Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom. Some species of yeast are opportunistic pathogens that can cause infection in people with compromised immune systems. Candida and Cryptococcus are significant pathogens of immunocompromised people.

Yellow fever

The disease caused by the yellow fever virus, characterized by fever, chills, loss of appetite, nausea, muscle pains and headaches. It is spread by the bite of an infected mosquito.