flies are disease-carrying pests, they seek food from carcasses and human waste.
We humans .........
It is perfectly natural that when people see flies around, they will assume the area is not clean.
Besides being a nuisance, some fly species bite and pose serious health risks.
For example, house flies are more often associated with human habitation; transmit various kinds of dangerous diseases. 
Flies can also spread the disease because of their breeding and eating habits.
therefore all steemit friends.
"Keep it clean".
Because cleanliness is halfway through faith.
"Do not litter".