Infectious Diseases and Pathogens

Study Notes

Caused by pathogens such as bacteria, viruses, fungi, and parasites
Can be transmitted through:
- Direct contact with an infected person
- Indirect contact with a contaminated surface or object
- Airborne transmission
- Vector-borne transmission (e.g. mosquitoes, ticks)
Examples of infectious diseases:
- Bacterial: Tuberculosis, Pneumonia, Meningitis
- Viral: Influenza, HIV, Hepatitis
- Fungal: Ringworm, Candidiasis
- Parasitic: Malaria, Toxoplasmosis

Long-term diseases that persist over time
Often caused by a combination of genetic and lifestyle factors
Characterized by:
- Gradual onset
- Persistent symptoms
- Requires ongoing management and treatment
Examples of chronic diseases:
- Diabetes
- Hypertension
- Asthma
- Chronic obstructive pulmonary disease (COPD)

A group of diseases characterized by uncontrolled cell growth and division
Can occur in any tissue or organ of the body
Caused by:
- Genetic mutations
- Environmental factors (e.g. radiation, carcinogens)
- Infections (e.g. HPV, H. pylori)
Types of cancer:
- Carcinomas (e.g. breast, lung, colon)
- Sarcomas (e.g. bone, soft tissue)
- Leukemias (e.g. blood, bone marrow)
- Lymphomas (e.g. immune system)

Caused by an immune system malfunction that attacks healthy cells and tissues
Characterized by:
- Overactive immune response
- Inflammation and tissue damage
- Often chronic and recurring
Examples of autoimmune diseases:
- Rheumatoid Arthritis
- Lupus
- Hashimoto's Thyroiditis
- Type 1 Diabetes
- Multiple Sclerosis

Pathogens like bacteria, viruses, fungi, and parasites cause infectious diseases
Transmission occurs through direct contact, indirect contact with contaminated surfaces, airborne transmission, or vector-borne transmission
Examples of infectious diseases include:
- Bacterial: Tuberculosis (affecting lungs), Pneumonia (affecting lungs), Meningitis (affecting brain and spinal cord)
- Viral: Influenza (affecting respiratory system), HIV (affecting immune system), Hepatitis (affecting liver)
- Fungal: Ringworm (affecting skin), Candidiasis (affecting mouth, throat, and genitals)
- Parasitic: Malaria (affecting red blood cells), Toxoplasmosis (affecting brain and eyes)

Long-term diseases persist over time, often caused by a combination of genetic and lifestyle factors
Characterized by gradual onset, persistent symptoms, and requiring ongoing management and treatment
Examples of chronic diseases include:
- Diabetes (affecting blood sugar levels)
- Hypertension (affecting blood pressure)
- Asthma (affecting airways)
- Chronic obstructive pulmonary disease (COPD) (affecting lungs)

Uncontrolled cell growth and division characterize cancer
Can occur in any tissue or organ of the body
Caused by genetic mutations, environmental factors, and infections
Types of cancer include:
- Carcinomas (affecting epithelial tissues, e.g. breast, lung, colon)
- Sarcomas (affecting connective tissues, e.g. bone, soft tissue)
- Leukemias (affecting blood and bone marrow)
- Lymphomas (affecting immune system)

Immune system malfunction attacks healthy cells and tissues, causing autoimmune diseases
Characterized by overactive immune response, inflammation, and tissue damage
Examples of autoimmune diseases include:
- Rheumatoid Arthritis (affecting joints)
- Lupus (affecting multiple organs and tissues)
- Hashimoto's Thyroiditis (affecting thyroid gland)
- Type 1 Diabetes (affecting pancreas)
- Multiple Sclerosis (affecting central nervous system)