Ascariasis is not only the most common parasitic infection, it's also one of the worst parasitic infections to get. Though ascariasis is rare in the United States, it is still prevalent in many countries with poor sanitation systems.
Ascariasis is caused by a type of roundworm (or ascaris). Technically, two different types of roundworms lead to the infection - ascaris suum is a pig roundworm and ascaris lumbricoides is a human roundworm. Both can infect humans, though, and they are virtually indistinguishable from one another. Once an infection takes hold, it can be difficult to get rid of it.
In people, ascariasis may not present symptoms for a long time. In livestock, the parasite is so hard to get rid of that widespread infection is almost guaranteed. The infection can usually be cured with medication that is relatively low-cost. However, if the infection is advanced and there is a full-fledged infestation of worms, it can be fatal.
You can protect yourself with basic hygiene, but if you're traveling abroad to a remote area or an area known to have roundworms, it's important to avoid contaminated soil that could contain roundworm eggs. You can get ascariasis directly from soil, or from food that was exposed to the soil.
Turns out, hitting up that McDonald's while you're abroad may not be such a bad idea after all.
The Roundworm Lifecycle Is Pretty Gross
A Roundworm Can Lay Two Million Eggs Per Day
There Are Ways To Tell If You Have A Roundworm Infection
60,000 People Die Every Year From The Infection
It's Easy To Become Infected
Anti-Parasitic Drugs Are Becoming More Accessible