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The second wave

发布时间:2019-03-07 06:15:01来源:未知点击:

By Tim Thwaites in Sydney MALAYSIA’s killer Nipah virus continues to haunt its victims. Doctors and virologists dealing with the outbreak of the new disease are concerned that survivors of the infection are beginning to relapse. As New Scientist went to press, five patients who had recovered from encephalitis caused by Nipah were readmitted to hospital with what looked like the same symptoms. One patient has died and the other survivors are being closely watched. Patients with diseases caused by other paramyxoviruses similar to Nipah may relapse after making an initial recovery. Lam Sai Kit of the University of Malaya told the virology congress that this pattern seems to hold true for the Nipah virus. “But we are not sure whether this time it is due to virus, or to some exaggerated response triggered in the immune system which does not require the presence of virus.” Since the Nipah virus first appeared in late February among pig farmers in the Negeri Sembilan region, southeast of Kuala Lumpur (New Scientist, 3 April, p 4), it has caused 106 deaths. No fresh cases have been reported since June. The Nipah virus weakens the walls of the blood vessels. The latest patient to die suffered a brain haemorrhage similar to those seen in earlier cases of acute infection. But no virus was detected in a post-mortem examination. Meanwhile, researchers at the Australian Animal Health Laboratory (AAHL) in Geelong, near Melbourne, have been focusing on pigs, from which the virus is thought to have jumped to people. Pigs which the team had deliberately infected with Nipah developed symptoms like those from Malaysia during the outbreak, including what Lam describes as the “one-mile” cough. “It is a cough so loud it can be heard one mile away,” he says. The AAHL team has also found virus in the saliva and nasal fluids of Malaysian pigs. “This result is important as it tells us that people involved in any future outbreaks should wear breathing masks to avoid infection,” says Deborah Middleton, who led the team. However, Lam suspects that contact with pigs’ body fluids is the main route of infection. Those affected, he says, were farm workers who had given medicine to pigs orally, bathed them or cut their teeth. So far, there is no evidence of human to human transmission of the virus. Bats are still suspected as the most likely natural host for the virus ( New Scientist, 22 May, p 12). Antibodies to the Nipah virus have been detected in four species of fruit bat, though the virus itself has still not been isolated from bat tissue. More on these topics: