BANGKOK, Thailand, September
30, 2004 (ENS): Thai health officials are investigating
the first possible human-to-human transmission of a highly virulent
form of avian influenza, and countries across Asia are scrambling
to prepare for another outbreak of the deadly virus. An 11 year
old girl and her mother both died since early September. Officials
believe the mother was infected while caring for her daughter, and
that this is a probable case of human-to-human transmission.
"Such a situation would be cause for alarm, as it might signal
the start of an influenza pandemic," warned the Ministry of
Public Health in Thailand. Still, evidence to date indicates that
transmission of the virus among humans has been limited to family
members and that no wider transmission in the community has occurred.
Altogether, Thailand has reported 15 cases, of which 10 were fatal,
since the first human cases were detected in January of this year.
Health officials confirm that these people were infected with the
avian influenza A (H5N1) virus, the same viral strain that caused
23 deaths and the slaughter of at least 100 million birds in an
outbreak across Asia last winter and spring.
The avian influenza epidemic in Asia is a "crisis of global
importance" and will continue to demand the attention of the
international community, the UN Food and Agriculture Organization
(FAO) and the World Organization for Animal Health (OIE) are warning.
Recent outbreaks in China, Vietnam, Cambodia, Malaysia and Thailand
show that the virus continues to circulate in the region and will
not probably be eradicated in the near future, the two organizations
said in a joint statement on Monday.
On Monday, the Ministry of Health of Vietnam has confirmed that
the death of a 14 month old boy early this month was caused by the
same viral strain. This is the third death from the virus in Vietnam
since August. The baby in Hanoi had typical symptoms of avian influenza
virus infection, including fever and cough.
China has required all localities to strengthen preventive efforts
against a possible outbreak of the highly pathogenic bird flu, during
autumn 2004 and winter 2005, according to a new circular issued
by the Ministry of Agriculture.
"Since the autumn and winter period is a key period for birds
to migrate, the bird flu is quite likely to break at any time,"
warns the circular, which cites the ongoing bird flu in other Asian
countries as a threat to China.
More research is urgently needed as the role of wildlife, domestic
ducks and pigs in transmitting the virus among animals is still
not fully understood, the FAO and OIE warned. "A permanent
threat to animal and human health continues to exist," they
While much progress has been made in early detection and reaction,
countries still need to step up proactive surveillance and control
measures. Major investments are required to strengthen veterinary
services, in particular for surveillance, early warning, detection,
reporting and response and for the rehabilitation and restructuring
of the poultry sector, the agencies said.
The newly published FAO Recommendations on the Prevention, Control
and Eradication of Highly Pathogenic Avian Influenza in Asia, prepared
in close collaboration with the OIE, review the factors that should
be taken into account in designing and implementing control programs
and explain how countries can adopt a strategy appropriate to their
In response to recent controversies on vaccination against bird
flu, the two agenices reiterated that the slaughter of infected
animals is the best way of controlling and ultimately stamping out
But officials acknowledged that this policy may not be practical
or adequate in certain countries because of social and economic
reasons or because of high viral challenge due to infection in villages,
wild birds or domestic waterfowl. In such cases, countries wishing
to eradicate the disease may choose to use vaccination as a complementary
measure to the stamping out policy.
China's bird flu control policy is based mainly upon mass preventative
vaccination. "Authorities should also prepare and improve their
emergency plans and ready vaccine and sterilizing drugs," says
the Ministry of Agriculture circular.
The two agencies stressed that vaccines, if used, should be produced
in accordance with the international guidelines prescribed in the
OIE Manual of Diagnostic Tests and Vaccines for Terrestrial Animals.
The OIE Terrestrial Code states that a country may be considered
free from highly pathogenic avian influenza based on the absence
of virus irrespective of whether vaccination has been carried out.
The two organizations confirmed that the use of vaccines does not
imply automatic loss of export markets.
It has been shown that the use of such vaccines does not only protect
healthy birds from disease but also reduces the load of viruses
excreted by infected birds and cuts the likelihood of transmission
of the virus to other birds and to humans.
The decision on whether to use vaccines has to be made by each
country based on its own situation, the two agencies said.
The factors countries should consider in making their decision
include their ability to detect and react to the disease as early
as possible and the need for transparent and timely notification.
This will have to be supported by a good institutional framework
and sound legislation underpinning veterinary services.
Any vaccination strategy should be developed in consultation with
all stakeholders, including the private sector. The types of poultry
and production sectors to be vaccinated must be determined and clearly
documented. Infected poultry and those in contact with the virus
should not be vaccinated.
The two agencies said vaccination should be carried out under the
supervision of official veterinary services and be accompanied by
a parallel surveillance strategy.
This would include the capacity of the veterinary services to identify
and monitor the circulating virus as well as the response to vaccination,
by means including the use of non-vaccinated sentinel birds and
the application of serological tests capable of differentiating
infected from vaccinated animals.
The World Health Organization's Southeast Asia Regional Office
says, "The risk of emergence of a new influenza virus due to
genetic modifications, which could trigger an outbreak with pandemic
potential, remains real as long as the avian influenza virus continues
to circulate in the environment."
It appears that the virus will continue to stay in the environment
in the foreseeable future so WHO officials emphasized the need for
enhanced and sustained surveillance.
Copyright Environment News Service (ENS) 2004. All Rights Reserved.