Nose: Unfortunately, there's no compact answer to this question. All that you can hope is that your friends are capable of adjudicating information.
Consider: I spent almost a decade in Toronto, so I was constantly in contact with sick people on the subway, bars, work, etc... and yet I was rarely sick. So, imagine that one day I became sick -- well, there are sick people everywhere, so 'obviously' I picked it up from them... but what about the other 359 days of the year!!!
Okay: so it's my 'immune system'... But consider: cold viruses, although they mutate, are, by and large, quite similar. So why would my 'immune system' flush out hundreds of cold viruses... and then have an absolutely catastrophic failure on the 101st virus? And why have I, personally, never had 'the flu'? Am I superhuman?!?
And, ultimately, the real truth is that 'colds/flus' have never been shown as transmissible in scientific experiments -- so the virus hypothesis has to be discarded.
An aside: Marek's disease in farmed chickens is often quoted as a 'proof' of viruses. But farmed chickens literally defecate on each other! Wild chickens, like the ones I see here in Cambodia, are never sick.
Nose: Unfortunately, there's no compact answer to this question. All that you can hope is that your friends are capable of adjudicating information.
Consider: I spent almost a decade in Toronto, so I was constantly in contact with sick people on the subway, bars, work, etc... and yet I was rarely sick. So, imagine that one day I became sick -- well, there are sick people everywhere, so 'obviously' I picked it up from them... but what about the other 359 days of the year!!!
Okay: so it's my 'immune system'... But consider: cold viruses, although they mutate, are, by and large, quite similar. So why would my 'immune system' flush out hundreds of cold viruses... and then have an absolutely catastrophic failure on the 101st virus? And why have I, personally, never had 'the flu'? Am I superhuman?!?
And, ultimately, the real truth is that 'colds/flus' have never been shown as transmissible in scientific experiments -- so the virus hypothesis has to be discarded.
An aside: Marek's disease in farmed chickens is often quoted as a 'proof' of viruses. But farmed chickens literally defecate on each other! Wild chickens, like the ones I see here in Cambodia, are never sick.