First Person-to-Person Avian Flu Transmission Confirmed
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BANGKOK, Thailand, January 31, 2005 (ENS) - The first documented case of human-to-human transmission of bird flu occurred in Thailand last September, Thai, U.S. and international health officials are saying.
The confirmation, which came last week in the form of a report in the "New England Journal of Medicine," prompted the Influenza Foundation of Thailand (IFT) to call for more information from the Thai government on the possibility that the bird flu virus could mutate and spread quickly from human to human, setting off a global pandemic.
IFT president Dr. Prasert Thongcharoen said, "The government should not shrink from the message that bird flu can mutate and change into a form that may transmit to humans so everyone will realize the gravity of the situation and come up with better ways to protect themselves without panicking."
In late 2003 and early 2004, a strain of avian flu known as H5N1 infected birds across 11 southeast Asian countries. Approximately 100 million birds died or were destroyed after becoming infected or exposed to the virus.
At least 44 people in eight countries sickened with the H5N1 bird flu, and 32 of them died. One of those who lost her life was an 11 year old Thai girl, Sakuntala Prepasee.
Health scientists say she most likely picked up the virus from exposure to infected chickens.
But the girl's mother, who came from another province to care for her sick daughter in the hospital, had no exposure to chickens. The mother spent less than 24 hours with Prepasee, but became ill herself four days later and died 12 days after her daughter.
Prepasee's aunt, with whom she lived, sickened after handling infected chickens with plastic bags on her hands, but did not become ill until a week after the incubation period for the disease had passed. During that week, she touched no chickens, but cared for her sick niece in the hospital.
Researchers say she probably contracted the flu from her niece. She survived the illness.
Writing in the current issue of the "New England Journal of Medicine," the team from Thai Ministry of Public Health in Nonthaburi, led by Dr. Kumnuan Ungchusak, said, "We believe that the most likely explanation for the family clustering of these three cases of avian influenza is that the virus was transmitted directly from the infected patient to her mother and to her aunt."
"Autopsy tissue from the mother and nasopharyngeal and throat swabs from the aunt were positive for influenza A H5N1," wrote Dr. Ungchusak.
"Disease in the mother and aunt probably resulted from person-to-person transmission," the team found. "It was reassuring that no further transmission of the virus has been detected."
When these deaths were first reported, the U.S. Centers for Disease Control and Prevention called the Thai family cluster "one isolated instance of probable limited human-to-human transmission occurring in Thailand in September."
World Heath Organization (WHO) officials downplayed the human-to-human risk, calling them one of a very few "inefficient, unsustained, dead-end-street" transmissions between humans.
But a few months later, the WHO assessment was different. In November 2004 the UN health organization stated, "Although the number of human cases of H5N1 is so far comparatively few, there is a sustained threat that the outbreak in poultry will evolve into an influenza pandemic, with considerable loss of human life."
At a meeting in Bangkok, Thailand in November called by the World Health Organization, health ministers and senior health officials from the 10 Southeast Asian countries plus China, Japan and the Republic of Korea were told that the threat of a pandemic was now greater than at any time in recent years
"We believe a pandemic is highly likely - unless intensified international efforts are made to take control of the situation," said Dr. Shigeru Omi, Regional Director of WHO's Western Pacific Region, which has taken the brunt of the outbreak.
Dr. Klaus Stohr, head of WHO's Geneva based Global Influenza Programme, has warned that up to about seven million people may die in an influenza pandemic.
"There is no doubt there will be another pandemic," Stohr said in December. "Even with the most optimistic scenario, the pandemic will cause a public health emergency with estimates which will put the number of deaths in the range of two and seven million.”
The H5N1 strain of avian flu is spreading across Asia once again this winter.
A 13 year old girl has died from bird flu, becoming Vietnam's eleventh victim of the disease in the past month, a doctor said Saturday after concerned Thai and UN experts met in the country for talks on the outbreak.
During the period January 1 to 28, avian influenza has been confirmed in 30 Vietnamese provinces and cities and more than 897,000 birds have died or have been culled.
On January 17, Vietnamese Prime Minister Phan Van Khai sent an urgent message to concerned ministries, sectors and provinces calling for "drastic" measures.
In his message, the Prime Minister says that bird flu is returning, particularly in the Mekong Delta and southern provinces, and tends to spread quickly; ministries must consider the fight against the outbreak as their "key and immediate mission" to ensure the health and safety of the public and food supplies during Lunar New Year.
Imports of poultry and poultry products from neighboring countries are temporarily suspended, with any detected consignments to be seized at the border and destroyed. The owners will not receive any compensation but will be requested to pay for the cost of culling birds.
The Ho Chi Minh City Police Department has deployed its forces to cooperate with the animal health bureau and market monitoring staff to check the trading at markets and, especially, the transport of fowl at gateways to the city. In Danang City, trade in live fowl at major markets is banned.
Up to December 29, 2004, the World Health Organization reported 27 human cases of bird flu in Vietnam, with 20 fatalities. This number increased by January 26, 2005, when a further 10 patients were confirmed as infected. Of these, nine have died.
Having lunar New Year on February 9, movement of poultry and poultry products will increase in the region, UN officials warn.
The need for biosecurity of domestic poultry to prevent infection and enhanced early warning in order to detect every additional case are highest during this season to avoid new cases of highly pathogenic avian influenza in poultry and to minimize the risk to humans.
Copyright Environment News Service (ENS) 2005. |
