Disease and Immunity

Microorganisms

Organisms that are too small to be seen with the naked eye and require a microscope to be seen.

Pathogens

Microorganisms that cause disease.

Bacteria

Unicellular microorganisms that do not have a nucleus and can vary in shape.

Viruses

Non-cellular pathogens that contain genetic material wrapped in a protein coat.

Fungi

Multicellular pathogens that vary in size and thrive in moist and warm environments.

Virulence

The degree of intensity or ability of a pathogen to cause disease.

Parasites

Unicellular or multicellular pathogens that live in or on a host and have hooks or suckers to attach to their host.

Disease

An abnormal condition or change that interferes with normal body functioning.

Environmental diseases

Diseases caused by pollution or exposure to harmful substances.

Social diseases

Diseases caused by human-induced factors such as addiction.

Genetic diseases

Diseases caused by genetic abnormalities that are inherited.

Nutritional diseases

Diseases caused by inadequate nutrition.

Degenerative diseases

Diseases that result from aging.

Mental diseases

Neurological diseases that affect mental health.

Zoonotic diseases

Diseases transmitted from animals to humans.

Asymptomatic

Carrying a disease without displaying any symptoms.

Contagious

Capable of being transmitted from one person to another.

Contagious diseases

Diseases caused by pathogens that can easily pass from person to person.

Chickenpox

An example of a contagious infectious disease caused by a pathogen that can easily spread from person to person.

Non-contagious infectious diseases

Diseases caused by pathogens that are not easily or at all passed from person to person.

Modes of transmission

Different ways in which infectious diseases spread.

Respiratory droplets

Droplets containing infectious pathogens expelled into the air through coughing, sneezing, talking, or breathing, which can be inhaled by nearby individuals.

Airborne transmission

Spread of pathogens through small particles that remain suspended in the air for an extended period of time.

Direct contact

Physical contact between an infected person or animal and a susceptible individual.

Indirect contact

Spread of a pathogen through contact with a contaminated object or surface, or through a vector such as a mosquito or tick.

Vector

An intermediate host, such as a mosquito or tick, that carries and transmits a pathogen from one host to another.

Bloodborne diseases

Diseases transmitted through the blood, often by vectors like mosquitoes.

Foodborne diseases

Diseases caused by pathogens found within food.

Waterborne diseases

Diseases caused by pathogens found within water.

Fecal-oral transmission

Pathogens in feces of an infected person contaminating food, water, or hands and entering the body through ingestion or contact with mucous membranes.

Importance of understanding mode of transmission

Understanding how infectious diseases spread is crucial for implementing prevention and control measures, targeted interventions, risk assessment, surveillance, identifying the source of infection, managing outbreaks, and allocating resources effectively.

Targeted interventions

Efforts focused on high-risk groups, screening, testing, educating, and raising awareness to minimize the risk of infection.

Risk assessment

Evaluating the impact of an infectious disease outbreak on individuals and communities and determining appropriate resources and measures.

Vaccines and treatment

Developing targeted vaccines and treatments to prevent and manage infectious diseases.

Surveillance

Monitoring and tracking the outbreak to identify patterns, assess severity, and trace the source of infection.

Asymptomatic

Individuals infected with a disease but showing no symptoms, which can complicate the assessment and management of an outbreak.

Minimizing spread and control

Implementing measures to prevent, manage, and control the spread of infectious diseases to minimize the risk and impact on individuals and communities.