PROPHYLAXIS OF TUBERCULOSIS

Prophylactic principle

• of health protection generally and, as far as tuberculosis is concerned, in particular should be a priority. Prophyaxis of tuberculosis consists of a complex of various measures. Social, sanitary, specific (inoculation and revaccination) and chemoprophylaxis are discriminated.

Social prophylaxis

• is carried out by means of performing prophylactic measures of social-economic character of the national scale. The social prophylaxis is aimed at organizing the people’s healthy way of life by improving the environmental conditions, increasing the population’s material well-being, strengthening its health through the development of mass physical culture, sports, rest homes, sanatoriums, improvement of nourishment and home living conditions, as well as fighting alcoholism and other harmful habits.

Sanitary prophylaxis

• is a systematic organization and performance of a system of sanitary-hygienic and prophylactic measures, aimed at warning healthy people against infecting and catching tuberculosis. It is aimed at the improvement of sanitary conditions of the nidi of tuberculous infection, performance of sanitary – educative work, veterinary control, early and timely detection as well as treatment of tuberculosis patients. Sanitary prophylaxis is generally performed in the centre of tuberculous infection.

An epidemiologic nidus of tuberculosis

• is meant as a tuberculosis patient, who excretes mycobacteria, his dwelling and the people sharing it with him. To antiepidemic measures in the cenrte of tuberculous infection belong disinfection, contacts investigation, their chemoprophylaxis, isolation of children from the bacteriocarrier, sanitary-hygienic education of a patient and the members of his family, improving the living conditions as well as the patient’s treatment.

The prophylactic work

• is realized in the centre according to its epidemiological danger defined jointly by a phthisiologist and an epidemiologist, taking into account the following factors: 1) the volume of bacterial excretion; 2) presence of children and teenagers in the family; 3) sanitary conditions under which a patient and his family live.

The criteria of epidemiological danger

• of a nidus of tuberculous infection are the mass scale and continuity of MBT excretion by a patient, his family life conditions, behaviour, general culture and sanitary enlightenment of the patient and his surrounding.

Depending on the mass scale and the term of bacterial excretion, it is

discriminated as: • A.massive, when over 100 colonies of

MBT are revealed at a simple bacterioscopy or by a sowing method;

• B.moderate, if 20-100 colonies are revealed;

C. scanty (meagre), if MBT are revealed only by bacteriological research, not more than 20 colonies;

     D. conditioned (formal): • at firstly diagnosed tuberculosis, when the

cessation of bacterial excretion is reached as a result of treatment and is confirmed by double negative result of bacterioscopic and cultural methods with 2-3 months intervals (during 10-12 months from the moment of the examination negative result); 2) at chronic pulmonary tuberculosis, when the cessation of bacterial excretion as a result of treatment is confirmed by repeated examinations with bacterioscopic and cultural methods with 2-3 months intervals during 1,5-2 years from the moment of the first negative result.

 The nidi of tuberculous infection are

divided into 3 groups • To the first, the most dangerous, group belong

nidi, where patients with abundant or meagre bacterial excretion live, but there are children and teenagers in the family or aggravating circumstances exist: poor living conditions, violation of hygienic rules, abuse of alcohol. An epidemiologist and a district phthisiologist should visit such a nidus once a quarter, a district nurse – not less than once a month.

• To the second group, epidemiologically less dangerous, belong nidi of tuberculous infection, in which patients with meagre bacterial excretion live and the unfavourable factors, enumerated above, or patients, considered to be conditional bacterial excretors, are absent, but there are children and teenagers in the family or there exists at least one of the aggravating factors mentioned above. A doctor pays a visit to these nidi once half a year, and a medical nurse once every two months.

• To the third group belong the nidi, where only adults live and the patients are formal bacterial excretors and any aggravating circumstances are absent. To this group belong families in whose private farms there is cattle injured with tuberculosis. A doctor visits these nidi once a year, a medical nurse – once half a year.

The complex of prophylactic measures • in a centre of tuberculous infection includes

performing a current and conclusive disinfection, isolation of children from the bacterial excretor by means of his hospitalization or sending the children to specialized children’s institutions, vaccinization of newly borns and revaccinization of noninfected contactual with BCG vaccine, regular examination of contactuals, performing chemoprophylaxis for them, sanitary-hygienic education of patients and the members of their families, improving their living conditions, intensive treatment of a patient in a clinic, followed by controlled chemotherapy at the dispensary stage.

The conclusive disinfection • is made in all cases of the patient’s temporary or

constant departing (hospitalization, change of the dwelling place, after death at home). Objects of small value are desirable to be burnt. The ceiling, the walls, the floor, the furniture (except polished one) are irrigated with 5 % solution of chloramine and the lodging is tightly closed for 2 hours. Afterwards it is aired and tidied. An effective method of disinfestation of lodgings is ultraviolet radiation. This pertains, first and foremost, to expensive objects, which are easily spoilt with disinfectant solutions; they are radiated with bactericidal lamps.

Before a patient’s hospitalization or when he stays at home for various reasons, current disinfection is systematically done by the patient himself or by the members of his family which consists in the following:

1) Daily airing and wet tiding of the lodging and objects of home use. The bacterial excretor should use only his personal table utensils, towels, bedding which are systematically disinfestated.

2) Sputum collection into an individual sputum flask, which is filled to a quarter of the volume with 5 % chloramine solution and its disinfestation, as is done with the table utensils and meal remnants.

3) Collection, putting into sacks, isolated keeping of used underclothes and its future disinfestation

Antituberculous vaccination and revaccination.

The most efficient method of specific prophylaxis of tuberculosis is vaccination and revaccination with BCG vaccine or vaccinoprophylaxis.

In 1923 the Hygienic Committee of the Nations League took a decision as to the wide use of the BCG vaccine for vaccination against tuberculosis in all the countries of the world.

A tuberculous vaccine

(BCG) are live mycobacteria of vaccine strain, lyophilicly dried in 1,5 % solution of sodium glutaminate. It is manufactured in ampullas of 1 mg of vaccine, which contains 20 doses, each of 0,05 mg of the preparation.

BCG vaccine

is used intracutaneously in a dose of 0,05 mg in the volume of 0,1 ml. The primary vaccination is done to healthy, delivered at the right time newly borns on the 3-5th day of their life

BCG-M vaccine

is manufactured in a half dose (0,5 mg in an ampulla, which contains 20 doses, each of 0,025 mg of the preparation), which is meant for vaccinating prematurely newly borns and children who were not immunised at birth in connection with contraindications.

At the proper technic a whitish papule of 5-6 mm in diameter is formed, which resolves in 15-20 minutes. In 3-4 weeks a small infiltration is formed in the site of the injection – a nodule of cyanotic colour, in which in 50 % of cases a small fistula with cereous secretion is formed. Later on a crust of brown colour is formed, which drops off in 2-4 months and a pink seam (of 4-10 mm in diameter) appears, which gradually undergoes depigmentation.

Contraindications for BCG vaccination are: 1) a prematurely born child, when the body mass at

birth is less than 2000 g; 2) intrauterine infection; 3) purulent-septic illnesses; 4) hemolytic disease of newly-borns (moderate and

severeforms); 5) severe puerperal traumas with neurologic

symptomatics; 6) generalized skin wounds; 7) any acute illnesses; 8) generalized BCG infection of other children in the

family

Children (babies), not immunised at a maternity home, in connection with contraindications are vaccinated after recovery at a children’s polyclinic or hospital-assistant’s health station with BCG-M vaccine during 1-6 months. However, if a baby has reached a 2-months age and more, the Mantoux test with 2 TU should be done before inoculation. Children with negative tuberculine reaction are vaccinated. The interval between Mantoux test and vaccination must be not less than 3 days and not more than 2 weeks.

The immunity after vaccination develops in 6-8 weeks, therefore vaccinated children from the family of tuberculosis patient are isolated from bacterial excretor for the period of the immunity formation, i.e. not less than 2 months.

In children BCG vaccinated at birth the immunity is preserved during 5-7 years.

Only healthy persons with negative Mantoux test are revaccinated. Vaccination and revaccination of BCG is an effective means of prophylaxis and it allows to prevent the illness five times more, and if it develops, then its course is much milder and has a restricted character.

Contraindications for revaccination of children and

teenagers: • 1) tuberculosis infestation or previously suffered

tuberculosis;• 2) acute and chronic illnesses in the aggravation

period;• 3) complication to previous BCG vaccine injection;• 4) allergic illnesses in the aggravation stage;• 5) malignant blood diseases and neoplasms;• 6) immunodeficite states, treatment with

immunodepressors;• 7) HIV-infestated children.

• Postvaccine seam and a positive tuberculin reaction are the criteria of vaccination quality and formation of antituberculous immunity. A local pediatrician does the observation for the development of local postvaccinal reaction and writes it down in the medical documentation in 1, 3 and 12 months after inoculation. The postvaccinal seam being absent and at negative tuberculin reaction the immunisation is considered to be ineffective.

The WHO International Union of Fighting Tuberculosis classifies postvaccinal

complications according to 4 categories:

• 1 category – local skin lesions (cold abscesses, ulcers, keloid seams, regional lymphadenites);

• 2 category – persisting and disseminated BCG – infection without a lethal result (lupus, ostites etc.);

• 3 category – disseminated BCG – infection, generalized lesions with a lethal result, which are noticed at a marked immunodeficiency;

• 4 category – post-BCG-syndrome (an illness, that arises immediately after BCG vaccination, mainly of allergic character, nodal fever, eruption, keloid seams).

• The most frequently observed are: subcutaneous cold abscesses, surface ulcers of 10 mm and more in diametre on the spot of intracutaneous injection of BCG vaccine; lymphadenites of regional lymphatic nodes (groin, neck, supra- and subclavian), the size of 1,5 cm and more; keloid seams of 10 mm and more in diametre.

Chemoprophylaxis.

• Specific prophylaxis is aimed not only to the increase of the body resistance to tuberculous infection by means of active immunisation (vaccination, revaccination), but also by using antimycobacterial means (chemoprophylaxis).

• Chemoprophylaxis is viewed as an urgent prophylaxis of tuberculosis, as its preventive action develops from the first hours after taking an antimycobacterial drug. Chemoprophylaxis is recognized to be the most efficient of all methods of tuberculosis prophylaxis.

The primary and the secondary

chemoprophylaxis are discriminated. • The primary chemoprophylaxis is performed to

noninfected persons, who react negatively to tuberculin.

• The secondary chemoprophylaxis is performed with a view to prevent the development of tuberculosis of persons infestated earlier, the ones who react positively to tuberculin and in whom active clinico-roentgenological manifestations of tuberculosis are absent.

Persons undergoing chemoprophylaxis:

• 1) clinically healthly children, teenagers and persons of young age up to 30, who are firstly MBT infestated;

• 2) persons with stable hyperergic reactions to tuberculin or their 6 mm and more increase comparing to the previous results;

• 3) children, teenagers and adults, who are in contact with epidemiologically dangerous tuberculosis patients;

• 4) persons, who have nonactive tuberculous changes, pregnancy or unfavou-rable factors being present (acute illnesses, operations, traumas), capable of provoking tuberculosis relapse;

• 5) persons with traces of previously suffered tuberculosis, their illnesses being present (bronchial asthma, collagenose, sarcoidosis,stomach ulcer), which are treated with various drugs, including corticosteroid hormones, which may provoke complications or tuberculosis relapse.

• Chemoprophylaxis is performed with isoniazidum or phtivasidum during 2-3 months, and, at the preservation of epidemiological danger, it is repeated twice a year. For adults and teenagers a daily dose of isoniazidum, when used every day, is 0,3 g, for children – 8-10 mg/kg of a body mass. A complex of vitamins is administered in 30 minutes after the intake of the drug with an obligatory inclusion of vitamin B6 (30-50 mg daily) and vitamin C.