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SARS has emerged from the fringes of  China's urban  Guandong Province. This much we have been told by the media reports that have driven a wave of medical hysteria around the world. However, there have been few reports on the unhealthy and overcrowded conditions that prevail in Guandong in which pigs, poultry and human beings live together. In the city of  Foshan a foul concoction of rotting leftovers from restaurants is boiled to make it sterile before being fed to pigs.(1) In some places chickens are kept above the pig pens, their faeces dropping into the food troughs in the pens below. Pigs that develop shortness of breath or become ill are injected with antibiotics obtained without veterinary advice or a prescription. Such squalid farming conditions create a crucible for the development of disease.

Proponents of organic farming and horticulture have long understood that poor or unnatural farming methods have a huge impact on the quality of the food that we eat and therefore on our health. The current epidemic of the disease dubbed SARS (Severe Acute Respiratory Syndrome) has brought into sharp focus the direct threat to our health from dangerous pathogens created through unsafe farming practices or genetic engineering. 

While medical researchers and the big players, such as the US Centres for Disease Control and the World Health Organisation, bicker about viruses and what the actual case fatality rate is, few reports in the New Zealand media have seriously addressed the issue of where SARS really came from. Few commentators have looked at the possible role of farming practices or genetic engineering in the emergence of this 'epidemic', or the implications of such issues for the health of human beings now and in the future.

Unsafe Farming Practices in China

The coronavirus espoused by many researchers as being responsible for SARS is similar to both avian and bovine coronaviruses that cause respiratory diseases in birds and cattle.(2) However, it is likely that pigs act as a medium for coronaviruses, allowing them to extend their host range into humans. Coronaviruses are known to mutate and switch hosts through recombination of genes, which can occur when two strains from the same virus family infect a cell at the same time.(3, 4) Research published in 1999 showed that coronaviruses are easily transmitted between pigs and people.(5)

Alternatively, the virus that causes SARS may have crossed the species barrier directly from pigs; pigs in  China suffer from several severe acute respiratory syndromes (e.g. Porcine Reproductive and Respiratory Syndrome - PRRS). Charles Ortleb, author and investigative journalist, states that coronavirus is found as a secondary infection with, but not causing, the pig version of SARS. A Canadian researcher, Dr Frank Plummer, was reported in the New York Times as saying that he has found the coronavirus that WHO has said is responsible for severe acute respiratory syndrome in only 40% of probable and suspect cases. Also, for unknown reasons, the portion of recent cases testing positive for the virus is declining, and a number of people who are not suspected of having the disease are testing positive. Maybe WHO has got it very wrong about what causes human SARS - the coronavirus that researchers have identified may not be responsible for the disease. Are they looking in all the wrong places?


Some researchers are looking at whether or not human SARS can infect other animals. Chinese civet cats have been reported to carry SARS but it has not been established whether they transmitted the virus or received the virus.(6) However, it is disturbing that, given the close physical association between unhealthy, poorly fed pigs and Chinese farmers, there have been no reports of researchers testing SARS patients for the PRRS or related viruses - a seemingly obvious starting point in determining the origin of SARS.

Does Genetic Engineering have a role?

New viruses have been created both deliberately and accidentally using genetic engineering. In the 1970s scientists discovered that viruses can replicate and recombine their genetic material in bacteria. Coronaviruses have been the subject of genetic engineering experiments since the late 1990s(3) and in 2000 a team of Spanish researchers used E. coli bacteria to engineer a transmissible gastroenteritis coronavirus that infects newborn pigs.(7) Earlier this year it was reported in the Journal of Virology that researchers had genetically engineered a lethal cat virus, producing a virus that can infect mice by replacing a single gene.(4) It was reported in New Scientist in 2001 that Australian researchers had accidentally created a lethal mousepox virus from a relatively benign virus while trying to genetically engineer a contraceptive vaccine for mice. 

Nature says that bioterrorists could abuse genetic transformation procedures "to turn an animal coronavirus into a dangerous human pathogen such as that responsible for SARS."(4) BLAST analysis matches sequences of DNA or protein against a database of known DNA and protein sequences. BLAST analysis of the SARS coronavirus shows significant alignment of sequences with numerous viruses including porcine transmissible gastroenteritis virus, murine hepatitis virus, feline infectious peritonitis virus, vaccinia virus, camelpox virus, stealth virus, bat lyssavirus and several plant viruses!(8) When a virologist was shown this analysis his reaction was that it had come from a laboratory not nature(9).

While more research is needed before SARS can be proven to be the result of GE, the fact that researchers have already deliberately genetically engineered coronaviruses, and have accidentally created other viruses, sends very strong signals about the potential for devastating global epidemics of emergent GE created diseases in both humans and animals. In the not too distant future mixed up plant genes could be the least of our concerns.

Irrespective of the role of GE in the emergence of SARS, this episode should serve as a potent reminder to all those who support GE that we have little ability to anticipate, or control, the results. At the very least we should heed the clear warning about how our food is raised and under what conditions.


[1] McDonald, H., 2003,  China's unsafe farming practices may be breeding more than pigs, Sydney Morning Herald,  April 7 2003 .

[2] MacKenzie, D., Young, E. and Carrington, D., 2003, Killer pneumonia virus linked to birds, New Scientist Online News, 3 April 2003 .

[3] Ho, M-W. and Cummins, J., 2003: SARS and Genetic Engineering?,  Institute of Science in  Society,  UK , at

[4] Pearson, H., 2003: Deadly Virus effortlessly hops species, Nature News Service, 2 April 2003, MacMillan Magazines Ltd.

[5] Hirano, N., Suzuki, Y. and Haga, S., 1999: Pigs with highly prevalent antibodies to human coronavirus and swine haemagglutinating encephalomyelitis virus in the Tohoku district of Japan, Epidemiology of Infectious Diseases, 122 (3): 545-51.

[6] Bradsher, K. and  Altman, L.K., 2003: Strain of SARS Is Found in 3 Animal Species in Asia, New York Times May 24 2003.

[7] Ho, M-W., 2001: Genetic Engineering Super-viruses, Institute of Science in Society, UK, at

[8] Lee, R.E., 2003: SARS DNA Genome - A Very Strange Mix at

[9] Personal communication, May 2003.

Copyright © 2003 Susan Claridge.

Has SARS Emerged From Pandora's box?

 By Sue Claridge

Originally published in Organic NZ, July August 2003, Vol. 62, No. 4, pg 16-17.

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