Avian influenza and other zoonotic

Avian influenza and other zoonotic

Avian influenza and other zoonotic diseases

Everyone seems to be on the alert about the latest outbreak of bird flu. People in China are being asked to kill their poultry in order to prevent the spread of the virus. Meanwhile, people in the United States are watching in fear of bird flu reaching their shores. So what exactly is all the fuss about? After all, every winter millions of people are infected with bird flu.

The origin of influenza

The term influenza came into use around 1504, although it has nothing to do with the virus. It came from the word: effect. At the time, the effect meant: "the ethereal power of the stars acting on men." It was basically a supernatural way of explaining the effects of disease on people at the time. During a bad outbreak of influenza in Europe in 1743, the term was officially attached to the name of the disease. After 96 years, the term has been shortened to a mere: the flu.

Influenza itself is a whole family of viruses called Orthomyxovirids. They are a diverse family commonly found in the guts of birds. The specific type of virus that infects birds is called the type of influenza. One of these was type A, which is thought to have infected people a long time ago. So we got the flu for the first time. Although the virus that initially infected humans, has long since evolved into a variety of strains specific to humans, the initial origin appears to lie directly among birds. As such, all human influenza bugs could, technically, be called: avian influenza.

Pathogens and privacy

Pathogens are viewed as any organism capable of causing disease. It is a term generally reserved for bacteria, fungi, and viruses. Pathogens are usually very specific as to who or what they infect. This has a lot to do with the way it is built.

Both bacterial and viral exoskeletons consist of receptor-binding proteins. These proteins give the pathogen a certain geometry. This engineering allows the pathogen to bind to complementary receptor sites on the cells of the creature it is trying to infect. Due to the great diversity of life forms on this planet, each cell type has a different arrangement of receptors. Most of the time, the geometry of the pathogen will not fit these receptors, and the creature remains immune. Only those unlucky few species, whose cellular receptors fit in, should suffer from the infection.

Every once in a while, a new pathogen comes in that has a general enough geometry to allow it to stick to many different species. These are the pathogens that are often the most deadly.

Influenza is one of these general viruses. It is capable of infecting most species of birds. It's also very good at doing what all life does. evolve. This allowed her to cross barriers of multiple species, jumping from birds to humans, to pigs, cows, and horses. Thus making influenza a very global viral family. That still doesn't explain all the concerns about the recent bird flu outbreak. Therefore, one must go back in time to 1918, the Spanish Flu.

It was the end of World War I, and the world seemed to be returning to a more peaceful state. Then, in different parts of the world, people began to get virulently infected with influenza. This was a unique case though. Instead of dying young and old, he was affecting young men and women instead. These are usually the most immune to the effects of the flu. By the end of 1918, this type of influenza had killed about 50 million people. It was the largest pandemic (global epidemic) in recorded history. so what happened?

Usually, when one has the flu, it's more troublesome than anything else. This has a lot to do with the fact that the types of flu we usually catch are viruses that have infected us before. They have changed enough that they can infect us again, but they are still recognizable by our immune system. As such, our bodies can keep the virus in check, and eventually eliminate it. But the 1918 flu was different. It is now largely believed to have been a case of a new influenza virus circulating. It passed from birds to humans, possibly after circulation and interbreeding within pigs (which can infect both birds and humans). This new bug was completely foreign to our immune system, and thus completely surprised many.

This has many worried about the latest bird flu virus (aka: H5N1, for the specific proteins found in it). It has proven to be particularly virulent among birds, and in a few cases, it has infected people worry a lot about another pandemic.

Zoonoses.

Influenza is a type of disease referred to as a zoonotic disease. This means that it can be transmitted from one animal group to another. Zoonoses used to be divided into those caught by humans from other animals (anthroponosis) and diseases caught by other animals from humans (anthroponosis). Unfortunately, both terms have been abused and confused a lot, and neither is particularly preferred. Now they are all seen as zoonotic diseases. In the end, this makes sense, because humans are animals anyway. To break things down more than just seem overzealous.

Influenza is not the only animal-transmitted disease that infects humans from other animals. Our primate cousins ​​have given us quite a few different diseases including malaria, hepatitis B, dengue, and lymphoma. Of course, HIV is probably one of the most notorious of these animal diseases.

Although there are those who would like to believe that HIV was a genetically modified weapon unleashed among the African population (they give a lot of credit to genetic engineers, who are proud enough to make yeast that can shine), the monkey origin of HIV is well established. HIV has close links with the monkey version: SIV (simian immunodeficiency virus). The big difference between the two, besides the initials, is that SIV rarely kills the monkeys it infects. In fact, many monkeys are able to carry viral loads equivalent to those seen in humans with advanced AIDS, yet they rarely show any signs of problems. This indicates that the host and pathogen have been doing this for a very long time, and the host's body has found a way to deal with the virus. It is only recently that humans have acquired HIV. As such, our bodies have yet to "learn" how to deal with the threat posed by this virus. It is one of the reasons why HIV is so virulent today.

These are just some of the diseases that other animals have given to humans. But what about the opposite? What did we give to our fellow animals?

Many of the "classic" diseases that most humans have are diseases that we can pass on to our primate cousins. This includes influenza, measles, chickenpox, and tuberculosis.

One of the nasty diseases we can transmit is foot and mouth disease (FMD). FMD rarely infects humans, but it uses us as its vector. The disease can spread in the nasal passages, throat, and on our clothes. It usually affects different types of livestock (cattle, pigs, sheep, and goats). Symptoms usually include fever and prominent sores on the feet and mouth (hence the name). Most infected animals survive. Only ~5% die from the disease.

The second disease is much more harmful, and the victims have to blame. It is a coral disease referred to as whitepox. This disease can kill up to 10 square centimeters of corals per day (about 120 feet per year). Over the past decade, more than 90% of Caribbean corals (Acropora palmitate) have died. The culprit behind this is the human small intestine bacteria: Serratia marcescens. While humans can sometimes fall victim to these bacteria, they do not usually infect us. Instead, it lives in our guts and is expelled in our feces. Improper treatment of sewage has led to a flow of human excrement into the Caribbean, where the newly released bacteria have infected local coral reefs.

So remember; The next time you start to feel the weather, don't worry about coughing on your dog. Chances are, your boyfriend probably won't understand it. Unless, of course, it's the flu.