A 35-year-old woman living in an urban slum in Delhi presents to a TB clinic with a 2-month history of cough, weight loss, and night sweats. She works as a domestic help in multiple households and lives with her 8-year-old daughter in a 10×10 ft room with poor ventilation. Sputum smear microscopy is negative on three occasions, but chest X-ray shows infiltrates in the right upper lobe. GeneXpert MTB/RIF confirms Mycobacterium tuberculosis (rifampicin-sensitive). Which epidemiological category does this case represent, and what is the primary public health implication?