OBJECTIVETo review the transmission models of tuberculosis in heterogeneous population.

DATA SOURCESThe data used in this review were adopted mainly from the studies of models of tuberculosis reported from 1995 to 2006.

STUDY SELECTIONRelevant literature on transmission models of tuberculosis in heterogeneous populations are referenced.

RESULTSCasual/random factors and genetic factors are the main reasons for epidemics of tuberculosis in recent years. Mass public transport is playing the primary role in casually close contact which can facilitate the transmission of tuberculosis. Genetic susceptibility not only varies endemic prevalence levels, but also drastically alters the effects of treatment for tuberculosis patients. Detailed studies further exhibit that casual contact and genetic factor are responsible for over 30% - 40% of the total new cases in recent years. The prevalence of tuberculosis could double (from 33% to 60%) if a genetically susceptible phenotype is present in only 30% of the population. And some challenges have emerged along with these exciting results.

CONCLUSIONSCasual/random contact, public transport and genetic susceptibility are responsible for most new tuberculosis cases and a wide variation in endemic tuberculosis levels between regions. Hence, the transmission model of tuberculosis in a heterogeneous population can provide more clues to underlying mechanism of tuberculosis transmission than in a homogeneous population. However, many challenges remain for us in understanding transmission of disease.