Early childhood tuberculosis in northwestern Tanzania

Abstract

Data on pediatric tuberculosis (TB) from TB-endemic, resource-constrained regions are limited, impacting awareness of disease burden and influencing diagnostic actions. To obtain recorded incidence of childhood (age <5 years) TB in Mwanza Municipality, Tanzania, to estimate true incidence and to explore setting-specific reasons for differences. Recorded incidence of pediatric TB (2006-2010) was obtained from Mwanzan TB registries. Incident smear-positive pulmonary TB cases recruited from four TB clinics were used to estimate children exposed and the theoretical incidence of disease, assuming that either 10% or 23% of children would progress to disease following exposure. Reasons for underestimation were evaluated in the medical records of children who died at a secondary hospital. Between 2006 and 2010, 279 early childhood TB cases were recorded (TB incidence 63/100,000/year). Over a 3-month period in 2011, 44% of smear-positive TB patients being treated in Mwanza were living with a total of 139 children. From census data, we estimated that 1279 children were exposed in Mwanza in 2011. Using estimates of the likelihood of disease progression, the theoretical incidence of early childhood TB ranged from 134.2 to 308.5/100,000/year. The true burden of early childhood TB is likely much higher than recorded. Age-specific reporting, increasing clinical awareness and screening may reduce the magnitude of underdiagnosis in this vulnerable population.