Hepatitis C, one of those insidious little viruses that has caused a stir this week, is really an innocent party.

All it is trying to do is survive in a hostile world.

As an organism incapable of intent or malice it has no desire to harm humans, but because it belongs to a group of viruses that have great difficulty spreading from host to host, in order to stand any chance of survival it has to persist in the human bloodstream for long enough to get the opportunity to be passed on.

Humans who remain infected for many years in this way without ill effects are called carriers of the disease.

So, although diseases like Hepatitis C are unlikely to cause mass destruction of the human race, they can quickly spread in cases where blood to blood contact is possible.

That is, sexual activity, intravenous drug abuse, blood transfusion, and yes, surgical operations.

For transmission during surgery there has to be interchange of infected blood.

This is most likely to occur from patient to surgeon, where a sharp instrument contaminated with the patient's blood enters the skin of the surgeon.

This is probably how the doctor we heard about this week was infected. He prompted a health scare after it became clear that one of his patients contracted the virus from him following surgery.

There have been well documented cases of such transmission occurring, but almost unheard of the other way around.

This is probably because it would be very difficult for a surgeon to sustain an injury causing a large blood loss into the patient - most are tiny nicks that hardly bleed at all.

So while surgeons can be vulnerable to contamination from the patient's blood, such wounds are unlikely to spread disease to the patient.

The recent Hepatitis C story suggests this can happen, albeit rarely.

Routine testing pointless

There are always the inevitable calls for surgeons to be regularly tested. However this makes little sense, unless accompanied by routine testing of all surgical patients.

Even if you test surgeons every year, there could be a chance of them becoming infected from a patient in the meantime, and posing a risk of infection until detected by their next test.

From the patient's viewpoint testing may cause an added problem as surgeons may not be keen to operate on those posing a risk of infection, especially if they know catching the disease would stop their career overnight.

Surgeons are encouraged to take universal precautions when operating, which essentially means adopting the same protective measures in all operations as if the patient were actually infected with hepatitis or HIV.

The trouble is that needle and sharps injuries can still occur, and it is not always easy to persuade surgeons to operate in this way, although things are gradually changing.

Today we know about, and can detect, Hepatitis C and HIV infections, but 10 to 15 years ago we certainly could not, and we were all blissfully unaware of the potential problems to be faced later on.