"You can see an all round effort now on the disease from the scientific community in China, which has both good and bad impacts."

Scientific findings

A team of researchers from the University of Hong Kong and the Center for Disease Control from the city of Shenzhen announced on May 23 that they had tested 25 animals, from eight species, on sale at a live animal market in Guangdong Province in South China.

They found a coronavirus that appears virtually identical to the SARS virus in the saliva and faeces of six small mammals, called masked palm civets (from the civet species or Viverridae).

The discovery is the strongest evidence of the long-standing suspicion that the SARS virus may have originated in wildlife and somehow jumped to humans from where it spread readily.

The researchers directly isolated the virus from four of the animals and found pieces of genetic material from the microbe in two others. Tests also showed genetic evidence of the virus in the faeces of another animal, known as the raccoon dog, and an eighth animal, the Chinese ferret badger -- all bearing similarities in appearance to the masked palm civet -- had antibodies to the virus in its blood. None of the animals was sick.

Genetic analysis of the virus isolated from the animals found it was identical to the SARS virus in human patients, except that it has 29 fewer nucleotides that carry instructions for the production of a small protein, known as a peptide.

Researchers suggest the change may have allowed the virus to jump to humans.

Ever since news of the findings was released, a good many Chinese scientists have followed up with either new research results or suggestions, while some have also voiced their suspicions over the plausibility of the conclusions.

In the past week, scientists have found coronaviruses in some other animal species, including the blue peacock, further supporting the speculation that the SARS virus may originate from, and widely exist, in the wild.

At almost the same time as the research team from Hong Kong and Shenzhen announced their findings, another team composed of scientists from the Ministry of Agriculture and local research institutes in Guangdong also went public with the disclosure that four types of genes, similar to those in the SARS virus, had been found in bats, monkeys, snakes and the civet.

The results came from tests conducted on 1,600 samples of 59 animal species the team have collected from wild animal markets in Guangzhou, the provincial capital of Guangdong, since early last month.

Rao Keqin, an epidemiologist from the Ministry of Health, said the discoveries fit the pattern of recent epidemics, such as bird flu and mad cow disease, that were traced back to viruses which somehow jumped from animals into humans. "(The discoveries), if confirmed, have great implications in cutting off the source of the infection," he said.

Opposing opinion

Disagreement also arose shortly after the discovery was made public.

Han Bin, a Shanghai-based biologist, was among the first Chinese researchers who voiced his doubts over the linking of the SARS virus to civets.

He noted that the coronavirus identified by the Hong Kong and Shenzhen scientists is reported to be 99 percent identical to the SARS virus, but a 1 percent discrepancy is rather significant in biological terms.

It is necessary to redo the sequencing of the DNA of the coronavirus taken from civets to confirm its identity with that taken from SARS patients, said Han.

Many questions remain unanswered, such as whether these tested civets are from the wild or bred by humans and where the virus in them comes from, all of which are critical for the control of disease, said Bi Shengli, a research fellow at the Center for Disease Control under the Ministry of Health.

He said if the SARS virus is confirmed to have originated in wildlife, people then have to change their attitude towards animals if they are to prevent any similar diseases occurring in the future. "We cannot, and shouldn't kill the animals that transmitted the virus, but keep ourselves away from them," he said. "It is the humans who destroyed the habitat of the wildlife, not the wildlife themselves that caused the epidemic."

Public reaction

If the reaction from the scientific community is cautious and contentious, the public reaction has been overheated during the past few days and, in some places, gone beyond normalcy.

Pet dogs and cats were deserted and killed in a few cities by residents or on local authority orders as early as late April, for fear that they may carry the SARS virus and infect humans.

The government of the northwestern city of Yinchuan in the Ningxia Hui Autonomous Region issued an order on April 23 that any stray animals were to be destroyed.

Despite the fact that no scientific evidence has been found linking pet animals with the SARS virus, the trend was soon followed by other major cities including Beijing, Lanzhou and Nanjing, where local government imposed strict control on pets and permitted the destruction of stray animals by the local public security bureaux.

The problem for pets worsened when civet cats were named as the likely source of the SARS virus, as people linked the totally unconnected domestic cat with that of the civet, which is quite different.

The televised news of sanctioned slaughter of strays shocked local residents. Especially in the city of Nanjing, local citizens telephoned government departments to complain, leading to the official easing of the government orders.

As for the civets, the discovery of the coronavirus in them may spare them, and other wild animals from ending up on the dinner table as more than one province has, or will draft stricter local regulations in the wake of the SARS epidemic to ban the trade and eating of wild animals.

Their fate will depend on what further research uncovers, scientists suggest.

(China Daily June 2, 2003)