BSE in the US

One single cow in the state of Washington, USA has made history by allegedly being the first cow to be stricken by the killer disease Mad Cow Disease (BSE: Bovine Spongiform Encephalopathy).

Sub-clinical forms of BSE have been suggested.

Immediately after this became known, many countries placed an embargo on beef coming from the US.

This episode has evoked in me the memories of thousands and thousands of cattle being slaughtered in the UK a decade ago when BSE spread in cow herds after being fed contaminated cattle feed; not to mention the picture of an English Cabinet minister and his young daughter eating a beef burger to convince the populace that meat was safe to eat.

I understand that in a somewhat similar manner the US agriculture secretary has stated publicly she will not desist from serving beef at her table.

We now know that BSE has a human counterpart, Creutzfeldt-Jakop Disease - CJ syndrome (and various other diseases of this same ilk in humans and animals). These disorders are caused by transmissible replicating infectious abnormal protein agents - the prions.

Apart from obvious contamination or nutritional incidents (cannibalism in New Guinea, corneal transplants, injections of human growth hormone, investigative brain surgical procedures), it is believed that, roughly speaking, the CJ disease may affect sporadically one in every one million persons anywhere in the world, without a cause being found to account for the nerve degeneration found in the patient. This may perhaps point to a pathological mutation of the normal gene (PrP gene) making the individual predisposed to the CJ disease.

Extrapolating this suggested mechanism from the human to the bovine, I wishfully pray and hope that the present incident will affect just one single cow in the US and that this would not give rise to the drama which devolved in the UK a decade ago and the US beef industry would be spared such an enormous economic disaster and the apprehension and over-reacting by the public would be allayed.

There is one proviso, however, which has to be kept in mind. These prion diseases are known to have a prolonged "incubation" silent period before the signs and symptoms of the disease take a firm irreversible hold of the unfortunate victim.

The concept of a replicating infectious protein, with no detectable nucleic acid component, transmissible vertically and horizontally, is revolutionary in modern biology and infectious diseases.