Indonesian Bird Flu Outbreak Raises Pandemic Fears Anew
http://www.medpagetoday.com/InfectiousDisease/URItheFlu/tb/3394
By Michael Smith, MedPage Today Staff Writer
Reviewed by Zalman S. Agus, MD; Emeritus Professor at the University of Pennsylvania School of Medicine.
May 24, 2006
Review
GENEVA, May 24 ? A 32-year-old Indonesian man who died Tuesday of avian influenza may have contracted the disease while caring for his 10-year-old son, who died earlier, according to World Health Organization experts.
"The father was closely involved in caring for his son, and this contact is considered a possible source of infection," the agency said in a statement.
The case may be the first in which the virus made a double jump, involving three people. In all earlier cases of suspected human-to-human transmission, the virus passed from an infected person to another after close and prolonged contact.
Most cases of human infection arise from close contact with infected birds, but experts fear small mutations in the virus could allow it to jump easily from human to human, which could spark a world-wide pandemic. The Indonesian cases are being watched closely because of fears that the virus there may have developed such an ability.
WHO scientists said it is clear the virus jumped from person to person in the Indonesian cluster, but only after prolonged exposure to an infected person who was coughing up infected particles.
The cases are part of a family cluster in the village of Kubu Sembelang in the north of the island of Sumatra.
Seven members of the family became infected after a family gathering on April 29 and six have died. The hostess of the gathering, who died May 4 of respiratory illness, was probably also a victim of the H5N1 strain of avian flu, but she was buried without specimens being taken so officials aren't confirming the flu possibility.
However, because the clinical course of her disease is "compatible with H5N1 infection," the agency said, officials are considering the 37-year-old woman to be the index case.
WHO officials noted that three of the infected family members slept in the same room as the index case, who was coughing heavily at the time. Those cases include the woman's two sons and a brother, who is the only surviving victim of the outbreak.
The WHO working hypothesis, in the case of the most recent death, is that the virus jumped twice between people?once from the index case to the boy, and then from the boy to his father.
But according to published reports, that's based on the assumption that the incubation time for the H5N1 strain is longer than the two to four days seen in regular human influenza.
If the assumption is wrong, that would imply the boy?who died May 13, two weeks after the family gathering?was infected by someone other than the index case. That would mean the virus made three human-to-human jumps, according to Henry Niman, Ph.D., of recombinomics.com, a company that studies the genetics of viral evolution. Dr. Niman was quoted by the New York Times.
So far, the WHO said, there's no evidence of "efficient human-to-human transmission" and no sign that the outbreak is spreading into the local community.
The H5N1 strain of avian flu is highly dangerous when it infects humans. As of Wednesday, WHO said, 218 people have been infected and 124 have died.
The H5N1 virus is known to prefer to attack receptors deep in human lungs, rather than those in the nose and throat, like the standard seasonal flu. That biological difference is regarded as the reason the virus is only transmitted through close contact with infected birds or other infected humans.
http://www.medpagetoday.com/InfectiousDisease/URItheFlu/tb/3394
By Michael Smith, MedPage Today Staff Writer
Reviewed by Zalman S. Agus, MD; Emeritus Professor at the University of Pennsylvania School of Medicine.
May 24, 2006
Review
GENEVA, May 24 ? A 32-year-old Indonesian man who died Tuesday of avian influenza may have contracted the disease while caring for his 10-year-old son, who died earlier, according to World Health Organization experts.
"The father was closely involved in caring for his son, and this contact is considered a possible source of infection," the agency said in a statement.
The case may be the first in which the virus made a double jump, involving three people. In all earlier cases of suspected human-to-human transmission, the virus passed from an infected person to another after close and prolonged contact.
Most cases of human infection arise from close contact with infected birds, but experts fear small mutations in the virus could allow it to jump easily from human to human, which could spark a world-wide pandemic. The Indonesian cases are being watched closely because of fears that the virus there may have developed such an ability.
WHO scientists said it is clear the virus jumped from person to person in the Indonesian cluster, but only after prolonged exposure to an infected person who was coughing up infected particles.
The cases are part of a family cluster in the village of Kubu Sembelang in the north of the island of Sumatra.
Seven members of the family became infected after a family gathering on April 29 and six have died. The hostess of the gathering, who died May 4 of respiratory illness, was probably also a victim of the H5N1 strain of avian flu, but she was buried without specimens being taken so officials aren't confirming the flu possibility.
However, because the clinical course of her disease is "compatible with H5N1 infection," the agency said, officials are considering the 37-year-old woman to be the index case.
WHO officials noted that three of the infected family members slept in the same room as the index case, who was coughing heavily at the time. Those cases include the woman's two sons and a brother, who is the only surviving victim of the outbreak.
The WHO working hypothesis, in the case of the most recent death, is that the virus jumped twice between people?once from the index case to the boy, and then from the boy to his father.
But according to published reports, that's based on the assumption that the incubation time for the H5N1 strain is longer than the two to four days seen in regular human influenza.
If the assumption is wrong, that would imply the boy?who died May 13, two weeks after the family gathering?was infected by someone other than the index case. That would mean the virus made three human-to-human jumps, according to Henry Niman, Ph.D., of recombinomics.com, a company that studies the genetics of viral evolution. Dr. Niman was quoted by the New York Times.
So far, the WHO said, there's no evidence of "efficient human-to-human transmission" and no sign that the outbreak is spreading into the local community.
The H5N1 strain of avian flu is highly dangerous when it infects humans. As of Wednesday, WHO said, 218 people have been infected and 124 have died.
The H5N1 virus is known to prefer to attack receptors deep in human lungs, rather than those in the nose and throat, like the standard seasonal flu. That biological difference is regarded as the reason the virus is only transmitted through close contact with infected birds or other infected humans.
