Dr. Khin Maung Lwin - Avian influenza, a disease that can be dangerous to humans

Chapter (1)

Background of avian influenza

Although it is easy to understand and call it bird flu, this disease is not just a disease of chickens. If it only affects chickens and the chickens die, this disease will not become a widespread and terrifying disease in the world. Now, bird flu is not only a disease of chickens, but also of humans, so it is fully translated as human-to-human avian flu. The reason why it has spread to humans is that it has spread from chickens. What makes it even more widespread is that not only chickens infect people, but also animals such as tigers, cats, and leopards have been infected with bird flu and died. When we look at how bird flu spreads to chickens, we see that it is transmitted from wild birds and wild birds. In the case of wild birds, waterfowl are the main carriers of this disease and infect chickens. Because of this spread, waterfowl can infect chickens, infect other birds, and eagles can also be infected and die.

The latest death of a parrot was reported in London, England. The spread of bird flu in animals is not a new disease. Historically, there is evidence that bird flu has been around for 300 years. In 1918, a bird flu epidemic spread to humans in Europe, killing many people. The common bird flu is not easily transmitted to humans. Chicken flu is more difficult to spread to humans. It is spread by people who have handled or come into contact with infected chickens, or by people who have been around infected chickens, sitting or touching them. This infection is not easily transmitted, so it can only spread to a small number of people. Chicken flu is caused by a virus. However, the bird flu virus mutates in the human body and is able to spread from person to person, so if a new strain of the virus were to emerge during human life, it could infect many people in a short period of time. This is also why the 1918 Spanish flu pandemic killed an estimated 20 to 40 million people, but the historical record of World War I shows that the death toll from bird flu was not as significant.

During that time, there was little communication and travel, and only 20 to 40 million people died. The nature of epidemics is that when people first start to spread, they don't have immunity, so they spread quickly and spread in large numbers. This means that as the epidemic progresses, the rate of transmission of the virus decreases. People also become more resistant, so the epidemic gradually becomes limited. Gradually, the speed decreases and people become more resistant, and the epidemic becomes less and less. However, on average, experts estimate that a pandemic, especially a flu pandemic, occurs once every 25 to 32 years. The last recorded case of avian flu mutating into human flu was in 1957. At that time, it was not in Europe, but in Asia. The Asian flu, which originated in Asia, killed about 4 million people after it spread to Europe. Another pandemic was the bird flu outbreak in Hong Kong in 1968, which killed 4 million people. In the case of bird flu, the virus is the same every time, but the structure and structure of the virus are different. The Hong Kong bird flu outbreak in 1968 spread to many countries around the world. In this global pandemic, not only chickens but also other animals were infected with the virus, which then spread to humans. Transmission from pigs was observed in New Jersey in 1967. This suggests that humans and pigs are similar in their ability to receive the bird flu virus. Humans also have human flu. If the human flu virus had entered the body of a person (or pig) infected with bird flu, the bird flu virus and the human flu virus would have combined to create a new virus that could spread from person to person, causing a pandemic that killed millions of people. Such events have also been seen to spread the disease, and some bird flu viruses infect only a few people and are not transmitted from person to person, so there are also situations where a large pandemic does not occur and a few people die and the epidemic stops.

In 1997, a bird flu outbreak occurred in Hong Kong. Millions of chickens and ducks died. However, only six people were recorded to have died. So it is safe to say that there was no human-to-human transmission of the flu at that time. The timing of the pandemic and the flu outbreak were not only short, but also long, which made experts worried. A recent bird flu outbreak in the Netherlands ended with only eye pain. The only human case of human transmission was eye pain and illness, and only one death. The only person who died was a veterinary surgeon.

I would like to continue with the latest outbreak of bird flu. This time, the bird flu outbreak began in 2003. In the first half of 2003, there were no human deaths. Only chickens and ducks were affected. At that time, tens of thousands of birds died from bird flu in Vietnam. In Japan, an epidemic of chickens in the western city of Ramaguchi killed more than 6,000 chickens. In South Korea, millions of chickens and ducks died. Bird flu has also occurred in Vietnam, Japan, South Korea, and China (Taipei). Due to this spread of the disease, human deaths have been reported in Vietnam and Thailand, with 12 deaths. Of these cases, 3 were the first to test positive for the bird flu virus. This is the first human-to-human transmission of avian influenza. In the case of human-to-human transmission, the virus was found to be the cause of death. It was first detected in January 2004. Since then, it has spread to many countries. Human-to-human transmission has been confirmed in Vietnam and Thailand, as well as in Cambodia and Indonesia. After 2005, there were deaths in China. In 2006, there were deaths in Turkey, as well as in Asian countries. If we look at these global events, we can see that the 1918 avian influenza, the subsequent Asian influenza, and the Hong Kong avian influenza epidemics not only transmitted from birds to humans, but also caused millions of deaths due to human-to-human transmission.

The most recent outbreaks in Hong Kong in 1997, the Netherlands in 2003, 2004, and 2005 in Vietnam, Thailand, Indonesia, Cambodia, and China have all caused human-to-human transmission of the disease. The number of cases has only been over 100. The number of deaths has not yet exceeded 100. So it is clear that there has not been a human-to-human influenza pandemic. However, experts predict that there is a possibility of human-to-human transmission. The 21st century is a time of rapid human-to-human communication due to globalization. Since the world's communication channels are wide open, experts predict that if a disease were to occur, it would spread much faster than before. Although there has not been a flu pandemic for many years, and currently, bird flu is spreading to humans, The world is rapidly taking action to prevent the spread of the virus as the global pandemic is rapidly approaching.

Chapter (2)

What is chicken flu?

(a) An infectious disease caused by a virus.

People often ask what bird flu is. In simple terms, it is a disease that causes a flu-like illness in birds. Birds naturally carry the virus. Wild birds, in particular, can fly around without getting sick even though they have the virus in their intestines. In particular, waterfowl, which carry the virus, fly around without getting sick (without getting the flu), spread the virus along their flight path. The virus then infects other birds that are not immune to it. Once infected, the infected birds get sick and die. The way the virus is transmitted is through bird droppings or bird droppings that fall into the water. Birds that drink this water can infect birds that swim in it. Among the infected birds, wild birds also spread the disease. Waterfowl include large migratory birds such as mallards, cranes, stilts, waterfowl, gannets, and grebes. These birds do not show symptoms when they are infected. The only animals that can easily spread the disease are domesticated ducks. Among domesticated ducks, ducks that feed in natural lakes, streams, and ditches are relatively immune. Until the avian influenza virus is transmitted to these ducks from wild birds, these ducks do not show symptoms, do not become ill, and do not die. However, ducks raised in the same flock, such as Peking ducks, can also die in closed cages. The most commonly infected and most quickly killed animals are chickens. In addition, in Turkey, turkeys have been infected with avian influenza and died. The main thing is that when it is transmitted to birds, the chickens get sick and die in flocks, so it is easily called chicken flu. Some people translate it as bird flu because it can also be transmitted to birds, so it is not easy to escape. However, most of them are chickens.

There are many strains of the same virus that causes bird flu. One strain can be fatal, while another strain can only cause illness and not death. Some strains can be asymptomatic. Viruses that develop in wild birds can spread more easily if they don't kill the birds they're feeding on. The disease spreads along the flight paths of those birds.

Among wild birds, waterfowl are also resistant to the virus, but they die from a new strain of the virus, not one they are resistant to. Last year, we saw a flock of gulls die in Europe. Gulls are a waterfowl species that are resistant to the disease, but the virus that killed them was a strain of the virus.

Most often, chickens get sick because of Newcastle Disease. This disease is also caused by a virus, but it can be prevented with a vaccine. Chickens can be protected by giving them eye drops. If a chicken falls sick in a chicken farm despite being vaccinated, you should consider whether it is possible that it is avian influenza.

If the vaccine is not given, it will be complicated when chickens get sick. Chickenpox, which is a contagious disease in chickens, is also a contagious disease. It can kill many chickens. The main thing is that chickenpox and chickenpox cannot be transmitted to humans. Only avian influenza can infect and kill humans.

( b) How to detect chicken flu in chickens

If chickens are infected with avian influenza, the main symptom is that the chickens in the chicken coop have stopped crowing. If many chickens are sick at the same time, the crowing of the chickens will naturally stop. If the crowing of the chickens has stopped, when you go to see these chickens, you will see that the chickens have become less active and quiet. Their food intake has decreased and they cannot eat as much as usual. They can drink a lot of water. They can also have diarrhea. At this time, if you are raising egg-laying chickens, you can see that the egg production in the farm has decreased. The chickens are sick. They no longer make noise, their egg production also decreases, their food intake decreases, and their water intake increases. After the diarrhea increases, you can see tears, drooling, and difficulty breathing. Due to this difficulty in breathing, the head and face become swollen, and the crests and cheeks turn blue. At this time, you can see red spots on the legs and ankles due to blood loss. If the respiratory distress is already present, a large number of deaths can occur at once, especially if the infection rate is severe and the entire poultry farm can be wiped out. If you are aware of the flu that these chickens are infected with, you can prevent avian influenza.

Bird flu can infect both chickens and humans. If it has spread to humans, it is mainly associated with people who have lived in areas where chickens have been infected or where there are many dead chickens. It is very similar to other flu. First, people get sick. They have a severe fever, cough, and shortness of breath from the cough, then difficulty breathing, severe fever, pneumonia, and death. Some doctors who treat bird flu say that in addition to these symptoms, people also have diarrhea.

Chickens have long necks, so if there is mucus in their throats, they can't cough and can't get it out. When the mucus builds up, it causes them to drool. If you see chickens drooling and getting sick, you might mistake it for chicken drooling and be careless.

In Southeast Asia, cockfighting is a cultural tradition. When cockfighting is performed, the cocks are forced to fight with their feet. If they get stuck in the throat, they can lose. Therefore, the owner of the cock will suck the mucus from the throat of his cock. The mucus must be sucked out of the cock's mouth, nose, and beak, and then into the mouth of the person. If a cock is infected with avian influenza, it will catch the bird flu and die. Experts suggest that this custom should be changed, but people are reluctant to change it. There is evidence that a person died of avian influenza in Thailand due to this behavior.

Usually, when chickens get sick with avian flu, there are no obvious signs of the disease, and one or two birds die without warning, and the entire farm suddenly dies. (48) The entire farm can die within 48 hours. This is a common occurrence in chicken farms, so if you notice it, it can be prevented. It can also happen in domestic chickens and small chicken farms without warning. Farmers cook them to spare, and sometimes they kill them quickly before they die and sell them. This is how the disease is transmitted in Vietnam, Thailand, and Turkey. Tigers in Thailand died after eating raw chicken, and more than a hundred birds were killed to prevent the spread of the disease. This is a problem caused by the greening of infected chickens.

It is difficult to predict the death of one or two pigeons or crows. If you find something like this, you should not be careless or worried. It is better to inform the relevant health (or animal husbandry and veterinary) departments.