Seen One Leech, Seen 'Em All

Apparently there was a mix-up:

DECADES of medical research and hundreds of academic papers have been called into question after the discovery that scientists may have been studying the wrong blood-sucking leech.

At least 115 chemical compounds have been developed from what researchers thought was the medicinal leech, Hirudo medicinalis, with many being used in drugs.

Genetic analysis has now shown that the leech that led to the discoveries may have been the species Hirudo verbana.

The findings could prove disastrous to scientists and pharmaceutical companies because it suggests that their researches, new drugs and patents were based on the false premise that the medicinal leech H. medicinalis was what was being studied.

It could be equally devastating for the leeches themselves, which as H. medicinalis have legal protection but as H. verbana have no defence against being collected from the wild in their hundreds of thousands.

...In the blood

• Leeches have three jaws, each with 115-120 teeth
• They leave a triangular bite mark that bleeds for ten hours. The bite contains a natural anaesthetic and anticoagulant
• Leeches can drink five times their own weight in blood
• Each has 32 brains
• Medicinal leech declared extinct in Britain in 1910. Rediscovered at Llangorse Lake, near Brecon, in 1938
• First used in medicine in about 1000BC
• In 1830 London hospitals used 7 million leeches a year
• In 1809 Leicester Royal Infirmary used 500 leeches. A leechwoman was employed there until 1928
• Stalin was reputedly treated with leeches shortly before he died
• George Washington’s death was hastened by being bled four times a day