Infectious Diseases and Bioterrorism



Prehospital personnel are usually the first health care personnel to encounter sudden illnesses or other health care emergencies in the community setting. Responding to these emergencies puts paramedic personnel at risk because the type, extent, and severity of this illness are not yet known. The Occupational Safety and Health Administration (OSHA) identifies there are more than 1.2 million community-based first-response personnel, including law enforcement, fire, and emergency medical service personnel, who are at risk for infectious exposure.1 This large number highlights the need to protect these personnel against such exposures.

At one time, infectious disease and bioterrorism preparation were not a priority in some EMS agencies. Terrorism events such as the 1995 sarin gas attack on the Tokyo subway, the 2001 World Trade Center in New York City, the 2005 London Underground bombings, and the 2003 severe acute respiratory syndrome (SARS) outbreaks made preparedness a priority. This was especially true in Tokyo where first response personnel were not adequately prepared for acts of terrorism and were exposed to sarin gas,2,3 and as emergency medical personnel responding to patients at the onset of the SARS outbreaks in Toronto4 and Taipei5 were exposed to or contracted SARS in significant numbers, and one paramedic died due to SARS. More importantly, in Toronto, the loss of paramedic availability for work due to exposure, illness, and quarantine impacted the ability to maintain staffing for many weeks during the outbreak.6 These two examples highlight the need for EMS systems to adequately prepare and protect the workforce from potential exposure.



  • Describe the five types of infectious agents.

  • Describe the seven modes of transmission of a contagious disease.

  • Discuss the use of standard prehospital PPE and when additional PPE should be used (eg, respiratory).

  • List common serious contagious and communicable diseases present in the prehospital environment.

  • List appropriate immunizations for prehospital personnel.

  • Describe how needlesticks and known exposures (HIV, hepatitis C, meningitis, TB) are managed.

  • Discuss ways EMS agencies can help prevent, and respond to, certain epidemics (eg, influenza).

  • List potential biological agents that may be released as an act of terrorism.

  • Discuss how the approach to an MCI with a bioterrorism element changes the approach of EMS to the operations.

  • Discuss stock-piling treatments for emergency responders and how to design a response plan to specific bioterrorism threats.

This chapter addresses communicable infectious disease and agents of terrorism in a manner relevant to EMS agencies and their personnel. The chapter is divided in three parts. The first is specific to infectious and communicable disease, describing the basics of communicable disease transmission and prevention, general approach to the patient with a suspected infectious or communicable disease, and specific disease conditions outlined by presenting complaint. The second is specific to agents of bioterrorism, and includes methods for detection and management of those exposed. The second part also includes the fundamentals of decontamination. The third includes the EMS agency’s role and planning for health care emergencies related to infectious disease, EMS interactions with public health agencies, and special considerations for EMS agencies in epidemics or pandemics.

Occupational health and safety is an important component of infection control and prevention of communicable disease in EMS. This includes aspects of routine EMS operations such as immunization of personnel, hand hygiene, personal protective equipment, sharps safety, and cleaning of equipment and disinfection. This is beyond the scope of this chapter and the reader should consult other resources dedicated to this subject.




OSHA defines an occupational exposure as “a reasonably anticipated skin, eye, mucous membrane, or parenteral contact with blood or other potentially infectious material that may result from the performance of the employee’s duties.”1 Infection control practices are designed to prevent exposure to blood or potentially infectious material, including cerebrospinal fluid, synovial fluid, pleural fluid, pericardial fluid, amniotic fluid, peritoneal fluid, and any other body fluid, secretion, or tissue.

Universal precautions is the term formerly used to describe aspects of the methods used to prevent exposure, but this term is no longer used by health care workers. The more favored terms are routine practices and additional precautions. These terms indicate the same basic, minimum level of precaution is taken for all patients.

The Association for Professionals in Infection Control and Epidemiology7 defines infection as an invasion and multiplication of microorganisms in or on body tissue, causing cellular damage through the production of toxins, multiplication, or competition with host metabolism. Infectious agents capable of causing disease include bacteria, viruses, fungi and moulds, parasites, and prions. These five types of microorganisms can be differentiated by their appearance on microscopic examination, reproductive cycle, chemical structure, growth requirements and by other detailed criteria. While bacteria and viruses are the most common causes of illness in the developed world, parasites are more prevalent in other settings.

The ability of a microorganism to cause an infection is dependent on several factors. The dose is the amount if viable organism received during an exposure. Infection occurs when there is a large enough number to overwhelm the body’s own defenses. Virulence refers to the ability of a microorganism to cause infection, and pathogenicity refers to the severity of infection. Incubation and communicability period are the intervals between when the organism enters the body and when symptoms appear, and the time during which the infected individual can spread the disease to others, respectively. The host status and resistance refer to the host’s ability to fight infection, which can be influenced by immune function and immunization status, nutritional state, and presence of comorbid illness.

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 person to another. Not all infectious diseases are communicable. For example, malaria is a serious infectious disease transmitted to the human blood stream by a mosquito bite, but malaria is infectious, not communicable. On the other hand, chickenpox is an infectious disease which 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 infected or colonized individual and a susceptible host. Transmission may occur, for example, by biting, kissing, sexual contact. Indirect contact occurs by passive transfer of infectious agent to a susceptible host through a contaminated intermediate object such as contaminated hands, equipment, or surfaces are not washed between patient contacts. Examples of diseases transmitted by direct or indirect contact include human immunodeficiency virus (HIV), hepatitis, methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), Clostridium difficile, and Norwalk virus.

Droplet transmission refers to large droplets generated from the respiratory tract of a patient when he/she coughs or sneezes, or during invasive airway procedures (intubation, suctioning). The droplets are propelled and can be deposited on the mucous membranes of the susceptible host. The droplets may also settle in the immediate environment and the infectious agents, remain viable for prolonged periods of time, and later transmitted by indirect contact. Examples of diseases transmitted by droplet transmission include meningitis, influenza, rhinovirus, respiratory syncytial virus (RSV), and SARS.

Airborne transmission is the spread of infectious agents to susceptible hosts by very small droplets containing the infectious agent. The droplets can remain suspended in the air for prolonged periods of time, disperse widely by air currents, and can be inhaled by susceptible host located at some distance from the source. Examples of diseases transmitted by airborne transmission include measles (rubeola), varicella (chicken pox), and tuberculosis.

Vector-borne transmission refers to the spread of infectious agents by an insect or animal (the “vector”). Examples of vector-borne illness include rabies, where the infected animal is the vector, and West Nile virus or malaria, where infected mosquitos are the vectors. Transmission or vector-borne illness does not occur between emergency personnel and their patients.

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 (E coli), contaminated food (Salmonella), or contaminated medication, medical equipment, or IV solutions.


The Society of Healthcare Epidemiologists of America, Association for Professionals in Infection Control and Prevention, and the American Academy of Pediatrics support the mandatory vaccination of all health care workers and the routine screening for TB. Vaccinations commonly recommended include HBV (hepatitis B) vaccine, MMR, TDaP, chickenpox vaccine, and the annual flu vaccine. The CDC published a Morbidity and Mortality Weekly Report (MMWR) on the topic on November 25, 2011, available on the Web site at


Despite the use of reasonable practices it is possible to be exposed through various means to body fluids that may be sources for exposure to certain serious diseases. Adherence to OSHA standards requires development of an exposure control plan that contains the following elements: assessment of a provider exposure prone tasks and procedures, exposure control methods, HBV vaccination, postexposure evaluation and follow-up, hazard communication (including labeling, signs, bags, etc), information and training (initial and annual), record keeping, annual review of exposure plan and enforcement activities, maintenance of confidential provider medical records (for employment period plus 30 years), and training records. Providers have a right to immediate health care provider examination and management in cases of specific exposures and should be in compliance with the agency or employer policy. Providers should be trained on exposure prevention, as well as immediate postexposure self-care. Postexposure prophylaxis should be a component of the policy for providers with an exposure that warrants such care. Every agency should have an infection/exposure control officer and have a mechanism by which exposed providers are alerted to possible occult exposures (such as TB or meningitis) and provided with follow-up instructions.



The risk of communicable disease is not as apparent as other physical risks, such as road traffic, power lines, or firearms. Responding personnel must use the same level of suspicion and precaution when approaching a patient before the risk of communicable disease is known. The use of routine practices, as a minimum, is necessary for every patient encounter in order to mitigate this risk.

The risk assessment begins with information from an EMS dispatch or communication center, prior to making patient contact. Call-taking procedures must include basic screening information to identify potential communicable disease threats and provide this information to all responding personnel. The screening information can identify patients with symptoms of fever, chills, cough, shortness of breath, or diarrhea. The call taking can also identify if the patient location, such as nursing home, group home, or other institutional setting, poses a potential risk to the responding personnel. This information helps responding personnel determine what precautions are necessary before they make contact.

When patient contact is made, personnel can identify the patient at risk for a communicable disease. A rapid history and physical examination can raise suspicion for a communicable disease. The following screening questions help assess if the patient has a communicable disease:

  • Do you have a new or worsening cough or shortness of breath?

  • Do you have a fever?

  • Have you had shakes or chills in the past 24 hours?

  • Have you had an abnormal temperature (>38°C)?

  • Have you taken medication for fever?

A screening physical examination will also identify obvious signs of a communicable disease. They may include any new symptom of infection (fever, headache, muscle ache, cough, sputum, weight loss, and exposure history), rash, diarrhea, skin lesions, or draining wounds.

All personnel must take appropriate precautions when a patient presents with any signs or symptoms suspected to be due to an infectious or communicable disease. All EMS and first responder agencies must provide appropriate training that enables personnel to identify at-risk patients and appropriate use of personal protective equipment (PPE).



This section will describe specific diseases grouped by common presenting complaints.


Respiratory infections may be suspected when there are symptoms which classically include any combination of cough, sneeze, shortness of breath, fever, chills, or shakes. Infections above the epiglottis are classified as upper respiratory tract infections, while those below the epiglottis are classified as lower respiratory tract infections. Upper respiratory infections may be suspected when patients present with “cold” symptoms such as rhinorrhea, sneezing, lacrimation, or coryza. More localized and possibly more serious upper respiratory may present with symptoms such as throat pain, fever, odynophagia, dysphagia, drooling, stridor, or muffled voice. Lower respiratory infections typically present with any of fever, shortness of breath, pleural pain, cough, sputum, and generalized symptoms such as chills, rigors, myalgia, arthralgia, malaise, and headache. More atypical symptoms of respiratory infection may be found in children, the elderly, and the immunocompromised. Children with respiratory infection may present with gastrointestinal symptoms such as nausea, vomiting, abdominal pain, and diarrhea.8,9 Elderly and the immunocompromised may not develop a fever in the presence of a respiratory infection.

Respiratory infections are spread when people cough or sneeze and the aerosolized respiratory secretions directly come in contact with the mouth, nose, or eyes of another person. As microorganisms in droplets can survive outside the body, indirect transmission can also occur when hands, objects, or surfaces become soiled with respiratory discharges. When respiratory infections are suspected in patients, EMS providers should use droplet precautions and apply them to a patient.


Febrile respiratory illness should be suspected when a patient presents with any combination of fever, new or worse cough, and shortness of breath. It should be emphasized that the elderly and immunocompromised may not have a febrile response to a respiratory infection.




In addition to cough, shortness of breath, and fever, patients with pneumonia may also present with additional symptoms of tachypnea, increased work of breathing, chest or upper abdominal pain, cough productive of phlegm, sputum, or blood. Generalized systemic symptoms such as myalgia, arthralgia, malaise, and headache may also be present. Gastrointestinal symptoms such as nausea, vomiting, and diarrhea may be associated with pneumonia.10

The signs and symptoms traditionally associated with pneumonia are actually not predictive of pneumonia, whereas diarrhea, dry cough, and fever were more predictive of pneumonia. In elderly patients, the diagnosis of pneumonia is more difficult as both respiratory and nonrespiratory symptoms are less commonly reported by this patient group.11

Infectious agents that typically cause pneumonia include Streptococcus pneumoniae, Mycoplasma pneumoniae, Chlamydia trachomatis, Chlamydia pneumoniae, Pneumocystis carinii, Haemophilus influenza.12 The incubation period from initial contact with the microorganism to development of symptoms is generally not well known for these organisms. For Streptococcus pneumoniae, it may be 1 to 3 days and Mycoplasma pneumoniae may range from 6 to 32 days. Pneumocystis carinii may appear 1 to 2 months after initial contact for those who are immunosuppressed. Streptococcus pneumoniae can be transmitted up to 48 hours after treatment is initiated. However, Mycoplasma pneumoniae can be transmissible for up to 20 days, and the organism may remain in the respiratory tract for up to 13 weeks posttreatment. The time period when transmissible is unknown for the other organisms listed.13


Pertussis should be in the differential diagnosis of a patient presenting with chronic cough. Pertussis presents in three stages: first, a catarrhal stage lasting 1 to 2 weeks, followed by a paroxysmal stage lasting 1 to 6 weeks, and finally ending with a convalescent stage lasting 2 to 3 weeks. In the first stage, pertussis is virtually indistinguishable from any other respiratory illness, as it is characterized by runny nose, sneezing, low-grade fever, and a mild cough. The EMS provider may suspect pertussis in the second, paroxysmal, stage, when the patient has bursts of rapid coughs. The cough usually ends with a long high-pitched inspiratory effort described as a whoop, or it may end with vomiting. The third state is the period of recovery where the cough becomes less paroxysmal. In adolescents, adults, and the vaccinated, pertussis is milder and, hence, may be indistinguishable from other respiratory illnesses, even in the paroxysmal stage.

Pertussis is caused by the Bordetella pertussis bacterium and transmitted by the respiratory route with airborne droplets. Hence, respiratory and contact precautions should be undertaken with known or suspected cases of pertussis. Unfortunately, routine precautions are not always sufficient because pertussis is most infectious during the nonspecific catarrhal period and the first 2 weeks of the paroxysmal phase. The time from infection to the development of symptoms is usually 7 to 10 days.14

Complications from pertussis most often occur in young infants. The major complication and most common cause of pertussis-related death is bacterial pneumonia. From 2001 to 2003, among the 56 pertussis-related deaths reported in the United States, 51 (96%) were among infants younger than 6 months of age.15

With the introduction of routine pertussis vaccination, pertussis had declined from about 140 cases per 100,000 population in the 1940s to about 1 per 100,000 population in the 1980s. However, since the 1980s pertussis rates have been steadily increasing. In 2002 in the United States, there were 3 cases per 100,000 population. The majority of cases were in children under 6 months of age, the age group most at risk of pertussis-related complications.15

Children in the United States are routinely vaccinated for pertussis in a four-dose schedule, starting at age 2 months. As these groups are often the source of infection in infants, an adolescent and adult vaccine was licensed in the United States in 2005. Pertussis is treated with macrolide antibiotics: erythromycin, clarithromycin, or azithromycin. Treatment ameliorates the illness and decreases the communicability period. Cases of pertussis treated with antibiotics should also be isolated for 5 days after antibiotic therapy has started to prevent further transmission. If exposed to a patient with pertussis, the contact should first assess their immunization status. In the event that the contact is nonimmunized, a 7-day course with macrolide antibiotics should be considered. Also, regardless of immunization status, if the contact is a child under age 1, a pregnant woman in the last 3 weeks of pregnancy, or if the person exposed has contact with infants or pregnant women in the last 3 weeks of pregnancy, macrolide antibiotic prophylaxis should be offered.16


Influenza classically presents with the abrupt onset of fever, usually 38 to 40°C, sore throat, nonproductive cough, myalgias, headache, and chills. Unfortunately, only about half of infected persons develop the “classic” symptoms of influenza infection.1719 Among those presenting with classic symptoms, studies have attempted to identify the signs and symptoms most predictive of influenza. Unfortunately, these clinical decision rules are no better than clinician judgment alone.20

Influenza is caused by a virus with three subtypes: influenza A, B, and C. Influenza A causes more severe disease and is mainly responsible for pandemics. Influenza A 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 has not been associated with epidemics.21

Influenza transmission occurs primarily through airborne spread when a person coughs or sneezes, but may also occur through direct contact of surfaces contaminated with respiratory secretions. Hand-washing and shielding coughs and sneezes help prevent spread. Influenza is transmissible from 1 day before symptom onset to about 5 days after symptoms begin and may last up to 10 days in children. Time from infection to development of symptoms is 1 to 4 days.22

Influenza has been responsible for at least 31 pandemics in history. The most lethal “Spanish flu” pandemic of 1918 to 1919 is estimated to have caused 40 million deaths globally with 700,000 of those deaths occurring in the United States in a single year. In this pandemic, deaths occurred mainly in healthy 20 to 40 year olds, which differs from the usual young children and elderly pattern of mortality and morbidity in the seasonal outbreaks of influenza.

Individuals at high risk of influenza complications include young children, people over age 65, the immunosuppressed, and those suffering from chronic medical conditions. Complications of influenza include pneumonia, either the more common secondary bacterial pneumonia or rare primary influenza viral pneumonia; Reye syndrome in children taking aspirin; myocarditis, encephalitis, and death. Death occurs in about 1 per 1000 cases of influenza, mainly in persons older than age 65. Studies estimate about 36,000 influenza-related deaths annually from 1990 to 1999 in the United States.23

Influenza vaccine is the principal means of preventing influenza morbidity and mortality. The vaccine changes yearly based on the antigenic and genetic composition of circulating strains of influenza A and B found in January to March, when influenza reaches its peak activity. When the vaccine strain is similar to the circulating strain, influenza vaccine is effective in protecting 70% to 90% of vaccinees younger than age 65 from illness. Among those aged 65 and older, the vaccine is 30% to 40% effective in preventing illness, 50% to 60% effective in preventing hospitalization, and up to 80% effective in preventing death. EMS providers should be immunized annually, typically in October.

Four antiviral drugs are available for preventing and treating influenza in the United States. Amantadine and rimantadine belong to a class of drugs adamantanes active against influenza A, and oseltamivir and zanamivir belong to the class of neuraminidase inhibitors active against influenza A and B. When used for prevention of influenza, they can be 70% to 90% effective in preventing influenza. When used for treatment, antivirals can reduce influenza illness duration by 1 day and attenuate the severity of illness. Antiviral agents should be used as an adjunct to vaccination, but should not replace vaccination. The CDC recommends influenza antivirals for individuals who have not as yet been vaccinated at the time of exposure, or who have a contraindication to vaccination, and are also at high risk of influenza complications. Also, if an influenza outbreak is caused by a variant strain of influenza not controlled by vaccination, chemoprophylaxis should be considered for health care providers caring for patients at high risk of influenza complications, regardless of their vaccination status. Since the 2005 to 2006 influenza season, a high proportion of influenza A viruses were resistant to the adamantanes. As a result, the CDC has recently recommended against the use of adamantanes for treatment and prophylaxis of influenza. The neuraminidase inhibitors continue to be recommended as a second line of defense against influenza. For prophylaxis, the neuraminidase inhibitors should be taken daily until the exposure exists or until immunity from vaccination develops, which can take about 2 weeks. For treatment, these antivirals should be started as soon as influenza symptoms develop, but no later than 48 hours after symptoms start, and treatment should continue for 5 days. In the setting of an influenza outbreak, EMS systems may opt to restrict duties for EMS providers who are not immunized or who have not yet received prophylactic antiviral therapy in attempt to prevent spread of the outbreak.21


Influenza A virus infects humans and can also be found naturally in birds. Wild birds carry a type of influenza A virus, called avian influenza virus, in their intestines and usually do not get sick from them. However, avian influenza virus can make domesticated birds, including chickens, turkeys, and ducks, quite ill and lead to death. The avian influenza virus is chiefly found in birds, but infection in humans from contact with infected poultry has been reported since 1996. A particular subtype of avian influenza A virus, H5N1, is highly contagious and deadly among birds. In 1997 in Hong Kong, an outbreak of avian influenza H5N1 occurred not only in poultry, but also in 18 humans, 6 of whom died. In subsequent infections of avian influenza H5N1 in humans, more than half of those infected with the virus have died. In contrast to seasonal influenza, most cases of avian influenza H5N1 have occurred in young adults and healthy children that have come in contact with poultry infected, or surfaces contaminated with H5N1 virus. As of the end of 2007, there were 346 documented human infections with influenza H5N1 and 213 deaths (62%). Although transmission of avian influenza H5N1 from human to human is rare, inefficient, and unsustained, there is concern that the H5N1 virus could adapt and acquire the ability for sustained transmission in the human population. If the H5N1 virus could gain the ability to transmit easily from person to person, a global influenza pandemic could occur. No vaccine for H5N1 current exists, but vaccine development is underway. The H5N1 virus is resistant to the adamantanes, but likely sensitive to the neuraminidase inhibitors.24


In April 2009, the H1N1 influenza strain emerged and spread globally. It differed from prior influenza strains and the global population did not have a natural immunity to protect against this virus. While its overall burden of disease was not significantly higher than prior influenza strains, surveillance showed that it affected more young and healthy people than the regular seasonal flu. In June 2009, the World Health Organization (WHO) declared a pandemic, resulting in many national and subnational immunization programs directed targeting H1N1. In August 2011, WHO declared the pandemic over. Postpandemic strategies to limit impact of further outbreaks are focused on including the H1N1 strain in annual influenza vaccines, and careful monitoring and surveillance because the strain will likely continue to circulate in the population, along with other influenza strains, for several more years.


Tuberculosis is caused by the Mycobacterium tuberculosis complex. The majority of active TB is pulmonary (70%), while the remainder is extrapulmonary (30%). Patients with active pulmonary TB will typically present with cough, scant amounts of nonpurulent sputum, and possibly hemoptysis. Systemic signs such as weight loss, loss of appetite, chills, night sweats, fever, and fatigue may also be present. Clinically, the EMS provider will be unable to distinguish pulmonary TB from other respiratory illness; however, certain risk factors may alert the EMS provider to the possibility of tuberculosis. These risk factors are immigration from a high-prevalence country, homelessness, exposure to active pulmonary TB, silicosis, HIV infection, chronic renal failure, cancer, transplantation, or any other immunosuppressed state.25,26

Active pulmonary TB is transmitted via droplet nuclei from people with pulmonary tuberculosis during coughing, sneezing, speaking, or singing. Procedures such as intubation or bronchoscopies are high risk for the transmission of TB. Respiratory secretions on a surface lose the potential for infection. About 21% to 23% of individuals in close contact with persons with infectious TB become infected through inhalation of aerosolized bacilli. The probability of infection is related to duration of exposure, distance from the case, concentration if bacilli in droplets, ventilation in the room, and the susceptibility of the host exposed. Effective medical therapy eliminates communicability within 2 to 4 weeks of starting treatment.27

If infected with TB, an individual may develop active TB with symptoms, or latent TB, which is asymptomatic. Time from infection to active symptoms or positive TB skin test is about 2 to 10 weeks. The risk of developing active TB is greatest in the first 2 years after infection. Latent TB may last a lifetime, with the risk that it may later progress to active TB. About 10% of patients with latent TB will progress to active TB in their lifetime.

If transporting a patient who is known or suspected of having TB, respiratory precautions should be undertaken by the EMS provider, in particular, a submicron mask. Patients should cover their mouth when coughing or sneezing, or wear a surgical mask. In the event of suspected exposure to a patient with active pulmonary tuberculosis, report the case and the exposure to the EMS system or public health authority. Close contacts should be monitored for the development of active TB symptoms. Two tuberculin skin tests should be performed, based on public health recommendations, on those closely exposed to patients with active TB.28 Because the incubation period after contact ranges from 2 to 10 weeks, the first test is typically done as soon as possible after exposure, and the second test typically done 8 to 12 after the exposure. If the EMS provider or contact develops either active TB with symptoms or latent asymptomatic TB, as diagnosed with a new positive TB skin test, treatment should be sought.

Treatment for latent TB is typically isoniazid (INH) for 6 to 9 months.28 This single-drug regimen is 65% to 80% effective. For active TB, a four-drug regimen is typically used for 2 months: isoniazid, rifampin, pyrazinamide, and ethambutol. This is followed by INH and rifampin for an additional 4 months. Several forms of multidrug-resistant (MDR)-TB and extensively drug-resistant (XDR)-TB have been identified.29 These forms require aggressive, multidrug regimen for prolonged periods of time and are dependent on the organism’s patterns of drug sensitivity and resistance. In all cases, a physician skilled in management of TB must initiate and monitor treatment and provide suitable follow-up. Public health officials must also be notified.30


It is difficult to distinguish SARS from other respiratory infections because patients present with symptoms similar to other febrile respiratory illnesses.31 On initial presentation, reliance on respiratory symptoms alone is not sufficient to distinguish SARS from non-SARS respiratory illness.32 Fever is the most common and earliest symptom of SARS often accompanied by headache, malaise, or myalgia.33 In patients with SARS, high fever, diarrhea, and vomiting were more common as compared to other patients with other respiratory illnesses.34 Cough occurred later in the course of disease and patients were less likely to have rhinorrhea or sore throat as compared to other lower respiratory tract illness.35 Since clinical features alone cannot reliably distinguish SARS from other respiratory illnesses, knowledge of contacts is essential.36 Contact with known SARS patients, contact with SARS-affected areas or linkage to a cluster of pneumonia cases should be obtained in the history.37

SARS was first recognized in 2003 after outbreaks occurred in Toronto (Canada),38 Singapore, Vietnam, Taiwan, and China. The illness is caused by a coronavirus. The incubation period ranges from 3 to 10 days, averaging 4 to 5 days from contact to symptom onset. About 11% of those who develop SARS eventually die, usually due to respiratory failure. The risk of mortality is highly dependent on the patient’s age and presence of comorbid illnesses. The case fatality is less than 1% for SARS patients less than age 24 and up to 50% for those age 65 and greater or those with comorbid illness.39

The coronavirus is found in respiratory secretions, urine, and fecal matter. Transmission is via droplet spread from respiratory secretions, with high risk transmission during intubation and procedures which aerosolize respiratory secretions. Transmission can also occur from fecal or urine contamination of surfaces. There have been no confirmed cases of transmission from asymptomatic cases. Preliminary studies show that transmission likely occurs after the development of symptoms with peak infectious period being 7 to 10 days after symptom onset, and declining to a low level after day 23 from onset of symptoms.40

If SARS is suspected, EMS providers must use all routine practices and additional precautions.41 EMS systems may also elect to limit or avoid any procedures that may increase risk to EMS personnel. These include tracheal intubation, deep suctioning, use of noninvasive ventilatory support (CPAP, BiPAP), administration of nebulized medication, and any other procedure that may aerosolize respiratory secretions. During the SARS outbreaks in Toronto, EMS medical direction modified medical directives such that paramedics did not intubate patients or deliver nebulized therapy in the prehospital setting.42 Finally, EMS personnel and systems must also notify the receiving facility of a patient suspected of SARS, permitting staff to have appropriate PPE in place and a suitable isolation room prepared for the patient.43,44




Skin infections with onset in the community or hospital may be caused by Staphylococcus aureus. Staphylococcus aureus is a bacterium that normally secretes β-lactamases rendering them normally resistant to antibiotics such as ampicillin and amoxicillin. Methicillin, a type of β-lactam antibiotic, developed in 1959, was not broken down by these bacterial β-lactamase enzymes. However, in the 1960s, infections of Staphylococcus aureus were found to be resistant to methicillin and other β-lactam antibiotics, resulting in the emergence of methicillin-resistant Staphylococcal aureus.45

In addition to common skin and soft tissue infections, MRSA may less commonly cause severe and invasive infections such as necrotizing pneumonia, sepsis, and musculoskeletal infections such as osteomyelitis and necrotizing fasciitis. MRSA skin infections typically present as necrotic skin lesions, and are often confused with spider bites. The severity of MRSA skin infections may range from mild to severe. Unfortunately, there are no reliable clinical or risk factor criteria to distinguish MRSA skin and soft tissue infections from those caused by other infectious agents.46

Initially, MRSA infections were found in patients in health care facilities (health care–associated MRSA or HA-MRSA). However, community-acquired MRSA (CA-MRSA) infections are increasingly identified in people who did not have the traditional risk factors of those with HA-MRSA, specifically contact with health care facilities. These community-acquired strains are new MRSA strains, different from those which cause HA-MRSA. Regardless, both HA-MRSA and CA-MRSA can mimic infections caused by less-resistant bacteria, but are more difficult to treat.47

Transmission of MRSA is mainly through hand contact from infected skin lesions, such as abscesses or boils. About 1% of the healthy population is also colonized with MRSA, mainly in the anterior nares, but also in the pharynx, axilla, rectum, and perineum. Therefore, autoinfection may also be a route of infection. The transmissible period lasts as long as skin lesions continue to drain or as long as the carrier state remains. Newborns, the elderly, and the immunosuppressed are most susceptible.

Transmission of infection is prevented by routine precautions. Draining wounds should be covered with clean, dry, bandages. Contaminated surfaces should be cleaned with disinfectants effective against Staphylococcus aureus, such as a solution of dilute bleach or quaternary ammonium compounds. One study has showed that EMS ambulances may have significant degree of MRSA contamination, highlighting the need for proper cleaning and decontamination of all equipment and the vehicle itself after every patient transport.48

There are no data to support the routine use of decolonization of MRSA with antiseptic agents or nasal mupirocin. Decolonization may be considered in select circumstances, when a person has multiple recurrent infections of MRSA, or there is ongoing transmission in a well-defined group of close contacts. Little data are available on effective decolonization agents, but topical chlorhexidine gluconate or diluted bleach (3.4 g of bleach diluted in 3.8 L of water) is suggested.49

In those with skin or soft tissue infections, any drainage should be cultured. Abscesses should be incised and drained. Antibiotic therapy may be considered if there are signs of cellulitis, systemic illness, associated immunosuppression, extremes of age, facial infection, or failure of initial incision and drainage. The choice of therapy should be dictated by local susceptibility patterns. Clindamycin, doxycycline, and trimethoprim-sulfamethoxazole (TMP-SMX) are considerations for treatment of CA-MRSA skin and soft-tissue infections. HA-MRSA may be resistant to many more classes of antibiotics, and vancomycin or linezolid may be necessary.50


Measles is a viral disease which initially presents with a 2- to 4-day prodrome of fever, cough, runny nose, and possibly conjunctivitis. In the prodrome stage, the EMS provider will be unable to clinically distinguish measles from any other viral upper respiratory illness. A measles rash follows, beginning on the hairline, then involving the face and neck, and over 3 days, proceeding downward and outward to the hands and feet. The rash produces discrete red maculopapular (flat and raised) lesions initially, which may become confluent. Initially, the lesions blanch, and after 3 to 4 days become nonblanchable spots, which appear within 1 to 2 days before or after the maculopapular rash. Koplik spots, punctuate blue-white spots on the red buccal mucosa of the mouth, are pathognomonic for measles and would alert the EMS provider to the presence of measles.51,52

Measles has a 0.2% mortality rate, mainly due to pneumonia in children in developing countries. Cases of measles have declined dramatically since the introduction of live attenuated virus vaccine in 1963, with a record low of 34 cases in 2004. Sporadic outbreaks occur in populations that refuse vaccination. Children in the United States are routinely vaccinated with two doses of measles vaccine (MMR) at ages 12 to 15 months and ages 4 to 6 years.

Measles is transmitted by aerosol or droplet spread and is communicable from 4 days prior to appearance of the rash to 4 days after rash appearance. EMS providers will likely encounter the patient in the transmissible stage, and should use routine practices to prevent spread of disease.

The incubation period is approximately 10 days. Those who have not been immunized or have never acquired measles (born after 1957) are susceptible to infection if exposed. If susceptible and exposed, immunoglobulin should be given to children under age 1, pregnant women, and the immunocompromised within 6 days of exposure. For other susceptible persons, live measles vaccine may prevent disease if given within 72 hours of exposure. There is no treatment for measles, but vitamin A supplementation should be considered to prevent ocular complications.53,54


Rubella is a viral disease with a prodrome that precedes rash. Clinical diagnosis alone is unreliable. The prodrome, consisting of consists of fever, upper respiratory symptoms, and prominent lymphadenopathy, lasts 1 to 5 days and mostly present in older children and adults. During the prodrome, rubella is clinically indistinguishable from any other viral URTI. A maculopapular rash 14 to 17 days after exposure and lasting 3 days, typically follows the prodrome. Like measles, the rash starts on the face and progresses downward. In contrast to a measles rash, the rash due to rubella is fainter, does not coalesce, and is more prominent after a hot shower or bath. Associated symptoms may include arthralgias or conjunctivitis. Confirmation of rubella infection is by laboratory diagnosis of virus or antibody.55

Rubella is transmitted from respiratory secretions via airborne transmission or droplet spread, with an incubation period of 14 to 17 days. Even though rubella is most contagious when the rash is present, it may be transmitted by subclinical or asymptomatic cases of rubella, and 7 days before the onset of rash.

Life-threatening complications of rubella include encephalitis and hemorrhagic, but these are uncommon. The main objective of immunization is to prevent congenital rubella syndrome (CRS), the main complication of rubella. CRS occurs when a pregnant woman in early gestation, mainly in the first trimester, is exposed to rubella. CRS may lead to fetal death, premature delivery, and congenital defects including deafness, ocular, cardiac, and neurologic abnormalities.

There is no specific treatment of rubella, only preventative vaccination. Rubella immunization is part of the routine childhood vaccinations, administered as a live vaccine along with measles and mumps as “MMR.” It is typically given at 12 months of age, and ages 4 to 6 years. Infants born to rubella immune mothers are protected for 6 to 9 months from transplacental maternal antibodies.56

If exposed to patients later diagnosed with rubella, immunity of the contact should be assessed. Subsequent immunization of the nonimmunized contact would not prevent infection or illness. In adults, rubella is generally a mild febrile disease, and control measures are aimed, preventing spread to nonimmunized pregnant women. In the case of spread, patients suspected of having rubella should be isolated with routine precautions in place. Pregnant women contacts should be investigated for immunity. In case of infection with rubella in nonimmune pregnant women in early pregnancy, counseling should be provided with consideration for abortion. Immunoglobulin in early pregnancy may also be given to modify or suppress symptoms, but there have been cases of CRS in spite of immunoglobulin therapy.5759


Like measles and rubella, varicella starts with a prodrome which subsequently leads to a rash. In children, the prodrome of fever and malaise may be absent. Unlike measles and rubella, varicella infection, chickenpox, can be clinically diagnosed by the EMS provider based on a more pathognomonic rash. The pruritic rash progresses from macules to papules and then to vesicles which later crust over. The vesicles are unilocular and collapsible, in contrast to the multilocular and noncollapsible vesicles of smallpox. Lesions start on the scalp, progress to the trunk, and later move to the extremities.60

Varicella virus infection leading to chickenpox typically lasts 3 to 4 days, with an incubation period of 14 to 16 days. Transmission is by airborne droplets from the respiratory tract or by inhalation of aerosolized vesicular fluid from skin lesions. Chickenpox is transmissible 1 to 2 days before the onset of rash until all papules become crusted.61

Complications in children include secondary bacterial skin infections, pneumonia, and dehydration. Nonimmunized adults may have more severe complications, including encephalitis, transverse myelitis, hemorrhagic varicella, and even death. In the United States, only 5% of the reported cases of varicella are from adults, while 35% of the mortality occurs in adults. The case-fatality rate is 1 per 100,000 cases in children aged 1 to 14, but 25.2 per 100,000 cases in adults aged 30 to 49 years of age.

Maternal varicella 5 days before to 48 hours after delivery may result in neonatal infection and subsequent mortality as high as 30%. Varicella infection in the mother at 20 weeks of gestation can lead to congenital varicella syndrome, which includes skin scarring, extremity atrophy, and eye and neurologic abnormalities.

Since the licensure of varicella vaccine in 1995 in the United States, cases of chickenpox have declined from 83% to 94% by 2004. Varicella vaccine is recommended for all children without contraindication at 12 to 18 months of age, and is administered as one dose. Adults and adolescents age 13 years and older who do not have evidence of immunity should receive two doses of varicella vaccine.

Cases of chickenpox should be excluded from public places until the vesicles become dry. In the hospital, strict isolation measures should be undertaken to avoid contact with susceptible immunocompromised persons. Articles soiled by discharges from the nose and throat should be disinfected.

If exposed to chickenpox, contacts should assess their susceptibility based on their immune status. If previously infected or vaccinated, contacts are immune. Susceptible nonimmune contacts have three choices to prevent infection: vaccination, varicella zoster immunoglobulin, or antiviral drugs. Varicella vaccine can prevent illness or attenuate severity if used within 3 days of contact. Vaccine is recommended in susceptible individuals. Varicella zoster immunoglobulin (VZIG) is recommended for newborns, the immunocompromised, and pregnant women and can also modify severity or prevent illness if given within 96 hours of exposure. Antiviral drugs such as acyclovir, if used within 24 hours of onset of rash, can reduce the severity of disease. These are not recommended for routine postexposure prophylaxis, but can be considered in persons aged >13 years, and the immunocompromised.62,63



Bites require treatment for the physical injury itself, and treatment for the infectious disease exposure due to the bite. Infection rates from bites mainly depend on the animal which has caused the bite and the site of injury.64 Cat bites can have an infection rate of up to 50%, while about 10% of dog bites become infected. Bites on the face, scalp, hand, wrist, foot, or joints have the highest rate of infection. Hands are the most common site of human, dog, and cat bites. Bite infections may cause cellulitis, osteomyelitis, abscess, septic arthritis, or even septicemia. In addition to antibiotic therapy, bites may also require treatment with rabies prophylaxis, tetanus prophylaxis, HIV, and hepatitis B prophylaxis. Prophylactic antibiotic treatment for bites depends on the specific infectious agents most commonly associated with the particular animal. Finally, EMS personnel should also be aware of the risk of transmission of hepatitis C due to human bites.65

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Jan 22, 2019 | Posted by in EMERGENCY MEDICINE | Comments Off on Infectious Diseases and Bioterrorism

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