Zhao Tong, Yunnan: Fighting TB in its mountain stronghold

Dr. Anh Innes is the Chief of Party of the CAP-TB Project.
 

Zhao Tong is a rural prefecture in the remote northeast corner of China’s Yunnan Province, where coal mining and subsistence farming have been the way of life for centuries.  Small villages in this prefecture are nestled along the mountain ranges, each connected by dusty roads riddled with holes and crevasses that make accessibility very difficult.  And at the eastern edge of Zhao Tong prefecture is the county that reports the highest TB prevalence among all 129 counties in Yunnan Province:  Zhen Xiong. 

I recently visited Zhen Xiong with the CAP-TB China team, flying first to Yunnan’s neighboring province of Guizhou and driving three hours in dense fog along the mountain roads to reach the city center.  Zhen Xiong has a population of 1.6 million, and it is one of the poorest counties in Yunnan Province.  The working-age demographic from this area comprise a large proportion of the migrant and mobile population, moving elsewhere in Yunnan to find work.  In Zhen Xiong, 2271 TB cases were reported in 2013; 480 of these TB cases were smear positive, and 43% of the smear positive cases were previously (or partially) treated cases---which raises some alarming issues, one of which is the risk for MDR-TB.  Due to limited human and financial resources, TB diagnosis is made almost exclusively by AFB smear, since Zhen Xiong county’s TB staff can only afford to complete their annual quota of 30 solid cultures—and no more---per year.  Even a ballpark estimate of drug resistance or multi-drug resistance is not currently known. 

Zhao Tong’s persistently high TB prevalence, combined with it being an impoverished prefecture with almost inaccessible mountainous terrain, has made the TB epidemic very difficult to control.  Last year, over 100 school children were diagnosed with TB in Zhen Xiong County. Many of these children live on campus in crowded school dormitories and sit in classrooms of 120 students each, with 3 children per desk — a significant infection control challenge.  The index case is, of course, likely infected from their home, and then continued transmission is perpetuated within the school.  Coal mining is one of the main industries in Zhen Xiong, and coal-burning stoves also heat most of the homes throughout the bitter winters.  Silicosis (from coal mining) is known to be a risk factor for TB, and coal-based indoor air pollution has been associated with increased risk for TB, although no one has conducted screening among this population in Zhen Xiong. Heavy tobacco smoking is a major problem, particularly among men. Environmental factors such as Vitamin D deficiency (from the persistent fog and smog) and both indoor and outdoor air pollution may contribute to the increased risk for TB in this population.    

The rural health system in China is well-established, with clear roles and responsibilities at the county, township, and village levels --- although communication among these levels is not systematically done.  Perhaps most importantly, directly observed therapy (DOT) is only possible if conducted by the patients’ family members, and no method is in place to monitor family DOT and track compliance throughout the patient’s treatment course.  In a setting with such limited human and financial resources, it is necessary to identify an effective and sustainable strategy to improve treatment outcomes if the TB epidemic in Zhen Xiong is to be contained. 

Although it may seem like TB control is an insurmountable challenge in this rural, mountainous county, it is simple to identify a starting point:  Focus on the basics of TB control, improving active TB case finding among risk groups and improving treatment outcomes by standardizing family DOT and coordination within the rural TB network. Fortunately, the existing infrastructure of the rural health system will enable us to adapt the model that CAP-TB has developed over two years in urban Kunming to the rural setting of Zhen Xiong.  Since the majority of Yunnan Province is rural and mountainous, it is essential to develop an effective strategy for TB and MDR-TB elimination for the rural setting if we hope to impact incidence, morbidity, and mortality from these diseases. Building on our past successes, and adapting to the daunting circumstances in the mountains of Yunnan, we believe we can make a difference.

Posted by: Dr. Anh Innes