April 22, 2009
New Strain Of Swine Flu Emerges In California
Health officials reported Tuesday that two children in California had been infected with a previously unidentified strain of swine flu. Medical experts remain unsure as to what percentage of the population may be susceptible to infection.
Both cases occurred last week; the first a 10-year old boy in San Diego County, the second a 9-year old girl in nearby Imperial County. Doctors say that both children have fully recovered.
"The CDC is concerned, but that's our job," said Tom Skinner, spokesman for the agency.
The emergence of a deadly super-flu has been a fear of health experts for some time. Thus far, however, there has been no marked increase in flu or flu-like illnesses. Experts continue to investigate the new viral strain, examining its genetic makeup and tracking down people who had been in direct contact with the infected children.
Though officials report that the children had not been in contact with each other, both contracted the illness in late March and exhibited relatively mild symptoms like cough and fever.
Other family members of both children also experienced flu-like symptoms in recent months, though none of the relatives were tested for the flu.
Health officials are also trying to locate two young children who sat beside the boy in early April during a flight to Dallas where he is now staying with relatives.
Historically, the CDC has recorded roughly one case of human infection with the swine influenza every one to two years. In the last few years however, that statistic has seen a dramatic increase, as more than a dozen cases of human infection have been identified since 2005.
Experts believe that the jump in recorded cases of human infection can likely be attributed to technological improvements in diagnosis techniques as well as an expansion of health care facilities able to test for the disease.
"Both of these kids came to our attention because they were seen in clinics which do routine surveillance for influenza infections," Dr. Lyn Finelli of the CDC told reporters.
The virus is typically spread through direct contact with pigs, though neither of the California children had touched animals in recent months. Officials suspect that the children may have been infected by other people rather than directly from animals, though the family of the girl did report that she had attended an agricultural fair in Imperial County some four weeks prior to coming down with the illness.
According to researchers at the CDC, the new flu strain, called H1N1, contains a novel combination of DNA segments never before identified in either human or swine influenza. The virus belongs to the same family as one of the seasonal flu that is now circulating in the population, but is also shares genetic similarities with a swine virus not found in humans.
Officials have yet to identify any pigs carrying the virus, though California epidemiologist Dr. Gil Chavez admits, "We don't test every pig for influenza, so we don't know all the strains that are circulating."
Preliminary tests of the new strain show indicate that it is resistant to amantadine and rimantadine, two of the most common anti-viral medications currently in use. Several other viruses going around this season have also exhibited immunity to these drugs.
Swine flu made a particularly bad name for itself when it infected a number soldiers at Fort Dix, N.J. in 1976. Health officials were alarmed by the striking resemblance between the swine-transmitted virus and another deadly strain of flu that had killed millions of people around the world between 1918 and 1919.
Some 40 million Americans were vaccinated against the flu during a national campaign in the late 1970's. Though a pandemic spread of the virus never occurred, thousands of people who had accepted the vaccines reported suffering from a paralyzing condition as well as various other side effects.
Image Caption: Pigs can harbor influenza viruses adapted to humans and others that are adapted to birds, allowing the viruses to exchange genes and create a pandemic strain.
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