eWizzard wroteHepatitis B is not known to be transmitted in swimming pools. But for the sake of discussion, let's assume that it can be, and we can say other transmittable diseases have similar prevalences.
So on average, in an average pool populated by 39 Lebanese and 1 Ethiopian (if you're lucky enough to see one) you're about 10 times more likely to catch a hepatitis B virus that originated from the Lebanese (1.85% chance) than from the Ethiopian (0.19%). To have equal chance of catching it from either, out of 40 swimmers you would need to have 32 Lebanese and 8 Ethiopians (1.5% chance for both). Have you ever seen that many Ethiopians in a Lebanese swimming pool, not even simultaneously, but cumulatively, i.e.
in your life? Because I haven't. In any case, those are very low percentages that are actually even lower in real life because pools have large volumes and the chlorinated water is continuously circulated and filtered. So then, where's the problem in letting Ethiopians swim with everyone else? With those percentages, the risks of infection are practically negligible, so there's no real health problem to worry about. It follows that pool owners are not basing their decision on rationality, but either misguidedness or ignorance.
nuclearcat wroteAdditionally, fungus and worm eggs are curable and not end of world at all, but hepatitis and other viral diseases might take serious cut from your lifespan and quite hard and expensive to cure.
It depends. Some people recover from hepatitis B on their own without problems. Others, not so much. Same with worms; some types don't do much, while others can cause anemia and various health problems, the worst possibly being hydatid cysts, which are very hard to cure and can be life-threatening.
edit: maths
Hepatitis B is blood-to-blood disease. In theory such infection should be safe in water prools. However, read guides for infected people, guess why they recommend them to not go water pools, saunas and etc, if they have any wounds, bruises... And guess why. Hint: Hepatitis B can survive in body fluids up to 7 days outside body. And some information are given in such ways, that it wont cause panic in public and it wont cause ostracization and isolation of infected people.
And statistics&theory of probability is not arithmetics, but i don't want to go deep on that.
Plus as i said problem of domestic workers is not that they are infected by hepatitis, or they are dirty or so. They are definitely not. Problem is that they are originated from countries with high risk of various infections/diseases, and when you mix that with fact that their medical information is often falsified, they are originated from poor demographical groups, and worse they don't pass routine checks (as it's expensive), all because medical system in lebanon and their countries is flawed in this - that's put population life in risk. So society trying to defend himself, as many who had business with domestic workers(especially resorts owners) - know this issues, but afraid or don't want to talk.
It is weird mix of social problems, psychology and flaws in medical system. So screaming "let the domestic workers enter public places and threat them as equal" wont be enough, subconscious fear will remain and society will keep resisting such noble (but stupid) efforts.
But if people works towards fixing _REAL_ issue - such as issuance of fake medical exams, for example making that as criminal offense by law and enforcing it by activists - situation will change.
Thats a problem of modern active society - they see and trying to solve problems very superficially, without trying to delve into them in details. For them it is enough to find a noble problem, loudly scream and voila - you are a hero.