to account for potential exposures in the workplace from patients, co‐workers, and the public. Additionally, contingency planning must account for the possibility of temporary losses of significant portions of the workforce at times when demands on the EMS system are increased.
EMS Clinician and Patient
An infectious disease results from the invasion of a host by disease producing organisms, such as bacteria, viruses, fungi, or parasites. A communicable (or contagious) disease is one that can be transmitted from one source (i.e., person or animal) to another, by contact with the infected individual or bodily fluids, contact with contaminated surfaces or objects, or ingestion of contaminated food or water, or by contact with disease vectors such as mosquitos, fleas, or mice. Not all infectious diseases are communicable. For example, malaria and schistosomiasis are spread by contact with disease vectors. These are not typically considered to be communicable or contagious diseases because they cannot be spread by direct contact with an infected person. On the other hand, chickenpox is an infectious disease that is also highly communicable, because it can be easily transmitted from one person to another.
The mode of transmission is the mechanism by which an agent is transferred to the host. Modes of transmission include contact transmission (direct, indirect, droplet), airborne, vector‐borne, or common vehicle (food, equipment). Contact transmission is the most common mode of transmission in the EMS setting and can be effectively prevented using routine practices.
Direct contact transmission occurs when there is direct contact between an infected or colonized individual and a susceptible host. Transmission may occur, for example, by biting, kissing, or sexual contact. Indirect contact occurs when there is passive transfer of an infectious agent to a susceptible host through a contaminated intermediate object. This can occur if contaminated hands, equipment, or surfaces are not appropriately washed and decontaminated after patient contacts. Examples of diseases transmitted by direct or indirect contact include human immunodeficiency virus (HIV), hepatitis, and methicillin‐resistant Staphylococcus aureus (MRSA).
Droplet transmission is a form of contact transmission requiring special attention. It refers to large droplets generated from the respiratory tract of a patient when coughing or sneezing, or during invasive airway procedures such as intubation and suctioning. These droplets are propelled and may be deposited on the mucous membranes of the susceptible host. The droplets may also settle in the immediate environment, and the infectious agents may remain viable for prolonged periods, to be later transmitted by indirect contact. Examples of diseases transmitted by droplet transmission include meningitis, influenza, rhinovirus, respiratory syncytial virus, and coronavirus diseases.
Airborne transmission refers to the spread of infectious agents to susceptible hosts through the air. In this case, infectious agents are contained in very small droplets that can remain suspended in the air for prolonged periods. These agents are dispersed widely by air currents and can be inhaled by a susceptible host located at some distance from the source. Examples of airborne transmission diseases include measles (rubeola), varicella (chicken pox), and tuberculosis.
Vector‐borne transmission refers to the spread of infectious agents by means of an insect or animal (the “vector”). Examples of vector‐borne illnesses include rabies, where the infected animal is the vector, and West Nile virus or malaria, where infected mosquitos are the vectors. Transmission of vector‐borne illness does not occur between patients and EMS personnel.
Common vehicle transmission refers to the spread of infectious agents by a single contaminated source to multiple hosts. This can result in large outbreaks of disease. Examples of this type of transmission include contaminated water sources (Escherichia coli); contaminated food (Salmonella); or contaminated medication, medical equipment, or intravenous solutions.
General Approach and Patient Assessment
The risk of communicable disease is not as apparent as other physical risks, such as road traffic, power lines, firearms, or chemical agents. EMS personnel must use the same heightened level of suspicion and precaution whenever approaching a patient. All personnel must take appropriate precautions when a patient presents with any signs or symptoms potentially due to an infectious or communicable disease. All EMS and first responder agencies must provide appropriate training that prepares personnel to identify at‐risk patients and to use personal protective equipment (PPE). Table 23.1 outlines suggested PPE based on procedure or intervention. Table 23.2 provides suggested precautions based on the suspected infection.
Appropriate use of PPE is tantamount to implementation of isolation as it might be described in a hospital setting. One important principal difference is that the patient’s location is far less static. Thus, it is important that personnel, EMS and hospital alike, soon to come in proximity to the patient, have enough forewarning to enable them similarly to prepare with appropriate PPE. Further, in the case of a receiving hospital, advance notice may facilitate preparation of an optimal isolated receiving area for an infectious patient.
The risk assessment begins with information from the public safety answering point, prior to making patient contact. Call‐taking procedures should include basic screening to identify potential communicable disease threats. The screening can identify patients with symptoms of fever, chills, cough, shortness of breath, or diarrhea. The call‐taker can also determine if the patient location, such as nursing home, group home, or other institutional setting, poses a potential risk to the responding personnel. This information appropriately conveyed to EMS clinicians helps them prepare and determine what precautions are necessary before they make patient contact.
When patient contact is made, personnel should continue to determine if the patient has a potential risk for a communicable disease. A brief history and physical examination can help raise suspicion. The following screening questions may help identify a patient with a communicable disease:
Do you have a new or worsening cough or shortness of breath?
Do you have a fever, shakes, or chills?
Do you have a sore throat, runny nose, or nasal congestion?
Do you have nausea, vomiting, or diarrhea?
Do you have a headache or muscle pains?
Have you had an abnormal temperature (above 38 degrees C)?
Have you been in close contact with anyone who is ill or known to have a communicable disease?
Have you been in contact with anyone who has traveled to an area affected by a communicable disease outbreak?
A screening physical examination will also identify obvious signs of a communicable disease. This may include a rash, skin lesions, or draining wounds.
Specific Illnesses
Influenza
Influenza classically presents with the abrupt onset of fever, usually 38‐40 degrees C, sore throat, nonproductive cough, myalgias, headache, and chills. Influenza is caused by a virus with three subtypes in humans: A, B, and C. Influenza A causes more severe disease and is mainly responsible for pandemics. It has different subtypes determined by surface antigens H (hemagglutinin) and N (neuraminidase). Influenza B causes more mild disease and mainly affects children. Influenza C rarely causes human illness and is not associated with epidemics [3].
Influenza transmission occurs primarily through droplets when a person coughs or sneezes but may also occur indirectly by contact with surfaces contaminated by respiratory secretions. Handwashing and shielding coughs and sneezes help to prevent spread. Influenza is transmissible from 1 day before symptom onset to approximately 5 days after symptoms begin and may last up to 10 days in children. Time from infection to development of symptoms is 1‐4 days [4].
Influenza