How hepatits A virus is transmitted through fecus?I mean how the first one got it?

Poor hygiene, most likely. Early peoples did not exactly have toilet paper. You might be surprised at how much healthier we are than they were, because we have sanitation and indoor plumbing and a culture that emphasizes cleanliness or at least minimizing offensive odors.

There was hepatitus A outbreak here in my State(Hi) last year. Started from contaminated scallops that came from the Philippines. I suppose sanitation had something to do with the contamination. All parties dealing with the scallops now have lawsuits by the sickened persons.