As the World Economic Forum kicks off in Davos, the charity Oxfam has issued its annual report on wealth, poverty and inequality. It makes some bold assertions. But there are skeptics.

Researchers at Oxfam, a nonprofit devoted to combating poverty, examined billionaires who collectively own $2.4 trillion in company equity, with investments across 183 companies.

The poverty-fighting charity points to unprecedented new wealth accrued by the ultra-rich — and asserts that the result of the world's growing inequality is "economic violence" for the impoverished.

In areas with limited access to clean running water, hand-washing stations can help limit the spread of disease. But experts say not all taps are created equal.