April 1, 2003, 8:47 PM EST Amid heightened concern about the new illness known as Severe Acute Respiratory Syndrome, the mystery of just what it is deepens.
Scientists working on the Toronto outbreak reported that the agent responsible is "a novel virus that is not closely related to any of the known clusters” of coronaviruses, the prime family of suspected microbes. An analysis of cases in Hong Kong from February 22 to March 22 found the virus was not hitting the customarily susceptible populations -- the very young and very old -- as the mean age of patients was 52. Similarly, few patients were smokers or people with underlying health problems. Autopsies revealed the virus caused parts of the lungs to hemorrhage blood, as would be the case with a hemorrhagic fever virus such as Ebola. And as numbers of cases around the globe continued to rise, leading to such dramatic measures as Hong Kong sending more than 240 residents to quarantine camps, an airplane was detained Tuesday on the tarmac at the San Jose, Calif., airport after five people on board complained of symptoms. Medical officials wearing face masks boarded the plane and transferred three passengers to an ambulance, which took them to a hospital. Doctors eventually determined that none of the five was showing signs of the disease. "If every flight coming from Asia has to go through a similar process, I just don't see how this is possible,” said Santa Clara County Health Department official Karen Smith. The findings about the Toronto and Hong Kong outbreaks are reported in the New England Journal of Medicine. Dr. Allison McGreer and her colleagues in the Canadian SARS Study Team isolated viruses from several patients, performed genetic analysis of the viral RNA and concluded that the culprit's "conserved region” -- the hallmarks of a species -- is 78 percent identical to similar sections of genes found in common coronaviruses. But the study found other sections of the virus' RNA bear no resemblance to any known coronavirus, either human or animal. The disease detective who led the World Health Organization team that scoured SARS medical records last week in Beijing said in an interview Tuesday that as-yet unpublished data indicate the virus "looks more like an animal coronavirus than a human one, but we don't know what animal yet.” Dr. John Mackenzie of the University of Queensland in Brisbane, Australia said it seems probable at this stage that the microbe's origin is an unknown rodent virus. The most dangerous coronavirus known is the mouse hepatitis virus, he said, though it is unlikely, based on the genetic evidence, that SARS is caused by a variant of that particular microbe. Mackenzie said Chinese health authorities were less than forthcoming until the third day of the WHO team's visit, when they became "totally frank,” and the scale of China's epidemic began to emerge. To date China has reported 806 cases, with 34 deaths. WHO officials said that the Chinese federal government's Ministry of Health has little control over disease reporting, as surveillance and most public health activities are carried out at the provincial level. Last week China mandated that SARS cases must now be reported to federal authorities. "I think the Chinese should have come clean earlier,” Mackenzie said. But he conceded local health officials had an understandably difficult time realizing the scale of the threat in November and December, when influenza was spreading simultaneously, "and the waters were muddied.” By January, it was clear that something unusual was afoot, and China should have alerted international health authorities, he said. "Certainly something major went on in Guangdong ” the site of China's outbreak, Mackenzie said. "Most of the pneumonia cases weren't in children or the elderly, which is what you would see if it was flu ... And most of the deaths were in young, healthy adults.” WHO said Tuesday the cumulative total of cases reached 1,804 worldwide, with 62 deaths. Sixty-nine of those cases are in the United States, 10 of them in New York. There have been no SARS deaths in the United States. ++++++++++++++++++++++++++++++++++ Phil M -- The silver-list is a moderated forum for discussion of colloidal silver. Instructions for unsubscribing may be found at: http://silverlist.org To post, address your message to: [email protected] Silver-list archive: http://escribe.com/health/thesilverlist/index.html List maintainer: Mike Devour <[email protected]>
