Medical Diseases and Their Causes

Definition of Disease

• A disease is an interruption, cessation, or disorder that affects the whole body or any of its parts.
• Diseases are identified by a recognizable set of physical signs, symptoms, and effects.

Causes of Diseases

• Common causes of diseases include genetic disorders, environmental factors, infection, inflammation, or the deficiency of a vital nutrient.
• Causes of diseases can be known or unknown.

Types of Diseases

• Communicable diseases are caused by the presence and growth of pathogenic biological agents in a human or an animal host.
• Examples of communicable diseases include HIV/AIDS, tuberculosis, malaria, viral hepatitis, influenza, and sexually transmitted infections.
• Noncommunicable diseases are also known as chronic diseases, caused by a combination of behavioral, physiological, environmental, and genetic factors.
• Examples of noncommunicable diseases include cardiovascular diseases, diabetes, cancers, and chronic respiratory diseases.

Characteristics of Communicable Diseases

• Communicable diseases can spread from one person to another in various ways, including direct physical contact, contact with contaminated surfaces, airborne transmission, and insect bites.
• These diseases can be transmitted from individuals with asymptomatic cases.
• Communicable diseases can cause a high social and economic burden and put international health security at risk.

Characteristics of Noncommunicable Diseases

• Noncommunicable diseases are not infectious and cannot spread from one individual to another.
• They are typically related to older age groups.
• These diseases are the number one cause of death worldwide, accounting for 74% of all global deaths.
• Many types of noncommunicable diseases can be prevented by avoiding common risk factors like tobacco consumption, abnormal use of alcohol, lack of physical activity, and eating junk foods.

Statistics

• HIV/AIDS has led to 36.3 million deaths so far.
• Covid-19 has claimed more than 6 million lives during the recent pandemic.
• The number of people who die from tuberculosis is about 1.5 million each year.
• Cardiovascular diseases are the leading cause of death among noncommunicable diseases, accounting for 17.9 million deaths per year.
• Cancers cause 9.3 million deaths, respiratory diseases cause 4.1 million deaths, and diabetes causes 1.5 million deaths per year.

Similarities and Differences between Communicable and Noncommunicable Diseases

• Both communicable and noncommunicable diseases are medical conditions that cause significant functional disruption in parts of the body.
• Both include fatal medical conditions that account for a high proportion of global death annually.
• Communicable diseases result from infection by biological agents, while noncommunicable diseases are influenced by genetic defects, environmental factors, and behavioral factors.
• Communicable diseases pass from one person or an animal to another person, while noncommunicable diseases are not contagious and do not spread to other people.

Learn about the definition of diseases, their physical signs, symptoms, and effects, and the common causes of diseases, including known and unknown factors.