Infectious Diseases: Definition, Types, Symptoms and Preventions

An infectious disease is define as disease or disorder caused by pathogens. A disease is simply an abnormal condition caused due to some functional disorders in the body of an organism. It affects either a part of the body or the whole body and shows unusual negative activities. There are various types of diseases, but they are generally caused by infectious or non-infectious causes. 

• A non-infectious disease is usually caused due to the internal factors of the body.
• It may be some genetic norms, habits such as smoking, unhealthy diets, and exposure to the environment.
• A few non-infectious diseases include asthma, lung diseases, stroke, heart attack, and so on.
• While an infectious disease is basically caused by microorganisms such as bacteria, fungi, viruses, etc.

Key terms: Disease, Pathogen, Hygeine, Viral infection, Bacterial infection, Fungal infection, Cold, Pain, Antibiotics.

Read Also: Diseases

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Definition of Infectious Diseases

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Infectious diseases are the types of diseases that are caused by pathogenic organisms like bacteria, viruses, parasites, and fungi. These diseases are generally caused when a microorganism seizes the body cell and releases some sort of toxins inside the body. Infectious diseases can be communicable or non-communicable.

Disease causing pathogens

A communicable disease can be transmitted from humans, animals, plants, and even insects. A very common example of infectious disease is a viral fever caused by viral infections and is a communicable disease.

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Types of Infectious Diseases

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There are various types of infectious diseases caused by microbial pathogens. The different types of infectious diseases are explained below:

Bacterial Infection

Bacterial infections are very common among living beings. These infections are caused by bacteria. However, not all bacteria cause infection. There are generally two types of bacteria, bad/ harmful bacteria is one whose bacterial strain causes infections and good bacteria that kills the bad bacteria. Bacteria can affect any part of the body. Some of the most common bacterial infections are typhoid, tuberculosis, boils, food poisoning, etc. These diseases are mostly treated with antibiotics.

Viral Infection

Viral infections are another common type of infectious disease that can be seen in humans, animals, insects, birds, and every other living being. These diseases are caused by viruses and can result in serious infections in the host's body. Viral infections occur when the virus enters the host's body, connects to the cell, and activates its genetic material. The virus then starts replicating itself and keeps on growing and infects more body cells of the host. 

In most cases, the virus damages the cells completely, like in the case of viral fever. On the other hand, some viruses prefer altering the cell structure, as can be seen in the case of Epstein Barr. 

Read more: Pathogens

Fungal Infection

A fungal infection is also known as mycosis that occurs mostly in the outer layer of the skin of the host's body. Skin problems such as irritations, redness, itching, swelling, etc are mainly caused due to fungal infections. These infections might appear anywhere in your body. Some fungal infections can further penetrate through your skin and infect the inner layers of the skin as well. Moreover, if these fungal spores are inhaled, they may even infect the entire body of the host. 

Piron Infection

Unlike bacteria and viruses, a piron is a protein. When this protein compound is folded abnormally, it hinders the structure of the other proteins within the body and puts a direct impact on the brain of the host. These infections are often life-risking and they spread throughout the host's body in a very short time. Pirons basically stimulate abnormal behavior in the host's body cells. 

More Infections

Apart from bacteria, viruses, pirons, and fungus, there are many other viruses causing other types of communicable diseases. The most common infections are explained below:

• Protozoa: These are single-celled organisms that are transferred through faeces. Protozoa are of various shapes and sizes. They live in moist environments such as marines, soils, freshwater, and more. 
• Helminths: They are basically work-like parasites that depend on the host's body to survive and nourish themselves. Helminths mostly cause human infection. 
• Ectoparasites: Ectoparasites live on the outside of the host's body. This includes microorganisms such as lice, ticks, etc that get attached to the skin and start infecting.

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Common Infectious Diseases

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The various common infectious diseases that are caused by pathogens are listed below in the table:

When an organism invades into the blood cells, releases toxins and activates various reactions in the host tissues, these infections are caused. 

Read more: Typhoid

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Symptoms of Infectious Diseases

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• The symptoms of infectious diseases are based on the site and the type of pathogens that affect the body.
• The viruses generally target specific cells, for example: the rabies virus affects the nervous system, some viruses cause muscle ache, warts, runny nose and so on.
• A person who is affected by a bacterial infection will experience such symptoms: heat, pain, fever, fever, swelling in the lymph gland and so on.
• The symptoms of fungal infections will be rashes on skin.
• Prion diseases damage the brain, memory loss and cognitive difficulties.

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How Infectious Diseases are Caused?

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 Infectious diseases can be transmitted by various ways:

• When someone sneezes or coughs, the droplets that contain pathogens of diseases like influenza, common cold etc might escalate in the air and might affect others.
• When we touch an infected person or their body fluids like saliva, urine, sweat, blood, transfer the infection to a healthy person. Example: chicken pox, measles and so on.
• When we touch any object or area touched by an infected person, can transfer the infection to a non-infected person. 

Read more: Pneumonia

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Preventions of Infectious Diseases

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Some of the practical ways through which the infectious diseases can be avoided or prevented are given below:

• Use of antibiotics 
• Vaccination 
• Maintaining a proper hygiene 
• Do avoid sharing personal belongings such as glass, toothbrush, comb, razor and so on.
• Try to avoid going out when you fall ill.
• Keep your kitchen clean by washing all the used utensils, cooking area before and after preparing food.
• Keeping in view the prevailing situation, it is of utmost importance to use sanitizers and masks while going out.
• Extra care must be taken while going to hospitals. 

Read more: Common Cold 

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Things to Remember

• Infectious diseases are caused and spreaded by pathogen such as bacteria, virus, fungi and insects.
• The common symptoms of infectious disease are common cold, pain, fever, weakness and loss of apetite.
• Viruses cannot reproduce themselves without a host's body. It requires the host's body cells to replicate and reproduce. 
• Viruses acquire energy from the host's body and make copies of themselves in order to reproduce. 
• There are millions of fungi species and can be found in every place, including our household surfaces and our skin. 
• Communicable diseases are transferred from one person to the other through the air, physical transmission, sexual transmission, and surface transmission. 
• Prvention and cure of such infectious disease includes physical distance from an infected person, use of antibiotics if found any symptoms, taking care about food and drinking water source as many pathogens are waterborne and causes typhoid.