Tuberculosis (TB) incidence, discontinuing to treatment and frequency of strains resistant to one or more drugs have been increasing in the last years stemming from the current AIDS epidemic and worsening of health care. According to WHO, one third of world population is infected by BK, there are 9 million new TB cases and it is the cause of 1.9 million deaths worldwide each year. Because of the increasing of multi-drug resistance (MDR), resulting from noncompliance to treatment and the high incidence of TB in crowded care facilities like hospitals and prisons with poor health conditions, especially in regions in which prevalence of HIV infection is high, establishing priorities urges to combat TB.
As reported by CNPS/FNS/MS, there were 90.661 new cases of TB notified in 1995 ( 76.573 in its pulmonary form and 14.,091 in the extra-pulmonary form), 45.539 of these being AFB smear positive. The analysis of the outcome of treatment revealed 76% of favorable results and 14% of discontinuing to treatment. Because of poor social and economical conditions and health care, the worse results in TB control took place in big cities.
A study realized in 12 capitals by CNPS/FNS/MS showed that, in 1992, only 179 (9%) of the 2054 examined medical records contained results of HIV research, 81 (4%) of them being positive. From 1858 patients treated with rifampin, isoniazid and pyrazinamide for 2 months and the two first for other 4 months, discontinuing to treatment occurred in 28%. The results are even worse in regions in which the prevalence of TB/HIV co-infection is high. According to SMSRJ, there were 9.487 new cases notified in 1995 ( 7.684 of pulmonary forms and 1.803 of extra pulmonary forms), 3.381 of these being AFB smear positive, proving to be the higher national incidence rate: 160/100.000 for all forms and 58..2/100.000 for AFB smear positive. The analysis of the 6.369 new cases notified in the 23 Health Centers revealed 10% of TB-HIV co-infection. Unlike the observed in the rest of the country, in RJ the attending patients rate in hospitals was high: 3.118 cases, 33% of total, with high HIV infection (25%). As there is no TB control program in hospitals, there are no data referring to treatment outcome (abandon, cure, death and side effects) and strains resistance rate. There are only two hospitals in which AFB culture is part of routine. In none of them the test of sensibility to the drugs used to treat TB is realized. Likely, there is why there are no reports of nosocomial transmission of TB in our country.
By the end of the 80’decade, when most of patients were attended in primary health care units, one observed that:
a) in some regions of the country, there was a tendency in privileging emergency attention with damage of patient’s accompany and lack of contacts and absents search;
b) poor familiarity from technician and non-pneumologist doctors with TB diagnosis and treatment, especially when association with other diseases was present;
c) lack of attention was given to patient’s participation in treatment;
d) lack of management preparation, motivation and training of people involved in the different system levels;
e) absence of an efficient tertiary system reference, with no attention being given to evaluation of abandon to treatment, re-treatment, MDR, side effects and CO-infection rates (especially TB-HIV CO-infection);
f) lack of attention given to beds need, MDR rates in crowded care facilities, administrative measures and engineering control;
g) no priority given to new diagnosing methods research.
Recently, due to increasing rates of discontinuing to TB treatment , TB and HIV association, and appearing of MDR cases , the WHO have considered TB as a world urgency and an important challenge for public health.
Several evidences show that co-infection by TB and HIV is the one of the main responsables for increased incidence of TB around the world, mainly by non-pulmonary TB .
HIV infected patients with pulmonary TB have a lower frequency of spontaneous expectoration and atypical chest radiograph. This kind of presentation makes hard the diagnosis and , consequently, the treatment is lately introduced ,what contributes to a higher morbidity and mortality. What is more , the transmission is made for a longer period , mainly inside hospitals.
One of the worse consequences of TB/HIV co-infection is the appearing of Multi Drugs Resistant - TB (MDR-TB) . In the last years, it was noticed an increase primary and acquired resistance in developed countries. In USA , the resistance to anti-TB drugs rose from 10% in 1983 to 23% in 1991. Almost 20 % of all HIV infected patients of New York city had MDR cultures.
Several microepidemics with great rates of mortality/morbidity were described in last years. Either patients as healthcare were affected. AIDS contributed for these microepidemics due to the fast progression to TB-disease of HIV infected patients. The risk of nosocomial transmission vary according to the kind of health unit, the local prevalence of TB disease/infection, and the effectiveness of control programs. Patients with pulmonary and laryngeal TB are those who more transmit the disease. Some procedures like bronchoscopy, endotracheal intubation, and sputum induction increase the risk of transmission. Failure in how to recognize, isolate, and manage patients with TB are causes for nosocomial microepidemics.
Due to HIV infected patients have high chances to develop TB, AIDS reference hospitals must introduce preventive programs for M. tuberculosis transmission. The early identification of pulmonary TB patient, the right treatment, and suitable physical conditions, have to be priorities in theses establishments.
The technics of molecular epidemiology have been introduced in TB studies. The utilization of DRE-PCR (double-repetitive-element polymerase chain reaction), followed by a molecular biology technic : RFLP (restriction length polimorphism) have made possible to distinguish different genotypes of M. tuberculosis. This technics with conventional epidemiologic technics have allowed the identification of TB microepidemics, such as the determination of common infection sources.
Prospect
In our country, the impact of decreasing in social and economical conditions, poor health care and the emerge of Aids epidemic urges to be analyzed in order to identify measures to be implemented to combat TB. Some initial measures have been established but they are just the beginning. TB control has to be a priority to society, and it will happen only with political decision and communication means settlement.
References
1- Raviglione MC, Snider D, Kochi A. Global Epidemiology of Tuberculosis: Morbidity and Mortality of a Worldwide Epidemic. J.A.M.A, 273(3): 220-226, 1995.
2- Fandinho FCO, Kritski AL, Conde H, Fonseca LS. Drug susceptibility of Mycobacterium Tuberculosis isolated from HIV infected and no infected in Rio de Janeiro (Brazil).Tubercle and Lung Dis. 76 (suppl 2): 94
3- Brasil, MS - Programa Nacional contra TB. Relatórios de Atividade de 1994.
4- Cantuel MF, Snider DF, Cauthen GM, Onorato IM. Epidemiology of Tuberculosis in the United States, 1985 trough 1992. JAMA, 272(7):535-539 1994
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