Guidelines on prevention and management of TB in office settings

 

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.

 

Arrangement of contact screening

 

• Contact examination of close contacts, usually the household members, will be arranged by chest clinics of the Department of Health.



• Examination of casual or social contacts is usually not indicated as the immune system of a normal healthy adult helps to fight and contain the infection.



• In fact, contact examination are generally adjunctive measures only. The more important issues are to observe preventive measures like healthy lifestyle, environmental hygiene, and early symptom awareness (see below).



• Colleague(s) who have symptoms suggestive of TB is/ are advised to seek prompt medical consultation at the chest clinics.



• In case of any signs of spread of the infectious disease or occurrence of an outbreak, further public health actions may be taken for control at an early stage.



• 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.

 

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

 

With the high local TB 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>