Efficient Transmission of H5N1 to a Family of Five in Haiphong
Recombinomics Commentary
March 28, 2005
>> A five-person family from Vietnam's northern Hai Phong city have been infected with bird flu virus strain H5N1, local newspaper Labor reported Tuesday.
According to initial testing by the Vietnam's National Institute for Hygiene and Epidemiology, specimens from the five patients, including a 39-year-old man named Vu Van Son, his wife and three children from Kien Thuy rural district, have been tested positive to the virus. They were admitted to the city-based Viet-Tiep Hospital on March 22 after having cough, fever and breathing difficulty.
The parents and their daughters aged 4 months old, 3 years old and 10 years old are now in stable health condition. Before exhibiting bird flu symptoms, they ate sick chicken raised by themselves.
Several days after admitting the five patients, the hospital received two suspected cases of bird flu infections: a 41-year-oldman and a child. All the seven patients live in the same commune <<
The efficient transmission of H5N1 to a family of five, signals a major change in the transmissibility of H5N1 to humans. The familial cluster is the largest reported to date, and the largest number of related patients admitted to the same hospital on the same day. Although the transmission may have come from the dead or culled chickens, it is not clear that a 4 month old baby would be infected from eating chicken.
However, regardless of the transmission source, the transmission was efficient. The admission of 2 or 3 additional patients a few days later is added cause for concern. It is not clear if the 41 year old male described above is the same person reported earlier as being a 41 year old female, Vu Thi Hoan, who was admitted on March 25. She lived near the family of five in Kien Thuy, and therefore was also probably in the same commune. The child would be the 7th or 8th member of the district hospitalized, signaling efficient transmission to several neighbors.
Between March 10-14 poultry was culled from farms of four families from the Hung Dao commune in Kien Thuy, so screening of all four families would be warranted. Similarly anyone in the commune who is not well should be tested.
The H5N1 positive results in the Kien Thuy district signals efficient transmission of H5N1 to humans. Milder symptoms are irrelevant because efficient transmission to large numbers of people will create a very favorable situation for further evolution and recombination of H5N1 via dual infections in human hosts.
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