4 Basic Types of Infectious Diseases and their Differences

4 Basic Types of Infectious Diseases and their Differences

Here’s a quick Bio 101 lesson to help you better understand what the Novel Coronavirus is. After reading this article, we highly recommend also reading our articles on the different types of major viruses, including SARS, MERS, and the Novel Coronavirus.

There are 4 basic types of infectious diseases in humans – viral, bacterial, fungal, parasitic.


These are living organism, sometimes large enough to be seen with the naked eye, that live inside our bodies usually attaching themselves to organs to feed. Symptoms are sometimes not easily noticed, and many people can live effectively normal for years with a parasitic infection. These can usually be easily cured with medicine once identified and rarely cause long term damage.


“Athletes foot”, or technically Ringworm, is one of the most well-known examples of a fungal infection. While the medical term “ringworm” contains the word “worm”, it’s not a parasite or animal at all. Instead, it’s a fungus just like mold or yeast. Fungal infections are rarely ever fatal and can nearly always be cured via medication. They usually cause discomfort and in some cases localized pain in the area of the infection. Detection can be much easier than other types of infections as they usually give clear indications such as rash, redness, skin discoloration, localized dead skin for outer infections, or a noticeable discharge for inner infections.


These are microscopic, living organism that attack our immune system. There are thousands of different bacteria, some of which are beneficial (our stomachs are filled with helpful bacteria). A bacterial infection can be diagnosed through blood and urine tests. Symptoms vary widely depending on which bacteria has caused the infection.

The good news for bacterial infections is that they are almost always curable through taking antibiotics, and symptoms often improve significantly within 3 days of beginning antibiotic treatment. However, many bacteria have developed immunity to common antibiotics and thus may need different and stronger treatments for full recovery. In absence of antibiotics, most people are able to recover on their own with rest, fluids, and proper nutrition (most people’s immune systems are strong enough to fight most bacterial infections); however in the absence of antibiotics, recovery can take an extended time and often there is further discomfort for the patient. In somewhat rare cases, both treated and untreated bacterial infections can be deadly, especially for people with weakened immune systems.


On the size scale, from large to small, it goes parasites (the largest), then fungus, then bacteria, and finally, the tiniest of the tiny are these pesky little guys – viruses. Some viruses can’t even be seen with a regular microscope and instead need the extra powerful electron microscope for visual confirmation. The Novel Coronavirus is a virus.

Also, on the scale of danger, viruses are nearly always considered to be the most dangerous of all infections. Why? Well, here’s the bad news – there are no “cures” for any viruses. Antibiotics only work on bacteria, not viruses. The best defense humans have for viral infections is immunization (aka, vaccine or inoculation). The process of how vaccines work is a bit complicated to fully explain here, but basically it involves giving humans a dead version of a virus so our bodies’ immune systems can make extra strong antibodies (note, that’s antiBODIES, not antiBOTICS – two very different things) and those antiBODIES are our best defense against viruses.

Vaccines will help your body beat a viral infection so you don’t develop symptoms (in other words, so you don’t contract the virus). But, if you don’t get vaccinated, and you do contract a virus, then since there is no cure, the only way to beat these microscopic beasties is to … just wait it out (cue disappointed sigh). Get lots of rest, plenty of fluids, proper nutrition, staying warm (even when running a fever), and eventually, most people will recover. In fact, the lack of having any cures for viruses is the leading reason why getting vaccinated is so important – it’s your biggest, most powerful defense. However, for some viruses (like 2019-nCoV), there doesn’t exist any vaccination (these can take years to develop, for complicated reasons, but often due to the scary fact that viruses can mutate and adapt, so a vaccine developed for virus X version 1.0 may be ineffective against virus X version 4.0). Having no cure after infection is what makes viruses so dangerous.

What are the symptoms of the Novel Coronavirus?

Symptoms for viral infections often mirror symptoms for bacterial infections, so the only way to know if you’re the “lucky one” with a curable bacterial infection or the “unlucky one” with a viral infection is via blood tests. For more information on the different types of major viruses, including SARS, MERS, and 2019-nCoV.

So what can I do to protect myself and my family from getting infected with viruses, such as 2019-nCoV, for which there are no vaccines? In one, mega-important word – “prevention”. This is hands down the absolute best way to protect oneself and one’s family – prevent, prevent, prevent. While it’s unnecessary and impractical to implement maximum prevention measures such as wearing a hazmat suit, during times of higher infection rates (ie, during the current outbreak of 2019-nCoV) there are several preventive measures we can take.

For important, possibly life-saving, information on the below actions, please read our article on this subject, “Best practices: Wearing masks, Covering our coughs/sneezes properly, Cleaning and Hand Washing to kill Viruses and Bacteria”. Taking the following actions, but doing them improperly, can put you and your family, at risk.

  • Wear a mask. For even more wear earplugs and eye protection.
  • Wash your hands for 20 seconds.
  • Wipe your hands with an alcohol pad and let them dry.
  • Use hand sanitizer and rub your hands for around 30 seconds, then let dry.
  • Cover all coughs and sneezes with your arm/inner elbow/tissue, NOT your hand.
  • Clean surfaces regularly with 10% bleach and leave it on for a while.

  • Should I use BLEACH or ALCOHOL? Do disinfectant wipes/sprays work? Check our article here.

  • Boost that immune system – (note: BE CAREFUL when reading online for this topic as there is an excessive amount of misleading/false information) For important information on this topic, please see our article “Top 3 ways to boost your immune system and protect yourself from 2019-nCoV”.
By Eric M. Meyer
Senior Editor


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