Any surgical procedure is a major, and unrecognised, source for the spread of Creutzfeldt Jakob disease, or mad cow disease, researchers have discovered.
Patients who had up to three operations were twice as likely to develop CJD as someone who had never had surgery.
But Australian researchers who made the extraordinary discovery about one of the most mysterious diseases also found that some procedures involve a greater risk than others. Patients who were treated for carpal tunnel syndrome, for instance, were nine times more likely to contract CJD from the procedure, and those who had cataract and eye surgery were six times more likely.
Two other procedures that both carried a risk of around four times were for haemorrhoids and for varicose veins.
The researchers, from the University of Melbourne, compared the medical histories of 241 definite and probable CJD sufferers with 784 controls. They found a 'significant' association with the development of CJD and surgical procedures. Another important factor, and another major source for the disease, was employment on a farm or market garden for more than 10 years. Surprisingly, there was no major risk found for blood transfusions, organ transplants or major dental work (Lancet, 1999; 353: 693-7).