Hookworm infestation is known as ancylostomiasis and serious cases can result in as much as 200 milliliters of blood loss per day. The condition tends to be most prevalent in tropical regions and may affect animals, such as dogs and cats, as well as humans. Symptoms of ancylostomiasis vary by host, but often include diarrhea, weight loss, and severe anemia. In fact, during the late 1800s an epidemic referred to as miners' anemia occurred among Italian laborers building the Saint Gotthard railway tunnel in the Swiss Alps. The hookworm species Ancylostoma duodenale was responsible for the outbreak.