Introduction
Tuberculosis (TB) is an airborne infectious disease caused by
the tubercle
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
infected,
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
individuals.
When a student or a staff member in a nursery or kindergarten
is diagnosed
as having TB, the 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 nursery or kindergarten, 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 below).
Arrangement 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 nursery or kindergarten and whether
contact screening is indicated. The nurse will help to alleviate their
anxiety and concerns regarding confidentiality and possible stigmatisation,
if necessary.
- The supervisor of the nursery or kindergarten 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 institutional environment may have to be collected.
- Health information on TB will be provided to the 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 for contacts of age 5 or above
may be arranged at one of the X-ray centres. Tuberculin skin testing may be
arranged for contacts below 5 when indicated.
Advice on prevention of TB
-
Symptom surveillance
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.
-
Environmental hygiene
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 the air-conditioners should be cleansed as usual.
-
Healthy lifestyle
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.
Conclusions
Prompt notification of TB cases inside institutions allows
proper assessment
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>
