Any form of chronic cough for more than 2 month will be screened for PTB. Constitutional symptoms such as loss of weight/appetite, coughing blood may or may not be experienced.

Like you said yourself, you first experiencing the symptoms only as simple as nose/throat infection.

Person next to you that manifesting the similar symptoms would think the same to themselves, but turn out might be having TB as well.

Thats can be as simple as that, the subtle way of TB transmission from one to another.