Did human remains start BSE?
08:37am 2nd September 2005
What is RSS?
Mad cow disease may have originated from human remains mixed into cattle feed, according to a controversial new theory.
A leading British expert on BSE believes there is strong evidence for linking the brain disease - which gave rise to variant CJD in humans - to a grisly trade in carcass material that was prevalent in the 1960s and '70s.
Over those decades Britain imported hundreds of thousands of tons of ground-up animal parts for use as fertiliser and the manufacture of feed. Nearly half this meat-and-bone meal came from the Indian sub-continent.
Professor Alan Colchester, from the University of Kent in Canterbury, argues that some of it almost certainly contained human as well as animal remains.
The human material could be traced to corpses disposed of in rivers in accordance with Hindu funeral custom.
Collecting and selling bones and carcasses is a common local trade among peasants, who may not be too selective about what kind of remains they pick up, says Prof Colchester.
"The inclusion of human remains in material delivered to processing mills has been clearly described," he wrote in The Lancet medical journal in a paper co-authored by his daughter, Nancy Colchester, from the University of Edinburgh.
The theory suggests that "ordinary", or sporadic, Creutzfeldt Jakob Disease which arises naturally in humans was initially passed to cattle via feed contaminated with infected human tissue.
It emerged in the cow population as Bovine Spongiform Encephalopathy, or BSE. Later, the infective agent was transmitted back to humans consuming meat products such as beef-burgers. In 1995 it re-emerged in a new form as "variant" or vCJD, a deadly and incurable brain disease.
The true origins of BSE are obscure. The conventional theory is that it first appeared as a result of sheep remains infected with a related disease, scrapie, being fed to cattle.
Epidemic
Feeding cows a "cannibal" diet - partly consisting of meal made from dead cattle - turned the disease into an epidemic which peaked in 1992 with more than 180,000 cases reported in the UK.
So far there have been 150 deaths definitely or probably caused by vCJD, with another seven suspected victims who are still alive.
Prof Colchester questions why BSE did not occur earlier than the 1990s, since meat and bone material containing sheep remains had been fed to cattle for up to 70 years. Scrapie has been endemic in Britain for at least 200 years.
He said it was "highly likely" that the mixing of human remains in meal material exported from India and Pakistan had occurred since the late 1950s, and may still be continuing.
"In India and Pakistan, gathering large bones and carcasses from the land and from rivers has long been an important trade for peasants," he wrote.
"Collectors encounter considerable quantities of human as well as animal remains as a result of religious customs. Hindus believe that it is essential for their remains after death to be disposed of in a river, preferably the Ganges.
"The ideal is for the body to be burned, but most people cannot afford enough wood for full cremation, and simply smoking the pelvis in women or the thorax in men has symbolic importance. Many complete corpses are thrown into the river."
The practice occurred on a "huge scale", he said. In the holy city of Varanasi, on the Ganges, some 40,000 funeral ceremonies took place each year at two main sites.
In 2004, a group of volunteers campaigning to reduce pollution retrieved 60 human corpses in two days from a 10 kilometre stretch of the river.
There were reports from various countries of the gruesome trade in human remains, said Prof Colchester.
In 2001, a dealer in Calcutta was prosecuted for exporting human bones to other parts of India, Pakistan and the United States.
During an investigation in the late 1960s of an anthrax outbreak among French and Belgian dock workers, a medical officer confirmed reports of human material in cargoes of mammalian by-products from the Indian subcontinent.
A British animal feed manufacturing company using high-protein meal imported from the region was so alarmed by the discovery that it re-organised its manufacturing facility.
Corpses
The Colchesters estimated that in the late 1960s and '70s about 120 Indian Hindus would have died each year from sporadic CJD. A "substantial proportion" of the corpses would have been disposed of in rivers in the traditional manner.
A number of factors may have led the BSE epidemic to have started in Britain rather than elsewhere, they claimed.
Firstly, Britain was the main recipient of animal by-products exported from India and Pakistan during the relevant period.
Between 1967 and 1969, the UK received two to six times more of the material than any other country.
Secondly, Britain was a world leader in research aimed at boosting milk production by feeding high protein meal to cattle.
Britain was also a leader in the practice of feeding meat and bonemeal to young calves, which may have increased the likelihood of initial cases arising in the UK.
Although the hypothesis was unproven there was enough evidence to justify further investigation, said Prof Colchester.
He added: "An important question is whether some countries are still receiving imports of animal by-products contaminated with human remains.
"Both exporting and importing countries are likely to be sensitive to the implications of our hypotheses, and may feel pressurised to issue denials without adequate investigation.
"Within as well as between countries, it will be particularly important to establish co-operation between public health, agricultural, and industry organisations, as well as researchers, to try to ensure that further investigations are sufficiently thorough."
Also writing in The Lancet, two Indian scientists appealed for caution, while agreeing that more research was needed.
Susarla Shankar and Parthasarathy Satishchandra, from the National Institute of Mental Health and Neurosciences in Bangalore, pointed out that most bodies of hospital patients in India did not receive a traditional Hindu funeral. Instead they were cremated or buried in community burial grounds.
Even in Varanasi, most Hindus did not throw half-burned bodies into the river, said Shankar and Satishchandra.
They stressed that a human body in a river undergoes substantial putrefaction, unlike fallen cattle.
No study had been carried out to establish whether or not decayed human brain and spinal cord tissue from the Ganges contained CJD, or whether such material could infect animals.
Furthermore not a single case of indigenous BSE or scrapie had been reported in India. One case of scrapie in a sheep from the Himalayan foothills had probably been imported.
"Scientists must proceed cautiously when hypothesising about a disease that has such wide geographic, cultural, and religious implications," Shankar and Satishchandra warned.
"We agree that the idea proposed by Colchesters needs to be probed further. Facts to support or refute their hypothesis now need to be gathered with urgency and great care."
08:37am 2nd September 2005
What is RSS?
Mad cow disease may have originated from human remains mixed into cattle feed, according to a controversial new theory.
A leading British expert on BSE believes there is strong evidence for linking the brain disease - which gave rise to variant CJD in humans - to a grisly trade in carcass material that was prevalent in the 1960s and '70s.
Over those decades Britain imported hundreds of thousands of tons of ground-up animal parts for use as fertiliser and the manufacture of feed. Nearly half this meat-and-bone meal came from the Indian sub-continent.
Professor Alan Colchester, from the University of Kent in Canterbury, argues that some of it almost certainly contained human as well as animal remains.
The human material could be traced to corpses disposed of in rivers in accordance with Hindu funeral custom.
Collecting and selling bones and carcasses is a common local trade among peasants, who may not be too selective about what kind of remains they pick up, says Prof Colchester.
"The inclusion of human remains in material delivered to processing mills has been clearly described," he wrote in The Lancet medical journal in a paper co-authored by his daughter, Nancy Colchester, from the University of Edinburgh.
The theory suggests that "ordinary", or sporadic, Creutzfeldt Jakob Disease which arises naturally in humans was initially passed to cattle via feed contaminated with infected human tissue.
It emerged in the cow population as Bovine Spongiform Encephalopathy, or BSE. Later, the infective agent was transmitted back to humans consuming meat products such as beef-burgers. In 1995 it re-emerged in a new form as "variant" or vCJD, a deadly and incurable brain disease.
The true origins of BSE are obscure. The conventional theory is that it first appeared as a result of sheep remains infected with a related disease, scrapie, being fed to cattle.
Epidemic
Feeding cows a "cannibal" diet - partly consisting of meal made from dead cattle - turned the disease into an epidemic which peaked in 1992 with more than 180,000 cases reported in the UK.
So far there have been 150 deaths definitely or probably caused by vCJD, with another seven suspected victims who are still alive.
Prof Colchester questions why BSE did not occur earlier than the 1990s, since meat and bone material containing sheep remains had been fed to cattle for up to 70 years. Scrapie has been endemic in Britain for at least 200 years.
He said it was "highly likely" that the mixing of human remains in meal material exported from India and Pakistan had occurred since the late 1950s, and may still be continuing.
"In India and Pakistan, gathering large bones and carcasses from the land and from rivers has long been an important trade for peasants," he wrote.
"Collectors encounter considerable quantities of human as well as animal remains as a result of religious customs. Hindus believe that it is essential for their remains after death to be disposed of in a river, preferably the Ganges.
"The ideal is for the body to be burned, but most people cannot afford enough wood for full cremation, and simply smoking the pelvis in women or the thorax in men has symbolic importance. Many complete corpses are thrown into the river."
The practice occurred on a "huge scale", he said. In the holy city of Varanasi, on the Ganges, some 40,000 funeral ceremonies took place each year at two main sites.
In 2004, a group of volunteers campaigning to reduce pollution retrieved 60 human corpses in two days from a 10 kilometre stretch of the river.
There were reports from various countries of the gruesome trade in human remains, said Prof Colchester.
In 2001, a dealer in Calcutta was prosecuted for exporting human bones to other parts of India, Pakistan and the United States.
During an investigation in the late 1960s of an anthrax outbreak among French and Belgian dock workers, a medical officer confirmed reports of human material in cargoes of mammalian by-products from the Indian subcontinent.
A British animal feed manufacturing company using high-protein meal imported from the region was so alarmed by the discovery that it re-organised its manufacturing facility.
Corpses
The Colchesters estimated that in the late 1960s and '70s about 120 Indian Hindus would have died each year from sporadic CJD. A "substantial proportion" of the corpses would have been disposed of in rivers in the traditional manner.
A number of factors may have led the BSE epidemic to have started in Britain rather than elsewhere, they claimed.
Firstly, Britain was the main recipient of animal by-products exported from India and Pakistan during the relevant period.
Between 1967 and 1969, the UK received two to six times more of the material than any other country.
Secondly, Britain was a world leader in research aimed at boosting milk production by feeding high protein meal to cattle.
Britain was also a leader in the practice of feeding meat and bonemeal to young calves, which may have increased the likelihood of initial cases arising in the UK.
Although the hypothesis was unproven there was enough evidence to justify further investigation, said Prof Colchester.
He added: "An important question is whether some countries are still receiving imports of animal by-products contaminated with human remains.
"Both exporting and importing countries are likely to be sensitive to the implications of our hypotheses, and may feel pressurised to issue denials without adequate investigation.
"Within as well as between countries, it will be particularly important to establish co-operation between public health, agricultural, and industry organisations, as well as researchers, to try to ensure that further investigations are sufficiently thorough."
Also writing in The Lancet, two Indian scientists appealed for caution, while agreeing that more research was needed.
Susarla Shankar and Parthasarathy Satishchandra, from the National Institute of Mental Health and Neurosciences in Bangalore, pointed out that most bodies of hospital patients in India did not receive a traditional Hindu funeral. Instead they were cremated or buried in community burial grounds.
Even in Varanasi, most Hindus did not throw half-burned bodies into the river, said Shankar and Satishchandra.
They stressed that a human body in a river undergoes substantial putrefaction, unlike fallen cattle.
No study had been carried out to establish whether or not decayed human brain and spinal cord tissue from the Ganges contained CJD, or whether such material could infect animals.
Furthermore not a single case of indigenous BSE or scrapie had been reported in India. One case of scrapie in a sheep from the Himalayan foothills had probably been imported.
"Scientists must proceed cautiously when hypothesising about a disease that has such wide geographic, cultural, and religious implications," Shankar and Satishchandra warned.
"We agree that the idea proposed by Colchesters needs to be probed further. Facts to support or refute their hypothesis now need to be gathered with urgency and great care."
Comment