'Sea Nomads' Are First Known Humans Genetically Adapted to Diving

We should note that finding an enlarged spleen in animal necropsies is normally a symptom of infection. In humans can be also a symptom of chronic alcohol abuse, but as 95% of them are muslims, we can probably discard that.

People living a nomadic style life in a boat, travelling at open sea, eating and cutting fishes and echinoderms in the ship deck all the time, could be exposed to higher loads of bacteria. Fishermen's boats can stink a lot after a day of work in a hot day.

As nomads, they could also experience a sub par medical care system.