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Swine Flu Probe Slowed by Backlog in Mexican Sample Testing
By John Lauerman and Jason Gale
May 1 (Bloomberg) -- Swine flu samples caught in a laboratory backlog in Mexico are slowing the probe into the severity of the virus that?s sweeping across the world, experts including the World Health Organization?s Francesco Checchi say.
Mexico, the first country known to be hit by the new H1N1 flu strain that has reached 11 nations, has about 35,000 samples waiting to be analyzed, said Dick Thompson, a spokesman at the World Health Organization. Those samples, which experts say hold the key to understanding the virus, are held in a guarded laboratory surrounded by walls, gates and guards, that?s less than 4 miles from downtown Mexico City.
The WHO on April 29 called a flu pandemic ?imminent,? and 13 people are confirmed to have died from H1N1 infection. Scientists say they need to how far the virus has spread in Mexico, where 12 of the deaths occurred, and how often it kills, to predict whether it will be as lethal as the so-called Spanish flu that killed about 50 million people in 1918.
?While we know of a given number of confirmed swine flu deaths, we do not know by any means the actual number of swine influenza cases that have occurred in Mexico,? Checchi, a WHO epidemiologist, said in an April 28 e-mail. ?It is extremely difficult to assess just how lethal the virus is in Mexico.?
The Canadian government said April 29 that it will test 200 patient samples to help get Mexico through the logjam. Canada has also given Mexico genetic analysis equipment that can pinpoint H1N1 in patients within a matter of hours, said Miguel Angel Lezana, director of the National Center of Epidemiologic Control in Mexico City. Scientists are working night and day on the effort, he said April 28 in an interview.
Statistics Will Vary
?As investigations advance in a very precise way and using the most advanced technology in the world here in Mexico City, we?ll be able to observe with greater punctuality the number of cases,? Mexican President Felipe Calderon said early today in a statement on the country?s flu-prevention Web site. ?These statistics will without doubt vary over the coming days.?
The number of confirmed swine flu cases in Mexico rose to 312 including the 12 deaths, Jose Cordova, the nation?s health minister, said yesterday. Health officials there had confirmed 49 cases the afternoon of April 29, and 99 cases that evening.
Eleven countries have reported 331 cases of H1N1 infection, the Geneva-based WHO said today. Mexico reported 156 confirmed swine-flu cases, including nine deaths, the organization said. The Mexican samples are at the National Institute of Epidemiologic Diagnosis and Reference.
Confirmed Cases
As testing ramps up, the number of people confirmed with swine flu is likely to jump into the thousands in the coming days to weeks, said Gustavo Reyes, laboratory chief at Mexico?s National Institute of Respiratory Diseases? Center for the Investigation of Infectious Diseases in Mexico City. About 90 percent of suspected cases of swine flu, which now number about 2,500, will soon be confirmed, he said.
?Overall we had an almost exponential growth compared with two weeks ago,? he said in an interview yesterday.
Many cases may never be diagnosed, Reyes said. The new virus has a tendency to disappear from sputum five to seven days after infection, and people who arrive at the hospital later than that often can?t be sampled, he said.
General hospitals that treat Mexico?s poor routinely give antivirals to those with influenza symptoms and send them on their way without taking samples, Reyes said.
?It?s probable that we?ve been missing some cases,? he said. ?The mild cases surely have been confused with a minor respiratory deficiency caused by other viruses.?
More Assistance
Mexico has just three laboratories with the level 3 biosafety rating required to do the precise testing to confirm swine flu, said Reyes, whose lab is one of them. Becton Dickinson and Co., the Franklin Lakes, New Jersey-based maker of medical devices, will donate equipment worth about $500,000 that will enable him to diagnose cases in hours, rather than the five or six days it took to send samples to the CDC for confirmation.
The Pan American Health Organization, a Washington-based division of the WHO, has an office of about 30 people in Mexico City and has sent at least 12 more scientists to Mexico to help trace and understand the virus, said Daniel Epstein, a spokesman.
CDC has lent five scientists to PAHO for the effort, said David Daigle, a spokesman for the Atlanta-based CDC.
Careful studies are needed to confirm which cases are caused by the H1N1 A strain, commonly known as swine flu, and which are linked to other viruses. Most of Mexico?s patients have been diagnosed only with rapid tests that can determine whether a patient has some form of flu, Lezana said.
Virus Genetics
Scientists identify flu viruses by comparing the composition of the germ?s eight genes. Special attention is paid to the genes that make hemagglutinin and neuraminidase, the namesakes of the ?H? and ?N? in flu-virus terminology.
Epidemiologists and virologists working at a government laboratory in Mexico City, the National Institute of Diagnostics and Reference Epidemiology, are using the new equipment from Canada to type the virus, Lezana said. That will enable them to determine exactly how many of people have the H1N1 flu, and how many of those are severely ill.
Health officials are trying to minimize the contagion in Mexico City, the world?s biggest metropolitan area with about 22 million people living on 3,000 square miles (7,800 square kilometers).
Cordova, the Mexican health minister, announced sweeping restrictions on non-essential work and business from May 1 to May 5. Restaurants, already closed in Mexico City since April 28, will remain closed through May 5.
Mexico?s Measures
On April 28, about 60 ambulances began fanning out in search of swine-flu infected people. Doctors and emergency medical technicians are giving antiviral medications, Roche Holding AG?s Tamiflu and GlaxoSmithKline Plc?s Relenza, to those who appear sick, and sending the worried well on their way.
?People are very scared,? said Marco Anton Perez-Lara, an emergency medical technician working outside an ambulance in Mexico City. A line of about a dozen stretched away from the van, which had been in place for about an hour. ?Most of them just have colds.?
Mexico?s citizens are confused by the government measures in light of the low numbers of confirmed cases. In a survey of 197 traders, Mexico City-based IXE Grupo Financiero SA found that 47 percent didn?t trust the government?s statistics. The doubters probably think the officials are holding back case numbers to avoid panic, said Carlos Ponce, head of equity research for the unit, who ran the study.
?The federal government can manage the numbers to control fear and panic in the population,? said Luis Roberto Agraz, a government prosecutor at the Office of Attorney General for the Mexican Republic, in an interview in Mexico City. ?So they don?t give the real thing.?
Swine Flu Probe Slowed by Backlog in Mexican Sample Testing
By John Lauerman and Jason Gale
May 1 (Bloomberg) -- Swine flu samples caught in a laboratory backlog in Mexico are slowing the probe into the severity of the virus that?s sweeping across the world, experts including the World Health Organization?s Francesco Checchi say.
Mexico, the first country known to be hit by the new H1N1 flu strain that has reached 11 nations, has about 35,000 samples waiting to be analyzed, said Dick Thompson, a spokesman at the World Health Organization. Those samples, which experts say hold the key to understanding the virus, are held in a guarded laboratory surrounded by walls, gates and guards, that?s less than 4 miles from downtown Mexico City.
The WHO on April 29 called a flu pandemic ?imminent,? and 13 people are confirmed to have died from H1N1 infection. Scientists say they need to how far the virus has spread in Mexico, where 12 of the deaths occurred, and how often it kills, to predict whether it will be as lethal as the so-called Spanish flu that killed about 50 million people in 1918.
?While we know of a given number of confirmed swine flu deaths, we do not know by any means the actual number of swine influenza cases that have occurred in Mexico,? Checchi, a WHO epidemiologist, said in an April 28 e-mail. ?It is extremely difficult to assess just how lethal the virus is in Mexico.?
The Canadian government said April 29 that it will test 200 patient samples to help get Mexico through the logjam. Canada has also given Mexico genetic analysis equipment that can pinpoint H1N1 in patients within a matter of hours, said Miguel Angel Lezana, director of the National Center of Epidemiologic Control in Mexico City. Scientists are working night and day on the effort, he said April 28 in an interview.
Statistics Will Vary
?As investigations advance in a very precise way and using the most advanced technology in the world here in Mexico City, we?ll be able to observe with greater punctuality the number of cases,? Mexican President Felipe Calderon said early today in a statement on the country?s flu-prevention Web site. ?These statistics will without doubt vary over the coming days.?
The number of confirmed swine flu cases in Mexico rose to 312 including the 12 deaths, Jose Cordova, the nation?s health minister, said yesterday. Health officials there had confirmed 49 cases the afternoon of April 29, and 99 cases that evening.
Eleven countries have reported 331 cases of H1N1 infection, the Geneva-based WHO said today. Mexico reported 156 confirmed swine-flu cases, including nine deaths, the organization said. The Mexican samples are at the National Institute of Epidemiologic Diagnosis and Reference.
Confirmed Cases
As testing ramps up, the number of people confirmed with swine flu is likely to jump into the thousands in the coming days to weeks, said Gustavo Reyes, laboratory chief at Mexico?s National Institute of Respiratory Diseases? Center for the Investigation of Infectious Diseases in Mexico City. About 90 percent of suspected cases of swine flu, which now number about 2,500, will soon be confirmed, he said.
?Overall we had an almost exponential growth compared with two weeks ago,? he said in an interview yesterday.
Many cases may never be diagnosed, Reyes said. The new virus has a tendency to disappear from sputum five to seven days after infection, and people who arrive at the hospital later than that often can?t be sampled, he said.
General hospitals that treat Mexico?s poor routinely give antivirals to those with influenza symptoms and send them on their way without taking samples, Reyes said.
?It?s probable that we?ve been missing some cases,? he said. ?The mild cases surely have been confused with a minor respiratory deficiency caused by other viruses.?
More Assistance
Mexico has just three laboratories with the level 3 biosafety rating required to do the precise testing to confirm swine flu, said Reyes, whose lab is one of them. Becton Dickinson and Co., the Franklin Lakes, New Jersey-based maker of medical devices, will donate equipment worth about $500,000 that will enable him to diagnose cases in hours, rather than the five or six days it took to send samples to the CDC for confirmation.
The Pan American Health Organization, a Washington-based division of the WHO, has an office of about 30 people in Mexico City and has sent at least 12 more scientists to Mexico to help trace and understand the virus, said Daniel Epstein, a spokesman.
CDC has lent five scientists to PAHO for the effort, said David Daigle, a spokesman for the Atlanta-based CDC.
Careful studies are needed to confirm which cases are caused by the H1N1 A strain, commonly known as swine flu, and which are linked to other viruses. Most of Mexico?s patients have been diagnosed only with rapid tests that can determine whether a patient has some form of flu, Lezana said.
Virus Genetics
Scientists identify flu viruses by comparing the composition of the germ?s eight genes. Special attention is paid to the genes that make hemagglutinin and neuraminidase, the namesakes of the ?H? and ?N? in flu-virus terminology.
Epidemiologists and virologists working at a government laboratory in Mexico City, the National Institute of Diagnostics and Reference Epidemiology, are using the new equipment from Canada to type the virus, Lezana said. That will enable them to determine exactly how many of people have the H1N1 flu, and how many of those are severely ill.
Health officials are trying to minimize the contagion in Mexico City, the world?s biggest metropolitan area with about 22 million people living on 3,000 square miles (7,800 square kilometers).
Cordova, the Mexican health minister, announced sweeping restrictions on non-essential work and business from May 1 to May 5. Restaurants, already closed in Mexico City since April 28, will remain closed through May 5.
Mexico?s Measures
On April 28, about 60 ambulances began fanning out in search of swine-flu infected people. Doctors and emergency medical technicians are giving antiviral medications, Roche Holding AG?s Tamiflu and GlaxoSmithKline Plc?s Relenza, to those who appear sick, and sending the worried well on their way.
?People are very scared,? said Marco Anton Perez-Lara, an emergency medical technician working outside an ambulance in Mexico City. A line of about a dozen stretched away from the van, which had been in place for about an hour. ?Most of them just have colds.?
Mexico?s citizens are confused by the government measures in light of the low numbers of confirmed cases. In a survey of 197 traders, Mexico City-based IXE Grupo Financiero SA found that 47 percent didn?t trust the government?s statistics. The doubters probably think the officials are holding back case numbers to avoid panic, said Carlos Ponce, head of equity research for the unit, who ran the study.
?The federal government can manage the numbers to control fear and panic in the population,? said Luis Roberto Agraz, a government prosecutor at the Office of Attorney General for the Mexican Republic, in an interview in Mexico City. ?So they don?t give the real thing.?
