationary form in the tissues , especially at
sites of infection) &
- Schwann cells (Schwann cells are the cells in the peripheral nervous system that produce
the myelin sheath around the axons of neurons)
25. Way of entry:
The pathogens enter the body through the
respiratory system (droplet spread) or by
contagious prolonged contact
with a diseased person.
Ability of M.laprae:
Generally, M. laprae has low pathogenicity and only a small
percentage of infected people develop signs of the disease.
26. M.laprae action inside macrophages & schwann cells
After entering the Schwann cells/ macrophages, the bacteria’s
action depends upon the resistance of the infected individual
towards the infecting organism.
Bacilli start multiplying slowly (a bacterium takes around 12- 14 days to
divide into two) within the cells.
After multiplication it tries to destroys the cell where it gets
divided.
Then it enters other unaffected cells for destruction.
27. Body’s initial response against M. laprae
As the bacilli multiply, bacterial load increases in the body.
Now the infection is recognised by the immunological system.
Lymphocytes and histiocytes (a stationary phagocytic cell
present in connective tissue) invade the infected tissues.
At this stage, clinical manifestations may appear as involvement
of nerves with impairment occurs.
28. Pathogenesis of M.laprae after its sign & symptom:
If it is not treated in the early stages, further progress of
the disease is determined by the strength of the patients
immune response.
Effective Cell Mediated Immunity (CMI) provides
protection to a person against leprosy.
29. If CMI is strong:
If CMI is effective in controlling the infection, lesions heal
spontaneously or it produces paucibacillary type of leprosy.
If CMI is weak:
If CMI is weak, the disease spreads in an uncontrolled
manner and produces multibacillary leprosy with
involvement of multiple systems.
31. Early signs include discolouration or light patches on
the skin with loss of sensation.
32. When nerves in the arm are affected, part of the hand
becomes numb and small muscles become paralysed,
leading to curling of the fingers and thumb.
33. When leprosy attacks nerves in the legs, it interrupts
communication of sensation to the feet.
34. As a result, the affected person does not feel pain, and
can have injuries to their hands and feet without
realizing it.
The damaged nerves also lead to the skin peeling off,
and the tissue beneath the skin is exposed.
35. Leprosy should be suspected if a person shows the
following signs and symptoms:
● dark-skinned people might have light patches on the
skin, while
pale-skinned people have darker or reddish patches
37. Faded or discolored skin lesions
Growths on the skin
Thick, stiff or dry skin
Severe pain
Numbness on affected areas of the skin
Muscle weakness or paralysis
Eye problems that lead to blindness
Enlarged nerves (especially those around the elbow and knee)
A stuffy nose
Ulcers on the soles of feet
39. Delayed diagnosis and treatment of leprosy can lead to the following
serious complications
1) disfigurement
2) hair loss (particularly on the eyebrows and eyelashes)
3) muscle weakness
4) permanent nerve damage in arms and legs
5) inability to use hands and feet
6) chronic nasal congestion, nosebleeds and collapse of the nasal
septum….
40. 7) iritis (inflammation of the iris of the eye)
8) glaucoma
9) blindness
10) erectile dysfunction & infertility
11) kidney failure
42. 1) Clinical diagnosis:
- Skin lesions with definite loss of sensation
- Involvement of peripheral nerves, characterised
by loss of sensation, muscle weakness of hands,
feet or face.
44. 2) Laboratory tests:
i) Lepromin test:
- In this test 0.1 ml of killed bacilli is injected under the skin .
- The response upto 72 hours in traced out (fernandez reaction).
- It indicates the previous exposure to the antigens of M. leprae.
45. 2) Laboratory tests:
ii) Biopsy:
- Lesion samples are stained with acid fast stain.
- This shows the presence of bacilli.
46. 2) Laboratory tests:
iii) Tissue/skin smear tests :
- In this test, 4 – 5 mm long superficial incision is made on the
affected area with a scapel blade to obtain a clear serous fluid from
the lesion.
- The serous fluid is stained by Ziehl-Neelsen acid fast method.
- (Initially, carbol fuchsin stains every cell including the bacteria. When they
are de-stained with acid-alcohol all body cells will be decolourised except the
bacteria).