How can we tell that a 10month old child is infected with TB disease?

Risk factors. A 10 month old child has to either have a TB diseased mother, or have a very close contact living with him who has tb. More than likely there is travel involved. If there is close contact with a person with tb, then a PPD test or a chest xray can be done on the baby to determine the presence of TB or the risk of TB exposure. Generally if somebody close has tb, they will test.
TB. Tb us becoming more common the last few years. At 6-12 months, during well check your pediatrician might have questionnaire for tb. If any of the questions is answered yes, they usually do TB skin test.