Snake and spider venom are types of toxin Virus: a super tiny germ that you can only see with a microscope. Viruses need a host in order to reproduce When we get sick and show symptoms of illness, it is most often because we are fighting off pathogens.
Image by Courtney Carmody. You wake up and for a few seconds, you feel okay. But when you sit up, it suddenly all hits you. Your head feels stuffy, your nose is running, and you feel hot all over. These symptoms are all signs that your body is fighting an infection. But how did you get an infection? Infections happen when you get a pathogen inside your body.
Pathogens are parasitic , and survive by taking energy from the host they are inside. In this case, you would be the host. Some pathogens also produce toxins that can hurt you if they are released. So what exactly is a pathogen?
You might better recognize three common kinds of pathogens: Bacteria, Viruses, and Fungi. These three kinds of organisms are very different from each other. Here we can compare a human hair to the scale of fungi, bacteria, and viruses. Bacteria are tiny, single-celled organisms that are found almost everywhere.
There are bacteria on your desk, your skin, inside you, and even on this computer screen. Most bacteria are not pathogens. This means that for the most part, they don't cause disease. Parasite is a name used to refer to any living being that lives off another, usually by producing some sort of damage or loss to its host.
A great example of parasites is intestinal worms which live in the human gastrointestinal system. Intestinal worms eat our food and deprive us of essential nutrients in order for them to grow and multiply. Some even migrate from the gastrointestinal system, producing varied and sometimes irreparable tissue damage to the lungs, brain, muscles or eyes. Intestinal parasites may cause weight loss, anemia, fatigue, nausea, apathy or irritability as a result of the vitamin and mineral deficiencies they generate.
However, not all parasites are harmful, some producing benefits for their host like the birds that eat leftovers from crocodiles teeth. Bacteria, viruses and even fungi can be called parasites in the sense that they somehow take advantage of other organisms to live and replicate. But parasites in the literal sense of the word refer to organisms that actually live in a biological association with others and rely on those organisms to live, grow and multiply, then move onto another host. The difference between bacteria and parasites, for example, is that bacteria can grow and spread on a surface for example, whereas parasites typically require a host and resources provided by said host to do so.
Here are some of the main diseases caused by bacteria, viruses and fungi as well as parasites: A Bacteria : sore throat, strep throat, foodborne illness, tuberculosis, pneumonia, meningitis, gastritis, stomach ulcers, foodborne illness.
D Parasites : intestinal parasites infection, liver and bile duct cancers, head lice etc. Moreover, some bacteria can produce toxins that kill healthy cells and cause a damaging immune reaction.
Luckily, there is a wide range of antibiotics available nowadays, whose purpose is to destroy the bacteria that are causing harm to our health. Antibiotics are also added to our food supply to ensure no harmful bacteria are present in it.
Unfortunately, some bacteria can quickly evolve to evade antibiotics, in which case the medication is no longer effective. Because bacteria share genes resistant to antibiotics, more strains can generate resistance to the medication we use to treat bacterial infections. Fungi is responsible for causing conditions such as yeast infections, valley fever, and meningitis.
Fungi are considerably more complex than bacteria , as they are eukaryotes, which means they have cells.
Out of the three pathogens, fungi are the most similar to animals in their structure. There are two types of fungi: environmental and commensals. While the former are yeast and mold that usually live in soil and rarely cause infection in people, the latter live inside our bodies but are rarely harmful. Surprisingly, certain fungi play a beneficial role in our health. However, some environmental fungi generate spores, tiny particles that can reach the inside of our bodies through the lungs or the skin.
They are particularly dangerous to people with a poor immune system, as they reproduce rapidly, thereby causing extensive damage to the body. If these measures do not make the blood temperature in the brain match the new setting, then shivering begins in order to use muscle movements to produce heat. A pyrogen is a substance that induces fever. These can be either internal or external to the body. The bacterial sugary fat substance lipopolysaccharide, present in the cell wall of bacteria, is an example of a pyrogen.
In extreme examples bacterial pyrogens can themselves cause rapid and dangerous fevers. All pyrogens, bacteria, fungi, and viruses produce cytokines, molecules that are a part of the immune system.
These can cause the increase in the thermoregulation set point in the hypothalamus. Symptoms of infection depend very much on the type of disease. General symptoms of infection include fatigue, loss of appetite, weight loss, fevers, night sweats, chills, aches, and pains. The classic symptoms of a bacterial infection are local redness, fever, swelling, and pain at the site of infection. In general, viral infections are systemic, involving many different parts of the body at the same time; i.
Antibacterial, antimycotic, and antiviral drugs have been developed that generally function by blocking bacteria, fungi, and viruses from replicating and surviving. Penicillin as an antibacterial, for instance, functions by inhibiting synthesis of bacterial cell walls. Examples of penicillin drugs include amoxicillin and ampicillin. Bacteria constantly try to rebuild their peptidoglycan cell wall.
Penicillin blocks the formation of peptidoglycan cross-links in the cell wall. As a consequence, transpeptidase cannot catalyze formation of these cross-links. The imbalance between cell wall production and degradation causes the bacteria cells to rapidly die. Streptomycin or streptomycin sulfate is an antibacterial; it is a ribosome protein synthesis inhibitor.
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