Rats may prove to be the missing link in a suspected case of
SARS (severe acute respiratory syndrome) first reported in
Guangzhou, capital city of south China's Guangdong
Province.
A mutated strain of the deadly virus was diagnosed on a
32-year-old freelance television producer, making him the first
suspected SARS patient on the mainland since last May.
However, health officials and top experts reached by China
Daily yesterday cautioned that more laboratory tests must be
done before any confirmation can be made.
New details surfaced when local Guangzhou media reported the
patient had set traps for rats that had invaded his apartment
before he showed SARS symptoms. Laboratory tests have shown that
some of the rats caught in his apartment also tested positive for
SARS.
However, this does not necessarily mean that the rats are the
definitive source of the new strain of corona virus, Liu Qiyong, an
expert on epidemics from the Chinese Centre for Diseases Control
and Prevention (CDC), said yesterday.
The result may have been caused by some other strain of corona
virus carried by the rats, since there is a slight difference from
the kind that caused the SARS outbreak in human beings last spring,
Liu said. In fact, other strains have been found in rats, as well
as in other animals long before the new case emerged.
Liu and his colleagues have checked out more than 10 kinds of
animals, including masked palm civets and rats over the past
several months trying to identify the virus that has caused SARS.
More work must be done to pinpoint one particular strain as the one
that jumped to human beings, Liu said.
Liu's remark was echoed by Mao Qun'an, spokesman for the
Ministry of Health, who told China Daily that scientists
must do further research before they can answer questions such as
how SARS was passed to human beings from animals or other
sources.
Mao said Chinese experts generally tend to agree that samples
from the Guangzhou man with positive SARS result in lab tests are
conclusive that he has contracted SARS.
However, Mao and World Health Organization spokesman Roy Wadia
both emphasized that experts from WHO are re-examining the results
submitted by their Chinese counterparts, and their conclusion is
expected to come out today or tomorrow.
However, some WHO experts have cautioned that, without obvious
SARS connection like a wild animal or lab contamination, and
without separating the virus from the man's body, it is still too
early to confirm the case. The positive results are not enough of
an indicator, they argue, because the man could have been infected
last spring but, due to internally developing antibody, may not
have shown any symptoms until now.
(China Daily January 5, 2004)