Spread by:

Contact with blood or body fluids.

Symptoms:

Fever, headache, weakness, vomiting, jaundice, joint pain, or there may be no symptoms.

Disease complications:

Chronic liver infection, liver failure, liver cancer.

Spread by:

The mouth

Symptoms:

Diarrhea, fever, vomiting

Disease complications:

Severe diarrhea, dehydration

Spread by:

Air and direct contact (diphtheria and pertussis); exposure through cuts in skin (tetanus).

Symptoms:

Sore throat, mild fever, weakness, swollen glands in neck (diphtheria); stiffness in neck and abdominal muscles, difficulty swallowing, muscle spasms, fever (tetanus); severe cough, runny nose, apnea (a pause in breathing in infants) (pertussis).

Disease complications:

Swelling of the heart muscle, heart failure, coma, paralysis, death (diphtheria); broken bones, breathing difficulty, death (tetanus); pneumonia, death (pertussis).

Spread by:

Air and direct contact

Symptoms:

There may be none unless bacteria enter the blood.

Disease complications:

Meningitis, intellectual disability, epiglottitis, pneumonia, death.

Spread by:

Air and direct contact.

Symptoms:

There may be none, or pneumonia can develop.

Disease complications:

Bacteremia, meningitis, death.

Spread by:

Air, direct contact, and the mouth

Symptoms:

Sore throat, fever, nausea, headache, or there may be no symptoms.

Disease complications:

Paralysis, death.

Spread by:

Air and direct contact.

Symptoms:

Fever, muscle pain, sore throat, cough, extreme fatigue.

Disease complications:

Pneumonia.

Spread by:

Air and direct contact.

Symptoms:

Rash, fever, cough, runny nose, pinkeye (measles); swollen salivary glands, fever, headache, fatigue, muscle pain (mumps); rash, fever, swollen lymph nodes (rubella).

Disease complications:

Encephalitis, pneumonia, and death (measles); meningitis, encephalitis, inflammation of show-overlayicles or ovaries, deafness (mumps). Rubella is very dangerous for pregnant women: It can lead to miscarriage, stillbirth, premature delivery, and birth defects.

Spread by:

Air and direct contact.

Symptoms:

Sudden onset of slight fever, feeling tired and weak. These symptoms are soon followed by an itchy, blister-like rash. The blisters tend to be more common on covered than on exposed parts of the body.

Disease complications:

Chickenpox is usually mild, but it can be serious in infants under 12 months of age, adolescents, adults, pregnant women, and people with weakened immune systems.

Spread by:

Direct contact and contaminated food or water.

Symptoms:

Fever, stomach pain, loss of appetite, fatigue, vomiting, jaundice, dark urine, or there may be no symptoms.

Disease complications:

Liver failure, joint pain, and kidney, pancreatic, and blood disorders.

Spread by:

Air and the mouth.

Symptoms:

Nausea, vomiting, confusion, sensitivity to light.

Disease complications:

Limb loss through amputation, hearing loss, problems with the nervous system, intellectual disability, seizures, strokes.