Definitions of Signs, Symptoms, and Conditions of Ill Travelers

To assist medical and non-medical staff in identifying ill persons, CDC provides the following signs and symptoms that might indicate communicable diseases.


  • CDC considers a person to have a fever when he or she has a measured temperature of at least 100.4 °F [38 °C].
  • Fever may be considered to be present if a person has not had a temperature measurement but
    • feels warm to the touch, or
    • gives a history of feeling feverish.

Note: Even though measured temperature is the preferred and most accurate method to determine fever, it is not always possible to do this. In certain situations, other methods of detecting a possible fever should be considered:

  • self-reported history of feeling feverish when a thermometer is not available or the ill person has taken medication that would lower the measured temperature.
  • appearance of a flushed face, glassy eyes, or chills if it is not feasible to touch the person or if the person does not report feeling feverish.

The presence of fever suggests an infectious cause, but fever is not always present with an infection.

Skin rash means abnormal areas on the skin that may appear as discolored bumps or flat spots or areas, or blisters or bumps containing fluid or pus that are intact or crusted over. “Rash” includes insect bites or parasite lesions.

  • Color: ranges from light-colored to red or pink, purple, or black, but can also be the same color as the person’s skin tone.
  • Texture: can be flat, raised, blister-like, or crusted. In some diseases, such as chickenpox, areas with more than one of these characteristics can be found at the same time.
  • Select the most appropriate description of the rash’s appearance:
    • Maculopapular: A red rash with both flat red areas (macules) and small bumps (papules) that may run together.
    • Vesicular/Pustular: Small bumps filled with fluid that can be clear or cloudy (vesicles) or filled with a thick, opaque fluid (pustules).
    • Purpuric/Petechial: Red or purple discolorations caused by bleeding under the skin or mucous membranes; they do not blanch or fade with pressure. Petechial lesions appear as small, reddish freckles, while purpuric lesions cover larger areas.
    • Scabbed: Lesions that are crusted over.
    • Other: Enter a short description of the rash appearance if the other options do not apply.
  • Pattern: can be disconnected (discrete) or run together (confluent).
  • Location: may include one area of the body, such as the face, or more than one area.

Fever plus rash may indicate communicable diseases such as chickenpox, measles, or rubella (German measles).

Conjunctivitis means the person has inflammation of the eye or inner eyelid tissue (conjunctiva). Symptoms include redness, pain or itching, and discharge (fluid or pus).

Coryza means the person has a runny nose or congestion caused by inflammation of the mucous membranes of the nose.

Persistent cough means that the cough is frequent and severe enough to catch the attention of the crew or another passenger.

Cough with blood (bloody sputum) means that the person is coughing up blood.

Persistent cough may indicate diseases of public health concern, such as pertussis, tuberculosis, legionellosis, or influenza.

Sore throat means painful throat or pain on swallowing.

Difficulty breathing or shortness of breath means the person is

  • unable to move enough air into or out of the lungs, or can do so only with an unusually great effort
  • gasping for air,
  • feeling “short of breath,” or unable to “catch” his/her breath
  • breathing too fast or shallowly, or using muscles of stomach, chest or neck to breathe (especially for children).

Difficulty breathing—especially with fever—may indicate a traveler has a respiratory infection, such as pneumonia, diphtheria, or influenza.

Swollen glands means the person has enlargement of the glands (lymph nodes) located in the head, neck, axilla (armpit), or groin.

Acute gastroenteritis (inflammation of stomach or intestines or both), defined as:

  • Diarrhea, defined as within a 24-hour period, 3 or more episodes of loose stools or an occurrence of loose stools that is above normal for the person, or
  • Vomiting and one or more of the following additional symptoms: one or more episodes of loose stools in a 24-hour period, abdominal cramps, headache, muscle aches, or fever (temperature of 100.4°F [38°C] or greater);

Diarrhea defined as above and the diarrhea is frequent and severe enough that

  • other people notice, for example, the person going to the restroom numerous times, or the
  • ill person or another passenger voices concern about it.

Diarrhea may indicate the person has acute gastroenteritis, such as norovirus, Salmonella, or cholera.

Persistent vomiting means that the person

  • has vomited two or more times (other than seasickness) and
  • either expresses concern to the crew or it comes to the attention of others onboard (crew or passengers).

Persistent vomiting may indicate the person has acute gastroenteritis, such as Salmonella or norovirus infection.

Jaundice means the person has yellowish discoloration of skin and/or whites (sclera) of the eyes.

Acute (new onset) jaundice can be a sign of a liver infection, such as hepatitis A.

Headache means the person has head pain of unusual severity.

Neck stiffness means the person has difficulty moving the neck or severe pain during neck movement.

Decreased level of consciousness or confusion means the person

  • is not fully aware of the surroundings and may be confused about who he or she is, where he or she is going, or the time of day/week,
  • does not respond normally to questions or painful sensations, or
  • may appear to be sleepy, groggy, unresponsive, or difficult to awaken.

Decreased consciousness, especially in the presence of fever or rash, may indicate the traveler has a serious neurological infection, such as meningococcal meningitis, or a serious infection in another body system.

Recent onset of focal weakness and/or paralysis means new weakness or complete paralysis (difficulty moving or unable to move) of the arms, legs, neck, or the muscles used for swallowing or breathing; unrelated to trauma.

Bruising or bleeding (without previous injury) means the person has noticeable and unusual bruising or bleeding from gums, ears, nose, or areas on the skin with no obvious explanation (such as injury), is vomiting blood, or has bloody stool or urine.

Bruising or bleeding, especially in the presence of fever, may indicate that the person has a hemorrhagic fever, such as Ebola.

Obviously unwell means the person appears ill enough to require medical care.

Chronic condition means the person has a noninfectious medical condition of at least 1 month’s duration, such as cancer, diabetes, cardiovascular disease, emphysema, asthma, rheumatoid arthritis, gastric reflux, inflammatory bowel disease, lupus, or glaucoma.

The passenger or crew member may be receiving treatment for these conditions, and the conditions may affect multiple organ systems.

Asymptomatic means a person who does not report or appear to have any symptoms or signs of illness.

Injury means a wound or trauma, harm or hurt, usually used to refer to damage inflicted on the body by an external force.

Pneumonia means an infection of the lungs that can cause mild to severe illness. It can be caused by viruses, bacteria, and fungi. Pneumonia can be diagnosed through a medical examination or by imaging of the lungs such as with a chest x-ray.

Muscle Aches

Other means the symptom or sign does not fall under any of the other listed signs or symptoms (e.g., pain, itching, feeling weak, dizziness, psychiatric symptoms [inappropriate behavior])

Abdominal Cramps