Search for Source of Anthrax

4/25/2006

Western Mail (Cardiff, Wales)

By Steve Dube

Experts continued yesterday to search for the source of the anthrax infection that hit a farming family for the second time in 35 years.

The Francis family at Ynysgau, Gwaelod-y-Garth, near Cardiff were yesterday helping state veterinary surgeons and Environment Agency and local authority public health officials to find out exactly how two cows picked up the deadly infection.

The farm is under restrictions with no people or animals allowed to leave or enter.

'There is no danger to man or beast except for the remaining animals on the farm which are potentially still exposed to infection,' said Wales Chief Veterinary Officer Christianne Glossop.

The cause of the infection is almost certain to be spores left in the ground from the last infection at Ynys-Gau 35 years ago, which killed seven cows. Infectious spores can remain in the ground undetected for decades until brought to the surface by various means, from erosion to earthworm casts.

'We have information about the fields that these cows were using, but we don't yet know the exact source of the infection,' said Dr Glossop, who asked people to stay away from the farm and respect the family's privacy.

'They have been through this before, but it doesn't make it any easier,' she said. 'They have seen this disease and know what to look for and they are helping to monitor the remaining cattle. They are upset, but farmers have so many things hitting them these days that they just accept it.'

A total of six cows have died this month from a herd of 35 suckler cows. There are also calves and two horses, all of which are now confined.

Anthrax was discovered in the last two of the six fatalities last Friday and the carcasses were incinerated on a pyre on the farm over the weekend by staff from Rhondda Cynon Taf County Borough Council with the help of the State Veterinary Service and the Environment Agency.

The decision was taken to incinerate on pyres after the council's mobile incinerator was found to be unsuitable.

The ashes will be disposed of in the near future in accordance with the strict biosecurity measures in the 1991 Anthrax Order.

Dr Glossop said the cause of death of the other four cows was 'a bit of a mystery'. She said the first two to die were not reported and the next two tested negative.

Those four carcasses were sent for incineration as fallen stock and officials have visited the two incinerators that were used and made sure that basic safety precautions are in place.

'The infection is contained on one farm and it's very likely that the source of contamination is on that farm,' said Dr Glossop.

'There's no reason for it to go anywhere else because it's most likely to be in the soil.

'The farm is closed off, and it's not like a virus that can spread on the wind to another farm. The most likely pattern is that both cows were infected from the same source.'

Dr Glossop said one possibility was disturbance by ground water bringing the spores to the surface and contaminating pasture.

'But we may never know exactly where it came from,' she said.

But experts said the infection had been detected at once, the farm isolated and the carcasses destroyed. There was no threat to neighbouring farms or people.

Yesterday a herd of cattle grazed in a nearby field but one cow had been put in a pen alone within the farmyard.

A number of footpaths at the tranquil spot, between Cardiff and Pontypridd, pass by the farmland but a notice, posted on Friday April 21, bans ramblers from using a path that goes directly through the farm.

The outbreak is the first since a dairy farm in Wrexham was hit for the fourth time in two decades on October 17, 2002. There were 19 separate outbreaks in the UK between 1990 and 1997, then five years when the disease lay completely dormant. But there were 166 separate incidents in one year in 1978.

Anthrax is an acute bacterial infection caused by the organism Bacillus anthracis, which is carried by wild and domestic grass-eating animals in Africa, Asia, Central America and some parts of Europe.

Under certain adverse circumstances the rod-shaped bacillus can form into spores, which are very hard to destroy and can survive in soils for decades.

Earthworms can carry buried spores to the surface where they can be swallowed by animals, particularly cattle and pigs.

Anthrax is uncommon in the UK, where only a handful of cases have been notified over the past decade. The last case in Wales was in a cow on a farm near Wrexham in 2002. Before that the most recent outbreak was in cattle in Lanarkshire in 1997.

Infections are more frequent in countries where the disease is common in animals, such as South and Central America, southern and eastern Europe, Asia and Africa.

Spores are generally found in the soil and in the wool and hair of sheep and goats.

Cattle are nearly always infected via the mouth and the digestive system, with the spores ingested through food or drink. The disease can also be spread by flies and by vaccine contaminated by spores, so inoculations should not be carried out in dusty sheds.

There are three forms of anthrax - peracute, acute and subacute.

Sheep and goats are nearly always infected with the peracute type - the animal is found dead without showing symptoms.

In the acute form, an animal shows a temperature of up to 107 degrees, with a thin rapid pulse, bloodshot eyes and nostrils and a coldness of the ears and feet. After a few hours it collapses and dies.

In the subacute form the animal can survive for 48 hours with nothing more alarming than a temperature and laboured breathing.

Anthrax in horses shows either as swelling in the throat neck and chest or by a fit of shivering, fever and abdominal pains.

Humans are rarely infected but there are three main human forms of anthrax. It can be contracted by contact with anthrax spores, by skin contact - 'cutaneous anthrax', ingestion - 'intestinal anthrax' - and inhalation - 'inhalational anthrax', which is very rare and results from the inhalation of spores, such as in certain industrial processes.

Most infections are very slight. A victim has to inhale 2,500 spores an hour to catch the disease, and it is extremely unusual for anthrax to be transmitted person-to-person.

Anthrax used to be known as 'wool-sorters' disease', an occupational hazard for people such as abattoir workers and tanners processing hides, hair, bone and bone products. Between 1961 and 1980 there were 145 cases of anthrax in human patients and 12 fatalities. There have been four cases since 1990 and a vaccine is now available for those at a high risk.

Defra routinely undertakes a large number of investigations for anthrax where there is a sudden and unexpected death in animals.

In 1979, after an accident at a biological warfare unit released a plume of spores over the Russian town of Ykaterinburg, at least 64 people are known to have died, and the unofficial toll is nearer 600.