Bacterial Infections and Viral Infections: Symptoms and Information

Though microscopic, bacteria and viruses can have massive implications for human health. Bacteria are tiny organisms that consist of a single cell,¹ and viruses are pieces of genetic material (DNA or RNA) contained in protein cases.² Both are among the most common causes of infection.³ Bacterial and viral infections happen when bacteria or viruses enter the body, reproduce, and cause disease.^4,5

Bacterial infections and viral infections can range from mild to severe. Some may go unnoticed, but others can be deadly.⁵

What are bacterial and viral infections?

Bacteria and viruses are everywhere. While some can make us sick, others are harmless or even support our health.⁶ Bacteria causes bacterial infections, some of which can be treated with antibiotics. Viruses cause viral infections, which cannot be addressed using antibiotics.⁷

Before a bacterial or viral infection can begin, viruses and bacteria first need to enter the body.⁴ They can get in through sources such as food, water, and wounds. Insect and animal bites can also transmit viruses and bacteria to people.⁶

Simple contact with viruses and bacteria can lead to viral infection and bacterial infection. For example, someone may fall ill after touching a contaminated surface and then touching their eyes, mouth, or nose. People can also breathe in droplets spread through coughs or sneezes.⁶

How do bacterial and viral infections affect the body?

Bacteria and viruses become problematic when they lead to infections.⁴ In an infection, the bacteria or virus damages healthy cells, which can cause symptoms you feel when you are sick.^8,9

Symptoms of bacterial and viral infections include but are not limited to:¹⁰

Fever¹⁰
Fast heartbeat¹⁰
Anxiety¹⁰
Fatigue¹¹
Decreased appetite¹¹
Pain¹¹

References
1. Bacteria. National Human Genome Research Institute. https://www.genome.gov/genetics-glossary/Bacteria. Updated March 24, 2023. Accessed May 10, 2023.
2. Virus. National Human Genome Research Institute. https://www.genome.gov/genetics-glossary/Virus. Updated March 24, 2023. Accessed May 10, 2023.
3. Are all infectious diseases caused by viruses and bacteria? National Academies of Science, Engineering, and Medicine. https://www.nationalacademies.org/based-on-science/are-all-infectious-diseases-caused-by-viruses-and-bacteria. Updated May 20, 2022. Accessed May 17, 2023.
4. How infections spread. Infection control. Centers for Disease Control and Prevention. https://www.cdc.gov/infectioncontrol/spread/index.html. Updated January 7, 2016. Accessed May 10, 2023.
5. Infectious diseases. MedlinePlus. https://medlineplus.gov/infectiousdiseases.html. Updated February 14, 2018. Accessed May 10, 2023.
6. Germs and hygiene. MedlinePlus. https://medlineplus.gov/germsandhygiene.html. Updated September 23, 2020. Accessed May 10, 2023.
7. Viruses or Bacteria: What’s Got You Sick? Centers for Disease Control and Prevention. https://www.cdc.gov/antibiotic-use/pdfs/VirusOrBacteria-Original-P.pdf. Accessed May 10, 2023.
8. Bacterial infections. MedlinePlus. https://medlineplus.gov/bacterialinfections.html. Updated June 28, 2018. Accessed May 10, 2023.
9. Viral infections. MedlinePlus. https://medlineplus.gov/viralinfections.html. Updated August 31, 2016. Accessed May 10, 2023.
10. Overview of infectious disease. Merck Manual. https://www.merckmanuals.com/home/infections/biology-of-infectious-disease/overview-of-infectious-disease. Updated September 2022. Accessed May 17, 2023.
11. Bacteria, virus, fungi, and infectious diseases. Human Physiology, Biochemistry, and Basic Medicine. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7173549/. Published October 30, 2017. Accessed May 17, 2023.