Infectious Disease

Infectious Disease

Shiken premium Upgrade Banner

Infectious disease is different from other diseases. While most diseases are caused by things like genetics or lifestyle choices, infectious diseases are caused by germs that can spread from person to person. There are many different types of infectious diseases, and they can affect both your body and your mind. Some infectious diseases are easy to catch, like the common cold, while others are more serious and can even be life-threatening. It's important to take steps to protect yourself from infectious diseases, like washing your hands frequently and getting vaccinated. By doing so, you can help keep yourself and those around you healthy.

What are Infectious Diseases?

Infectious diseases are caused by tiny organisms called pathogens, which can make you sick if they get into your body. These diseases can be spread from person to person, or from animals to people. Some infectious diseases, like the flu, can make you feel sick for a few days. Others, like tuberculosis, can last for a long time and cause serious health problems. There are many different types of infectious diseases, and each one is caused by a different pathogen. It's important to take steps to protect yourself from these diseases, like washing your hands and avoiding contact with sick people. By doing so, you can help prevent the spread of infectious diseases and keep yourself healthy.

How are Infectious Diseases spread?

Infectious diseases can spread from one person to another through direct contact with an infected person. This means that the pathogen must spread through its host, as it can't survive outside the human body. However, some infectious diseases can be transmitted indirectly, such as through contaminated water or food, or through contact with animals or faeces. Vectors, such as mosquitoes, can also transmit diseases like malaria from one host to another.

The host is the organism that carries the pathogen, while a fomite is an object that can transmit the disease. A vector is a living organism that can spread the pathogen from one host to another. Communicable diseases can affect animals and plants too, and can be passed between organisms of the same species or even jump species.

Sometimes, a person can be infected with a pathogen without showing any symptoms. They may not even know they're infected, but can still spread the disease to others. These people are known as asymptomatic carriers.

Each pathogen has its own way of causing illness and spreading among a population. It's important to understand these mechanisms in order to prevent, treat, and cure infectious diseases.

Importance of Infectious Diseases

Infectious diseases continue to be a major global health problem, even though we have made significant progress in reducing deaths caused by them. Diseases like TB and malaria still kill many people, especially in low-income countries where health services are weaker and less effective treatment options are available.

The COVID-19 pandemic is a stark reminder of how quickly an infectious disease can spread and cause devastation across the world. It has caused millions of deaths and has become an endemic disease that we will likely have to live with for a long time. However, vaccines have been developed to help prevent the spread of the virus and reduce severe illness and death.

Infectious diseases can cause epidemics and pandemics, which can have a significant impact on global health. Vaccinations are an essential tool in breaking the transmission cycle of pathogens and preventing the spread of infectious diseases. Although the number of deaths caused by infectious diseases has decreased in recent years, we must continue to invest in research to develop more effective treatments and vaccines to combat these diseases and improve global health.

Types of Infectious Diseases

Infectious diseases are caused by different types of pathogens, including bacteria, viruses, protoctista, and fungi. Bacteria are prokaryotic organisms that can cause diseases such as tuberculosis and cholera. They are divided into two main categories, Gram-positive and Gram-negative bacteria, based on their cell wall structure.

Viruses are non-living entities that require a host to replicate and cause various viral infections such as COVID-19 and HIV. Protoctista are eukaryotic parasitic organisms that can affect humans, animals, or plants, causing infections, most notably malaria. Fungi are eukaryotic organisms that cause fungal infectious diseases that primarily affect plants.

All of these pathogens cause damage to the host's tissue, either directly or through the production of toxins, which can result in various symptoms of the infectious disease. The type of damage and how the body responds to it determine the severity and course of the disease. Effective treatments and prevention strategies depend on understanding the specific pathogen responsible for the infectious disease.

Infectious Diseases examples

Infectious diseases continue to pose a significant threat to global health, with bacterial and viral infections being the most concerning. However, efforts to eradicate diseases like smallpox have been successful, demonstrating the effectiveness of vaccination and surveillance programs.

Malaria remains a significant threat to human health, particularly in areas where effective prevention and treatment options are limited. Despite efforts to decrease mortality rates, a substantial portion of the world's population still lives in areas at risk of contracting the disease.

Continued research and development of effective treatments and prevention strategies for infectious diseases are critical to improving global health outcomes and reducing the impact of these diseases on our communities. 

Infectious Viral Diseases

HIV/AIDS and COVID-19 are two of the most well-known viral infectious diseases today. Acquired immune deficiency syndrome (AIDS) is caused by the retrovirus Human Immunodeficiency Virus (HIV) and was officially recognized in 1981. According to the World Health Organization (WHO), at least 25 million people had died from this disease by 2010, and people are still dying today, especially in low-income countries in sub-Saharan Africa, where approximately 70% of deaths from this disease occur.

HIV remains one of the most elusive infectious diseases to treat. As of 2022, there is still no cure for AIDS or vaccination against HIV, but treatment options have been very successful at increasing life expectancy and delaying the onset of AIDS. HIV attacks and destroys the body’s immune system, specifically helper T lymphocytes, which are involved in responding to infections. When these cells are damaged, and our immune system is compromised, it gives rise to opportunistic infections. AIDS is a collection of these diseases brought about by the immunodeficiency caused by HIV.

To learn more about HIV treatment, the CDC provides information about two types of HIV treatment: pills and shots. The classes of anti-HIV drugs include non-nucleoside reverse transcriptase inhibitors (NNRTIs), nucleoside reverse transcriptase inhibitors (NRTIs), protease inhibitors (PIs), fusion inhibitors, CCR5 antagonists, integrase strand transfer inhibitors (INSTIs), and post-attachment inhibitors. The National Institutes of Health (NIH) also provides information about HIV treatment, which involves taking a combination of HIV medicines (called an HIV treatment regimen) every day. provides an overview of HIV treatment, which is recommended for everyone with HIV.Finally, NIH also provides information about what to start when choosing an HIV treatment regimen.

Infectious Bacterial Diseases

Cholera and TB are two examples of infectious bacterial diseases that continue to pose a threat to global health. Cholera is caused by the pathogenic bacteria Vibrio cholerae and is transmitted through contaminated water and food sources, particularly in developing countries where access to proper sanitation and uncontaminated food is problematic. TB, on the other hand, is caused by the Mycobacterium tuberculosis or the Mycobacterium bovis bacteria and primarily targets human cells in the lungs. TB is a serious condition that leads to the death of millions of people every year, with the HIV pandemic exacerbating the problem.

Successful antibiotic treatments exist for both cholera and TB, but antibiotic-resistant bacteria are becoming a problem. As antibiotic resistance spreads, it brings a re-emergence of these diseases that were once thought to be nearly eradicated. Continued research and development of new treatments and prevention strategies that take into account antibiotic resistance are essential to combat these diseases effectively.

It is crucial to note that infectious diseases are divided into four main groups according to the pathogen responsible: bacteria, viruses, Protoctista, and fungi. Understanding the different types of infectious diseases and their causes is essential to developing effective treatment and prevention strategies and improving global health outcomes.

Infectious Disease

What are infectious diseases?

Infectious diseases are illnesses caused by pathogens that can spread between organisms and infect people, animals, or plants simply through exposure to the pathogen or other infected organism.

What are the different types of infectious diseases? 

Infectious diseases are divided according to the disease-causing pathogen: BacteriaVirusesFungiProtozoa/Protoctista

What are some examples of infectious diseases?

Tuberculosis (TB), COVID-19, cholera, Malaria, HIV/AIDS.

What are the causes of infectious diseases?

Infectious diseases are caused by pathogens, which are infective agents of disease.

How are infectious diseases spread?

Contact with an infected organism or direct contact with the pathogen.

Join Shiken For FREE

Gumbo Study Buddy

Try Shiken Premium
for Free

14-day free trial. Cancel anytime.
Get Started
Join 20,000+ learners worldwide.
The first 14 days are on us
96% of learners report x2 faster learning
Free hands-on onboarding & support
Cancel Anytime