Background: White blood cells also make chemicals that cause a fever. A fever is a higher-than-normal body temperature. Normal human body temperature is 98.6°F (37°C). Most bacteria and viruses that infect people reproduce fastest at this temperature. When the temperature is higher, the pathogens cannot reproduce as fast, so the body raises the temperature to kill them. A fever also causes the immune system to make more white blood cells. In these ways, a fever helps the body fight infection.

Situation: Ben was feeling tired and ache all day so he decided to go to bed. When Ben woke  up he felt even worse and his head felt hot. Ben went to the doctor who told him he had a fever and should get plenty of rest.

Question: Was Ben's temperature above or below 98.6 degrees F?

Situation: Ben was feeling tired and ache all day so he decided to go to bed. When Ben woke  up he felt even worse and his head felt hot. Ben went to the doctor who told him he had a virus that had caused a fever and he should get plenty of rest.

Question: Was the virus reproducing faster or slower?

Situation: Ben was feeling tired and ache all day so he decided to go to bed. When Ben woke  up he felt even worse and his head felt hot. Ben went to the doctor who told him he had a virus that had caused a fever and he should get plenty of rest.

Question: Was the fever helping or hurting the virus?

Situation: Ben was feeling tired and ache all day so he decided to go to bed. When Ben woke  up he felt even worse and his head felt hot. Ben went to the doctor who told him he had a virus that had caused a fever and he should get plenty of rest.

Question: Did Ben have more or less white blood cells?

Situation: Ann had not been feeling well for several days. When she woke up this morning she had a fever. She went to the doctors and was told she had the flu and should rest.

Question: Is Ann's temerature above or below 98.6°F?

Situation: Ann had not been feeling well for several days. When she woke up this morning she had a fever. She went to the doctors and was told she had the flu and should rest.

Question: Is Ann's temerature higher or lower than yesterday?

Situation: Ann had not been feeling well for several days. When she woke up this morning she had a fever. She went to the doctors and was told she had the flu virus and should rest.

Question: What is Ann's body fighting??

Situation: Ann had not been feeling well for several days. When she woke up this morning she had a fever. She went to the doctors and was told she had the flu virus and should rest.

Question: Is Ann's body making more or less white blood cells?

Situation: Ann had not been feeling well since yesterday. When she woke up this morning she had a fever. She went to the doctors and was told she had the flu virus and should rest.

Question: When was the virus reproducing fastest?

Situation: Ann had not been feeling well since yesterday. When she woke up this morning she had a fever. She went to the doctors and was told she had the flu virus and should rest.

Question: When was the virus reproducing slowest?

Situation: Ann had not been feeling well since yesterday. When she woke up this morning she had a fever. She went to the doctors and was told she had the flu virus and should rest.

Question: Is Ann's immune system working or not?