What is an Infectious Disease?

• It is a disease that is caused by a pathogen

Infectious Diseases cause millions of death every year and can be leading causes of death.

Pathogen: Organism that causes infectious disease to a host

Contagiousness is huge factor in the infectiousness of a disease. It determines the severity and level of how infectious a disease is.

What is Contagious? Contagious or a Contagion is a disease that is passible from human to human

Another word for Contagious is Communicable. This word can be used to describe contagiousness as well. If something is noncommunicable then it is not passed from human to human.

• An example of noncommunicable disease is Rabies.

Infectious diseases are heavily studied across the world and this is known as Epidemiology. Epidemiology discusses the different levels of infectiousness and helps lay out the levels for health professions to label health crisis’s.

• Endemic: A disease that affects low levels of populations, such as a few cities in a country suffering from an issue

• Epidemic: Epidemics affect large numbers of victims in a specific area, such as an entire country being afflicted with something like Polio but the disease not spreading past the borders of the area.

• Pandemic: Pandemics have a large number of victims and affects large areas. The Covid-19 pandemic is a good example because millions were affected all across the world.

• Outbreak: Sudden and unexpected emergence of a disease that affects many people but dies out quickly

• Notifiable Disease: Majorly infectious diseases that are considered highly dangerous to the world and must be reported to the World Health Organization. Ex: Measles, Mumps, Smallpox

All of these infectious diseases must come from somewhere, meaning they all have a point of origin. The source, or the origin, is known as the ‘reservoir’. There are 2 different ways that a disease can be passed from the reservoir to a human.

• Horizontal Transmission: passed directly from a site to a victim. Such as being coughed on by someone with a cold and then picking up a cold yourself.

• Vertical Transmission: a disease that is passed generationally from mother to child. This can be something like HIV/Aids or Rubella.

How the disease makes its way into the host is its ‘portal of entry’. Portal of Entry can be through the skin, through the mouth, or through the nose when something is inhaled or ingested.

• Fomites are reservoirs that can transmit diseases but are inanimate. They somehow make contact with the portal of entry and pass along a disease.

But how does one control the spread of an Infectious Disease?

3 Steps.

1. Isolation- remove the infected individual from the public so that the disease can no longer be transmitted from human to human

2. Quarantine- Quarantine the victim so that they can be safely treated and overcome the disease without endangering others. Quarantine can also be done by those who have yet to be infected and works to prevent anyone from being infected.

3. Disinfection- clean and disinfect anywhere or anything that the infected person made contact with. This minimizes the chances of the disease being passed along. Disinfection is especially important for Bloodborne Pathogens.

Examples of Bloodborne Pathogens are things like: HIV, HBV, and HBC