Definitions of Signs, Symptoms, and Conditions of Ill Travelers

At a glance

CDC provides the following explanations and examples of signs and symptoms that might indicate communicable diseases to assist medical and non-medical staff on conveyances, such as aircraft crew or vessel (ship) staff, in identifying ill persons for whom there is a regulatory requirement to report to CDC, or who may have a communicable disease with potential for transmission on board.

Ill Person

Federal regulations found at 42 Code of Federal Regulations (CFR) parts 70 and 71 define an "ill person" as someone who meets criteria for certain signs and symptoms. The definition depends on whether the person is on an aircraft or a vessel.

Aircraft

A person who has:

  1. A fever (has a measured temperature of 100.4 °F [38 °C] or greater, or feels warm to the touch, or gives a history of feeling feverish) accompanied by one or more of the following:
    1. skin rash
    2. difficulty breathing
    3. persistent cough
    4. decreased consciousness or confusion of recent onset
    5. new unexplained bruising or bleeding (without previous injury)
    6. persistent diarrhea
    7. persistent vomiting (other than air sickness)
    8. headache with stiff neck, or
    9. appears obviously unwell
  2. A fever that has persistent for more than 48 hours
  3. Symptoms or other indications of communicable disease, as the CDC may announce through posting of a notice in the Federal Register.

Vessel

A person who has:

  1. A fever (has a measured temperature of 100.4 °F [38 °C] or greater, or feels warm to the touch, or gives a history of feeling feverish) accompanied by one or more of the following:
    1. skin rash
    2. difficulty breathing or suspected or confrimed pneumonia
    3. persistent cough or cough with bloody sputum
    4. decreased consciousness or confusion of recnt onset
    5. new unexplained brusing or bleeding (without previous injury)
    6. persistent vomiting (other than sea sickness)
    7. headache with stiff neck, or
  2. A fever that persisted for more than 48 hours
  3. Acute gastroenteritis
  4. Symptoms or other indications of communicable disease, as the CDC may announce through posting of a notice in the Federal Register.

Definitions below with an asterisk (*)‎

Apply only to vessels to assist in completing the Maritime Conveyance Illness or Death Investigation Form.

Fever

For the purpose of this guidance, a measured temperature of 100.4°F [38°C] or greater, feeling warm to the touch, or giving 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 a measured temperature of 100.4°F [38°C] or greater
  • 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
  • feeling warm to the touch (for eample, a parent touching an ill child)
  • appearance of a flushed face or chills

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

Skin Rash

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

  • 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, meningococcal disease, or rubella (German measles).

Conjunctivitis*

Inflammation of the eye or inner eyelid tissue (conjunctiva); symptoms can include redness, pain, itching, and discharge (fluid or pus).

Coryza*

A runny nose or congestion caused by inflammation of the mucous membranes of the nose.

Conjunctivitis and coryza are early signs of measles but can be present with other infections (e.g., some viral respiratory infections) and noninfectious conditions (e.g., allergies).

Difficulty breathing or shortness of breath

  • Inability to move enough air into or out of the lungs, or doing so only with an unusually great effort,
  • gasping for air,
  • feeling "short of breath," or inability to "catch" one's 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 person has a respiratory infection, such as pneumonia or tuberculosis.

Persistent cough

Cough that is frequent or severe

Cough with bloody sputum

Mucus or phlegm coughed up from the lungs is tinged or flecked with blood.

Persistent cough may indicate a respiratory infection, such as pertussis, tuberculosis, legionellosis, or influenza. Cough with bloody sputum can be a sign of tuberculosis.

Sore throat*

Painful throat or pain on swallowing

Swollen glands*

Enlargement of the glands (lymph nodes) located in the head, neck, axilla (armpit), or groin

Acute gastroenteritis

Illness involving the stomach or intestines or both, defined in the regulations as:

  • Diarrhea, 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

Persistent diarrhea

Two or more episodes of diarrhea during a flight

Persistent diarrhea may indicate the person has a gastrointestinal infection, such as norovirus, Salmonella, or cholera.

Persistent vomiting

Two or more episodes of vomiting (other than motion sickness) during a flight

Persistent vomiting may indicate the person has a gastrointestinal infection, such as Salmonella or norovirus.

Jaundice*

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

Head pain of unusual severity.

Neck stiffness

The person has difficulty moving the neck or severe pain during neck movement, especially touching the chin to the chest.

Severe headache and neck stiffness, especially in the presence of fever or rash, may indicate the person has a serious neurological infection, such as meningitis.

Decreased level of consciousness or confusion

  • Being not fully aware of the surroundings and or confusion about identity, location, or the date or time of day
  • Not responding normally to questions or painful sensations (such as pinching), or
  • Appearing to be sleepy, groggy, unresponsive, or difficult to awaken

Decreased consciousness, unrelated to use of alcohol or other substances, especially in the presence of fever or rash, may indicate the person has a serious neurological infection, such as meningitis, or a serious infection in another body system.

Recent onset of focal weakness and/or paralysis*

New weakness (difficulty moving) or paralysis (inability to move), unrelated to injury, of the arms, legs, neck, or the muscles used for swallowing or breathing

New weakness of paralysis unrelated to injury can be a sign of an infection of the nervous system, such as polio.

New unexplained bruising or bleeding (without previous injury)

Noticeable and unusual bruising or bleeding from gums, ears, nose, or areas on the skin with no obvious explanation (such as injury), vomiting blood, or bloody stool or urine

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

Obviously unwell

Illness that appears severe enough to require medical care

Chronic condition*

A noninfectious (usually) 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 ill person may be receiving treatment for one or more chronic conditions, and the conditions may affect multiple organ systems.

Asymptomatic*

No reported or visible symptoms or signs of illness

Injury*

A wound or trauma, harm or hurt, usually used to refer to damage inflicted on the body by an external force

Pneumonia*

An infection of the lungs that can cause mild to severe illness that can include fever, cough, and difficulty breathing or shortness of breath.

Pneumonia can be caused by viruses, bacteria, or fungi. Pneumonia can be diagnosed through a medical examination and/or by imaging of the lungs such as with a chest x-ray.

Muscle aches*

Pain or discomfort in the muscles

Muscle aches that are experienced throughout the body and are not related to activity or injury may be caused by a viral infection, such as influenza or COVID-19.

Abdominal cramps*

A painful pulling or squeezing sensation in the abdomen/gastrointestinal tract.

Abdominal cramps may be caused by a gastrointestinal infection, such as norovirus, Salmonella, or cholera.

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])