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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

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