The true prevalence rates of multidrug-resistant tuberculosis (MDRT) are unknown for most regions of Russia. This study was conducted in the Samara Region that differs from other regions in the rapid spread of HIV infection. The purpose of this study was to determine the primary and acquired resistance of Mycobacterium tuberculosis (MBT) to first-line antituberculous drugs in patients from civil and penitentiary sectors and to reveal risk factors of drug resistance of MBT. Six hundred patients (309 civilians and 291 prisoners who had been bacteriologically diagnosed as having tuberculosis. The authors have established the following:--in new cases, primary drug resistance is as follows: to isoniazid [38.9% (95% CI, 31.3-36.9%)], to rifampicin [25.9% (95% CI, 19.4-33.4%)] and to MDRT [23.0% (95% CI, 16.7-30.3%)];--in prisoners, the primary resistance of MBT was statistically more significant than in civilians;--male sex, in adequate prior or current treatment for tuberculosis for more than 4 weeks, the presence of fibrocavernous tuberculosis and previous prison stay are essential risk factors of the development of resistance of MBT to both any first-line drug and MDRT;--HIV infection is unassociated with resistance.
The impact of exogenous infection on the course of an epidemic process was considered. The spread of tuberculosis infection from an ill patient to children and adolescents within a territorial focus was observed. A mapping study allowed the authors to make a goal-oriented search for patients with tuberculosis, as well as primarily infected children and adolescents.
Correlation and cross-correlation analyses were used to predict the rate of mortality. The equations of linear and multiple regressions were derived. The indices and factors, which are related and affect the rate of tuberculosis mortality, are defined. Based on the indices, the authors have developed short- and long-term predictions of the rate of mortality. The latter is expected to reduce and stabilize by 2010.
This paper documents and attempts to explain the epidemic spread of tuberculosis (TB) in Russia during the 1990s. After several decades of decline, the notification rate of all new TB cases among permanent residents increased by 7.5% per year from 1991-1999 and the death rate by 11% per year. Growth was quickest from 1993-1995 but increased again after the economic crisis of August 1998. Approximately 120 000 new cases and 30 000 deaths were reported in 1999. Case detection and cure rates have fallen in Russia since the mid-1980s; the fall has been accompanied by a higher frequency of severe disease among cases, and higher death and case fatality rates. With a mathematical model describing the deterioration in case finding and cure rates we could replicate the average rate of increase in incidence 1991-1999 but not the precise timing of the observed changes. Other factors that probably helped to shape the observed rise in caseload include enhanced transmission due to the mixing of prison and civilian populations, an increase in susceptibility to disease, and changes in the proportion of cases detected by surveillance. Although our explanation for the resurgence of TB is incomplete, we have identified a set of measures that can be implemented now to cut transmission, incidence and deaths.
This study shows the dynamics of the epidemiological process over the last decade and presents the causes of the deterioration in TB control. Explanations are given for the TB mortality rate increase, the trustworthiness of the data, and the factors influencing its formation. The present-day TB epidemiological situation in Russia is characterized by an increase in exogenous infection. Peaks of epidemiological deterioration were registered in 1993 and 1999. Marked deterioration of the epidemiological situation in 1999 resulted from an economic crisis in August 1998 and a consequent dramatic decrease in the living standards of the population. In the 1990s this trend has changed. TB infection spreads according to trends that are quite similar to those at the beginning of 20th century. The official TB morbidity rate does not reflect the true level of incidence because of undetected TB cases (approx. 10%).