Frequently Asked Questions About H5N1 Influenza
What is Avian Influenza?
It is called avian influenza because the infection is caused by birds [avian] and the virus is an influenza virus passed by birds to birds for the most part in a virulent manner. Wild, feral birds are known to host these viruses in their intestinal tract and are well able to do so without getting ill. The flu virus is much more infectious in domestic bird flocks such as ducks, chickens and turkeys. These domicile avian species become ill from the excrement and secretions that contaminate surfaces from these wild and infected birds.
The avian viruses are divided into two groups, High contagion and low contagion. The majority of avian viruses fall under the low Contagion [or low Pathogenicity] Avian Influenza [LPAI] group, developing mild infections in the diseased birds. Birds will commonly present with disheveled plumage, loss of appetite, a reduced egg production, sneezing, and coughing. Often this class of pathogen will go undiagnosed.
High contagion [or high Pathogenicity] Avian Influenza [HPAI] presents with more harsh symptoms that comprise sudden death, no interest in food and low energy, reduction in egg laying, facial swelling, malformed eggs and diarrhea. The fatality rate for HPAI can be as high as one hundred percent.
What is the H5N1 variation of avian influenza?
Every flu virus falls under one of Influenza A, B, or C based on their structural makeup. Type A is the virus variety that is the cause of fatal pandemics and can infect both humans and animals. The B variety is responsible for local outbreaks of influenza infections. The C type is the one virus version that seems to be the steadiest of all three, displaying just mild symptoms in infected humans. Varieties B and C are normally discovered in humans. Both of types B and C appear more stable than Type A and do not get grouped on the basis of subtypes.
Type A influenza viruses are separated into sub units and are named based on surface proteins Hemagglutinin [HA] and Neuraminidase [NA]. There are in existence sixteen varieties of HA and nine variations of NA which means a full 144 combinations are potentially likely.
Therefore, the H5N1 is a type A virus and its name is derived from HA 5 protein and NA 1 protein found on its outer membrane surface.
How Do Type A Viruses Cause A Pandemic?
Influenza Type A viruses are sub categorized into strains. The strains are constantly evolving into other strains. They possess a unique ability to trade genetic substance with other viruses to fashion novel viruses that make them volatile and tough to defend against. People are required to build up a different immunity [or antibodies] whenever a novel strain appears active.
Viruses are not able to restore the genetic harm done in the trade process, hence a process known as Antigen drift takes effect casing newer strains of virus through small alterations. In the event that this genetic substance from two species such as birds and human Influenza A in come together and mix, a totally new strain is produced. The process is referred to as antigen shift to which humans have no immunity, this results in quickened transmissibility and a serious pandemic can develop.
How Does The Virus Go to Humans From Birds?
Avian influenza viruses are not normally a threat to humans. Birds in migration are responsible for carrying the viruses but remain unaffected by them. These migratory birds then make contact with the domicile variety like poultry stocks and ducks thus transmitting an infection into them. The domestic avian populations can also become infected when they are exposed to tainted surfaces as well. When the virus lodges in these domestic bird populations it can become the foundation for a severe epidemic within those avian populations it infects. Humans contract the illness when they are exposed to these infected birds and their virus or if they come in contact with impure feces ridden areas of avian activity.
When the virus reaches the human host it begins the transformation of antigenic shift, mixing with the genetic substance of the human influenza form producing some unique variation strain of virus that unfortunately humans have no way of combating naturally since they don’t have an immunity to it. These genetic shifts can also happen in a third party species when they are susceptible to each of the bird and human viruses, for example the pig. When a human influenza virus and an avian flu virus meet, their genetic imprint comingle thus producing a new virus that has the potential of infecting people.
What Makes The H5N1 Virus So Harmful?
In 1997, the first cases of H5N1 influenza were noticed in Geese in China’s southern area. Combined, there were infections documented in eighteen people, six of those people became fatalities. From here the disease rapidly moved into Hong Kong, infecting poultry which led to the culling of a million and a half chickens in order to seize the advantage from the H5N1 virus. There was no sign of the virus for several more years when it once again reared up in 2002, once again plaguing Hong Kong. From then until now it has been responsible for killing millions of domestic birds in Asia and human infections have now been recorded.
The specific strain of H5N1 virus has been particularly virulent and the apprehension for human populations is growing. Currently it is no simple feat for a person to become infected with the virus, but those who become infected face a severe battle with the illness. Fifty percent of those humans infected have become fatalities and this number is worrisome to say the least. Everyone who succumbed to the illness was previously in robust health having never been previously infected. What is now more disconcerting to world health officials is the prospect of H5N1 virus mutating via antigenic shift which could produce a form of the virus that is deadly because of human to human exposure. If this were to happen the result could be a pandemic globally that could result in the human mortality rate soaring.
Is It Still Safe To Eat Poultry?
Yes it is quite safe to eat your favorite bird dish provided it is PREPARED WELL AND COOKED THOROUGHLY. H5N1 virus is susceptible to heat and is killed by heat sources of 70° – 100° Celsius, normal cooking heat. It is imperative that none of the poultry meat you eat is uncooked or raw and that goes for eggs as well. Remember to cook your birds well.
What Are The Chances Of A Pandemic Occurring?
On three occasions in the last century the world has been under siege by a bird flu pandemic. The Spanish influenza of 1918 to 1919 killed millions and estimates have been as high as 100 million but probably closer to half that. During that pandemic the United States recorded half a million fatalities. There was the Asian influenza pandemic of 1957 to 1958 which claimed seventy thousand people in the U.S. at the time. The Hong Kong influenza of 1968 to 1969 contributed thirty four thousand deaths.
The odds are high that there will be a pandemic of H5N1 influenza because the attempts to control the rapidly spreading virus have been unsuccessful. Human raised ducks are known to be a haven for the virus, acting as unwitting hosts of the bug without any indications of illness. The virus laden birds then release enormous amounts of the contagion through their fluids and excrement transmitting the virus to other vulnerable birds or humans. Virus detection in outback locations in various nations make it tricky to control the spread.
Health officials have stated that the virus is now meeting two of three conditions for a pandemic to be called. It has begun infecting humans who are susceptible because no immunity exists and also it is contagious and it is sufficiently virulent to make humans seriously ill and cause death.
The only factor keeping the H5N1 virus at non pandemic levels is that it has yet to go through a genetic exchange or antigenic shift causing it to mutate into a more transmittable virus spreading human to human more easily. If this occurs the infection rate for humans will skyrocket bringing about a pandemic condition level globally in quick succession. The world’s first warning that this mutation has occurred will be grouped infections of patients presenting influenza signs that are near in timing and location. This makes it clear that the strain has the power to spread person to person.
Right now there is not a vaccine available to fight a strain of H5N1 bird flu that is infecting humans. Experts are working concurrently in most countries trying to produce a vaccine. S of spring 2008 the WHO was still pressing to launch a worldwide stockpiling of an effective vaccine with some success. Producing enough vaccine for global markets is difficult and so many manufacturers are stepping up research and testing but the demand is high. Maximizing the available vaccine via testing dose efficiency is also being undertaken.
What can Be one To Avert A Pandemic?
It would seem obvious that the disease must be controlled while still transmitting among the avian population. Not an easy task given that bird infections have reached epidemic levels in many Asian nations and it is spreading rapidly.
Health experts know that they need to keep the disease from infecting the human population. Individuals such as poultry workers who are contact with domestic bird populations are instructed to continuously observe the birds for indications of illness and contact the health system officials of ANY sign of infection in their birds and also restrict any exposure to ill birds at all cost. Ducks in particular have become highly infectious carriers of the disease without showing any illness.
In the event of a pandemic the entire world becomes at risk and certain best practices of prevention become important like personal cleanliness. You should also avoid crowds and populace locations and avoid raw eggs and poultry.
Getting a seasonal influenza injection won’t aid in fighting H5N1 but it will keep you healthy from other flu viruses and aid in avoiding further health situations that could complicate H5N1. All high risk groups such as first responders for health care, the elderly, children, chronic respiratory patients, those who must travel to infected countries, those with lowered immune systems and pregnant women should seek an appointment with their physician regarding a vaccine injection.
Are there Treatments available For H5N1 Flu And What are the symptoms?
The same symptoms will present with H5N1 as you would normally have with seasonal influenza. relentless coughing, body aches, sneezing, sore throat and hyperthermia. There is concern of complications like pneumonia, bronchitis, ear and eye infection and upper and lower respiratory problems. There are currently two drugs available, antivirals, which will aid in combating influenza. Oseltamivir or Tamiflu and Zanamivir or Relenza. These two medications can decrease the harshness of the infection and the length of time one is ill. They could prove to be ineffectual if the virus remains in the system for an extended period. The use of Tamiflu – Oseltamivir needs to be administered within a forty eight hour window from the onset of symptoms.
Both Oseltamivir /tamiflu and Zanamivir/ Relenza are in a class of antivirals called Neuraminidase inhibitors and they attack and block the surface proteins of the virus inhibiting or stopping the reproduction of the virus cell to cell. This blocking action halts the virus and patients recuperate.
There is another drug type available known as M2 inhibitors but the viruses have proven able to build a resistance to these medications making them ineffective at halting viral spread. Amantadine and Rimantadine are the names of the drugs. The stopping action of the meds works on the M2 proteins ability to multiply. The M2 inhibitors have been disappointing in their lack of wherewithal when fighting certain viruses but The oseltamivir-tamiflu and zanamivir-relenza medications are still potent in their attack. The drugs act as a treatment or as a prophylaxis in people who have been exposed to illness but are not presenting.
These drugs are currently stockpiled by many countries and require a prescription for use. You should consult a primary physician before taking Tamiflu or relenza since they have shown adverse reactions in some patients i.e. Relenza is an inhaled medication and those with asthma or other breathing ailments have displayed problems.