Concerns by US health official's have been raised about a disease known as Oropouche virus, which is also called Sloth Fever. Here's what is known at the time of writing. As reported by USA Today, the disease known as the Oropouche virus was recently found in the United States. The sickness was first discovered in 1955 in the nation of Trinidad and Tobago. The sickness also spreads in a very simple way, from bites from a midge or a mosquito.