1. Prompt and effective treatment
of patients with active tuberculosis and careful follow – up of their contacts
with tuberculosis tests, x-rays and appropriate treatment are the main stays of
public tuberculosis control measures.
2. Drug treatment of asymptomatic
tuberculin positive persons in the age groups most prone to develop
complications (e.g children) and in tuberculin positive persons who must receive
immune suppressive drugs greatly reduces reactivation of infection. (Delahauty,
2008).
3. Individual host resistance
nonspecific factors may reduce host resistance, thus favoring the conversion of
asymptomatic infection into disease. Such factors
include starvation,
gastrectomy, and immune suppression of cellular immunity by drugs (eg corticosteroids)
or infection. HIV infection is a major risk factor for tuberculosis. Prevention
of these conditions is a good strategy for prevention. (Siege, 1998).
4. Immunization: Various living
virulent tubercle bacilli particularly BCG (bacillus Calmitte-Guerin, an
attenuated bovine organism), have been used to induce a certain amount of
resistance in those heavily exposed to infection. Vaccination with these
organisms is a substitute for primary infection with virulent tubercle bacilli
without the danger inherent in the later. The available vaccines are inadequate
from many technical and biologic stand points. Nevertheless, BCG is given to
children in many countries. In the USA, the use of BCG is suggested only for tuberculin
negative persons who are heavily exposed (members of tuberculosis families,
medical personnels). Statistical evidence indicates that an increased
resistance for a limited period follows BCG vaccination ( Seige, 1998).
5. The reduction of tuberculosis
in cattle and the pasteurization of milk have greatly reduced m. bovis infection. (Delahauty, 2008).
Summarily, TB prevention and control takes two parallel
approaches. In the first, people with TB and their contacts are identified and then
treated. Identification of infections often involves testing high-risk groups
for TB. In the second approach, children are vaccinated to protect them from
TB. Unfortunately, no vaccine is available that provides reliable protection
for adults. However, in tropical areas where the levels of other species of mycobacterium
are high, exposure to non tuberculosis mycobacterium gives some protection
against TB. (Frive P. et al 2001).
Vaccines Used.
Many countries use Bacillus Calmitte – Guerin
(BCG) vaccines as part of their TB control programs, especially for infants.
According to W.H.O, this is the most often used vaccine world wide. This was
the first vaccine for TB and developed at the Pasteur Institute in France
between 1905-1921.
The protective efficacy of BCG for preventing serious forms
of TB (e.g meningitis) in children is greater than 80%, its protective
efficacy for preventing pulmonary TB in
adolescents and adults is variable, ranging from 0 – 80% (Counstock G. 1994).