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THE ANTHRAX ISSUE

Great House Farm signTowards the end of 2011, Dr Ian Thwaites of KSG became aware, quite by chance, that there had been an outbreak of anthrax in the cattle on Great House Farm during the 1960s. He investigated and found there is absolutely no doubt about it. The current farmer, a child at the time, remembers it. A local vet confirms he saw it and that the source of the infection was identified.

During the 1960s outbreak, animals and their bedding were burned and buried somewhere on the 13 acre field that is in front of Great House Farm and abuts the Worthing Road. This would have been normal practice at the time. There is some evidence that there was another outbreak at an earlier date but that remains unconfirmed.

Dr Thwaites’ medical background is such that he was at once very aware of the importance of this information, both in relation to the planning application by Berkeley Homes and because of the potential risk to public health if not correctly handled.

The information obtained was made available to Horsham District Council as soon as Dr Thwaites was sure the facts were correct, that recent scientific papers supported his understanding of the serious nature of the disease, and that current specialist medical opinion still considered this infection to be very dangerous to man.

Representatives of Berkeley Homes say they are taking this seriously. They have undertaken a new geophysics survey and say they would have someone from the government health agency present if they dig that field. But this misses the point, which is that no survey can exclude it and simply stopping work if they disturb a carcass is too late – the bird (i.e. the spores) will have flown.

There is a risk of a terrible event, which would endanger not only the workmen but other people on or near the site, including the schools close by. Surely, neither Berkeley Homes nor Horsham District Council is entitled to accept that risk on behalf of the people of Southwater? And it’s important to understand that the risk will continue to exist long after these homes are built and occupied – the groundwork for an extension to a house in 20 or even 40 years time could equally uncover infection. It would have to be noted specifically in the deeds of all homes built in that field.

The Health Protection Agency says the risk is small, although not zero. However, that is an opinion, nothing more, and from the same agency that stated “BSE carries no risk to human health” – the death toll from which is now over 200 and still rising! The fact is, the risk can be avoided entirely if that field is left alone.

At the present time, Great House Farm pasture land, which has suffered no major disturbance for centuries, is believed to be entirely safe for cattle to graze upon and humans to walk on. Since no-one knows exactly where, within the field, the burial site was in the 1960s anthrax outbreak, and since it is unsafe to drill or dig to obtain evidence, it follows that the only totally safe option is to register the whole field as potentially contaminated and to impose a wide exclusion zone in terms of land disturbance of any kind around it.

While most people will have heard of anthrax, few will know much about it. The infection is now very rare in humans in the UK and much less common in animals than was the case 50 years ago. The review below was written by Dr Thwaites with the general public in mind but includes references from recent scientific journals where appropriate.

The disease and its occurrence

Anthrax is an infectious disease that has been known about for 3,000 years. It was almost certainly responsible for the fifth and sixth plagues that struck Egypt around 1491 BC (Exodus, Chapters 7 to 9). Writers from antiquity such as Homer, Livy and Plutarch described in detail a disease of livestock that is characteristic of anthrax. The bacteria that causes the disease, Bacillus anthracis, was first identified in 1876.

It was, and still can be, a major cause of livestock death and was noted to be highly dangerous to man, so much so that several nations developed its potential as a biological weapon during the 20th century.

In 2001, it was used as a weapon of bio-terrorism in the USA. Five envelopes containing small quantities of anthrax spores were sent out by post. More than 30,000 people became contaminated, of which 17 became seriously ill and five died (Jernigan et al Emerging Infectious Diseases.2001 7 (6) 933-944 and 8 1019-1028).

In animals, serious outbreaks still occur in many countries worldwide, and not only in developing areas. In 2005, there was a large naturally created outbreak in the northern USA and Canada in which 243 animals were infected and died. (Zoonoses and Public Health 55 2008 279-290 Review of Anthrax outbreak in North Dakota in 2005).

Why is the bacteria so dangerous?

The bacteria itself can only reproduce freely when it is within an animal (or human) and causing disease. When it leaves the animal, either as excreta or because the animal dies and the carcass decomposes, it is relatively easy to destroy. However, it then has the ability to form itself into what are called spores. This is the property that makes it so dangerous. In effect, this means it forms an immensely strong shield around itself so it can live independently in the soil, or within the bones of the animal, for very long periods of time. When the spore enters an animal host it quickly changes back to the active bacteria and causes disease afresh.

So strong is that shield and so resistant is it to decay or destruction that it is considered THE most efficient and advanced form of protection known in nature. Active spores have been found in animal bones of 200 years of age (Smith et al Journal of Clinical Microbiology2000 38 (10) 3780-3784).

Furthermore, the spores have a capacity to float in water, which enables them to migrate through subsoil away from their original site. This can occur even without soil disturbance (Dragon & Rennie Canadian Veterinary Journal 1995 36 295-301), as the spores can float to the surface under flood conditions (Turner et al Journal of Applied Microbiology 1999 87 294-297).

Nature produces few opportunities for the bacteria to reproduce itself. It may have to wait inactive in the soil for long periods of time before it gets the chance to enter another animal host. To compensate for this biological disadvantage it has developed quite exceptional toxicity. Exceptionally rapid multiplication of the bacteria occurs when it gets the chance, and the animal rapidly dies (Fasanella et al Veterinary Microbiology 2010 140 318-331).

How is it transmitted?

In animals, cattle are much the most susceptible to the infection. Herbivores, which lack top cutting teeth, rip up the grass, taking in significant quantities of soil with it. Spores may enter through abrasions in the animal’s mouth or be taken directly into the gut. Historically, infected animals were burned and buried deeply on their own farms. Wild animals such as deer may also be infected and their carcasses often escape detection and protective burial.

Cases of anthrax in cattle have been directly connected to the disturbance of burial pits by subsequent deep digging – for example, by digging wells in the Dakota outbreak of 2005. Soil disturbance through road construction was the cause of another outbreak in the same State (see review of North Dakota outbreak above). As described earlier, flood water may bring spores to the surface from deep in the soil. Outbreaks are known to have been caused this way.

Spores may also be transmitted from outside the farm via animal feed. In fact, the 1960s outbreak in Southwater was caused by the farmer purchasing ground nuts from Nigeria to grind down for a high protein food. He could not know that these had been grown on infected land (Personal communication from Mr Julian Peters, Veterinary Surgeon, 2011).

Summary

Anthrax is primarily a disease that affects livestock and wildlife; its distribution is still worldwide; it can represent a serious danger to humans. It can be especially dangerous today when it occurs in areas thought to be free of the disease. As few doctors in the UK have ever seen a case of anthrax, it could easily be misdiagnosed by GPs, with extremely serious consequences. Incorrect management, including the disturbance of the soil near burial sites, will cause an inevitable risk of human infection. The biggest risk of all is to underestimate this infection (Fasanella et al above).