It is very vital and updated evidence on TB produced by referring various literature.

1. BY
MULUSEW ANDUALEM( A S S I S TA N T P R O F E S S O R & P H D F E L LOW )
SCHOOL OF PUBLIC HEALTH, COLLEGE OF MEDICINE AND
HEALTH SCIENCES, BAHIR DAR UNIVERSITY, ETHIOPIA
2018
Update on Tuberculosis
epidemiology, transmission and
pathogenesis

2. TB transmission
 TB caused by Mycobacterium complexes, mainly the
Mycobacterium Tuberculosis bacillus (MTB)
 Transmitted through the inhalation of air droplets
 Smear positive pulmonary TB patient is major source
of infection
 While coughing, sneezing, talking, …
 The inhaled MTB will stay trapped on the
trachea/upper lung on the mucus

3.  Only 5-15% of infected people develop active TB through out
their life
 But up to 20% developed TB per year if people are HIV positive
 About 5% of infected people will develop active TB from few
months to 5 years
 MTB will pass through lung to alveoli and invaded by the
immune system = form granuloma/ghost cell

4.  The bacteria with in the granuloma will become
hidden and do not cause infection for long period of
time = latent TB
 Only about 5-10% of latent TB becomes to active TB
through reactivation due to HIV, DM, malnutrition,
smoking, alcoholism, aging,…
 The rest 90% continues silent
 After certain period, the granuloma will be affected by
other factors and reaction of bacteria occurs= form
lung cavity

5.  Due to infection, immune decline and granuloma
necrosis, latent MTB will burst and move to lung to
cause MTB
 And the rest moves to d/t parts of the body via blood
and lymphatic system: lymphadenitis, bone,
kidney,…EPTB
 Hence, we have two types of TB based on the site MTB
affects:
 PTB- affects lung, most common
 EPTB- affects body parts other than the lung

6.  Mostly, TB infection is asymptomatic/ slow growing
 EPTB mostly common on children and immune
compromised
 PTB common among adults
 Male are mostly affected by TB than women, but the
diseases progression is higher among women in the
reproductive age= biological, work load, immune
status, malnutrition,…
 Why male most affected? May be high mobility,
workplace/more employed than women/, personal
behavior/ smoking, alcohol, chat, unsafe sex, drug
abuse,

7. TB Epidemiology
 TB is a diseases of all age groups, human kind
 Major public health problem since human life time
 Continues among top ten diseases causing
 First killer among people with HIV
 About 10.4 million people were estimated to have new TB
cases in 2015, mainly in tropical regions
 India, china, Pakistan, Indonesia, Nigeria, and South Africa,
took 60% of global new TB cases
 The African region shared about 28% of the new TB cases

8. Why TB continued public health despite several anti
TB intervention?
 High HIV
 High comorbidities: DM, chronic diseases
 Climate change
 Unhealthy Human behaviors: smoking, khat, alcoholism,
malnutrition, high mobility, being homeless
 Poverty and malnutrition, high susceptibility,
 Poor healthcare services/ inaccessibility of facilities
 Aging,
 MDR-TB/XDR-TB
 Poor community wariness and poor adherence
 High urbanization
 Conflicts and instabilities,
 Absence of effective vaccine ,mainly to adults
 Long treatment period/less innovation
 Resource shortage
 Poor commitment and coordination efforts,…..

9. Signs and symptoms
Major signs and symptoms are:
 Chough for 2 or above weeks
 Weight loss
 Night sweet
 Loss of apatite
 Fatigue
 Bloody sputum

10. Diagnosis
❑ TB could be diagnosis clinically based on the
symptoms plus
 Bacteriological: microscopy, culture, Xpert,
 Immunological: skin test, immunoglobulin assay,..
 Pathological;
 Radiological: chest x-ray,
❑Biological Samples:
▪ Sputum, blood, body floods, skin, bone aspiration,…

11. ▪ Microscopic
 Use sputum samples (spot-morning-spot)
 Most feasible and applicable to developing
 Less sensitive to culture, immunological, …
 Use ZN and immune.. Stains
 Bacilli seen red or florescence against attained fields

12. Prevention
 Detection and Treatment
 Isolation
 Using surgical masks
 Using air respirator
 Open window, door and fan= air dilution
 Use UV rays
 Use negative pressure
 Contact screening
 Vaccination
 Chemotherapy
 create adequate distance

13. Treatment
 TB has effective treatment even if the RX period is longer
 Latent TB can be treated with single Isoniazid
 Active TB can be treated with combined treatments for 6
months (two months intensive & late 4 months
continuation phase)- first line anti TB drugs
 MDR-TB- can be treated with second line drugs for up to
two years

14. Prevention
 Nutritional assessment, counseling and support
 Treatment of comorbidities
 Improving life styles: chat, alcohol, cigarette,…
 Improve social supports
 Improve awareness/health seeking behavior
 Improving service quality, equity,
 Improve TB service inputs

15. Prevention
 Improving
 Personal,
 Environmental,
 Institutions, and related services is important to
prevent TB

16. Thank you!