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Southeast Asia Avian Flu Outbreak 2003 -2004
Southeast Asia Avian Flu Outbreak 2003 –2004
The Avian Flu outbreak of Hong Kong in 1997 made international news about its potential to lead to a global influenza pandemic in humans. It was during this time that the Avian Flu Virus subtype H5N1 crossed the species barrier to infect humans. As a result, eighteen people were hospitalized with severe respiratory failure associated with the influenza virus, of which, six people tragically died. To control the spread of infection, Hong Kong authorities ordered the cull of all chickens on the island. In total, approximately 1.5-million birds that also included geese, ducks, pigeons, and quails were slaughtered, which ultimately led to effective control of the outbreak.
Avian Flu was thought to be under control following the Hong Kong incident, that is, until 2003 and 2004, where the disease reemerged to threaten many Asian countries. In late 2003, South Korea reported the presence of Avian Flu virus and ordered the cull of millions of domestic poultry to prevent any episode reminiscent of Hong Kong. However, the devastation brought upon by Avian Flu was felt most in Southeast Asia, particularly the nations of Vietnam and Thailand.
Although Vietnam did not report the presence of Avian Flu until January 2004, recent evidence shows that the virus may have affected the country as early as July 2003. It was during this time, where the first signs of an epidemic reared its head in Tam Duong district in Northern Vietnam. A poultry company, Giapfa Comfeed Vietnam Ltd. reported that 20,000 of its chickens had died with symptoms correlating with avian flu. The company sent blood samples to Vietnam’s Ministry of Agriculture and Rural Development, whose tests revealed inconclusive evidence.
At the time, Vietnam was preparing actively for the 22nd Southeast Asian Games and government officials did not announce the news since they believed they could contain and control the mysterious disease. Vietnam did not report the poultry mortalities to the World Office of Animal Health (WOAH). Reporting to the WOAH is strictly voluntary – although it acts as a double-edged sword. On one hand, reporting diseases is a critical step to controlling disease outbreaks, on the other hand, it will usually mean exporting embargos will be placed on those countries, which often results in dire political and economic consequences, more so for a developing country like Vietnam.
By December 2003, more birds continued to die in Vietnam and then the first cases of humans coming down with avian flu became evident. During this time, doctors at the National Institute of Pediatrics and Epidemiology in Hanoi, Vietnam contacted Dr. Timothy Uyeki, a leading influenza expert for the Atlanta-based Center for Disease Control (CDC). In a private and informal email, virologists working at the Institute had asked for his advice about a mysterious virus that was causing severe respiratory symptoms in several young children from all over Vietnam at a pediatric hospital in Hanoi.
Dr. Uyeki urged the virologist to test for Human Influenza virus. He received several more messages the following days informing him that one of the affected patients, a young child, had died due to the disease. At the time, there were growing rumors circulating among influenza scientists about mass chicken deaths in Vietnam, Thailand, and elsewhere. Dr. Uyeki then sent the virologist specialized tests that would detect all kinds of Type A Influenza viruses – including Avian Flu. A few days later, the virologist found that the diseased child had the notorious H5N1 Avian Flu virus, the same that had caused deaths in Hong Kong a few years back.
By early January 2004, more than 1 million birds had died due to disease, and at least another 800,000 have been slaughtered as a precaution. Twelve patients had also been admitted to hospitals with severe influenza-like symptoms. On January 8th, Vietnam announced the presence of Avian Flu in its poultry. It was confirmed that 14 people had the H5N1 Flu virus circulating in their bodies. In ensuing days, twelve of the fourteen affected patients had tragically died from the disease – 11 children and 1 adult.
The high mortality rate that the virus had suggested that it was more pathogenic than when it occurred in Hong Kong (6 dead from 18 infected). Scientists speculated that the appearance of avian flu in July, and the apparent Vietnamese cover-up, would mean that this virus has had months to roll through the chicken population, possibly mutating and becoming more pathogenic over time. Anton Rychener, a United Nations Food and Agriculture Organization representative in Vietnam, confirmed that ministry officials told him there had been previous outbreaks, although ministry officials denied his assertions.
In Thailand, a disturbingly similar trend was occurring on par with Vietnam. In 2003, farmers in the Bangkok region had complained about a plague affecting their chickens. Despite this, Thai officials repeatedly denied a bird flu outbreak in their country chickens instead attributing the widespread death of chickens over the last two months to fowl cholera, which poses little danger to humans.
The Thai government, however, began to seriously investigate the problem after people began being admitted to the hospital with symptoms associated with the bird flu. Two children were tested to determine the presence of Avian Flu virus – and the results showed that indeed, the disease among both poultry and people were caused by the infamous H5N1 Avian Flu virus. In late January, Thailand announced the presence of Avian Flu within its borders.
The situation appeared to worsen as other countries reported the presence of the H5N1 virus. These countries were China, Laos, Cambodia, Indonesia, and Japan, but all human tolls took place in Vietnam and Thailand. By March, twelve confirmed human cases of avian influenza A (H5N1) were reported in Thailand and twenty-three in Vietnam, resulting in a total of twenty-three deaths.
With strategic international efforts, the outbreak of the disease was widely believed to be contained in March with the culling of over 100-million birds in these countries. Most of the infected people had contracted the disease by being in close contact with infected birds either on the farm, processing plants, or wholesale markets. By the end of March, no cases of humans affected with the avian flu were reported.
The optimism was short lived as Avian Flu reappeared in the summer of 2004. Beginning in late June 2004, new lethal outbreaks of H5N1 among poultry were reported by several countries in Asia: Cambodia, China, Indonesia, Thailand, Vietnam, and for the first time, Malaysia. An 18 year-old man in Thailand died from the bird flu in early September, the first human casualty in that country since the disease re-emerged in Asia. The man raised fighting cocks, and routinely sucked blood and other fluids from the mouths of his birds when they were injured in a fight. This was regarded as the probable route of virus entry.
At the end of September, another Avian flu case was reported in Thailand. This case generated much interest among health organizations, as it may have been the first reported case of human-to-human transmission of Avian Flu. The person, a woman, was one of four members of an extended family who appear to have contracted the H5N1 avian influenza virus. At least two of them had contact with dead chickens, the usual source of the rare infection, but the 26-year-old victim had contact only with an ill child, not any birds, according to a World Health Organization (WHO) report. The WHO was also quick to indicate that this could be just an isolated case.
Not limited to just humans, the H5N1 Avian Flu virus has also been detected in domestic and wild cats, and pigs. An eastern Thailand zoo was devastated by the Avian Flu when more than 20 tigers died. Workers believe that the tigers became infected when they were fed infected chicken carcasses. However, it has since been shown that the Avian flu virus is transmittable from cat to cat, which no avian flu has been before.
The avian influenza A (H5N1) epizootic outbreak in Asia is not expected to diminish significantly in the short term. It is likely that H5N1 infection among birds has become endemic to the region and that human infections will continue to occur. The presence of the H5N1 virus in other mammals, particularly pigs, is particularly troubling. The reason being that pigs can harbor both avian and human influenza viruses. These animals may prove to be ‘mixing vessels’ where both strains of viruses can interact and exchange genetic information with one another. This could result in antigenic shift of the flu virus, transforming it into a new form of flu virus that can be more easily transmittable from humans to humans.
A new form of virus, one which no human has been exposed to, can cause catastrophe – a global pandemic. Experts from the Center of Disease Control and World Health Organization are not opportunistic about the prospect of containing such an event. These experts consider it a matter of timing - when will it occur. Such a global epidemic has been speculated to affect as little as 7-million people worldwide to over a 100-million people. These experts often refer to the Global Spanish Flu Pandemic that killed approximately 50-million people in 1917-18. That flu virus was believed to evolve from both Avian and Human Flu viruses.