Difference between Virus and Bacteria

Difference between virus and bacteria provides the information for scientific studies to analyze the main causative agents of various diseases. Virus and bacteria are microscopic agents, they can cause various diseases and even cancers. Virus exhibits host-dependent reproduction (requires living host). While, bacteria can grow anywhere on the earth without any host.


Difference between virus and bacteria (Virus vs Bacteria)
S.NO Characteristics/


Virus Bacteria
1 Examples Bacteriophage, HIV, Hepatitis A virus, Rhino Virus, etc. Clostridium tetani, Acinetobacter baumannii, Klebsiella pneumoniae, Pseudomonas aeruginosa, etc.
2 Living/Non-Living Between living and non-living things. True living organism.
3 Size Smaller in size ranging from 20-400 nm. Larger in size, around 1000 nm.
4 Number of cells Viruses is not a cell, hence, considered as particle, the genetic material is enclosed by protein coat. Bacterium is unicellular organism contains cytoplasm but doesn’t contain cellular organelles like eukaryotic cell.
5 Cell Wall Cell wall is absent. Instead, Protein coat protect the genetic material. The well-organized cell wall is present (composite of Peptidoglycan and Lipopolysaccharide).
6 Cellular Machinery Lack cellular machinery. Contain a cellular machinery.
7 Energy production Virus cannot produce any energy molecule. Bacteria can produce ATP as energy molecule.
8 Ribosomes Absent. Present 70S Ribosomes. (Made of 50S and 30S subunits).
9 Microscopic study We can study only under Electron Microscope (EM). We can study under Light Microscope and EM.
10 Genetic material Genetic material of the virus is either DNA or RNA. Bacterial genetic material is only DNA, however, RNA act as messenger molecule for DNA.
11 DNA and RNA DNA or RNA enclosed inside the protein coat. DNA and RNA are freely floating in cytoplasm.
12 Reproduce Requires living host or cell to reproduce. Bacterium can reproduce itself.
13 Reproduction Enters  the host cell and takes over the cell using it to replicate  viral DNA/RNA copies. Destroys the host cell releasing new viruses. Fission- a form of asexual reproduction.
Type of Infection
Affects the entire body (Systemic) ex:- Flu. Bacteria generally show localized infection, however, sometime, localized invasive infection will be resulted into further systemic manifestations such as sepsis.
15 Durability of illness Most viral symptoms last 2 to 10 days. Bacterial symptom commonly will last longer than 10 to 20 days.
16 Fever A viral infection may or may not cause a fever. A bacterial illness significantly causes a fever.
17 Benefits Viruses are not directly useful, however some viruses can be used in genetic engineering to transfer the gene and used in treatment of brain cancer to kill inhibit the cell growth. Some bacteria are directly beneficial to eukaryotes (Normal Flora) and indirectly benefit for food production (food and beverage industry).
18 Diseases/Infections Rubella, Measles, AIDS, Chickenpox, Chikungunya, Common cold, influenza, etc. Tetanus, Botulism, and Ulcers, Lyme disease, Leprosy, Tuberculosis, Typhoid fever, Cholera, plague, Diphtheria, Meningitis, Pneumonia, etc.
19 Treatment Antibodies cannot inhibit the viral infection. However, treatment with interferons may give best result. Antibiotics are major drugs to kill the bacteria. Different chemical compounds (organic and inorganic) also can inhibit the growth of this organism.


Important points

  1. Regular use of particular antibiotic provides bacteria to get resistance.
  2. Virus particle size is very small compared to bacteria and need living cell — such as human cell, plants or animal cell to reproduce. Otherwise, they can’t persist.
  3. Both bacteria and virus can cause their distinct diseases. However, in some cases, it may be hard to conclude whether a bacterium or a virus is causing the symptoms. For instant diarrhea, pneumonia, and meningitis can be caused by either viruses or bacteria.
  4. The large difference between viruses and bacteria is viruses can only grow and replicate inside the living cell – such as bacteria, plant or animal – to reproduce, while bacteria can grow on non-living surfaces such as normal agar media.
  5. Bacterium is intercellular organism (they live in-between cells); whereas viruses are intracellular organisms, they must enter the cell, otherwise they will not survive.
  6. Viral infection some times related to cause cancer and there is some evidence that bacteriamay be directly carcinogenic.
  7. Interferon if protein molecule that able to inhibit the multiplication of viruses.
  8. Interferon medication used to treat virus infections (e.g., chronic hepatitis B, chronic hepatitis C, condylomata acuminata). In some cases, it is also used to treat several cancers (e.g., leukemia, melanoma, AIDS-related Kaposi’s sarcoma).



Data source

  1. Nasir A, Sun FJ, Kim KM, Caetano-Anollés G Untangling the origin of viruses and their impact on cellular evolution.Ann N Y Acad Sci. 2015 Apr;1341:61-74. doi: 10.1111/nyas.12735. Epub 2015 Mar 10.
  2. Chapter 41Structure and Classification of Viruses. Hans R. Gelderblom.
  3. Hong C, Oksanen HM, Liu X, Jakana J, Bamford DH, Chiu W. A structural model of the genome packaging process in a membrane-containing double stranded DNA virus. PLoS Biol. 2014 Dec 16;12(12):e1002024. doi: 10.1371/journal.pbio.1002024. eCollection 2014 Dec.
  4. Bamford JK, Bamford DH, Li T, Thomas GJ Jr. Structural studies of the enveloped dsRNA bacteriophage phi 6 of Pseudomonas syringae by Raman spectroscopy. II. Nucleocapsid structure and thermostability of the virion, nucleocapsid and polymerase complex. J Mol Biol. 1993 Mar 20;230(2):473-82.
  5. Milton R.J. Salton and Kwang-Shin Kim. Chapter 2Structure. Medical Microbiology. 4th edition.
  6. Thomas J. Silhavy, Daniel Kahne, and Suzanne Walker. The Bacterial Cell Envelope. Cold Spring Harb Perspect Biol. 2010 May; 2(5): a000414. doi: [10.1101/cshperspect.a000414].


Leave a Reply

Your email address will not be published. Required fields are marked *