Two Vietnamese sisters, who died of bird flu, may have caught
the virus from their brother, who had also died, the World Health
Organization said in a statement on Sunday.
While the source of infection for the two sisters cannot be
conclusively identified, WHO "considers that limited human-to-human
transmission, from their brother to the sisters, is one possible
explanation," said WHO.
The statement said that the two women, aged 23 and 30 years old,
were admitted to the Hanoi-based Hospital of Tropical Diseases on
Jan 13. Both died on Jan. 23.
They are part of a cluster of four cases of respiratory illness:
the two sisters, their elder brother and his wife in the northern
province of Thai Binh. Their brother died before them, but no
samples were available from him for testing.
A detailed investigation of this cluster has been undertaken by
WHO.
Vietnam's Hygiene and Epidemiology Institute had confirmed
thatthe two sisters were victims of the highly pathogenic H5N1 form
of the virus before WHO did.
The WHO investigation did not reveal a specific event, such as
contact with sick fowls, or an environmental source to explain the
cases. However, WHO stated that H5N1 infection in poultry is
widespread in Vietnam, and that direct transmission from fowls to
humans cannot be ruled out on the basis of available evidence.
"At present, there is no evidence of efficient human-to-human
transmission of H5N1 occurring in Vietnam or elsewhere. Further
investigations will be carried out, but it is doubtful that they
will provide any more conclusive information about how these people
became infected," said WHO.
Vietnam's Central Veterinarian Department said that by Sunday
afternoon, 47 out of 64 cities and provinces nationwide were hit by
bird flu which had affected nearly seven million poultry.
(Xinhua News Agency February 1, 2004)