Natalya Lepyoshkina smiled as she fed her three-week-old "children" a meal of warm cow's blood, rinsed them off with water and poured them into an array of glass jars.
"They're happy, they're full," she said as the young leeches, squirming and swollen from their meal, settled into the containers that would be their home until the next feeding.
Lepyoshkina's charges were among the three million leeches raised every year at the International Medical Leech Centre, an institution founded in 1937 that touts itself as the world's largest leech-growing facility.
Located in Udelnaya, a village of humble wooden houses several kilometres (miles) southeast of Moscow, the centre is now enjoying strong sales as scientists reassess their attitude to the bloodsucking creatures.
Researchers, Western governments and even Hollywood stars have endorsed the use of leeches in recent years, after decades during which the practice fell into disuse and was regarded as a relic of medieval times.
The American Journal of Nursing wrote this year that leech therapy was having a "resurgence", mainly in helping patients of plastic and reconstructive surgery, and was useful for certain blood and tissue conditions.
The US government approved the use of leeches as medical "devices" in 2004, and the actress Demi Moore revealed last year that she had undergone leech therapy in Austria to "detoxify" her blood.
"Now this is a scientifically proven form of healing," Gennady Nikonov, the director of the Udelnaya leech centre, said in his office, near a wall covered with awards from European and Russian institutes.
Nikonov hopes researchers will find new uses for the leech -- and bring more business to his centre, which besides dominating the Russian market, sells tens of thousands of leeches annually to a French company that distributes them in the West.
"The leech is revealing more and more of its secrets to us," Nikonov said.
A walk through the leech centre reveals room after room of towering metal shelves, each of which is packed with glass jars holding leeches in various stages of development floating in water.
Some doors are marked with signs reading "Mating Room", where leeches are given extra space and held in heat and light conditions ideally suited for leech romance.
A small army of women dressed in blue smocks and white aprons oversees the life cycle of each leech, from tearing open cocoons full of slithering babies to preparing adults for medical use.
The existence of such a facility is a legacy of the Soviet Union, where pharmacies remained stocked with leeches even as Western medicine stopped using them amid the 20th-century antiobiotics revolution.
Following the 1991 collapse of the Soviet Union and its centrally planned economy, the leech centre experienced hard times as production plunged and employees became disillusioned.
"There was no money to pay the salaries. The building was falling apart," recalled Nikonov.
Since then, however, Russia's economic revival and the growing popularity of leech therapy have helped reinvigorate the centre, with production rising tenfold from the early 1990s low.
In 2007, to mark its 70th anniversary, the centre even set up a monument in its courtyard featuring a bronze leech crawling up a marble column.
Proud employees say it is the world's only monument to hirudo medicinalis, the species of leech used for medical purposes.
In perhaps its most daring leap into capitalism, the centre sells a line of cosmetics called "Bioenergy" where bits of leeches are turned into shampoo, face cream and other beauty products.
"Leech cosmetics, unlike the ordinary kind, heal the skin from within instead of just plastering over it," said Yelena Titova, director of the centre's laboratories.
Leech skin cream may seem exotic but it is hardly unusual for Russia, where doctors apply leeches to treat problems ranging from infertility and gynecological ailments to tooth disease.
Experts at the Udelnaya leech centre insist that such practices have a firm scientific basis, even if they have yet to gain acceptance in mainstream Western medicine.
While ancient people believed leeches healed the sick by purging bad blood, today's scientists say their benefit lies in the substances they inject into the bloodstream, including hirudin, which stops blood from clotting.
"Here you have a whole factory of medicines, more than 30 components, and all created by nature," Titova said.
The Udelnaya centre is well poised to take advantage of increasing demand for leeches because of its rigorous approach to breeding them, she said, describing it as unique in the world.
An important element of the centre's method is to have one caretaker oversee each batch of leeches from start to finish, which motivates workers to ensure that every leech is healthy, Titova explained.
That approach also creates an emotional bond between the women who work in the centre and their leeches.
"If I didn't love them, I wouldn't have worked here so many years," said Lepyoshkina, who has worked at the centre for 25 years and raises more than 100,000 leeches annually. "They are practically our children."