[micro] mycobacterium leprae
TRANSCRIPT
Mycobacterium Leprae
Causes and Meaning of Scientific Name
• Causes Leprosy also known as Hanson’s disease1873
• Chronic infectious disease affects:
• Skin• Peripheral nerves• upper resp tract• Eyes
TRANSMISSION
• Respiratory tract• Skin• Prolonged exposure
needed• Low prevalence of
disease
incidence
• 10 million cases glob• ASIA effected • Pakistan: 1996 contr
Karachi; 56000 t/m• 0.027/10,000 or • 1.68/100,000 pop • Punjab increase• 400 new cases/year
INCUBATION• 2-10yrs• 10% children acquire • Treatment of cases
abolishes infectivityTRANSMISSION• Small children exposed
to heavy shedders of nasal sec
PATHOLOGY
AFB• Single• Parallel bundles• Globular massesSites:• Skin• Mucosa; nasal
septum
CELL• Endotheleal cells BV• Mononuclear cellsGROWTH:• Footpads of mice• Granulomatous L• Armadello: LL
TYPES
TUBERCULOIDNon-progressiveBenignSKIN: macular lesionsAFB: few or noneNerves: asymmetric,
sudden; thick nerveLepromin test: +CD4++
LEPROMATOUS• Progressive• Malignant• Skin: nodular,
abundant AFB• Nerves: symetrical• CD 8 +++ in skin• Lepromin test: -
Classification & immunity
• High level of immunity/granulatio in Tuberculoid
• One or few skin lesio• Flattened with raised
edges/plaque• Hypo-pigmented• No prespiration
• T cell poor/absent• Wide areas affected• Lesions
small,many,shiny, no sensory loss
• Large no of AFB in body even normal skin & nasal smear in histiocytes of dermis
BORDERLINE LEPROSY
• BT: good immunity• Moderate ….mark
loss of pig/perspirat/sensation
• Skin smearsFew or no bacteriaBiopsy may be needed
to classify
• BB; BL: poor immunty
• Slight….moderate
• Several….many
INDETERMINATE STAGES
• Small macule in early stages
• Cant classify in clinical forms
• Persist for months/yrs• Heal completely• Or progress to a
typical
PAUCIBACILLARY• V few bacilli seen• Include tuberculoid• Borderline
tubercuoid• IndeterminateMultibacillaryLep,bl
PAUCIBACILLARY:MULTIBACILLARY
• 1-5 LESIONS• Hypo-pigmented• Assymetrical• Loss f sensation• One nerve involved• (loss of
sensation/muscle weakness)
• More than 5 lesions• Symmetrical lesions• Loss of sensation• Many nerves involved• SKIN SMEAR : for
these 2 states • Go to dermis, 100hp
fields
SYSTEMIC EFFECTS
• Anemia: normocytic• Lymphadenopathy• Eye • Amylodosis• Rheumatoid factor+• Anti-nuclear factor+• LE cells may be seen
in buffy coat
DIAGNOSIS
SCRAPINGS• SKIN• NASAL MUCOSACaution: HIV, HBV,HCVBIOPSYEar lobe skinHistologyZN stain
• ENZYME: Diphenoloxidase
• Serology: none• False + for syphilus• DIAGNOSIS IS
CLINICAL• SMEAR: PAUCI &
MULTI STATE FOR THERAPY
Morphology, Gram Staining, and Oxygen Requirements
• A straight or slightly non-sporing curved rod ZN stain done,1% HCL; fix gently• It is non-motile. Measures .2-.5*5-8um,
Temperature and pH it grows best at and Motility
• It grows best in pH of humans which is 7.35 to 7.45
• It grows best in tropical climates• It also grows on feral armadillos
Contraction of disease
through direct contact air dispersement from coughing or sneezing• Contracting the disease depends on • how susceptible the person is to the disease,
how long you are exposed, • and environmental conditions• Only 10 to 29% of people actually develop
leprosy
Treatment ( yrs)
• Dapsone has been successfully used for over 50 years with emergence of drug resistant.
• Multidrug therapy since 1985 Rifampicin, Clofazamine, and Dapsone has reduced the global incidence by 85%
• Minocycline, clarithromycin, flouroquinolones• Goal: elimination to < 1 per 10,000 population• 2 million need yet to be detected; rehabilitatd
Symptoms
• Symptoms usually take 3 to 5 years to show up after a person has been infected.
• Severe pain, muscle weakness• Loss of fingers or toes• Skin lesions• Symmetrical skin rash mostly found on face, ears,
wrists, elbows, knees, or butt• More severe forms of leprosy can include the
collapsing of the nose
PREVENTION
THOROUGH EXAMINATION• HOUSEHOLD CONTACTS• RELATIVES• Skin• PNS• Therapeutic trial for suspected cases
armadello