Epidemiology of leprosy

This ppt contains all the information about the Epidemiology of leprosy. It is useful for students of the medical field learning Preventive and social medicine, Swasthavritta (Ayurved), and everyone who is interested in knowing about it

1. Leprosy
Dr. ShubhangiS. Kshirsagar
Assistant professor
Department of Swasthavritta& Yoga

2. Leprosy(Hansen'sdisease)isachronicinfectious
diseasecausedbyM.leprae.
Itaffectsmainlytheperipheralnerves.
Italsoaffectstheskin,muscles,eyes,bones,testesand
internalorgans.
Thediseasemanifestsitselfintwopolarforms–
a.Lepromatousleprosy
b.Tuberculoidleprosy
Betweenthesetwopolartypesoccurtheborderlineand
indeterminateformsdependinguponthehostresponse
toinfection.

3. Cardinal features
Leprosy is clinically characterized by one OR
more of -the following cardinal features -
1. Hypopigmentedpatches
2. Partial or total loss of cutaneoussensation in the
affected areas (the earliest sensation to be
affected is usually light touch)
3. Presence of thickened nerves
4. Presence of acid-fast bacilli in the skin or nasal
smears.

4. Hypopigmentedpatches

5. Signs of advanced disease
Nodules or lumps
especially in the skin of the
face and ears
Plantar ulcers
Loss of fingers or toes
Nasal depression
Foot drop
Claw toes and other
deformities.

6. Epidemiological
determinants

7. Agent factors
1. Agent
Leprosy is caused by M. leprae
M. lepraeare Acid-fast bacilli
They occur in the human host both intracellularlyand
extracellularly.
Occur characteristically in clumps or bundles (called globi).
They have an affinity for Schwann cells and cells of the
reticulo-endothelial system.
They remain dormant in various sites and cause relapse.
The bacterial load is the highest in the lepromatouscases.

8. 2.Sourceofinfection
Multibacillarycasesarethemostimportant
sourceofinfection.
Theinapparentinfectionsarealsosourceof
infection.
Allpatientswith"activeleprosy"mustbe
consideredinfectious.
Manistheonlyhostandsourceofinfection.
Leprosyinwildanimalsisathreattopublichealth.

9. 3.Portalofexit
Noseisamajorportalofexit
LepromatouscasesharbourmillionsofM.
lepraeintheirnasalmucosawhichare
discharged,whentheysneezeorblowthe
nose.
Thebacillicanalsoexitthroughulceratedor
brokenskinofbacteriologicallypositivecases
ofleprosy.

10. 4. Infectivity
Leprosy is a highly infectious disease but of low
pathogenicity.
An infectious patient can be rendered non-
infectious by treatment with Dapsonefor about
90 days or with Rifampicinfor 3 weeks .
Local application of Rifampicin(drops or spray)
might destroy all the bacilli within 8 days.

11. Host factors
1.Age -in endemic areas commonly during childhood
Highest incidence during between 10-20years and
then fall.
2. Sex -Both the incidence and prevalence of leprosy
appear to be higher in malesthan in females.
3. Migration -Mostly a rural problem. However,
because of the movement of population from rural
to urban areas; leprosy is creating a problem in the
urban areas also.

12. 4.Geneticfactors–Humanlymphocyte
antigen(HLA)linkedantigenesinfluencethe
typeofimmuneresponsethatdevelops.

13. Environmental factors
HumidityfavoursthesurvivalofM.leprae,Ifthe
infectiouscasespresentinthatenvironment.
M.lepraecanremainviableindriednasal
secretionsforatleast9daysandinmoistsoilat
roomtemperaturefor46days.
Overcrowdingandlackofventilationwithin
households.

14. Mode of transmission
1.Droplet infection –via aerosols containing M.
leprae
2.Contact transmission -person to person by
close contact
3.Other routes –by insect vector or tattooing
needles(but no evidences)

15. Incubation period
Lepromatouscases -Long incubation period,
an average of 3 o 5 years or more.
Tuberculoidleprosy -Symptoms can take as long
as 20 years to appear.

16. Classification of leprosy
1.Indian classification
2.Madrid classification
3.Ridley-Joplingclassification

17. Classification of leprosy
Indian classification
1.Indeterminate Type
2.TuberculoidType
3.Borderline Type
4.LepromatousType
5.Pure NeuriticType
Madrid classification
1.Indeterminate
2.Tuberculoid
3.Borderline
4.Lepromatous

18. Ridley and Jopling
1.Tuberculoid(TT)
2.Borderline tuberculoid(BL)
3.Borderline (BB)
4.Borderline lepromatous(BL)
5.Lpromatous(LL)

19. Indianclassification
Indeterminate 1or 2hypopigmentedmacules,
definite sensory impairment
Bacteriologically
negative
Tuberculoid 1or 2 well-defined lesions,
flat or raised, hypopigmentedor
erythematous, anaesthetic
Bacteriologically
negative
Borderline 4 or more lesion
flat or raised, well or illdefined,
hypopigmentedor erythematous
Bacteriological
positivity -
variable
Lepromatousdiffuse infiltration or numerous
flat or raised, poorly defined,
shiny, smooth, symmetrically
distributed lesions
Bacteriologically
positive
Pure neuriticnerve involvement but do not
have any lesion in the skin.
Bacteriologically
negative

20. Clinical classification for control programme
1.Paucibacillaryleprosy (1-5 skin lesions)
2.Multibacillaryleprosy (more than six
skin lesions)

21. Diagnosis
1.Clinical examination
a.Interrogation
b.Physical examination
a.Interrogation
Collection of biodataex. name, age, sex, occupation
Family history
History of contact with leprosy cases
Details of previous history of treatment for leprosy, if
any presenting complaint or symptom.

22. b.Physicalexamination
a.Inspectionofthebodysurface(skin)
b.Palpationofthecommonlyinvolved
peripheralandcoetaneousnervesforthe
presenceofthickeningand/ortenderness.Ex.
Ulnarnerve,lateralpoplitealnerve
c.Testingfor
lossofsensationforheat,cold,painandlight
touchintheskinpatches
paralysisofthemusclesofthehandsandfeet,
leadingtothedisabilitiesordeformities.

23. 2. Bacteriological examination
a.Skin smear
b.Nasal smear or blow
c.Nasal scraping

24. 2. Bacteriological examination
a.Skin smears
By the "slit and scrape" method.
Two sites examination active
lesion and one of the ear lobe
Skin is cleaned with ether or
spirit and allowed to dry.
Pinch the site tight
Incision
Scrape and collect material
(tissue pulp)
Smear on slide
Air dry and fix
Stain Z-N method

25. b. Nasal smear or blows
Done in the early morning from first blowing of
nose ( Early morning mucus material)
Patient blows his nose into a clean dry sheet of
cellophane or plastic.
Nasal smear is used for assessing the patients
infectivity.

26. 3. Nasal scraping
Insert nasal mucosal scraper 4.5cm in the
nasal cavity
The blade rotates toward the septum and
scrape a few times and withdraw
Not recommended as a routine , because It is
painful.

27. Immunological Tests
•Two types of immunological tests
1. Tests for detecting cell mediated immunity
(CMI)
a. Lepromintest
b. LIT ( Lymphocyte transformation test)and
LMIT (Leucocytemigration inhibition test)
2. Tests for humoralantibodies (serological tests)
a.FLA-ABS test ( Fluorescent Leprosy Antibody
Absorption teat)
b.Monoclonal antibodies

28. Leprosy control
A.Medical measures
1.Estimation of the problem
2.Early case detection
3.Multidrug therapy
4.Surveillance
5.Immunoprophylaxis
6.Chemoprophylaxis
7.Deformities
8.Rehabilitation
9.Eealtheducation
B. Social support
C. Programme management
D. Evaluation

29. Multidrug therapy
Objectivesofmultidrugchemotherapy-
a.Tointerrupttransmissionoftheinfectionin
thecommunitybysterilizinginfectiouspatients
asrapidlyaspossiblewithbactericidaldrugs
b.Toensureearlydetectionandtreatmentof
casestopreventdeformities
c.Topreventdrugresistance.

30. Recommended regimens of
Chemotherapy (WHO)
1. For adult
Drug MultibacillaryPaucibacillaryministt
Rifampicin 600mg 600mg Once
monthly
Under
supervision
Dapsone 100mg 100mg Daily Self
administra
tion
Clofamazimi
ne
300mg Once
monthly
Under
supervision
50mg Daily Self
administra
tion

31. Recommended regimens of
Chemotherapy (WHO)
1.For Children (10-14yrs)
Drug Multib
acillary
Paucib
acillary
Rifampicin450mg 450mg Once monthlyUnder
supervision
Dapsone 50mg 50mgDaily Self
administration
Clofamazimine150mg Once monthlyUnder
supervision
50mg Daily Self
administration

32. Duration of treatment
1.Multibacillaryleprosy -MB blisterpacksfor
12months, within 18 months.
2.Paucibacillaryleprosy –PB blisterpacksfor 6
months, within 9 months.

33. 4. Surveillance
•Clinicalsurveillanceofcasesaftercompletionoftreatment
•Itisessentialfortheassuranceoflong-termsuccessof
treatmentandfortheearlydetectionofanyrelapses.
a.Paucibacillaryleprosy:examinedclinicallyatleastoncea
yearforaminimumof2yearsaftercompletionof
treatment.
b.Multibacillaryleprosy:examinedclinicallyatleastoncea
yearforaminimumperiodof5yearsaftercompletionof
therapy.
•Apatientwhohascompletedtherequiredperiodof
surveillancefollowingthecourseofmultidrugtherapyand
showsnoevidenceofrelapseisconsideredtohave
completedsurveillance.

34. 5. Immunoprophylaxis
•BCGvaccine-Trialsindifferentpopulation
groupswithBCGvaccineeitheraloneorin
combinationwithothervaccine(fromkilled
MycobacteriumlepraeoratypicalMycobacteria),
haveshownprotectiveefficacyrangingbetween
28percentand60percent.
•HighBCGcoverageremainsanimportant
contributiontoreducingthediseaseburdendue
toleprosy

36. Thank You