Introduction to Diseases
A Disease is a condition that is abnormal and negatively affects the structure and functioning of organs or tissues or parts of a living organism. It has to be noted that it is not due to any immediate external injury and disease is a medical condition that has specific signs and symptoms.
Therefore, it can be stated that a disease is a discomfortable condition that deteriorates the normal functioning of the cells, organs, and tissues.
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Any risk caused due to divergence from the normal or functional state of an entity can be termed as a disease.
Any adverse variation from an organism's normal structural or functional condition is usually associated with specific signs and symptoms and distinct from physical injury. A diseased organism will frequently display indications or symptoms that indicate its aberrant state. To recognize the symptoms of sickness, one must first understand the normal state of an organism. Nonetheless, there isn't always a clear line between disease and wellness.
Acute Disease
A few diseases appear out of nowhere and persist only a few days. Acute diseases, such as the common cold, are examples of them. Medical treatment or self-treatment are also options for treating this illness. Acute diseases frequently become chronic if they are not treated.
Acute illnesses can affect any part of the body. An asthma episode, for example, is acute and then becomes chronic. Acute diseases include strep throat, fractured bones, appendicitis, influenza, pneumonia, and others.
Symptoms and Treatments
Acute diseases develop quickly and are accompanied by unique symptoms that necessitate immediate or short-term treatment and improve once treated. A fractured bone, for example, that may occur as a result of a fall, must be treated by a doctor and will recover over time. Acute illnesses, such as the common cold, can sometimes go away on their own. The majority of those who suffer from acute illnesses will recover quickly. If you've been hospitalized for an acute illness, you'll probably be ready to get back to the comfort and familiarity of the home once your condition improves. However, just because you've been released from the hospital doesn't imply you've entirely recovered. Find out what steps you may take to speed up your return to your regular routine.
Chronic Diseases
Chronic diseases are illnesses that develop over time and endure for a long time or even a lifetime. Chronic disease is defined as a disease that lasts more than three years. The symptoms are relatively modest at first. The chronic disease develops slowly and causes significant damage to the body. It has the potential to be lethal at times.
Age, gender, and an unhealthy lifestyle, among other things, are risk factors for such diseases. Medication may or may not be able to cure a chronic disease. Vaccines are also ineffective in preventing it. Chronic diseases include hypertension, arthritis, diabetes, and psoriasis.
Symptoms and Treatments
Chronic illnesses take longer to develop can progress over time and can present with a variety of warning signs or none at all. Arthritis, Alzheimer's disease, diabetes, heart disease, high blood pressure, and chronic kidney disease are all common chronic illnesses. Chronic illnesses, unlike acute illnesses, cannot be cured; they can only be managed. Living with chronic illness or managing the symptoms of a chronic condition can often be accomplished by working with your doctor to develop a health care plan that includes medication, healthy eating, physical or occupational therapy, exercise, and complementary treatments like acupuncture or meditation. Staying physically active, maintaining a healthy weight and nutritional status, minimizing sun exposure, and refraining from smoking are all examples of good lifestyle practices that can help prevent chronic diseases.
In order to decide the appropriate course of treatment, it is necessary to correctly identify the etiology of an illness.
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We have classified various types of diseases based on their nature and the parts of the body they affect in the below tabular form-
Types of Diseases
Different Types of Diseases and Their Causes
Two Classification of Diseases
Infectious Diseases
Non-infectious Diseases
Infectious Diseases
Diseases that can spread from one person to another are called communicable diseases and are caused by microorganisms. The microorganisms that usually cause infectious diseases are called pathogens include viruses, bacteria, fungi, rickettsia, worms, and protozoans. It spreads when the infected person transmits his/her bodily fluids to another person, and the pathogens may exit the host to infect the new person, it takes place during sneezing, coughing, etc. Various examples of this kind of disease are cholera, chickenpox, malaria, COVID-19, etc.
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Non-Infectious Diseases
These kinds of diseases are caused due to pathogens as well as other factors that include age, gender of an individual, deficiency in nutrition, unhealthy lifestyle, etc. Some of the examples include hypertension, cancer, and diabetes. These are noncommunicable and do not spread from one person to another. These restrain within a person who contracts them. Some of the examples include cataracts, Alzheimer's, cataracts, and heart diseases.
Depending on which Above Categories of Diseases it Falls into, Diseases can be further Classified as
Degenerative Diseases
Are caused due to the malfunctioning of vital body organs as a result of the deterioration of cells over time. One of the best examples is Osteoporosis which causes increased bone weakness with time and it increases the risk of bone fracturing. Another is a neurodegenerative disorder when degeneration happens to the cells of the CNS like neurons. In Alzheimer's, it often happens due to aging and bodywear. Some of these diseases are hereditary and because of bad lifestyle choices.
Allergies
When the body becomes hypersensitive to certain foreign substances namely allergens, allergic reactions take place. It occurs when the immune system reacts abnormally to any foreign substances which can be harmless. Common allergens are dust, pollen, mites, animal dander, latex, feathers, and also certain food products like gluten and nuts. Many people face allergies from food substances such as peanuts or other nuts and induce life-threatening conditions. It aggravates difficulty in breathing, swelling of tissues, and blocking of airways.
Other common symptoms that are less life-threatening include coughing, running nose, sneezing, itchy and red eyes, skin rashes. Asthma is an example of an allergic disease, others include bee stings, ant bites, etc.
Deficiency Diseases
Deficiency diseases are caused due to the deficiencies of hormones, vitamins, minerals, and nutrients in the body. For example, diabetes occurs due to an inability to produce or utilize insulin, goiter is caused due to iodine deficiency, kwashiorkor is caused due to deficiency of proteins in the diet. Vitamin B1 deficiency results in a disease called beriberi.
Goitres
An abnormal enlargement of the thyroid gland that results with blockage of the oesophagus or other organs of the chest and neck is called Goitre. It causes difficulty in breathing and eating.
Blood Diseases
Blood disorders result due to the effects on the blood plasma, platelets, white blood cells, and red blood cells. For example, Sickle Cell Anaemia is a condition when the red blood cells are destroyed or distorted in the shape of a sickle. It loses the ability to carry oxygen. As a result, it shows symptoms the same as in chronic anemia that includes shortness of breath and tiredness.
FAQs on Diseases- Types of Diseases and Their Symptoms
1. What is a disease, and how is it defined in biology?
In biology, a disease is defined as any condition that impairs the normal functioning of an organism's body or one of its parts. It is characterised by specific signs and symptoms and is not simply the direct result of a physical injury. A disease can affect the structure or function of cells, tissues, and organs, leading to a state of ill health.
2. What is the main difference between infectious and non-infectious diseases?
The primary difference lies in their cause and transmission. Infectious diseases are caused by pathogenic microorganisms, such as bacteria, viruses, fungi, or parasites, and can be spread, directly or indirectly, from one person to another. In contrast, non-infectious diseases are not caused by pathogens and cannot be spread between people. They typically result from a combination of genetic, physiological, environmental, and behavioural factors.
3. What are some common examples of infectious diseases and their causative agents?
Infectious diseases are caused by various pathogens. Some common examples include:
- Tuberculosis: Caused by the bacterium Mycobacterium tuberculosis.
- Common Cold: Caused by various viruses, most commonly the Rhinovirus.
- Malaria: Caused by a protozoan parasite of the genus Plasmodium, transmitted by mosquitoes.
- Typhoid: Caused by the bacterium Salmonella typhi, often spread through contaminated food and water.
4. What are non-infectious diseases, and what factors typically cause them?
Non-infectious diseases, also known as non-communicable diseases, are medical conditions that are not transmissible. Their causes are generally linked to:
- Genetic factors: Such as inherited conditions like cystic fibrosis or haemophilia.
- Lifestyle factors: Including diet, physical activity, and use of tobacco, which can lead to conditions like heart disease and type 2 diabetes.
- Environmental factors: Exposure to pollutants, radiation, or other harmful substances that can contribute to cancers or respiratory conditions like asthma.
5. How are diseases classified based on their duration, like acute and chronic?
Diseases can be classified based on how long they last. Acute diseases appear suddenly and last for a short period, often a few days or weeks, like the common cold or influenza. Chronic diseases, on the other hand, develop slowly and persist for a long time, often for a lifetime. Examples of chronic diseases include diabetes, arthritis, and cardiovascular diseases.
6. How do the 'signs' of a disease differ from its 'symptoms'?
While often used interchangeably, 'signs' and 'symptoms' have distinct meanings in medicine. A symptom is a subjective experience that a patient feels or reports, such as a headache, nausea, or pain. It cannot be directly observed by a doctor. A sign, however, is an objective, observable indication of a disease that can be measured or seen by a healthcare professional, such as a fever, high blood pressure, or a skin rash.
7. Why is the proper classification of diseases so important for diagnosis and treatment?
Properly classifying a disease is crucial because it helps healthcare professionals understand its cause, mechanism, and likely progression. This understanding is fundamental for determining the most effective treatment strategy. For instance, classifying a disease as infectious and bacterial (like pneumonia) leads to treatment with antibiotics, whereas a non-infectious, genetic disease (like sickle-cell anaemia) requires entirely different management approaches. Classification also aids in public health efforts for prevention and control.
8. Can a single disease be both congenital and infectious? Explain with an example.
Yes, a disease can be both. A congenital disease is one that is present at birth. While many congenital conditions are genetic, some can be caused by infections transmitted from the mother to the foetus during pregnancy. A key example is congenital rubella syndrome. If a pregnant woman contracts the rubella virus, she can pass the infection to her developing baby, who is then born with the disease, leading to conditions like deafness, cataracts, and heart defects.
