Dr. Nortey Omaboe, Geneva Veterinarian Answers Questions – Avian Flu Outbreaks
Bird Flu Strikes Again…Leaving Birds and Humans Literal Sitting Ducks
Heard any news about the bird flu lately? Assuming that no news is good news? Well, don’t count your pandemics before they’re hatched. I’ve been asked about the bird flu a lot lately, and as it turns out, it’s been out and about, and has reared its hideous head in the province of Thai Nguyen in Northern Vietnam, among others.
Ailing chickens plucked from a farmstead in the Luong Son commune have proven to be infected with strain H5N1 of the avian flu. Over 100 of the family’s chickens, on that same property, were lost to the flu prior to intervention, as testing of the carcasses confirmed. This outbreak, recognized on December 28, 2008, is the second outbreak of this strain in the province within the calendar year. In the same province of Thai Nguyen, a chicken and some ducks on a separate farm “mysteriously” perished from what has since been determined to be the same strain of avian flu.
As a result of this most recent outbreak, 4,000 chickens and 100 ducks have been seized by Vietnamese veterinary officials. The lives of 4,200 chickens have been sacrificed in an effort to impede the proliferation of this fast-spreading, and deadly, disease. The Department of Animal Health has speculated that the latest outbreak could be due to illegally imported animals. Smuggling from China into North Vietnam generally spikes in preparation for the New Year celebration, as does handling and consumption of potentially infected animals.
This Flu’s Sordid History
We might all remember the 1997 outbreak of the avian flu in Hong Kong. No human cases were reported in Hong Kong that year, but the months of December through March of subsequent years brought additional poultry outbreaks, despite the yearly culling of all Hong Kong poultry. The first Hong Kong dual family member death occurred in 2003. Three family members were infected, while two died.
Also in 2003, the bird flu presented itself in South Korea, Northern Vietnam, Japan, and Indonesia. Vietnam and Thailand bore human infections, with a 70% fatality rate. Family infections were common among the case numbers, indicating a high rate of human-to-human transmission. Later, in 2005, Indonesia, China, and Cambodia, followed with human cases. Also that year, the virus was found in migratory waterfowl in China, as well as in the excrement left behind. Following this discovery, the virus was isolated in the regions of Volga Delta, Danube Delta, the Crimean Peninsula, and Nile Delta, indicating migratory birds’ ability to transport the virus to touchdown points. By the end of 2005, human deaths in Turkey were reported. But maybe more importantly, those victims in Turkey did not test positive for the H5N1 virus until near death’s door – an indicator that the virus was developing a sub-strain.
In 2007, Egypt was revisited by the avian flu, while a sub-strain was discovered in Europe, western Africa, and Pakistan. Birds were infected by this newer strain, while human-to-human transmission in Pakistan was the longest lived on record.
2008 brought with it Myanmar and Bangladesh human cases, and Indian and South Korean poultry onslaughts.
A large number of poultry deaths in India in 2008 have pointed officials toward a possible human outbreak in that country, but nothing can be determined until cases surface. Officials in Dimapur have imposed a ban on the sale of all poultry products (meat and eggs) and are currently seizing any illegally traded items.
Since 2003, 391 human avian flu infections have been quantified, worldwide. Of those cases, 247 people have perished, according to the World Health Organization. 106 of those infections (and 52 deaths) took place in Vietnam, second in severity only to Indonesia (113 confirmed deaths).
In early 2008, 5 people died in Northern Vietnam, out of 6 confirmed H5N1 cases. Veterinary authorities in Northern Vietnam fear a rerun, or an exaggerated sequel, in early 2009, mostly due to the fact that this strain of avian flu takes a liking to the upcoming cooler, wetter climate. The country’s health ministry has donned a bird flu alert, appealing to citizens for tighter disease control measures.
The Bird Flu’s Suspiciously Changing Face
Though the numbers remain devastating, the human deaths attributed to the H5N1 strain of the avian flu have supposedly decreased over the past few years. In 2006, 79 deaths were recorded, followed by 59 in 2007, and 30 in 2008, according to the World Health Organization. Indonesia, Vietnam, China, and Egypt were home to all of the 2008 deaths, and no significant family clusters of infection were discovered.
During the period of 2005 – 2007, the largest percentage of family unit deaths were reported. That means that transmission from person-to-person was highest in that time period.
Though heartening at first glance, the reduction in human bird flu deaths could be equivalent to a “false negative.” Indonesia’s first place death numbers are likely more catastrophic than recorded. Some experts question the country’s admittance of H5N1 human deaths over past years, which is only somewhat confirmed by the country’s unwillingness to report any cases during the year of 2008. Lab-confirmed test results have been rebuffed by Indonesia. Tamiflu is administered as treatment for infection, which may reduce fatalities, but should not affect the reporting of non-fatal infections. An unnamed “respiratory disease” is blamed for a number of deaths, many of which occurred within family units (this lack of reporting could explain the seeming “decline” in family cluster cases). Likewise, Indonesia has not actively reported on poultry infection numbers since 2006.
Though numbers on paper are brighter than they were years ago, consider this: Human deaths have scarred the faces of 15 countries, including deadly infections by H5N1 and its two sub-clades (strains). Birds are now migrating…temperatures are dropping. Though the virus has been a concern for 12 years, its grip has tightened and expanded over the past 5 years…in global and biological terms.
India does not currently vaccinate against the H5N1 virus, and in turn is now experiencing a rapidly rising number of poultry infections. China does vaccinate its poultry, but its use of the H5N2 vaccine is not effective against H5N1.
In 2007, the United States approved an H5N1 vaccine for humans. It will, however, not be distributed to the general public. It will be kept in stockpile, in the case of a pandemic (person-to-person transmission on a large scale).
The Flu’s Most Current Long Arm
Health officers in India have not only culled over 421,000 chickens in Assam and West Bengal, but have incited a campaign to cull the Indian public’s relative unawareness of the problem. Through television, radio, and open public declarations, officials are educating Indian villagers in the transmission of the avian flu, while spearheading clean-up operations.
As of December 29, 2008, several chickens had already been burned and buried in the area of Cibuntu, Indonesia. Chicken deaths have not yet been confirmed as caused by H5N1, but the Indonesian public has been caught in a panic, destroying poultry for fear of a repeated outbreak.
In Indonesia, in the area of Giriwoyo, dozens of chickens have been found dead. As of December 29, 2008, villagers reported a number of dead chickens in excess of 50. More disconcerting to authorities is the discovery that villagers have been disposing of the possibly infected carcasses into the river and littering them throughout residential areas. Those same authorities have now embarked upon a mission to educate residents in a proper disposal method (burning).
Additionally, in Indonesia…Susukan’s village of Pare…all poultry has been required to be turned in. Any poultry that is not surrendered will be destroyed by Pare villagers. The Hamlet of Susukan holds a previous record of 158 H5N1 chicken deaths, spread over 32 farmsteads.
Two Egyptian children have recently lost their lives to H5N1, and one teenager was found to be infected in Cambodia. That teenager has survived.
150 villages in Assam have given up 510,000 fowl in an effort to control the confirmed presence of H5N1. More recently (December 2008), 15 previously unaffected villages had been added to the list.
An Infectious Story…of Avian Flu, Birds, and Humans
When speaking of transmission of the avian flu from birds to humans, the first concern is, obviously, the transmission itself. The second is the ability of the virus to change form and become transmissible from human to human. When this happens, the chance of widespread human infection is multiplied...along with the possibility of a pandemic.
Contraction of bird flu cannot be accomplished through the eating of appropriately prepared poultry meat or eggs. Meat should be cooked to 165 degrees F, and eggs should be cooked until whites are firm. All surfaces that have been contacted by raw meat or eggs should be disinfected with soap and hot water or bleach. Raw poultry or eggs should not be permitted to come in contact with other food items. And, washing of hands with hot water and soap prior to, and following, the handling of raw eggs and poultry should never be skipped.
There is currently a ban in effect that prevents poultry products from being imported to the United States from regions where avian flu has been discovered, including birds, hatching eggs, and untreated feather and down products.
Human infection is most commonly caused by close contact with infected birds (alive or dead), and contact with that bird’s bodily excretions, especially excrement.
Travel to bird-flu-notorious countries is not currently restricted, but it is recommended that travelers steer clear of contact with birds, bird excrement, and bird products while in those countries.
Cleaning or filling wild bird feeders in the United States has not proven to cause any human bird flu cases. Most instances of infection in wild birds have been found in water fowl and seashore dwellers. The flu has been isolated in wild sparrows and finches, but transmission to humans in the United States has not been documented.
The avian flu has been known to be transmitted to martens, ferrets, cats, tigers, leopards, and pigs. Tiger and leopard deaths are believed to be results of the consumption of raw, infected chicken carcasses, along with cat-to-cat transmission. Domestic cats are not generally vulnerable to influenza A, but can contract H5N1, and transmit it to other cats. Most cat infection cases are believed to be contracted through the cats’ consumption of wild infected birds, or domestic infected chickens.
p.s. As a doctor of veterinary medicine, I can grasp the weight of what a disease such as bird flu could do to the human race. I also believe that education is the single most important factor in the prevention of what some say is a looming avian flu pandemic. Informing the public of proper handling procedures, enforcing bans on the importation of potentially infected birds, isolating the virus when discovered, and reporting infection occurrences will all contribute to the control of its spread.
p.p.s. It is important to understand that birds do not display flu symptoms before dying. The CDC should be contacted if dead birds (domestic or wild) are found, so that testing can be conducted.
p.p.p.s. By taking precautions when traveling, reporting dead birds, and following proper procedures when preparing poultry and fowl products for consumption, we can all help to keep the bird flu at bay…because a bird in hand is worth nothing if it makes you a sitting duck.