Concerns that the Guangzhou patient has Sars could have been resolved sooner if the patient's samples had been sent to Hong Kong much earlier for verification, a medical activist said yesterday. The Hong Kong Department of Health and the University of Hong Kong's microbiology department were asked to test the patient's samples only on Thursday - 12 days after he was first suspected of having Sars. The request came a day after Hong Kong medical activist Kwok Ka-ki complained the city had been kept from helping the investigation. Yesterday Dr Kwok, convenor of the Action Group on Medical Policy, said the mainland health authorities and the WHO had been late in seeking help from Hong Kong, whose laboratories were 'highly experienced' in Sars testing as a result of last year's outbreak. 'Hong Kong is more experienced than other countries in carrying out tests on Sars and the city is part of China. I do not see why the samples were not given to Hong Kong earlier,' Dr Kwok said. 'It [probably would have caused] less confusion and anxiety if the samples had been sent for testing to Hong Kong earlier.' Meanwhile, Stephen Ng Kam-cheung, special lecturer in epidemiology at New York's Columbia University and an adjunct associate professor of community medicine at Chinese University, said mainland authorities should examine whether the Guangzhou patient could have contracted Sars through rats. Wild animals are believed to be Sars carriers. 'Before the Guangzhou patient fell sick, he spent most of the time at home. It could be the case that rats carrying the virus got into his home and infected him,' Dr Ng said. He published an article in the medical journal, The Lancet, explaining his theory that rats transmit Sars to humans. But Paul Chan Kay-sheung, a microbiologist at Chinese University, said it was premature to blame rats for spreading Sars. 'What we know so far is that [the] Sars virus can replicate in rats and cats, and the animals can become infectious, but there is still no evidence to prove they spread the virus to humans.'