SITREP - WHO | Avian influenza A(H5N1) - update 18: FAO/OIE/WHO Technical Consultation on the Control of Avian Influenza,

Avian influenza A(H5N1) - update 18: FAO/OIE/WHO Technical Consultation on the Control of Avian Influenza,
Situation (human) in Thailand and Viet Nam

5 February 2004

Situation (human) in Viet Nam

The Ministry of Health in Viet Nam has informed WHO that two additional cases of H5N1 infection in humans have been confirmed. Both cases were fatal.

The two cases were in young women, aged 16 and 17 years, from the southern part of the country. Both were treated at hospitals in Ho Chi Minh City. The 16-year-old woman died on 3 February. The 17-year-old woman died on 27 January.

These cases bring the number of laboratory confirmed H5N1 infections in Viet Nam to 15. Of these, 11 have died, two remain hospitalized, and two have recovered.

Situation (human) in Thailand

The Ministry of Public Health in Thailand has confirmed the country?s fifth human case of H5N1 infection. The case, a six-year-old boy from Kanchanaburi Province, developed illness on 24 January and died on 2 February.

All five laboratory-confirmed cases in Thailand have been fatal.

FAO/OIE/WHO Technical Consultation on the Control of Avian Influenza
(Rome, 3?4 February 2004)

Several conclusions and recommendations made during this consultation strengthen WHO recommendations for protecting humans from the consequences of widespread outbreaks of highly pathogenic H5N1 avian influenza in poultry in several Asian countries.

Experts at the consultation recognized the need for immediate application of measures to prevent human infection in groups, notably poultry workers and cullers, at high risk of exposure to the H5N1 avian influenza virus. Personal protective equipment should be available for persons in these groups, who also need training in the proper use of this equipment. WHO has issued guidelines for the protection of cullers.

The experts further recognized the need to reduce opportunities for the simultaneous infection of humans with H5N1 and human strains of influenza virus. Such dual infections give the avian and human viruses opportunities to exchange genes, possibly resulting in the emergence of a new influenza virus subtype. The consultation recommended that poultry workers, who can experience intensive exposures, be given the existing seasonal influenza vaccine. (The vaccine protects against infection with currently circulating human influenza viruses, but does not protect against H5N1 infection). WHO has issued guidelines for the targeted administration of seasonal vaccines.

WHO priorities for responding to the current situation include rapid control of the animal reservoir of H5N1, as doing so reduces the risk of both more cases and deaths in humans and more opportunities for a new subtype of the influenza virus to emerge. Recommendations from the consultation also support this priority.

The consultation concluded that culling, or ?stamping out?, of infected flocks remains the preferred option for controlling H5N1 outbreaks in poultry. However, the present outbreaks in poultry are historically unprecedented in their scale, geographical spread, and devastating economic consequences for both the poultry industry and rural farmers.

While culling remains the preferred option for infected flocks, targeted vaccination of healthy poultry can be used as a complementary tool for achieving the rapid reduction of the risk posed by the H5N1 virus in its avian host ? an objective which supports both elimination of the disease in poultry and prevention of further human cases and deaths.

Vaccination alone will not be sufficient to bring the present outbreaks in poultry under control.

Experts at the consultation stressed that, where vaccination is being considered as a complementary control tool, it must be used in conjunction with a comprehensive strategy that includes culling of all diseased or exposed poultry, strict biosecurity, quarantine, and other measures aimed at preventing further spread of the disease.

WHO Avian influenza A(H5N1) - update 18: FAO/OIE/WHO Technical Consultation on the Control of Avian Influenza,
Situation (human) in Thailand and Viet Nam

SITREP - WHO | Avian influenza A(H5N1) - update 17: Situation (human) in Thailand and (poultry) in China, Indonesia and Worldwide

Avian influenza A(H5N1) - update 17: Situation (human) in Thailand and (poultry) in China, Indonesia and Worldwide

4 February 2004

Situation (human) in Thailand

The Ministry of Public Health in Thailand has announced the death, on 3 February, of a previously confirmed case of H5N1 infection. This latest death was in a 6-year-old boy from Suphanburi province

To date, Thailand has reported 4 laboratory confirmed cases of H5N1 in humans. All have died.

Situation (poultry) in China

Authorities in China have confirmed suspected outbreaks of H5N1 avian inflenza in poultry at farms in an additional two provinces, Gansu and Shaanxi. To date, confirmed or suspected outbreaks of highly pathogenic H5N1 avian influenza have been reported at poultry farms in 12 of the country?s 31 provinces, autonomous regions, and municipalities.

Situation (poultry) in Indonesia

The outbreak of suspected avian influenza in poultry, previously announced by Indonesian authorities, has now been confirmed as caused by the H5N1 strain.

Situation (poultry) worldwide

Full details on poultry outbreaks are available at the OIE website.

To date, outbreaks in poultry caused by the H5N1 strain have been confirmed in the following countries (listed in order of reporting):


Republic of Korea (12 December 2003 ? first outbreak of this disease ever reported)
Viet Nam (8 January 2004 ? first outbreak of this disease ever reported)
Japan (12 January 2004 ? first outbreak of this disease since 1925)
Thailand (23 January 2004 ? first outbreak of this disease ever reported)
Cambodia (24 January 2004)
China (27 January 2004)
Laos (27 January 2004 ? H5 confirmed, testing for H5N1 under way)
Indonesia (2 February 2004 ? first outbreak of this disease ever reported)

Two other areas (Taiwan, China and Pakistan) have reported outbreaks of avian influenza in poultry. However, tests have confirmed that these outbreaks are not caused by the H5N1 strain.

In addition, authorities in Hong Kong SAR have reported H5N1 in a single peregrine falcon found dead on 19 January. In Hong Kong, monitoring of diseases in both wild and domestic birds is systematic and efficient. No other cases of H5N1 infection have been detected.

WHO Avian influenza A(H5N1) - update 17: Situation (human) in Thailand and (poultry) in China, Indonesia and Worldwide

SITREP - WHO | Avian influenza A(H5N1) - update 16: Situation in Viet Nam

Avian influenza A(H5N1) - update 16: Situation in Viet Nam

3 February 2004

The Ministry of Health in Viet Nam has today officially confirmed three additional cases, including one fatality, of avian influenza H5N1 infection in humans.

Two of the newly reported cases, a 19-year-old man and a 20-year-old woman, have been under treatment at a hospital in Hanoi. The 19-year-old man has recovered and the 20-year-old woman remains hospitalized.

The third case, which was fatal, was in an 18-year-old man who died on 2 February at a hospital in Ho Chi Minh City. He is the country?s first confirmed case from the Central Highlands area.

These newly reported cases bring the number of laboratory confirmed H5N1 cases in Viet Nam to 13. Of these, nine have died, two remain hospitalized, and two have recovered.

Authorities in Viet Nam have reported that 52 of the country?s 64 provinces have now detected outbreaks of highly pathogenic H5N1 avian influenza in poultry.

WHO Avian influenza A(H5N1) - update 16: Situation in Viet Nam

SITREP - WHO | Avian influenza A(H5N1) - update 15: Additional confirmed human case in Thailand

Avian influenza A(H5N1) - update 15: Additional confirmed human case in Thailand; China announces suspected spread of infection in poultry; investigation of possible human-to-human transmission

2 February 2004

New human case confirmed in Thailand

Health authorities in Thailand have today announced a new laboratory-confirmed case of human infection with H5N1 avian influenza. The case, a 58-year-old woman, fell ill on 19 January and died on 27 January.

This latest case brings the total of human cases in Thailand to 4, of whom 3 have died.

To date, human cases of H5N1 have been reported only in Thailand and Viet Nam. Both countries have widespread outbreaks of the disease in poultry. The new case in Thailand brings the total number of cases in these two countries to 14, of whom 11 have died.

China announces spread of suspected H5N1 infection in poultry to additional areas

WHO has been informed by Chinese authorities that outbreaks in poultry of highly pathogenic H5N1 avian influenza are suspected in additional parts of the country.

The new suspected poultry outbreaks have been detected at farms in the eastern province of Zhejiang (geese), in the southwestern province of Yunnan (chickens), in the central province of Henan (chickens), and in Xinjiang Uygar Autonomous Region (chickens) in northwestern China.

In addition, further suspected outbreaks have been reported in Hubei (chickens and ducks) and Guangdong (geese) provinces. Both provinces had previously reported outbreaks.

Samples taken from diseased birds at all these sites are now being tested in China for the presence of the H5N1 strain.

Altogether, confirmed or suspected outbreaks of highly pathogenic H5N1 avian influenza have been reported on poultry farms in 10 of China?s 31 provinces, autonomous regions, and municipalities.

The additional areas with outbreaks in poultry, announced last week, are Guangxi, Hunan, Hubei, Shanghai, Guangdong, and Anhui provinces. Of these, highly pathogenic H5N1 avian influenza has been confirmed in Guangxi, Hunan, and Hubei.

No cases of human H5N1 infection have been reported in China to date.

Investigation of possible human-to-human transmission

WHO has investigated a cluster of respiratory illness in members of a family from Thai Binh province, Viet Nam. The cluster involves a 31-year-old man, his two sisters, aged 23 and 30 years, and his 28-year-old wife. Both the man and his two sisters have died. The wife has fully recovered. Laboratory tests received over the weekend have confirmed H5N1 infection in the sisters. Neither the man nor his wife was tested.

The family members gathered in late December to prepare for the man?s wedding on 3 January. Both the man and one sister are reported to have handled ducks while preparing a meal on 4 January. However, the investigation failed to reveal any direct contact with poultry for the man?s other sister and his wife.

In the absence of evidence of direct exposure to poultry in these two cases, WHO epidemiologists are considering various alternative explanations. Both sisters are known to have provided health care for their brother, prior to his hospitalization, and would thus have had opportunities for close exposure. Direct human-to-human transmission following this close exposure is thus one possible explanation.

However, contact with an infected bird, or some other environmental source of the virus, is another possible route of infection that has not been ruled out. Outbreaks of H5N1 in poultry are widespread in Viet Nam. Large amounts of the virus are excreted in bird droppings, and can survive for some time in the environment.

Limited human-to-human transmission of a highly pathogenic avian influenza virus is not entirely unexpected, as this has been documented to have occurred on two occasions in the recent past (in Hong Kong in 1997 and in the Netherlands in 2003).

Local authorities report that no other family members or wedding guests developed an illness. No illness has been detected in members of the community where the wedding was held, or in health staff involved in care of these cases.

WHO stresses the need to continue to investigate each human case of H5N1 in order to identify the source of infection.

WHO Avian influenza A(H5N1) - update 15: Additional confirmed human case in Thailand; China announces suspected spread of infection in poultry; investigation of possible human-to-human transmission

SITREP - WHO | Avian influenza A(H5N1) - update 14: Two additional human cases of H5N1 infection

Avian influenza A(H5N1) - update 14: Two additional human cases of H5N1 infection laboratory confirmed in Viet Nam,
Investigation of a family cluster

1 February 2004

Two additional human cases of H5N1 infection laboratory confirmed in Viet Nam

Laboratory tests have confirmed an additional 2 cases of human infection with H5N1 avian influenza in Viet Nam. Both have died.

The two deaths announced today were in sisters, aged 23 and 30 years. Both women fell ill on 10 January, were admitted to hospital on 13 January, and died on 23 January. The results from initial local testing of these two cases were inconclusive. Today?s official confirmation follows more extensive testing at a WHO influenza reference laboratory in Hong Kong.

Altogether, 10 cases of human infection with H5N1 avian influenza have been confirmed in Viet Nam. Of these 10 cases, 8 have died, one has recovered and one remains in hospital.

Investigation of a family cluster

The two sisters who died are part of a cluster of four cases of severe respiratory illness in a family from Thai Binh province. The cluster includes the two sisters, their brother, and his wife, who has fully recovered. The brother was hospitalized in Hanoi with a severe respiratory illness on 7 January and died on 12 January. No samples were available for testing.

A detailed investigation of this cluster has been undertaken by WHO, Viet Nam?s National Institute of Hygiene and Epidemiology, and local health officials.

To date, the investigation has not been able to conclusively identify the source of infection for the two sisters. With the exception of this family cluster, all human cases in the Viet Nam outbreak have been linked to contact with infected poultry.

In Hong Kong in 1997, extensive studies, using both molecular and epidemiological data, eventually linked all 18 cases of human H5N1 infection to contact with live infected poultry.

In addition to these 18 cases, WHO notes that laboratory evidence indicated very limited human-to-human transmission during the H5N1 outbreak in Hong Kong, and during a 2003 outbreak of highly pathogenic H7N7 avian influenza in the Netherlands. However, no cases of severe disease in humans occurred as a result of this very limited secondary transmission.

In the current family cluster of cases in Viet Nam, WHO considers that limited human-to-human transmission, from the brother to his sisters, is one possible explanation. The investigation failed to reveal a specific event, such as contact with infected poultry or an environmental source, that might explain the source of infection in these cases. However, as H5N1 infection in poultry is widespread in Viet Nam, direct transmission from poultry to humans cannot be entirely ruled out on the basis of available evidence.

At present, no evidence indicates that efficient human-to-human transmission is occurring in Viet Nam or elsewhere. WHO and health authorities in Viet Nam and globally are continuing to assess the outbreak in terms of its epidemiological evolution. Human cases are being investigated to identify the source of infection, and evidence to date is reassuring.

WHO teams are supporting national investigations in Viet Nam and Thailand, and will arrive soon in other countries that have requested such support.

WHO Avian influenza A(H5N1) - update 14: Two additional human cases of H5N1 infection laboratory confirmed in Viet Nam,
Investigation of a family cluster