The name "microbe" suggests creatures that are so tiny you need a microscope to see them. For most microbes this is true, but there are some gargantuan microbes that we can actually see with the unaided eye. On this page, you’ll read about the biggest of the big in each of the main categories of microbes: viruses, bacteria, protists, fungi and, as an extra added bonus, parasitic worms.
Largest Virus
Viruses are super tiny. There’s not a single type of virus that can be seen without a microscope and regular light microscopes that allow us to see bacteria and protists aren’t powerful enough to view viruses. Scientists use special types of electron microscopes to see viruses.
However, viruses come in a wide range of sizes and there are some biggies among them (big being a very relative term here). The largest of them all are a group called the Filoviridae . This family includes the Ebola virus, which you might have heard of. Filoviridae are long, thin viruses that look like bent tubes. They can reach up to 1,000 nanometers or 1/10,000th of a centimeter in length. This makes them actually longer than some of the smaller bacteria. However, these long viruses are only about 80 nanometers in diameter.
Filoviridae are big for viruses, but they are mere pipsqueaks next to the largest of the bacteria.