Though they display similar symptoms, and are similar in many respects, there are many differences between bacteria and viruses, and especially the diseases that they cause.

Every infection that the human body is afflicted by is primarily caused by two sources – bacteria or viruses. Both these class of organisms are pathogens (dangerous microscopic organisms), and have the ability to cause some form of illness to human beings.

Viruses are parasites, and as a result all viruses cause harm to the body, but bacteria are actually useful to the body as well. Only about 10% of the bacteria actually cause harm to the human body.

Differences between Viral Infection and Bacterial Infection

The infections caused by both sets of pathogens can escalate immensely if left untreated. The fundamental differences between the two sets of organisms are discussed below.

What is Viral Infection?

Viruses are microscopic organisms that are parasitic in nature. What this means is that they are dormant when they exist by themselves in the air, but when they enter a host’s body they get active and begin multiplying and reproducing.

Viruses unequivocally require a host in order to get active and reproduce, and share a symbiotic relationship with the host’s body. The strain that they generate on the host’s body produces an illness in the host, and this is the primary difference between the two.

In human beings, the most vulnerable cells of the body that are prone to getting attacked by viruses are the mucous membrane cells. Since there is no protective skin surrounding these cells, they are easily attacked.

Common colds, flu and various other viral infections are caused by the viruses attacking these mucous membranes. The following are the 4 basic types of viruses.

Helical; Enveloped; Complex; Icosahedral

Once a virus enters inside the body it becomes very hard for the body’s natural antibodies to locate and fight these viruses, as they hide themselves well behind various cells of the body. But once the infection starts spreading, antibodies are produced to combat these viruses, which eventually knock them out.

What is Bacterial Infection?

Unlike viruses, bacteria are one celled organisms that are asexual in nature. This means that they are capable of reproducing on their own. There are millions of different types of bacteria present in the air, and they all perform fixed tasks.

Not all these bacteria are harmful to the human body, and this is a crucial difference in the study. The four types of bacteria, based on their shapes, are as follows.

Cocci; Bacilli; Vibrio; Spirochaetes

The body releases many types of antibodies to combat the diseases, if they happen to enter the body. In most cases, a certain dosage of antibiotics is also necessary to aid the body in this process.

Unlike viruses, bacteria are not parasitic in nature and do not need to depend on a host in order to get active and reproduce.

How Viral Infection and Bacterial Infection enter in to the Body:

As is evident from the difference in properties of the two sets of pathogens, the ways they enter the human body are different from each other. The following are the ways that viral infections enter the body through viruses.

Coughing by an infected person; Sneezing by an infected person; Vomiting by an infected person; Bite from an infected insect or animal; Inadequate personal hygiene.

Now we shall see the ways that bacterial infections enter our body through disease causing bacterium.

Close contact with a person who is infected; Food or water that is contaminated; Touching surfaces or objects that are contaminated; Cuts and abrasions on the surface of the skin.

What is Protozoa Infection?

Protozoa are Single-celled eukaryotes (organisms that possess membrane-bound organelles and nuclei) Protozoa are found as ubiquitous free-living organisms in the environment.

They are classified as sporozoa (intracellular parasites), flagellates (which possess tail-like structures for movement), amoeba (which move using temporary cell body projections called pseudopods), and ciliates (which move by beating multiple hair-like structures called cilia).

Infections caused by protozoa can be spread through ingestion of cysts (the dormant life stage), sexual transmission, or through insect vectors. Common infectious diseases caused by protozoans include malaria, giardia and toxoplasmosis.

As components of the micro- and meiofauna, protozoa are an important food source for micro-invertebrates. Thus, the ecological role of protozoa in the transfer of bacterial and algal production to successive atrophic levels is important.

As predators, they prey upon unicellular or filamentous algae, bacteria, and micro-fungi. Protozoa are both herbivores and consumers in the decomposer link of the food chain.

They also control bacteria populations and biomass to some extent. Protozoa such as the malaria parasites (Plasmodium spp.) trypanosomes and leish-mania, are also important disease causing agents in humans.

In summary, we have briefly discussed the viral, bacterial and protozoan and how they enter the body. The various ways through which these pathogen cause diseases and how they are transmitted.