TOKYO Long confined to the mountains, Japanese leeches are invading residential areas, causing swelling, itching and general discomfort with their blood-thirsty ways.
Yamabiru, or land leeches, have become a problem in 29 of Japan's 47 prefectures, according to the Institute for Environmental Culture, a private research facility in Chiba prefecture, east of Tokyo.
The little suckers are riding into towns and villages, hitching lifts on deer and boar whose numbers have grown due to re-forestation and dwindling rural populations.
Once there, the leeches, which measure in at about 1.5 cms before a meal, take to feasting on warm human flesh.
"Yamabiru will climb into people's socks and stay for about an hour, growing five to 10 times in size. Unlike with water leeches, people don't immediately realize they've been bitten. Only later when they see their blood-soaked feet, do they realize what has happened," said Shigekazu Tani, the institute's director.
"The real problem is that the bleeding won't stop and the affected area swells up and really itches," he added.
The best way to deal with the tiny vampires?
"We can cut down trees and mow long grass to dissuade wild animals from coming too close, and create sunny habitats that are inhospitable to leeches. We can also spread pesticides that kill the leeches," Tani said.
"Or we can just tough it out."