The three cases are among a group of patients, admitted to hospitals in
Initial tests have identified the virus as belonging to the H5 subtype.
Further testing is needed to determine whether the virus belongs to the same
H5N1 strain that caused 22 cases, with 15 deaths in
with eight deaths, in
To date, H5N1 is the only strain of the H5 subtype known to jump directly
from infected poultry to cause illness in humans.
Two of the fatal cases occurred in the northern Ha Tay province. The
third case occurred in the southern province of Hau Giang. Staff from the WHO
country office in
afternoon to gather further details about these cases and work out plans for
addressing the situation. The government has today announced an initial
series of measures aimed at controlling the disease in poultry and preventing
further cases in humans.
WHO regards it as particularly important that viruses from these cases be
made available for further analysis by laboratories in the WHO Global
Influenza Surveillance Network. Further studies can help determine whether
the virus has mutated and thus yield valuable information about the further
evolution of the outbreak, the risks to humans, and the best preventive
measures. Studies of the virus are also important in the further development,
presently under way, of an effective human vaccine.
Thorough epidemiological and clinical investigation of these cases and
their contacts is needed to improve understanding of the risks to humans.
Earlier this year, Vietnam reported outbreaks of highly pathogenic H5N1
avian influenza in poultry in 57 of the country's 64 provinces, resulting in
the death or destruction of more than 43 million poultry. After a period of
quiescence, Vietnam reported fresh outbreaks in poultry in July in provinces
in northern, central, and southern parts of the country. Outbreaks were also
reported in July in China, Indonesia, and Thailand.
The confirmation of these latest human cases underscores the risk of virus
transmission to humans from infected poultry. This risk will continue as long
as outbreaks are occurring in poultry. Of greatest concern is the risk that
continuing transmission of the virus to humans will give avian and influenza
viruses an opportunity to exchange genes, potentially giving rise to a new
virus with pandemic potential.
Source: World Health Organization