Faculty Bibliography

Dr. [Salter] said that W.H.O. has ''a significant amount of information that no risk to health workers has occurred when they take sensible standard respiratory precautions such as wearing masks, gowns, gloves and goggles in caring for patients in isolation rooms.'' Referring to the death rate, which is about 3 percent, Dr. [David L. Heymann] said, ''It's not AIDS.'' But while the death rate is low, the illness causes severe breathing difficulty, forcing some patients to be connected to mechanical ventilators and requiring other time consuming work by hospital staff, Dr. Heymann said. Workers hosing down an area near the Metropole Hotel in Hong Kong, where a mysterious illness called severe acute respiratory syndrome is believed to have been started by a sick doctor who had visited China. (Agence France-Presse)

Local circuits in the spinal cord that generate locomotion are termed central pattern generators (CPGs). These provide coordinated bilateral control over the normal limb alternation that underlies walking. The molecules that organize the mammalian CPG are unknown. Isolated spinal cords from mice lacking either the EphA4 receptor or its ligand ephrinB3 have lost left-right limb alternation and instead exhibit synchrony. We identified EphA4-positive neurons as an excitatory component of the locomotor CPG. Our study shows that dramatic locomotor changes can occur as a consequence of local genetic rewiring and identifies genes required for the development of normal locomotor behavior.

Scientists have found clues that a virus might be the cause of the mysterious respiratory illness that has affected hundreds of people in Asia and other countries, the World Health Organization said. But the agency cautioned Tuesday that more work needed to be done to be sure that a virus is the cause of the illness and not a coincidental finding in a few patients. Using electron microscopes, two laboratories in Germany and a third in Hong Kong reported finding particles that seem to belong to a large family of viruses, paramyxoviridae, that includes those that cause croup, measles, mumps, respiratory disease, rubella and other ailments. Still, Dr. Klaus Stoehr, a virologist and epidemiologist who is leading the health organization's scientific team investigating the illness, said that none of those viruses had caused a disease like the one under investigation, which doctors are calling severe acute respiratory syndrome, or SARS. Instead, the findings suggest that the virus might be a hitherto unknown member of the paramyxoviridae family. Tests seem to have ruled out two recently discovered members of the family, the Nipah virus and the Hendra virus, Stoehr said. Dr. James Hughes, the director of center for infectious diseases at the Centers for Disease Control and Prevention in Atlanta, urged the public not to draw conclusions from the findings. Federal health officials were not yet ready to accept the paramyxoviridiae as the final explanation, he said. The three laboratories are part of a network of 11 in nine countries that the World Health Organization has created to find the cause of the ailment, which it has declared 'a worldwide health threat.' On Tuesday, other scientists in the network were testing throat swabs and sputum specimens from other SARS cases to see if they, too, could identify similar particles, Stoehr said

Much more work needs to be done to be sure that the suspect virus is the true cause of the ailment that W.H.O. calls SARS, for severe acute respiratory syndrome. The agency has declared the condition a ''worldwide health threat.'' On Tuesday, scientists from laboratories in Hong Kong and Germany reported having found particles that seem to belong to a large family of viruses, paramyxoviridae, in three patients with suspect SARS cases. The family includes the viruses that cause croup, respiratory disease, measles, mumps, rubella and a number of diseases in animals, including Newcastle disease, which is lethal to chickens; canine distemper virus and rinderpest, which affects cattle and other animals. Dr. [Larissa Kolesnikova] said she had peered into an electron microscope at the doctor's specimens for three hours on Saturday, then came back and identified the particles on Sunday morning. Meanwhile, scientists at the Chinese University in Hong Kong were identifying similar particles, also using an electron microscope. ''With the confirmation from Hong Kong, we are more confident'' that the virus might be the cause of the outbreak, said Dr. Hans-Dietrech Klenk, the director of the Marburg institute

The World Health Organization has expanded its network of laboratories in an urgent effort to find the cause of a mysterious respiratory illness that has spread with the aid of international airplane travel from Asia to Canada and countries in Europe. The agency is coordinating scientists from 11 laboratories in 10 countries to seek the cause of severe acute respiratory syndrome, or SARS, which it says is a threat to world health. So far scientists at five laboratories have failed to identify any known infectious agent as its cause. 'The current outbreak is of concern to everyone,' Tommy Thompson, the U.S. secretary of health and human services, said at a news conference Monday after briefing White House and Defense Department officials about the ailment. Thompson oversees the Centers for Disease Control, one of the laboratories in the World Health Organization network. Dr. Julie Gerberding, director of the centers, in Atlanta, said that scientists at her agency were focusing the hunt either for an unusual known infectious agent that is difficult to grow in a laboratory or for a novel agent. No cases have been reported in the United States, Gerberding said. Doctors have reported 14 suspicious cases, she added, but 10 have been judged not to be SARS, and it is unlikely that the four others will turn out to be. Nevertheless, the four cases are being fully investigated because health officials do not want to miss one, Gerberding said. She declined to provide further details of the cases because state and local health departments, not her agency, were conducting the investigations. The number of cases rose to 111 in Hong Kong on Tuesday, and officials said that more cases were under investigation

Using electron microscopes, two laboratories in Germany and a third in Hong Kong reported finding particles that seem to belong to a large family of viruses, paramyxoviridae, that includes the viruses that cause croup, respiratory disease, measles, mumps and other ailments. Still, Dr. Klaus Stohr, a virologist and epidemiologist who is leading the health organization's scientific team investigating the illness, said that none of those viruses had caused a disease like the one under investigation, which doctors are calling severe acute respiratory syndrome, or SARS. Instead, the findings suggest that the virus might be a hitherto unknown member of the paramyxoviridae family. Yesterday, other scientists in the network raced to test throat swabs and sputum specimens from other SARS cases to see if they, too, could identify similar particles, said Dr. Stohr, the W.H.O. virologist

Chinese health officials have given the World Health Organization the first sketchy details about a mysterious respiratory ailment that is believed to have first broken out in Guangdong Province in November and that Chinese officials say has tapered off in recent weeks. It was the first official communication from China about the illness, and it provided a longer-term view to the health organization of how the illness has behaved since the first cases were detected. Although the new information hinted that the outbreak may be tapering off for unknown reasons in Guangdong, World Health Organization officials said they needed more information to be certain. 'If it has burned out, it certainly will give us optimism over its control' elsewhere, said Dr. David Heymann, a health agency official. 'That is why we need more information to know what the natural history of the illness has been since November.' The World Health Organization, an agency of the United Nations, on Saturday declared the ailment 'a worldwide health threat.' The agency calls the ailment severe acute respiratory syndrome, or SARS, and says it has caused at least nine deaths in six countries in recent weeks. The spread of the ailment, a form of atypical pneumonia, has been aided by international travel. New cases, including those of many hospital workers, are being reported daily in affected countries, a World Health Organization official. Laboratories in at least five countries have failed to detect any known infectious agent as a cause of the illness. The illness generally starts with the sudden onset of a fever of 101.4 degrees Fahrenheit (38.6 centigrade) or higher, muscle aches, headache, sore throat, dry cough and shortness of breath. X-rays show pneumonia or respiratory distress syndrome. Laboratory tests show low numbers of white blood cells and platelets, which help blood clot. A 32-year-old doctor from Singapore and his 62-year-old mother-in-law were being treated for pneumonia in isolation in a German hospital after having attended a medical conference in New York. Officials believe the doctor may have contracted the illness in treating the first two cases in Singapore, where 20 cases now have been reported. The doctor had a fever and a slight cough, and the mother-in-law had a high fever, doctors at the Johann Wolfgang Goethe-University Hospital in Frankfurt said. They said the doctor's 30-year-old wife, who is pregnant, has shown no symptoms of the ailment

No cases have been reported in the United States, Dr. [Julie L. Gerberding] said. Doctors have reported 14 suspicious cases, but 10 have been judged not to be SARS, and it is unlikely that the four others will turn out to be, Dr. Gerberding said. So microbiologists at major laboratories often use molecular biology methods known as DNA probes to identify an agent. If SARS is a co-infection, say by a bacteria and a virus, ''we should be able to figure it out,'' Dr. Gerberding said. But, she added, even the most sensitive DNA technology can fail to detect a microbe if it is present in tiny amounts. The second feature was the rapidity and severity with which pneumonia developed in some patients. Even among patients who suffer a system illness with influenza, ''it is quite unusual to develop pneumonia,'' Dr. Gerberding said. ''Here we had a very high proportion of individuals developing pneumonia, and that signaled something unusual,'' requiring a closer look

In recent weeks scientists at laboratories in at least five countries have failed to detect the avian flu strain in any SARS case. Dr. David L. Heymann, executive director in charge of communicable diseases for the W.H.O., said, ''We have not ruled out influenza definitively.'' But many experts are wondering whether they are confronting a previously unknown infectious agent, possibly one of animals that has jumped species to humans. For reasons not fully understood, SARS has exerted its heaviest toll so far on health care workers in third world countries like Vietnam where there are relatively few trained personnel. The ninth victim of SARS was a nurse who died in Hanoi late last week. The incubation period of SARS seems to range from two to seven days, most commonly four to five days. That is shorter than the period for influenza, which can spread in less than a day. In controlling outbreaks of known diseases, health officials use that kind of information to detect healthy carriers of an infectious agent or people who have mild cases that do not normally require medical attention. But without any tests for SARS there is no way to find such carriers, if any exist. So far chest X-rays have been the only way to detect mild cases