L20: Schistosomiasis & Leprosy Flashcards
Global Epidemeology of Schistosomiasis
National Epidemeology of Schistosomiasis
Schistosomiasis is endemic in Egypt since β¦..
Ancient Egypt (1250 B.C).
The prevalence of S. mansoni was β¦.. and S. haematobium was β¦β¦ in 1983 before the national control program
38.6%, 35%
In 2014 the prevalence 0f S. mansoni was β¦.. and S. haematobium was β¦..
0.2%, 0.3%
- S. mansoni is endemic in β¦.. while
- S. haematobium is endemic in β¦..
Delta, Upper Egypt
Epidemic Threshold of Shistosomaisis
If the prevalence reaches 3% in a small population or 2% in schools.
Suspected Case of Shistosomaisis
Probable Case of Shistosomaisis
None
Confirmed Case of Shistosomaisis
Presence of Schistosoma eggs in urine and stool
CA of Shistosomaisis
the major species causing human disease
βΆ Schistosoma haematobium
β· S. manosni
βΈ S. Japonicum
Reservoir of Shistosomaisis
Man: Infected persons with S. haematobium or mansoni
Intermediate Host of Shistosomaisis
βΆ Bulinus Trancatus: for S.haematobium
β· Biomphalaria alexandrina: for S.mansoni
MOT of Shistosomaisis
contact infection (cercaria penetrate bare skin) .
IP of Shistosomaisis
6-8 weeks
Infectivity Period of Shistosomaisis
No man-to-man transmission but infected person can transmit infection by contaminating water up to 10 years.
Susceptibility & resistance Shistosomaisis
- Genetic Predisposition
βΆ HLA class I & II antigens: more severe manifestations of
the disease.
β· HLA-B16 & Cw2: S. haematobium associated bladder
cancer in Egypt.
βΈ HLA-DR, DQ, DP: protection from hepatic fibrosis.
βΉ 5q31-q35: Resistance to re-infection.
Susceptibility & resistance Shistosomaisis
- Age
any age is susceptible, the peak at age 15-20y
Susceptibility & resistance Shistosomaisis
- Sex
more in males: more exposure (working in the field & swimming in canals).
Susceptibility & resistance Shistosomaisis
- education
educated may avoid polluting the environment & exposure to infection.
Susceptibility & resistance Shistosomaisis
- faculty Habits & Behaviours
Pollution of water by passing excreta in water channels.
Exposure to infection by water contact: bathing, ablution,
washing of clothes.
Ecology of Schistosomiasis
(factors favoring endemicity)
- Host Factors
(Previously described under susceptibility & resistance)
Susceptibility & resistance Shistosomaisis
- Occupation
famers, fishermen & workers of water channels clearance
Ecology of Schistosomiasis
(factors favoring endemicity)
- Host Factors
- Agent Factors
- Environmental Factors
Ecology of Schistosomiasis
(factors favoring endemicity)
- Agent Factors
Ecology of Schistosomiasis
(factors favoring endemicity)
- Environmental Factors
Schistosomiasis may be introduced to the new reclamation areas in Toshki or Sinai through the previous factors .
β¦
General Prevention of Shistosomaisis
- Environmental Sanitation
General Prevention of Shistosomaisis
- Snail Control
Requirements of ideal Molluscicide
What is the Name of molluscicide of choice?
Niclosamide
General Prevention of Shistosomaisis
- Health Education
General Prevention of Shistosomaisis
- Protection of Man
Protective clothing unpractical by gloves & boots
Specific Prevention of Shistosomaisis
Vx: under trial.
Case Control Measures for Shistosomaisis
- Early case Finding
Case Control Measures for Shistosomaisis
Case Control Measures for Shistosomaisis
- Notification
Case Control Measures for Shistosomaisis
- Isolation
not required
Case Control Measures for Shistosomaisis
- TTT
Contact Control Measures for Shistosomaisis
Urine and stool analysis.
Outbreak (Community) Control Measures for Shistosomaisis
Mass treatment if the prevalence reaches the epidemic threshold .
Def of Leprosy [Hansenβs disease]
- is an infection caused by slow-growing bacteria called
Mycobacterium leprae.
Previously feared as highly contagious & devastating disease but now we know it doesnβt spread easily and treatment is very effective
β¦..
Global Epidemeology of Leprosy
- There were 202,256 new leprosy cases registered globally in 2019, according to official figures from 161 countries from the 6 WHO Regions
- The prevalence corresponds to 22.9 per million population
National Epidemeology of Leprosy
- Since 1994, Egypt has met WHOβs global leprosy elimination goal of reducing prevalence to less than 1 per 10 000 population
Study Epidemic Threshold
Suspected Case of Leprosy
- Person showing one or more of the following features
βΆ Hypopigmented or reddish skin lesions with definite loss of
sensation
β· Thickening of the peripheral nerves with loss of sensation
CC of Leprosy
Skin smear positive for acid-fast bacilli (M Leprae).
CA of Leprosy
Mycobacterium Leprae (acid fast bacilli)
Reservoir of Leprosy
Only human
Exit of Leprosy
Nasal discharge
MOT of Leprosy
The bacillus is likely transmitted via droplets, from the nose and mouth, during close and frequent contact with untreated cases
IP of Leprosy
on average, is 5 years. Symptoms may occur within 1 year but can also take as long as 20 years or even more.
Types of Leprosy
Susceptible Age of Leprosy
5-15 years is most susceptible
Susceptible Families of Leprosy
βΆ Familial tendency (runs in families but the inheritance pattern is unknown)
β· Genetic susceptibility
General Prevention of Leprosy
Specific Prevention of Leprosy
Specific Prevention of Leprosy
- Active Immunization
βΆ BCG vaccine offers a variable amount of protection against leprosy.
β· Novel vaccine called LepVax entered clinical trials in 2017.
Specific Prevention of Leprosy
- Chemoprophylaxis
Single dose rifampicin for close contact of newly diagnosed patient
Case Control measures of Leprosy
Case Control measures of Leprosy
- Early Case Finding
the most important measure in control of leprosy
Case Control measures of Leprosy
- Notification
local health office
Case Control measures of Leprosy
- Isolation
no need for isolation, Patients are no longer infectious after the first monthly dose
Case Control measures of Leprosy
- TTT
Case Control measures of Leprosy
- rehab
for patient with deformities and disabilities
Contact Control Measures for Leprosy
βΆ Enlistment by age, sex, vaccination history.
β· Surveillance for early case finding annually for 5 years .
βΈ Specific protection using BCG vaccine and single dose Rifampicin