Fighting the tuberculosis epidemic in the Western Pacific region: current situation and challenges ahead.
BACKGROUND
Tuberculosis (TB) remains a major public health problem in the Western Pacific Region. More than 20% of the global burden of TB is found in the Region. In 2007, the latest year for which data is available, there were an estimated 1.9 million incident cases (109 per 100,000 population). Four countries (Cambodia, China, the Philippines and Vietnam) account for 93% of the total estimated incident cases in the Region. Every year an estimated 300 thousand persons die due to TB. The Region is host to an estimated 135,000 multi-drug resistant TB cases, most of which can be found in China.
The Regional Stop TB strategy aims to halve the prevalence and mortality rates of 2000 by 2010. Based on current estimates, the TB prevalence declined with 24% between 2000 and 2007, while TB mortality declined with 19% in the same period. Given the current annual decrease in TB prevalence and mortality, it is unlikely that the Region will achieve the 50% reduction by 2010.
Approximately 1.4 million new TB cases were notified in the Region in 2007, of which close to 0.7 million smear-positive cases. Cases from China accounted for 70% of the total notified smear-positive cases. The Regional case detection rate was sustained at 78%. Case detection rates in China, the Lao People's Democratic Republic, Mongolia, the Philippines and Vietnam exceeded the 70% target.
A total of 92% of the 0.7 million new pulmonary smear-positive cases registered for treatment in 2006 were successfully treated. The treatment success rates exceed the 85% target in all countries with a high burden of TB, except Papua New Guinea where it was reported at 73%. MULTIDRUG-RESISTANT TB: In 2007, the proportion of MDR-TB in new TB cases was estimated to be 4%. A total of 135,411 MDR-TB cases was estimated to have occurred in 2007. Based on the overall case management data, 10,231 new patients and 1,596 re-treatment patients were reported with available drug susceptibility testing (DST) results in the Region. Of these, 1% (89/10,231) and 29% (468/1,596) had MDR-TB, respectively. Capacity to detect and treat MDR-TB cases is still very limited in most countries in the Region. Eighteen countries and areas in the Region have conducted drug resistance surveillance (DRS) since 2000, according to the Global Project on Anti-tuberculosis Drug Resistance Surveillance. Among new TB cases, the prevalence of multidrug-resistant TB (MDR-TB) ranged from 0% in Cambodia to 11.1% in the Commonwealth of the Northern Mariana Islands. MDR-TB prevalence among re-treatment cases ranged from 3.1% in Cambodia to 27.5% in Mongolia. In the five countries with a high burden of TB with available data from surveys (Cambodia, China, Mongolia, the Philippines, and Vietnam), MDR-TB prevalence in new cases and re-treatment cases ranged from 0% in Cambodia to 4.9% in China and from 3.1% in Cambodia to 27.5% in Mongolia, respectively. Notably, there were alarming rates of MDR-TB in several provinces in China among both new and retreatment cases. Increasing numbers of MDR-TB cases are reported from Papua New Guinea. TB-HIV CO-INFECTION: The overall estimated prevalence of HIV in new TB cases in 2007 was 2.7%. With 8.0% in 2008 compared to 11.8% in 2003, Cambodia shows a declining prevalence of HIV in new TB cases. There was a significant increase in the use of anti-retroviral therapy (ART) in the Region. However, detailed and complete data as well as strong collaboration in HIV and TB management are needed to be able to closely monitor the use of ART and its impact on TB-HIV co-infection in the Region.


CONCLUSIONS
In spite of the substantial progress made in most countries with a high burden of TB, substantial challenges remain in the Region. The rate of decline in TB prevalence and mortality is too low to reach the 50% reduction goal in 2010. It will be necessary to further increase TB case detection and address the emerging spread of drug-resistant TB. The slow response in the most affected countries in the Region is a cause for concern. Strong commitment by national governments and their partners is needed to sustain and further strengthen the current TB control efforts.
WHO Western Pacific Region, Manila, Philippines. vanmaarenp@wpro.who.int
Pieter J M
PJ
van Maaren
D000995:Antitubercular Agents / Q000008:administration & dosage; D001210:Asia, Southeastern / Q000453:epidemiology; D015897:Comorbidity; D023801:Directly Observed Therapy; D015658:HIV Infections / Q000453:epidemiology; D006801:Humans; D015995:Prevalence; D013997:Time Factors; D014376:Tuberculosis / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology / Q000517:prevention & control; D018088:Tuberculosis, Multidrug-Resistant / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology / Q000517:prevention & control; D014944:World Health Organization
D000995:Antitubercular Agents