Sewage pipe leak / human fecal matter — how unsanitary is it and how do you clean/wash?

I noticed some brown semi-dried stains on the car I rode here in the Philippines. It was on one side of the car, passenger area. Not sure if it’s bird poop, human feces thrown onto the car (cause unfortunately that happens in the more chaotic areas), or maybe a leaky sewage pipe or whatever. Anyhow, definitely one of those three. Based on its looks it either came from above or thrown with a projectile, unlikely that it’s mud. What could it be? It was just brown didn’t really see white, and it looked a little muddle but also a little smooth. Weird.

My next question is, the clothes that I was wearing touched the brown stuff. How exactly do I clean this off or sanitize my clothes? Can I just throw it in the washer?

Let’s assume the worst that I could either be from a sewage leak or human poop, Would one regular wash cycle with detergent be enough? Any reason to wash twice? Unfortunately, I don’t have a dryer on here. Just a basic washing machine with cold/room temperate water.