Is my camera infected with fungus?

First, fungus that grows on glass grows very slowly, and likely will not bother you or other lenses, directly. However,the smear might also be condensation from plastic outgassing plasticizer. Evaporating plasticizer from car parts can leave a similar smear on the windows.

In any event, you can try to clean the outer surfaces of the lens... but if the mess is on the inside, professional cleaning may cost more than a replacement lens.