DTBE in Cambodia
Capital City: Phnom Penh
Area*: 181,040 sq. km. (69,900 sq. mi.)
Population (est.), 2008*: 13.4 million
Estimated TB Incidence, 2010**: 437/100,000
Estimated TB Prevalence, 2010**: 660/100,000
Adult HIV Prevalence Rate, 2009***: 0.5%
Number of people living with HIV (PLHIV), 2009***: 63,000
Percent of tested TB patients who were HIV-positive, 2010**: 7%
**Source: WHO Global TB Control Report 2011
***Source: UNAIDS, Report on the Global AIDS Epidemic, 2010
While still among the world’s 22 high-burden tuberculosis (TB) countries, Cambodia’s TB incidence, prevalence, and mortality rates have steadily fallen over the past decade. Similarly, Cambodia’s HIV-infection rate has fallen below 1%. However, there are concerns that the TB case detection rate has fallen as well, resulting in under-diagnosis of TB. The Centers for Disease Control and Prevention’s Division of Tuberculosis Elimination’s (CDC/DTBE) Regional TB Technical Advisor stationed in Bangkok, Thailand works closely with the Thai Ministry of Public Health (MOPH) U.S. CDC collaboration (TUC) Southeast Asia Regional TB Program to provide technical support for Cambodia. Program staff also provides technical assistance to other countries in the region, including Laos and Vietnam, and to World Health Organization (WHO) regional offices in New Delhi, India and Manila, Philippines. Strategies used to reduce the burden of TB in Southeast Asia include developing models for better TB screening and diagnosis, measuring incidence and mortality, promoting best practices, and training clinical and program staff.
Recent Accomplishments & Ongoing Collaborations
Program Strengthening and Epidemiology
Laboratory diagnostic support: Since 2008, CDC/DTBE’s regional office has provided extensive technical support for training and implementation of faster and more sensitive diagnostic technologies, including TB liquid culture and GeneXpert MTB/RIF, in the national TB reference laboratory and at a regional laboratory in Battambang Province. Ongoing monitoring and assistance with laboratory information systems and quality assurance has continued. Support has included biosafety assessments, renovation recommendations, procurement of equipment and supplies, training, and site visits.
Household Contact Investigations: In 2010, the regional TB program conducted an evaluation of contact investigations to find contacts of TB cases that may also have TB disease or infection so those persons could start appropriate therapy. This evaluation showed TB screening among adult household contacts of TB patients to be high-yield, meaning this approach identified more cases for the effort than other types of case-finding activities. The evaluation also showed that screening should focus on contacts with current symptoms. Screening children who were household contacts of TB patients through this process was one of the best ways to identify children who would benefit most from treatment of TB. It’s possible to scale-up this TB screening approach, especially when integrated with the community-directly observed therapy (DOT) programs so that Directly Observed Therapy Short-course (DOTS) community health workers can conduct contact investigations.
Multidrug-resistant TB (MDR TB), TB/HIV, and Other At-Risk Populations
Impact of new TB diagnostics in combatting drug resistance: Drug‐resistant TB is an emerging concern in the region and CDC supports pilot implementation of a new rapid test for drug resistance (GeneXpert MTB/RIF) to evaluate its impact on time of diagnosis and treatment as well as treatment outcomes.
Intensified TB case finding for people living with HIV (PLHIV): CDC/DTBE led a cross-sectional study (Improving Diagnosis of TB in HIV-Infected Persons: The ID-TB/HIV Study), enrolling more than 2,000 PLHIV from eight anti-retroviral therapy (ART) clinics in Cambodia, Thailand, and Vietnam to determine the best method for screening and diagnosing TB in PLHIV. The study found that using previously recommended screening approaches failed to detect more than two-thirds of patients with TB disease. However, screening PLHIV for TB using a combination of three symptoms detected almost all cases (93%) among this population. The presence of one or more symptom (cough, fever, or night sweats) is a positive symptoms screen, whereas absence of all symptoms is a negative symptom screen. Patients with a positive symptom screen need further evaluation to accurately diagnose TB disease. Patients with a negative symptom screen have TB disease reliably ruled-out (97% without TB had no symptoms), allowing isoniazid preventive therapy (IPT) to be started more quickly. In follow up to this study, CDC/DTBE and WHO collaborated on a meta-analysis which led to a change in WHO’s international guidelines for screening for TB among PLHIV. These updated guidelines are available here: WHO Guidelines for ICF and IPT