Tuberculosis (TB) is an airborne infectious disease caused by
bacillus. TB cases can be broadly classified as "open"
and "non-open". Tiny tubercle bacilli can be
seen, with special staining, inside the sputum under direct
microscopy for "open" cases. "Open"
cases are generally considered infectious.
Not everyone exposed to an infectious TB patient will be
and those infected may not develop disease. The occurrence
of infection and disease depends on a number of factors,
in particular the intensity of exposure, and each individual's
body immunity. Only about one out of ten infected individuals
will develop disease as a life-time risk. The disease
may develop weeks, months, years, or even decades after
the infection. Unless disease develops, the infected individual
will remain well and non-infectious like other healthy
When a staff or student in a school is diagnosed as having TB,
attending doctor should notify the case to the Department
of Health. In general, contact examination will be conducted
for close contacts of an "open" case. In the
school, close contacts usually refer to those in the same
class or those in frequent contact with the index patient.
However, the actual decision will depend on careful assessment
of the individual circumstances which often vary. Advice
may be sought from the nearby chest clinics of the Department
of Health. In fact, contact examination should be regarded
as an adjunctive measure only. The more important issues
are to observe preventive measures like healthy lifestyle,
environmental hygiene, and early symptom awareness (see
of contact screening
- The client or his/ her
guardians will be contacted by phone or interviewed by
a health nurse and explained of the need for any public
health actions including any need to contact the school
and whether contact screening is indicated. The nurse
will help to alleviate their anxiety and concerns regarding
confidentiality and possible stigmatisation,
- The principal/ supervisor
of the school may be interviewed by the health nurse and
explained of the necessary public health actions. Information
about the staff/ student's close contacts, previous
cases of TB and the school environment may have to be
- Health information on TB
will be provided to the principal/ supervisor. This may
be supplemented by distribution of pamphlets, video show,
or health talks, depending on the actual needs.
- Staff or other students
with symptoms suggestive of TB will be advised to seek
prompt medical consultation at the chest clinics.
- Advice will be provided
on the need for examination of asymptomatic contacts.
In case of need, X-ray examination may be arranged at
one of the X-ray centres.
on prevention of TB
At any time, staff or students with symptoms
suggestive of TB including persistent cough over 3 to
4 weeks, blood in sputum, weight loss, afternoon fever
and night sweating should seek prompt medical consultation.
TB spreads mainly by air. It is essential to
maintain good indoor ventilation by means of natural ventilation
or mechanical ventilation such as exhaust fans. Furniture,
tables and walls do not play any significant role in the
transmission of the infection. Regular cleaning of the
environment should be done as general hygienic practice.
The dust filtres of air-conditioners should be cleansed as usual.
A healthy lifestyle helps to build up good body
resistance. This includes observation of good personal
hygiene, balanced diet, exercise, adequate rest, maintaining
a cheerful mood, quit smoking and refraining from alcohol.
Need to isolate TB patients?
"Non-open" TB cases are non-infectious.
For "open" cases, once anti-TB treatment is
started, the risk of spreading the infection is rapidly
reduced. For most TB patients, strict isolation is not
necessary. However, sick leave may be recommended for
patient when indicated (usually 2 weeks or more). The
patient may resume usual school work after medical assessment
for the rest of the treatment period. The total duration
of treatment usually lasts for 6 or more months.
Prompt notification of TB cases inside institutions allows
and institution of appropriate public health actions,
which are important adjunctive measure in the overall
control of TB. However, with the high local prevalence
and variable latency of this disease, we have to maintain
our vigilance, even in absence of any
recent contact history.
TB telephone hotline:(852) 2572 6024
TB website: <http://www.info.gov.hk/tb_chest/en/index.htm>