What Are the Main Causes of Disease and Their Types
A disease is a condition that worsens or impairs the normal conditions of organisms. Do you know most people die because of heart disease? And most heart diseases are due to a sedentary lifestyle. These factors are modifiable. Do you know the types of diseases? There are acute and chronic diseases. Acute diseases affect us for a short period, whereas chronic disease affects us for a long period.
There are various causes of disease, such as pathogens or unhealthy lifestyles. You might be surprised to know that fever is not a disease, it is a protective mechanism of the body against pathogens.
Types of Diseases
Diseases are of various types based on their nature.
Infectious diseases, also known as communicable diseases
Non-infectious diseases, also known as non-communicable diseases
Degenerative diseases
Allergies
Deficiency diseases
Infectious Diseases
Infectious diseases are diseases that spread from one person to another person through some agent. These diseases are caused by microorganisms such as bacteria, viruses, worms, and protozoans. Examples of infectious diseases are the common cold, pneumonia, tuberculosis, etc.
Non-Infectious Diseases
These are diseases that do not transmit from one person to another. These diseases may be caused by some pathogens or factors such as gender, lifestyle, and nutritional deficiency. Examples are hypertension, diabetes, cancer, asthma, etc.
Degenerative Diseases
Degenerative diseases are diseases caused by degenerative changes in cells, tissues, and organs. Examples of degenerative diseases are Alzheimer's disease and osteoporosis.
Allergies
Allergy is a hypersensitivity type reaction caused because of some substances. Things that cause allergic reactions are called allergens. Dust, mites, pollen, latex, and animal dander are allergens.
Deficiency Diseases
Deficiency diseases are diseases caused due to a decreasing or less amount of hormones, minerals, nutrients, and vitamins in the body. For example, diabetes occurs due to a deficiency of insulin in the blood. Insulin is the hormone produced by the pancreas and converts glucose into glycogen in the liver.
Kwashiorkor or Marasmus are diseases caused due to protein-energy malnutrition, goiter is the disease caused by the deficiency of thyroid hormone.
How are Diseases Caused?
There are various types of causes. Some of the causes are given below:
Airborne Diseases - These are diseases caused by pathogens and transmitted through the air. Examples of these diseases are tuberculosis and the common cold.
Foodborne Diseases - These are the diseases caused by contaminated food and drinks with pathogens, toxins, and parasites. Examples of these diseases are food poisoning.
Lifestyle Diseases - These diseases are caused by a sedentary lifestyle or consumption of unhealthy food or a bad lifestyle. The frequency of these diseases increases with time, especially in developed countries.
Communicable Diseases - These diseases are caused by various pathogens. Pathogens include:
Bacteria - Microscopic organisms that cause various types of diseases such as Streptococcus, Mycobacterium, etc.
Virus - Viral diseases are the common cold, hepatitis, mumps, influenza, and measles. These diseases are caused by rhinovirus, paramyxovirus, etc.
Fungus - Fungal infections include athlete's foot, and toenail fungus, fungal infections mostly occur in warm and humid places.
Protozoa - Protozoan infections include dysentery, amoebiasis, malaria, etc. Protozoans are Entamoeba histolytica and Plasmodium.
Worms - Disease causing worms are guinea worm, giardiasis, etc.
Symptoms of Diseases
Symptoms change according to the nature of the disease. But some of the signs and symptoms are very common and occur in almost every disease. Some of these symptoms are:
Headache
Pain
Vomiting
Nausea
Nasal congestion
Diarrhea
Altered urination
Redness
Swelling or edema
Sore throat
Chills or sweat
Treatment of Diseases
Treatment of diseases also depends on the nature and causative agent.
Antibiotics are drugs used for the treatment of bacterial diseases and infections. Examples of antibiotics are amikacin, penicillin, streptomycin, etc.
Antivirals are used for the treatment of viral diseases. Examples of antiviral drugs are peramivir and oseltamivir.
Antihypertensive drugs are calcium Channel blockers, diuretics, ace inhibitors, beta-blockers, etc.
There are other medications, too given according to diseased conditions.
Preventions of Diseases
It is well said that prevention is better than cure. So to save ourselves from diseases we have to follow certain healthy practices and protective measures. Some of the healthy habits are given below:
Wash hands regularly.
Always eat cooked food.
Exercise daily.
Say no to smoking and alcohol.
Eat less junk food.
Drink more water.
Interesting Facts
Laron syndrome is a disease in which the life span of a patient gets increased, and immunity against cancer develops.
In 5000 years of human history, humans are only able to eradicate two diseases till now - smallpox and rinderpest.
The lack of a toilet in India causes a loss of more than 50 billion dollars per year because of premature deaths and hygiene-related issues.
There was a man named James Harrison whose blood contain a rare antigen that can cure rhesus disease.
Approximately, 90-95% of cases of cancer are due to environmental conditions.
Important Questions
Q1. What are the most common infectious diseases?
Ans: There are many types of infectious diseases. But the most commonly occurring diseases are - influenza, pneumonia, Staphylococcus aureus infection, E.coli infection, etc.
Q2. What are some deadliest diseases?
Ans: There are many deadliest diseases. Some of the deadliest diseases are given below:
Cancer, heart diseases such as heart attack, HIV, and aids. Some of the diseases do not have any treatment.
Q3. What are the rarest diseases?
Ans: Rarest diseases are the diseases that occur very rarely such as alkaptonuria, encephalitis, Alice In Wonderland Syndrome ( AIWS), and Stoneman syndrome.
Key Features
In this article, we discussed disease and what causes disease, causes and prevention of communicable diseases.
There are various types of diseases, such as infectious, non-infectious, degenerative diseases, etc.
Causes of diseases are various pathogens such as bacteria, viruses, and fungus some lifestyle factors also cause disease.
Practice Questions
Q1. What is black urine disease?
Q2. What is the most common disease in the world?
Q3. What is the most difficult disease to cure?
Q4. Which disease is the silent killer?
FAQs on Understanding Disease and Its Causes in Biology
1. What is a disease in biology?
A disease is a condition that disrupts the normal structure or function of the body and produces specific signs and symptoms. In biology, disease refers to any abnormal state that affects cells, tissues, organs, or systems.
- It may be caused by pathogens, genetic defects, lifestyle factors, or environmental agents.
- Diseases can affect humans, animals, and even plants.
- They often show symptoms such as fever, pain, fatigue, or abnormal growth.
2. What are the main causes of diseases?
The main causes of diseases include infectious agents, genetic factors, lifestyle habits, and environmental influences. These causes are broadly classified as:
- Infectious causes: Bacteria, viruses, fungi, and parasites.
- Genetic causes: Mutations or inherited disorders.
- Nutritional deficiencies: Lack of essential vitamins or minerals.
- Environmental factors: Pollution, radiation, and toxins.
- Lifestyle factors: Poor diet, smoking, and lack of exercise.
3. What is the difference between infectious and non-infectious diseases?
The key difference is that infectious diseases are caused by pathogens and can spread between individuals, while non-infectious diseases do not spread and are caused by internal or environmental factors.
- Infectious diseases: Caused by bacteria, viruses, fungi, or parasites (e.g., tuberculosis, malaria).
- Non-infectious diseases: Caused by genetics, lifestyle, or deficiencies (e.g., diabetes, cancer).
- Infectious diseases are often communicable; non-infectious diseases are not.
4. How do pathogens cause disease in the human body?
Pathogens cause disease by entering the body, multiplying, and damaging tissues or producing toxins. The process typically involves:
- Entry through air, food, water, wounds, or vectors.
- Multiplication inside host cells or tissues.
- Toxin production or direct cell damage.
- Triggering an immune response that may cause inflammation and symptoms.
5. What are communicable diseases?
Communicable diseases are infectious diseases that can spread from one person to another directly or indirectly. They are caused by microorganisms such as bacteria, viruses, fungi, or parasites.
- Spread through air (e.g., influenza).
- Spread through contaminated food or water (e.g., cholera).
- Spread by vectors like mosquitoes (e.g., malaria).
6. What are deficiency diseases and what causes them?
Deficiency diseases are diseases caused by the lack of essential nutrients in the diet. They occur when the body does not receive adequate vitamins, minerals, or proteins.
- Scurvy: Caused by vitamin C deficiency.
- Rickets: Caused by vitamin D deficiency.
- Anaemia: Often due to iron deficiency.
7. What is a genetic disease and how is it caused?
A genetic disease is a disorder caused by abnormalities in genes or chromosomes. It results from mutations in DNA that may be inherited or occur spontaneously.
- Caused by single-gene mutations (e.g., sickle cell anaemia).
- Caused by chromosomal abnormalities (e.g., Down syndrome).
- Can be inherited from parents or arise during cell division.
8. How do lifestyle factors contribute to diseases?
Lifestyle factors contribute to diseases by affecting body systems over time and increasing the risk of chronic conditions. Harmful habits can lead to non-communicable diseases.
- Smoking increases risk of lung cancer and heart disease.
- Poor diet contributes to obesity and type 2 diabetes.
- Lack of exercise weakens cardiovascular health.
- Excess alcohol damages the liver.
9. What are the common signs and symptoms of disease?
Signs and symptoms of disease are changes in the body that indicate abnormal functioning. Signs are observable by others, while symptoms are experienced by the patient.
- Common signs: Fever, swelling, rash.
- Common symptoms: Pain, fatigue, nausea.
- Severity depends on the type and cause of the disease.
10. How can diseases be prevented?
Diseases can be prevented through hygiene, vaccination, balanced nutrition, and healthy lifestyle practices. Prevention reduces exposure to pathogens and risk factors.
- Maintain personal and community hygiene.
- Get vaccinations to build immunity.
- Eat a balanced diet rich in essential nutrients.
- Exercise regularly and avoid harmful habits.
