9781422276150

How Does a Virus Infect? In order to grow and reproduce, viruses must enter the host cells. Once inside, they multiply in number and spread, making the host sick. Inside the host body they multiply by replicating their genetic material (DNA or RNA) with the help of the host’s genetic material.

Body’s Response to Viral Infection The immune system of our body protects us against germs. Germs generally get

stuck in thick mucus or the hairy lining of the nose. Once the germs reach the organs, they cause diseases. However, in that case the body’s own defensive mechanism— the immune system—is activated. In case of a strong viral attack, external help in the form of vaccines prescribed by a doctor may be required.

SIDEBAR: DID YOU KNOW?

• While antibiotics can kill bacteria, they are not effective against viruses. • Viruses can lie dormant in the body for long periods of time and may not show any symptoms of the disease.

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