What is the difference between bacterial and viral infections? 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That said, colonization does not necessarily cause infectious disease, as some viruses and bacteria can multiply within the body without causing harm. Bacteria and viruses exert their effect in similar ways, for example, by killing cells. However, bacteria can also cause the body to mount an excessive immune response, which in itself can cause significant damage to the body. In order to reduce the rate of bacterial and viral infections, scientists spend a lot of time learning how these pathogens interact with the body. Only then can they sufficiently prevent or treat the spread of disease. Read on to learn more about the difference between bacterial and viral infections. How are bacteria and viruses different Share on PinterestBacteria and viruses are two types of microbes. The table below outlines the differences between them. Bacteria Viruses 10–100 times larger than viruses Very small and are 20–40 nanometers (nm) in diameter Some are treated with antibiotics Some are treated with antiviral medications Reproduce by dividingEnter a living organism’s cells and use the cell’s machinery to reproduce Bacterial vs viral infections Initially, the body responds in a similar way to a bacterial or viral infection. Early symptoms usually indicate the body is trying to rid itself of a pathogen. A high temperature, for example, can inactivate viruses and help to denature bacteria, which is why fever is an initial infection symptom. Another immune response is to produce more interferon, a substance that plays a part in the body’s defense system. Interferon helps to stop viruses and bacteria from reproducing. However, in concentrated amounts, it can make someone feel tired and achy. Share on PinterestInfographic by Bailey Mariner How to tell the difference between bacterial and viral infections Common differences between bacterial and viral infections are the following: Bacterial infection Key signs include: symptoms lasting longer than 10–14 days fever can become exceptionally high fever gets worse over time rather than improving Viral infection Key signs include: if due to influenza virus (“the flu”), symptoms respond well to antiviral medication (within the first 48 hours)fever eases with time fever is uncomfortable but usually not dangerous What is a bacterial infection Bacterial infection occurs when one or more bacteria have entered the body and begin to multiply. However, not all bacterial infections cause disease. Bacteria have evolved to evade or manipulate the body’s immune system. So when pathogenic bacteria enter the body, they: release toxins may multiply very quickly to dominate an area kill cells can lead to a dangerously high immune response Examples of bacterial infections Common bacterial infections include: Bacterial skin infections Staphylococcus and Streptococcus cause skin infections, such as: impetigo cellulitis methicillin-resistant Staphylococcus aureus (MRSA) Bacterial respiratory infection Streptococcus pneumoniae bacterium commonly causes pneumonia. Pneumonia presents with lung inflammation and is a very serious and sometimes lethal infection. Other symptoms include: fever coughing up blood labored breathing breathlessness rapid heartbeat Bacterial sexually transmitted infections STIs Bacterial STIs include: chlamydia gonorrhea mycoplasma genitalium syphilis bacterial vaginosis What are viral infections Viruses are packets of DNA or RNA encased in a protein shell. Outside of the body, they lack the ability to reproduce. However, upon entering a living organism, the virus invades its cells and seizes control over the cell’s metabolic machinery to make copies of itself. After the virus makes enough copies, the cell bursts releasing them to infect more cells. Examples of viral infections There are many different types of viral infections. Viral skin infections Common viral skin infections include: chickenpox molluscum contagiosum shingles roseola Viral respiratory infections Common respiratory viruses include: Coronaviruses According to the Centers for Disease Control and Prevention (CDC), there are multiple different types of coronavirus. Some cause minor cold-like symptoms, while others result in severe health complications. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a new type of coronavirus. People exposed to the SARS-CoV-2 virus may go on to develop the novel coronavirus disease (COVID-19). Influenza and cold viruses Influenza viruses cause influenza, also called “the flu.” People who get flu typically experience: sore throat cough headachebody achesfever People with a common cold experience less severe symptoms and rarely develop fever. Viral STIs Viral STIs include: HIV hepatitis B virus herpes simplex virus human papilloma virus (HPV) Transmission of bacterial vs viral infections Bacteria and viruses move from one person to another by: Touch: If people do not wash their hands, they can transmit bacteria and viruses onto other surfaces, including food. Droplets: When a person sneezes or coughs, they create droplets that carry viruses and bacteria, which another person can inhale. Injury: Some bacteria and viruses enter the body through cuts and puncture wounds. Diagnosing bacterial vs viral infections To determine if a person has a viral or bacterial infection, a doctor will usually ask questions about their symptoms and perform a physical exam. To confirm a diagnosis, they may request tests, such as: Enzyme-linked immunosorbent assay (ELISA): This test can help to detect infection due to many viruses, including HIV and bacterial infections such as Lyme disease. Polymerase chain reaction (PCR): This test sequences the DNA of microorganisms, and can detect viral infections, such as HPV, in addition to bacterial infections including, Escherichia coli (E. coli). Electron microscopy: This type of imaging can be used to identify rare viral and bacterial infections that require high resolution to detect. However, because electron microscopy is an expensive diagnostic tool, doctors rarely request it. Treatment for bacterial vs viral infections Treatment for bacteria and viruses is different, and consequently, a prompt diagnosis is very important. Antibiotics Antibiotics are medicines that either kill or stop bacteria from reproducing. Different types of antibiotics target different bacterial infections. Antibiotics are not effective against viral infections. Antibiotics are available in the following forms: oral forms, such as pills, capsules, and liquids ear drops and eye drops topical forms, such as creams, ointments, and sprays If the infection is more severe, a doctor may recommend an antibiotic injection, intravenous infusion, or drip. Antivirals Antiviral drugs are medicines that work to stop viruses from reproducing. Each antiviral medication usually works on one specific virus or only a group of viruses. Remdesivir was the first antiviral to receive approval for the treatment of COVID-19 in October 2020. Preventing bacterial vs viral infections Preventing bacterial and viral infections is the best action to take to stop the spread of disease. Steps people can take to protect themselves include: washing their hands bandaging cuts covering their mouths when they cough or sneeze receiving vaccinations seeking advice before traveling to tropical destinations Summary Bacteria and viruses are different types of microorganisms, and some cause disease. Doctors typically use antibiotics to treat bacterial infections and antivirals for some viral infections. However, some infections are untreatable. The best way to prevent any type of infection is with good hygiene. Vaccines are an effective method for preventing certain viral and bacterial infections. A person should speak with their doctor if they think they have an infection. Last medically reviewed on May 24, 2022Public HealthInfectious Diseases / Bacteria / Viruses 16 sourcescollapsedMedical News Today has strict sourcing guidelines and draws only from peer-reviewed studies, academic research institutions, and medical journals and associations. We avoid using tertiary references. We link primary sources — including studies, scientific references, and statistics — within each article and also list them in the resources section at the bottom of our articles. You can learn more about how we ensure our content is accurate and current by reading our editorial policy.Antivirals. (2022).https://www.idsociety.org/covid-19-real-time-learning-network/therapeutics-and-interventions/antivirals/Antibiotic prescribing and use. (2021).https://www.cdc.gov/antibiotic-use/q-a.htmlCommon bacterial infections. (n.d.).https://www.antibioticresearch.org.uk/about-antibiotic-resistance/bacterial-infections/common-bacterial-infections/Drexier, M. (2010). What you need to know about infectious disease.https://www.ncbi.nlm.nih.gov/books/NBK209710/How to prevent infections. (2021).https://www.health.harvard.edu/staying-healthy/how-to-prevent-infectionsHuman coronavirus types. (2020).https://www.cdc.gov/coronavirus/types.htmlInfection control. (2016).https://www.cdc.gov/infectioncontrol/spread/index.htmlInfluenza (Flu). (2021).https://www.cdc.gov/flu/symptoms/symptoms.htmIs it a bacterial infection or virus? (2019).https://www.dukehealth.org/blog/it-bacterial-infection-or-virusLaboratory tests for viral infections. (n.d.).https://dermnetnz.org/topics/laboratory-tests-for-viral-infectionsOverview: Antibiotics. (2019).https://www.nhs.uk/conditions/antibiotics/Reich, N., et al. (2019). Too much of a good thing: Detrimental effects of interferon.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6884074/#:~:text=Adverse%20side%20effects%20can%20include,effects%20%5B7%2C%208%5D.Sexually transmitted infections (STIs). (2021).https://www.who.int/news-room/fact-sheets/detail/sexually-transmitted-infections-(stis)Singh Thandi, C., et al. (2021). Diagnosis and management of common viral skin infections.https://wchh.onlinelibrary.wiley.com/doi/full/10.1002/psb.1907#:~:text=Viral%20skin%20infections%20are%20a,)%2C%20molluscum%20contagiosum%20and%20roseola.Szymanski, C. M., et al. (2017). Essentials of glycobiology.https://www.ncbi.nlm.nih.gov/books/NBK453060/Tsao, Y. T., et al. (2020). Differential markers of bacterial and viral infections in children for point-of-care testing.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7522093/FEEDBACK:Medically reviewed by Stacy Sampson, D.O. — By Amanda Barrell on May 24, 2022 Latest newsWhat sets 'SuperAgers' apart? Their unusually large neuronsOmega-3 may provide a brain boost for people in midlifeSeasonal affective disorder (SAD): How to beat it this fall and winterCDC: Monkeypox in the US 'unlikely to be eliminated in the near future'Why are more women prone to Alzheimer's? 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