Biomedical subjects

Catherine J Watt

Publications and source records attributed to Catherine J Watt.

5 recordsLinked to original sources

PubMed2003

Tuberculosis.

Among communicable diseases, tuberculosis is the second leading cause of death worldwide, killing nearly 2 million people each year. Most cases are in less-developed countries; over the past decade, tuberculosis incidence has increased in Africa, mainly as a result of the burden of HIV infection, and in the former Soviet Union, owing to socioeconomic change and decline of the health-care system. Definitive diagnosis of tuberculosis remains based on culture for Mycobacterium tuberculosis, but rapid diagnosis of infectious tuberculosis by simple sputum smear for acid-fast bacilli remains an important tool, and more rapid molecular techniques hold promise. Treatment with several drugs for 6 months or more can cure more than 95% of patients; direct observation of treatment, a component of the recommended five-element DOTS strategy, is judged to be the standard of care by most authorities, but currently only a third of cases worldwide are treated under this approach. Systematic monitoring of case detection and treatment outcomes is essential to effective service delivery. The proportion of patients diagnosed and treated effectively has increased greatly over the past decade but is still far short of global targets. Efforts to develop more effective tuberculosis vaccines are under way, but even if one is identified, more effective treatment systems are likely to be required for decades. Other modes of tuberculosis control, such as treatment of latent infection, have a potentially important role in some contexts. Until tuberculosis is controlled worldwide, it will continue to be a major killer in less-developed countries and a constant threat in most of the more-developed countries.

Adolescent↗

PubMed2003

The growing burden of tuberculosis: global trends and interactions with the HIV epidemic.

BACKGROUND: The increasing global burden of tuberculosis (TB) is linked to human immunodeficiency virus (HIV) infection. METHODS: We reviewed data from notifications of TB cases, cohort treatment outcomes, surveys of Mycobacterium tuberculosis infection, and HIV prevalence in patients with TB and other subgroups. Information was collated from published literature and databases held by the World Health Organization (WHO), the Joint United Nations Programme on HIV/Acquired Immunodeficiency Syndrome (UNAIDS), the US Census Bureau, and the US Centers for Disease Control and Prevention. RESULTS: There were an estimated 8.3 million (5th-95th centiles, 7.3-9.2 million) new TB cases in 2000 (137/100,000 population; range, 121/100,000-151/100,000). Tuberculosis incidence rates were highest in the WHO African Region (290/100,000 per year; range, 265/100,000-331/100,000), as was the annual rate of increase in the number of cases (6%). Nine percent (7%-12%) of all new TB cases in adults (aged 15-49 years) were attributable to HIV infection, but the proportion was much greater in the WHO African Region (31%) and some industrialized countries, notably the United States (26%). There were an estimated 1.8 million (5th-95th centiles, 1.6-2.2 million) deaths from TB, of which 12% (226 000) were attributable to HIV. Tuberculosis was the cause of 11% of all adult AIDS deaths. The prevalence of M tuberculosis-HIV coinfection in adults was 0.36% (11 million people). Coinfection prevalence rates equaled or exceeded 5% in 8 African countries. In South Africa alone there were 2 million coinfected adults. CONCLUSIONS: The HIV pandemic presents a massive challenge to global TB control. The prevention of HIV and TB, the extension of WHO DOTS programs, and a focused effort to control HIV-related TB in areas of high HIV prevalence are matters of great urgency.

AIDS-Related Opportunistic Infections↗

PubMed2003

What is the limit to case detection under the DOTS strategy for tuberculosis control?

In year 2000, the WHO DOTS strategy for tuberculosis (TB) control had been adopted by 148 out of 212 countries, but only 27% of all estimated sputum smear-positive patients were notified under DOTS in that year. Here we investigate the way in which gains in case detection under DOTS were made up until 2000 in an attempt to anticipate future progress towards the global target of 70% case detection. The analysis draws on annual reports of DOTS geographical coverage and case notifications, and focuses on the 22 high-burden countries (HBCs) that account for about 80% of new TB cases arising globally each year. Our principal observation is that, as TB programmes in the 22 HBCs have expanded geographically, the fraction of the estimated number of sputum smear-positive cases detected within designated DOTS areas has remained constant at 40-50% although there are significant differences between countries. This fraction is about the same as the percentage of all smear-positive cases notified annually to WHO via public health systems worldwide. The implication is that, unless the DOTS strategy can reach beyond traditional public health reporting systems, or unless these systems can be improved, case detection will not rise much above 40% in the 22 HBCs, or in the world as a whole, even when the geographical coverage of DOTS is nominally 100%. We estimate that, under full DOTS coverage, three-quarters of the undetected smear-positive cases will be living in India, China, Indonesia, Nigeria, Bangladesh and Pakistan. But case detection could also remain low in countries with smaller populations: in year 2000, over half of all smear-positive TB cases were living in 49 countries that detected less than 40% of cases within DOTS areas. Substantial efforts are therefore needed (a) to develop new case finding and management methods to bridge the gap between current and target case detection, and (b) to improve the accuracy of national estimates of TB incidence, above all by reinforcing and expanding routine surveillance.

Antitubercular Agents↗

PubMed2002

Worldwide incidence of multidrug-resistant tuberculosis.

Planning for tuberculosis (TB) control requires an assessment of the number and distribution of drug-resistant cases. This study used results of resistance surveys from 64 countries, together with data predictive of resistance rates from 72 others, to estimate the number of new multidrug-resistant (MDR) TB cases that occurred in 2000. By these methods, an estimated 273,000 (95% confidence limits, 185,000 and 414,000) new cases of MDR TB occurred worldwide in 2000, 3.2% of all new TB cases. The analysis provides the first comprehensive set of estimates of the MDR TB burden by country and globally.

Humans↗

PubMed2002

Low access to a highly effective therapy: a challenge for international tuberculosis control.

OBJECTIVE: To determine the scale of the tuberculosis (TB) problem facing the international Stop TB Partnership by measuring the gap between present rates of case detection and treatment success, and the global targets (70% and 85%, respectively) to be reached by 2005 under the WHO DOTS strategy. METHODS: We analysed case notifications submitted annually to WHO from up to 202 (of 210) countries and territories between 1980 and 2000, and the results of treatment for patients registered between 1994 and 1999. FINDINGS: Many of the 148 national DOTS programmes in existence by the end of 2000 have shown that they can achieve high treatment success rates, close to or exceeding the target of 85%. However, we estimate that only 27% of all the new smear-positive cases that arose in 2000 were notified under DOTS, and only 19% were successfully treated. The increment in case-finding has been steady at about 133 000 additional smear-positive cases in each year since 1994. In the interval 1999- 2000, more than half of the extra cases notified under DOTS were in Ethiopia, India, Myanmar, the Philippines, and South Africa. CONCLUSION: With the current rate of progress in DOTS expansion, the target of 70% case detection will not be reached until 2013. To reach this target by 2005, DOTS programmes must find an additional 333 000 cases each year. The challenge now is to show that DOTS expansion in the major endemic countries can significantly accelerate case finding while maintaining high cure rates.

Antitubercular Agents↗