caused by the bacterium Francisella tularensis, has various clinical manifestations related to the route of introduction. People can become infected in several ways, including tick and deer fly bites, skin contact with infected animals and their carcasses, eating insufficiently cooked contaminated meat, drinking contaminated water, inhaling contaminated aerosols or agricultural and landscaping dust, and bioterrorism. The incubation period is usually 3‐5 days, but can range from 1 to 14 days.
All forms of tularemia result in a sudden onset of non‐specific influenza‐like symptoms, including high fever, cough, sore throat, chills, headache, and generalized body aches. Sometimes, nausea, vomiting, and diarrhea may also occur. All forms may lead to sepsis, pneumonia, and meningitis. The clinical forms include ulceroglandular, glandular, oculoglandular septic, oropharyngeal, and pneumonic [53].
Ulceroglandular tularemia is the most common form. It begins at the skin site of the bite of a tick or fly. A papule appears that becomes pustular, later ulcerates, and finally develops into an eschar. Regional lymph nodes become swollen, painful, and tender and rarely suppurate and discharge purulent material. Glandular tularemia has no skin involvement, only regional lymphadenopathy similar to ulceroglandular disease. Oculoglandular tularemia is caused by the bacillus entering the eye. Conjunctival ulceration occurs followed by regional lymphadenopathy of the cervical and pre‐auricular nodes. Septic tularemia begins with non‐specific symptoms of fever, nausea, vomiting, and abdominal pain, eventually leading to confusion, coma, multisystem organ failure, and septic shock.
Oropharyngeal tularemia is caused by consumption of contaminated water or food, leading to exudative pharyngitis, which may be accompanied by oral ulceration. Abdominal pain, diarrhea, and vomiting may accompany this type. Regional lymphadenopathy occurs, affecting the cervical and retropharyngeal nodes.
Pneumonic tularemia may be caused by lung exposure to an infective aerosol from soil, grain, or hay. An infective aerosol can also result from a bioterrorist attack. The clinical presentation may be cough, pleuritic pain, and rarely dyspnea. Despite the lungs being the primary route of entry, it is not uncommon for tularemic pneumonia to present as non‐specific systemic signs without respiratory symptoms, and often a normal chest x‐ray.
There is no documented person‐person transmission of tularemia. Routine precautions are adequate when transporting and caring for patients. The vehicle and equipment, however, must be thoroughly cleaned and decontaminated after patient transport. Antibiotics such as streptomycin or gentamycin are effective, and antibiotics for treating patients infected with tularemia in a bioterrorist event are included in the national pharmaceutical stockpile maintained by the CDC.
Viral Hemorrhagic Fevers
Viral hemorrhagic fevers are caused by different families of viruses and lead to similar clinical syndromes. In the case of bioterrorist attack, it is essential that first‐responders are able to recognize the illness associated with the intentional release of the biological agent.
In hemorrhagic fever, the initial signs and symptoms are nonspecific and include high fever, headache, muscle aches, and severe fatigue. There may be associated gastrointestinal symptoms of nausea, vomiting, diarrhea, and abdominal pain. Respiratory symptoms of cough and sore throat may also occur. Approximately 5 days after the onset of illness, a truncal maculopapular rash develops in most patients. As the disease progresses, bleeding occurs from internal organs, the mouth, eyes, ears, and from under the skin, as evidenced by petechiae and ecchymosis. Shock, coma, seizures and kidney failure may ensue in severe cases.
Viral hemorrhagic fevers are caused by viruses in four families: arenaviruses, bunyaviruses, flaviviruses, and filoviruses, causing diseases such as Ebola hemorrhagic fever, hantavirus pulmonary syndrome, Lassa fever, Marburg hemorrhagic fever, hemorrhagic fever with renal syndrome, and Crimean‐Congo hemorrhagic fever [54]. Transmission occurs when humans have direct contact with infected animals, mainly rodents, or are bitten by a mosquito or tick vector. Once a person has become infected, some viruses can be transmitted from person to person, mainly by close contact with infected people, but also indirectly by objects contaminated with infected body fluids.
Transmission of viral hemorrhagic fever mainly occurs in the latter stage of illness when the patient suffers vomiting, diarrhea, shock, and hemorrhage. In the case of Ebola virus, there are reports of transmission within a few days of the onset of fever. The incubation period ranges from 2 days to 3 weeks, and no transmission has been documented during the incubation period.
To prevent infection, contact with rodents, and bites from ticks and mosquitos, should be prevented. Person‐to‐person transmission can be prevented by strict adherence to routine precautions. If clinicians are exposed to viral hemorrhagic fever, they should be placed under surveillance for fever. In addition, patients with known or suspected viral hemorrhagic fever must be isolated. While this is not possible in the EMS setting, the transporting vehicle can serve to isolate the patient from the scene and while in transit.
During the 2018 outbreak of Ebola in the Democratic Republic of the Congo, four investigational treatments were initially available to treat confirmed patients. Of these, patients receiving one of two investigational antiviral drugs had higher overall survival. While these two drugs are not currently licensed by the U.S. FDA, they are currently in use in other countries for patients with Ebola. In December 2019, Ebola Zaire vaccine, live (Ervebo®, Merck Sharp & Dohme Corp.) became the first FDA‐approved vaccine for the prevention of Ebola. Another investigational vaccine was introduced under a research protocol in 2019 to combat an Ebola outbreak in the Democratic Republic of the Congo. This vaccine requires two doses, with an initial dose followed by a booster 56 days later.
The CDC has prepared a number of documents specific to viral hemorrhagic fever, with detailed and comprehensive strategies to prevent spread and protect health care workers and provide guidance to EMS agencies and personnel [55, 56]. In collaboration with the CDC, the National Ebola Training and Education Center offers training, resources, readiness assessments, and expertise to help prepare for pandemics and other emerging threats related to infectious disease outbreaks [57] (Figure 23.1). Finally, to strengthen the United States’ infectious disease response capability, ten special regional treatment centers were established in 2015 to treat patients with Ebola or other severe, highly infectious diseases. These facilities have enhanced capabilities to receive special pathogen patients, and have the capacity for at least ten patients with high‐risk infectious diseases (Figure 23.2).
Figure 23.1 Health care workers exiting a containerized biocontainment system.
Source: Photo courtesy of U.S. Department of Health and Human Services Office of the Assistant Secretary for Preparedness and Response.
Figure 23.2 Transport team arrives with a patient at the dedicated entrance of a Regional Ebola and Other Special Pathogen Treatment Center.
Source: Photo courtesy of U.S. Department of Health and Human Services, Office of the Assistant Secretary for Preparedness and Response. public domain photos from the U.S. federal government.
Varicella
