An Introduction
A virus is a microscopic organism and can be found in soil, water and even in other living organisms like humans, plants, animals, etc. Though a human body hosts viruses, not all become a cause of disease.
The immune system is responsible for protecting human beings against diseases caused by viruses by producing antigens. Notably, these antibodies do not just identify infection but also destroy them effectively.
Keeping that in mind, let us proceed to find out more about viral diseases!
What are Viral Diseases?
In simple words, these are infections or diseases caused by viruses. Now, the type of viral disease depends entirely on the virus that is causing it.
Often an infection caused by a virus can be fatal, while at other times the impact may not even be noticeable. Also, the same virus can affect different organisms in different ways.
These are Some of the Most Common Examples of Viral Diseases
Common cold
Influenza
Measles
Herpes
Rabies
Ebola
Severe Acute Respiratory Syndrome
Chickenpox
Mumps
Viral Hepatitis
AIDS
Polio
Viruses like human papillomavirus (HPV) can even become a cause of cancer in their host.
Test Your Knowledge:
Which of these is a Contagious Venereal Disease?
Cancer
Phenylketonuria
Rabies
Typhoid.
Along with this above information, let us now find out more about the list of diseases caused by a virus and their symptoms.
This Table Below Highlights Diseases Caused By Viruses in Human Beings.
Types of Viral Diseases
Table: List of Viral Diseases in Humans
Causes of Viral Diseases
It is noteworthy that viruses cannot replicate on their own and are entirely dependent on a host. As a result, they are classified as parasites.
They transmit when an infected person comes in close contact with a healthy person. Notably, the composition of a virus influences its ability to spread.
Some of the conventional means of transmission include touch, contact with body fluids, ingesting contaminated water and diet, sexual contact, etc.
Symptoms of Viral Diseases
These are among the most common symptoms of viral diseases –
Fever and fatigue
Sore throat
Headache
Rashes
Swollen tonsils
Running nose
Body ache
Diarrhea and/or vomiting
It is noteworthy that symptoms for a particular viral disease may differ from those one another.
Treatment of Viral Diseases
There is no cure for most viruses. However, vaccination proves immensely useful when it comes to containing them.
Besides vaccination, the following is the advice that goes a long way in fighting against diseases caused by viruses.
Nutritious diet
Drinking adequate fluids
Proper rest
Prescribed medication for fatigue, fever, and body aches.
It must be noted that the treatment of a viral disease may vary widely, so it is best to avail medical treatment and avoid self-diagnosis.
Immunity
An organism can resist or combat the venereal infection and prevent it from turning into a full-fledged disease. In a broader sense, immunity is classified into two types – innate immunity and acquired immunity.
Innate immunity is present in organisms since birth and is usually inherited from their parents. Innate immunity is manifested as barriers, which include – physical, cellular, and physiological, and cytokine.
On the other hand, acquired immunity develops over time throughout an organism’s lifetime. It is further manifested as active immunity or passive immunity.
The human immune system comprises lymphoid organs, antibodies, lymphoid tissues, and immune cells. Human beings with strong immunity are less likely to succumb to diseases caused by viruses.
Find out more about such a list of diseases caused by a virus and their symptoms by joining our free live online classes today. Also, access our free PDF study materials to strengthen your knowledge about other related topics. Now you can also download our Vedantu app for easier access to related study material and online sessions.
Benefits of Learning About Viral Diseases
Learning about Viral Diseases will be quite beneficial for you. It is one of the most important topics of biology that will help you score excellent marks in the exam. Below are some of the benefits of learning about Viral Diseases.
By Learning About Viral Diseases you can understand the different types of diseases you can get infected with and take measures to prevent them.
If You Have A Good Understanding of Viral Diseases you can identify if you have any infections and start the treatment earlier.
Learning about Viral Diseases will help you secure a good score in the biology exam and improve your overall percentage.
One of the significant benefits of learning about Viral Diseases is that it gives you enough information about common diseases, allowing you to take preventive measures and stay healthy.
If you want to pursue the medical field in the future, knowing everything about Viral Disease will surely help you in your career.
Viral Diseases will also teach you how to take care of yourself and treat different types of infections as soon as possible.
With Viral Diseases, you can learn which type of viruses causes a particular infection and what you can do to prevent such diseases.
Another Advantage of Learning About Viral Diseases is that it explains the symptoms, causes, and treatment of each disease in detail, which enhances your knowledge.
How to Learn About Viral Diseases?
Learning about Viral Diseases will not be that difficult, especially if you are using Vedantu's services. Our platform contains detailed explanations of the meanings, symptoms, causes, and treatments of all viral diseases. You can use our mobile application to start learning about Viral Diseases - Introduction, Examples, Causes, Symptoms, and Treatment and improve your understanding of different infections. Apart from this, below are some ways to help you learn and understand this topic.
You Can Start Learning About Viral Diseases from your textbooks to get an idea of what this topic is about.
Once You Have Read Everything About Viral Diseases thoroughly, you should try attempting questions based on this topic to test your knowledge and see where you stand.
Try to understand the difference between different types of viral diseases and their symptoms.
You can go through sample papers and previous year's question papers of biology to analyze the difficulty level and pattern of questions related to Viral Diseases
Try to memorize the names of the viral diseases and the viruses that cause these infections.
Make sure you have a clear understanding of every viral disease so that you can differentiate between the symptoms, causes, and treatment.
FAQs on Viral Diseases
1. What is a viral disease?
A viral disease is an illness caused by a virus, which is a microscopic infectious agent. Viruses are considered obligate intracellular parasites, meaning they cannot replicate on their own and must invade the living cells of a host (like humans, animals, or plants) to multiply. These infections can range from mild conditions like the common cold to life-threatening diseases such as AIDS.
2. What are some common examples of viral diseases in humans as per the NCERT syllabus?
According to the CBSE/NCERT syllabus for Biology, some important examples of viral diseases affecting humans include:
- Common Cold (caused by Rhinoviruses)
- Influenza (caused by Influenza virus)
- AIDS (Acquired Immuno Deficiency Syndrome, caused by HIV)
- Polio (caused by Poliovirus)
- Dengue (caused by Dengue virus)
- Chikungunya (caused by Chikungunya virus)
- Measles (caused by Morbillivirus)
- Mumps (caused by Mumps virus)
3. What are the general symptoms of a viral infection?
While symptoms vary depending on the specific virus, many viral infections share a set of common signs as the body's immune system responds. These often include fever, fatigue, body aches (myalgia), headache, and a general feeling of being unwell (malaise). Other symptoms like a sore throat, runny nose, cough, or skin rashes are also common depending on the type of virus.
4. How do viral diseases differ from bacterial diseases in terms of treatment?
The primary difference in treatment lies in the type of medication used. Bacterial infections are treated with antibiotics, which kill bacteria or inhibit their growth. However, antibiotics are completely ineffective against viruses. Treatment for viral diseases primarily focuses on:
- Symptomatic relief: Managing symptoms like fever and pain.
- Antiviral drugs: These are available for specific viruses (like HIV and Influenza) and work by inhibiting viral replication.
- Prevention: The most effective strategy against many viral diseases is vaccination, which helps the body build immunity beforehand.
5. What are the common modes of transmission for viral diseases?
Viruses spread from an infected person to a healthy person through various routes. The mode of transmission often depends on the type of virus. Common modes include:
- Airborne transmission: Through respiratory droplets released during coughing or sneezing (e.g., Influenza, Common Cold).
- Direct contact: Physical contact with an infected person (e.g., Herpes).
- Fomites: Contact with contaminated objects or surfaces (e.g., Rhinoviruses on doorknobs).
- Contaminated food and water: Ingesting items contaminated with the virus (e.g., Hepatitis A).
- Vectors: Transmitted by insects, such as mosquitoes (e.g., Dengue, Chikungunya).
- Body fluids: Through contact with infected blood or other body fluids (e.g., HIV, Hepatitis B).
6. Why are viruses considered obligate intracellular parasites?
Viruses are classified as obligate intracellular parasites because they lack the essential cellular machinery required for their own replication. They do not have ribosomes to synthesise proteins, nor do they have enzymes for metabolism. To multiply, a virus must invade a living host cell and hijack its machinery, forcing the cell to produce new virus particles. Outside a host cell, a virus is essentially an inert particle, unable to perform any life processes.
7. Can a person develop lifelong immunity to a viral disease after being infected once?
It depends on the virus. For some viral diseases like measles and chickenpox, a single infection often leads to lifelong immunity. This is because the immune system develops memory B and T-cells that recognise and quickly eliminate the virus upon re-exposure. However, for other viruses like Influenza, immunity is short-lived because the virus constantly mutates its surface antigens (a process called antigenic drift), making it unrecognisable to the immune system's memory cells.
8. What is the role of vaccination in preventing viral diseases?
Vaccination is a crucial public health tool for preventing viral diseases. A vaccine introduces a harmless form of a virus (weakened, inactivated, or just a piece of it) into the body. This exposure triggers a primary immune response, leading to the production of antibodies and memory cells specific to that virus. If the vaccinated person is later exposed to the actual virus, their immune system can mount a rapid and strong secondary response, preventing the disease from developing. This is a form of active, acquired immunity.
9. How does the human immune system distinguish between the body's own cells and cells infected by a virus?
The immune system uses a sophisticated recognition system involving the Major Histocompatibility Complex (MHC). All healthy nucleated cells in the body present fragments of their own proteins ('self' antigens) on their surface using MHC-I molecules. When a virus infects a cell, the cell starts producing viral proteins. It then presents fragments of these foreign viral proteins on its MHC-I molecules. Cytotoxic T-lymphocytes (a type of immune cell) patrol the body and can recognise these foreign antigens, identifying the cell as infected and destroying it to stop the virus from spreading.
