Ebola

The Reston virus was discovered in 1989 when monkeys from a research lab were imported from the Philippines to the United States (US). During this time, it was determined that the virus spread via droplets among the monkeys within the facility; this form of transmission has not been proven in humans, but it did give way to the fact that Ebola was not purely confined to Africa (CDC, 2023c).

The Reston virus differs markedly from the others because it is maintained in an animal reservoir in the Philippines and has not been found in Africa. Serologic studies have shown that a small percentage of Philippine pig farmers have IgG antibodies against the agent without developing severe symptoms, proving that the Ebola Reston virus can cause mild or asymptomatic human infection (CDC, 2023c).

Bombali ebolavirus is the most recent species to be named and was isolated from Angolan free-tailed bats in Sierra Leone. Bombali ebolavirus can infect human cells, although it has not yet been shown to be pathogenic.

The natural reservoir for Ebola has yet to be confirmed; however, African fruit bats (Pteropodidae) are the most likely candidate species. Chimpanzees, gorillas, and other mammals have been other known suspects, though they are considered dead-end hosts, like humans. In other words, once infected with the virus, the organism dies and fails to continue to spread the virus (CDC, 2021d).

Person-to-person transmission is associated with direct contact with the body fluids of individuals who are ill with EVD or have died from the infection. Examples of transmission include (CDC, 2021b):

• Any contact with bodily fluids, such as saliva, sweat, urine, vomit, feces, semen, breast milk, or blood.
• Contact with objects contaminated by blood or bodily fluids, such as clothing, blankets, needles, etc.
• Sexual contact or contact with semen from a male who has recovered from EVD. The virus can remain in the semen even after the person has recovered and is no longer experiencing symptoms.
• Contact with infected primates or fruit bats.

The likelihood of infection depends, in part, upon the type of body fluid an individual is exposed to and the amount of virus it contains. Transmission is most likely to occur through direct contact of broken skin or mucous membranes with virus-containing body fluids from a person who has developed signs and symptoms of illness (CDC, 2021b).

According to the World Health Organization (WHO), the most infectious body fluids are blood, feces, and vomitus (WHO, 2021).

The Ebola virus can also be spread through direct contact with a patient's skin, but the risk of developing an infection from this type of exposure is lower than from exposure to blood or body fluids (CDC, 2021b). Viruses on the skin surface might result from viral replication in dermal and epidermal structures, contamination with blood or other body fluids, or both.

The risk of Ebola transmission also depends upon the quantity of virus in the fluid. During the early phase of illness, the amount of virus in the blood may be low, but levels then increase rapidly in severely ill and moribund patients (CDC, 2021b).

The infectious virus or viral RNA can persist in some body fluids of patients recovering from EVD even after it is no longer detected in the blood. For example:

• Follow-up studies of approximately 40 survivors of the 1995 outbreak in Kikwit, Democratic Republic of the Congo, found that reverse transcription-polymerase chain reaction (RT-PCR) could detect viral RNA sequences in the semen of male patients for up to three months and infectious virus was recovered from the semen of one individual 82 days after disease onset.
• A study of patient samples collected during the Sudan EVD outbreak in Gulu, Uganda, in 2000, detected the virus in the breast milk of a patient even after the virus was no longer detectable in the bloodstream. Two children who infected mothers breastfed died of the disease.
• The percentage of patients with persistent virus and the level of virus detected in semen decreased over time. In a patient treated in the US, the concentration of viral RNA in semen during early recovery was 4 logs higher than in blood during peak infection (Barnes et al., 2017). A modeling study from a 2014 - 2016 outbreak suggests the median time to semen RT-PCR negativity is 47 days after symptom onset, and the probability of shedding at 18 months is <1% (Subtil et al., 2017).

The Ebola virus may be transmitted through contact with contaminated surfaces and objects. The US Centers for Disease Control and Prevention (CDC) indicates that the virus on surfaces may remain infectious from hours to days at room temperature (CDC, 2021a). Disinfection with hospital-grade cleansers should be done to prevent transmission of the virus.

There are no reported cases of the Ebola virus being spread from person to person by the respiratory route (Dickson et al., 2018). However, laboratory experiments have shown that the Ebola virus released as a small-particle aerosol is infectious for rodents and nonhuman primates (Mattia et al., 2016). Healthcare workers may, therefore, be at risk of EVD if exposed to aerosols generated during medical procedures.

Transmission to healthcare workers may occur when appropriate PPE is not available or used correctly, especially when caring for a severely ill patient who is not recognized as having EVD (CDC, 2023c).

During the epidemic in West Africa, many doctors and nurses became infected with EVD. In Sierra Leone, the incidence of confirmed cases over seven months was approximately 100-fold higher in healthcare workers than in the general population. Several factors accounted for these infections, including:

• Delayed laboratory diagnoses
• Inadequate training about the safe management of contaminated waste and burial of corpses
• Incorrect triage and failure to recognize patients and corpses with EVD
• Limited availability of appropriate PPE and handwashing facilities

Medical procedures played a significant role in some past Ebola epidemics by amplifying the spread of infection. For example:

• An iatrogenic point source outbreak occurred in 1976 when an individual infected with the Ebola virus was among the patients treated in a small missionary hospital in Yambuku, Zaire. At this hospital, the medical staff routinely injected all febrile patients with antimalarial medications, employing syringes rinsed in the same pan of water and then reusing them (CDC, 2023c).
• A different type of iatrogenic amplification occurred in 1995 in Kikwit, Democratic Republic of the Congo, when an infected patient was hospitalized with abdominal pain and underwent an exploratory laparotomy. The entire surgical team became infected, probably through unprotected respiratory exposure to aerosolized blood. Once those persons were hospitalized, the disease spread to hospital staff, patients, and family members through direct physical contact.

Assistance from the international medical community has played an essential role in controlling large epidemics in Africa. Intervention strategies have focused on helping local healthcare workers identify Ebola patients, transfer them to isolation facilities, provide basic supportive care, monitor all persons in direct contact with cases, and rigorously enforce infection control practices. During the West African epidemic, the massive international response made it possible to supplement isolation procedures with more effective supportive care.

After entering the body through mucous membranes, breaks in the skin, or parenterally, the Ebola virus infects many different cell types. Macrophages and dendritic cells are the first to be infected. Filoviruses replicate readily within these ubiquitous "sentinel" cells, causing their necrosis and releasing large numbers of new viral particles into the extracellular fluid.

Rapid systemic spread is aided by virus-induced suppression of type I interferon responses (Basler, 2017). Dissemination to regional lymph nodes results in further rounds of replication, followed by spread through the bloodstream to dendritic cells and fixed and mobile macrophages in the liver, spleen, thymus, and other lymphoid tissues. Necropsies of infected animals have shown that many cell types may be infected, including endothelial cells, fibroblasts, hepatocytes, adrenal cortical cells, and epithelial cells. Lymphocytes and neurons are the only major cell types that remain uninfected. The fatal disease is characterized by multifocal necrosis in tissues such as the liver and spleen.

Patients with EVD commonly suffer from vomiting and diarrhea, resulting in acute volume depletion, hypotension, and shock. It is unclear if such dysfunction in EVD results from a viral infection of the gastrointestinal tract or if circulating cytokines or both induce it.

In addition to causing extensive tissue damage, EVD also produces a systemic inflammatory syndrome by causing the release of cytokines, chemokines, and other proinflammatory mediators from macrophages and other cells.

Infected macrophages produce tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-6, macrophage chemotactic protein (MCP)-1, and nitric oxide (NO). These and other substances have also been identified in blood samples from Ebola-infected macaques and acutely ill African patients. Breakdown products of necrotic cells also stimulate the release of the same mediators.

The systemic inflammatory response may play a role in inducing gastrointestinal dysfunction, as well as the diffuse vascular leak and multiorgan failure seen later in the disease course.

The coagulation defects seen in EVD appear to be induced indirectly through the host inflammatory response. Virus-infected macrophages synthesize cell-surface tissue factor (TF), triggering the extrinsic coagulation pathway. Proinflammatory cytokines also induce macrophages to produce TF. The simultaneous occurrence of these two stimuli helps to explain the rapid development and severity of coagulopathy in EVD.

Additional factors may also play a role in the coagulation defects seen with EVD. For example, blood samples from Ebola-infected monkeys contain D-dimers within 24 hours; D-dimers are also present in the plasma of humans with EVD. In Ebola virus-infected macaques, activated protein C is decreased on day two. Still, the platelet count does not begin to fall until days three or four, suggesting that activated platelets are adhering to endothelial cells. As the disease progresses, the hepatic injury may also cause a decline in plasma levels of certain coagulation factors (Geisbert et al., 2003).

The virus has an incubation period of 2-21 days and is spread when individuals become symptomatic (O'Keefe, 2016). Identifying those at risk relies primarily on early recognition of travel history and symptoms. Upon identifying the potentially infected, all healthcare personnel should don appropriate PPE, as standard droplet and contact precautions are generally observed (O'Keefe, 2016).

Most cases of EVD begin with sudden fever, malaise, muscle aches, headache, and sore throat. Other symptoms that may follow include (WHO, 2021; CDC, 2023f):

• Diarrhea
• Vomiting
• Signs of liver and kidney dysfunction
• Rash
• Bleeding (internally and externally, such as bloody stools and oozing from the gums)
• Lab findings may indicate low blood counts and increased liver enzymes

Rash

• A diffuse erythematous, nonpruritic maculopapular rash may develop by days 5 to 7 of illness.
• The rash usually involves the face, neck, trunk, and arms and can desquamate. It is generally easier to see in light-skinned persons.
• During the outbreak in Sierra Leone, the rash was reported as rare. It was, however, clearly described in case reports of infected healthcare workers.

Gastrointestinal

• Gastrointestinal signs and symptoms are common and usually develop within the first few days of illness. These include:
  • Abdominal pain
  • Nausea
  • Vomiting
  • Watery diarrhea (can be excessive and quickly lead to dehydration, hypotension, and shock if not controlled)

Hemorrhage

• Case series from the West African epidemic indicate that many patients develop some degree of bleeding during their illness, most commonly manifested as:
  • Blood in the stool
  • Ecchymoses
  • Mucosal bleeding
  • Oozing from venipuncture sites
  • Petechiae
• Clinically significant hemorrhage may be seen in the terminal phase of illness and pregnancy

Neurologic

• Patients occasionally develop meningoencephalitis, with findings such as:
  • Altered level of consciousness
  • Gait instability
  • Hyperreflexia
  • Myopathy
  • Seizures
  • Stiff neck
• These clinical manifestations typically develop around days 8 to 10 of illness

Cardiac

• Pulse-temperature dissociation with relative bradycardia may be observed during acute illness.
• In addition, retrosternal chest pain attributed to pericarditis has been reported.
• Myocarditis has also been described.

Respiratory

• Tachypnea and shortness of breath may represent hypoxia or hypoventilation due to respiratory muscle fatigue, contributing to impending respiratory failure. These symptoms were observed in nearly one-third of patients treated in Europe and the US in the setting of intravenous fluid resuscitation.

Ocular

• Patients may develop conjunctival injection and signs and symptoms of uveitis (blurred vision, photophobia, blindness) during the acute phase of the illness.
• In addition, uveitis has been documented during convalescence.

Symptomatic Patients with Identifiable Risk

• Clinical findings consistent with EVD include fever, severe headache, weakness, muscle pain, vomiting, diarrhea, abdominal pain, or unexplained hemorrhage (CDC, 2023b). Infection control precautions should be used for all symptomatic patients with an identifiable risk for EVD. In addition, the hospital infection control program and other appropriate staff should be notified, as well as local and state health departments.
• Such patients should be isolated in a single room with a private bathroom and a closed door to the hallway. All healthcare workers should also use standard, contact, and droplet precautions. PPE is recommended for the care of patients with EVD.
• In patients suspected of having EVD, phlebotomy, and laboratory testing should be limited to tests essential for diagnosing or ruling out the disease, assessing for an alternative or concurrent infection (e.g., malaria), and emergency care. In consultation with local and state health officials, evaluation for other potential causes of their illness may also be indicated, particularly for those individuals whose recent history suggests a low risk of exposure to the virus (CDC, 2023b).
• In the US, certain hospitals have been designated as "Ebola assessment hospitals." They are prepared to evaluate and care for patients with possible EVD until a diagnosis can be confirmed or ruled out (CDC, 2022f).

Asymptomatic Individuals with Identifiable Risk

• Monitoring for signs and symptoms of EVD should be performed for asymptomatic persons exposed to the Ebola virus at any risk level (i.e., high, moderate, or low risk).
• Such individuals should be monitored for 21 days after the last known exposure and immediately report the development of fever or other clinical manifestations suggestive of EVD (CDC, 2023b). The type of monitoring (e.g., self-monitoring and reporting versus direct observation by a designated health official), the need for travel restrictions, restricted movement within the community, and quarantine depend in part upon the type of exposure. Public health authorities typically dictate specific guidelines for managing asymptomatic individuals exposed to the Ebola virus.

Patients with No Identifiable Risk

• If patients are determined to have no identifiable risk for infection after initial evaluation, monitoring or diagnostic testing for EVD is not warranted. However, if patients have a fever and other signs or symptoms of illness, they should be evaluated for other causes of febrile disease (e.g., malaria, Lassa fever, influenza). Appropriate infection control precautions will depend upon the patient's clinical findings, as well as the specific pathogens that are being considered.

Indications

• All patients with suspected EVD should be evaluated in conjunction with local and state health departments (CDC, 2022c).
• Testing for EVD is performed in symptomatic patients with any possible risk of exposure to the Ebola virus (high, moderate, or low risk).
• Testing is not warranted for patients with an identifiable risk but no signs or symptoms of EVD. These patients should be monitored and tested if they become ill.
• Testing is not warranted for patients without any identifiable risk of exposure.

The Ebola virus is generally detectable in blood samples by RT-PCR within three days after the onset of symptoms. Repeat testing may be needed for patients with symptoms for fewer than three days (CDC, 2022c). According to CDC guidelines for discharging a person under investigation for EVD, a negative RT-PCR test collected ≥72 hours after the onset of symptoms excludes EVD (CDC, 2022b).

Patients who have confirmed EVD should be transferred to specialized Ebola treatment centers.

Diagnosing an Ebola virus infection may be challenging to differentiate from other diseases such as typhoid fever, malaria, and meningitis (WHO, 2021). Diagnostics are based on detecting specific RNA sequences by RT-PCR in blood or other body fluids. Viral antigens can also be detected using immunoassays. Any presumptive positive Ebola test in the US should be confirmed at the CDC (CDC, 2022e).

The local or state health department should be contacted immediately if testing is indicated. Clinicians, nurses, and laboratory workers need to be aware that CDC regulations apply to handling patient specimens confirmed to contain infectious Ebola viruses (CDC, 2022e). Additional details on collecting and handling specimens from patients with suspected EVD can be found in the CDC documents that guide laboratories and submission information (CDC, 2022c). For clinicians outside the US, the WHO has also issued guidance for diagnosing, safely collecting, and shipping samples from patients with suspected EVD (WHO, 2021).

When evaluating a patient for possible EVD, it is essential to consider alternative and concurrent diagnoses, including infectious and noninfectious disorders.

The differential diagnosis depends, in part, upon the individual's symptoms, where they have traveled or resided, if they have had close contact with someone who is ill, their vaccination history, and their age and comorbid conditions (CDC, 2023b).

Since most patients suspected of possible EVD will have traveled to and reside in West or Central Africa, the following disorders should be considered:

• Influenza
  • Influenza often presents with the abrupt onset of fever, headache, myalgia, and malaise, like the presenting signs and symptoms of EVD. However, with influenza, these manifestations are usually accompanied by respiratory signs and symptoms, such as nonproductive cough, sore throat, and nasal discharge, which are not typically part of EVD. Direct fluorescent antibodies or other rapid assays are used to diagnose influenza.
• Lassa Fever
  • Lassa fever is restricted to West Africa, though infected travelers have become ill in countries of Europe, as well as in the US. Although symptoms may be mild, approximately 20% of patients develop a severe clinical syndrome that can progress to fatal shock. Transmission to humans occurs primarily through exposure to the aerosolized excretions of local multimammate rats or, in rare cases, through contact with the body fluids of infected individuals. Diagnosis is made by RT-PCR testing and serology (CDC, 2023a).
• Malaria
  • Travelers who develop a febrile illness after returning from West or Central Africa should be evaluated for malaria, which can present similar findings to EVD and may occur concurrently (CDC, 2022b). Microscopic examination of blood smears and rapid antigen testing are typically used to diagnose malaria.
• Marburg Virus Disease
  • Marburg virus causes clinical manifestations like EVD. Cases have been identified in Central Africa but not in West Africa. The diagnosis is typically made by RT-PCR testing.
• Measles
  • The prodromal phases of measles and EVD are similar and are characterized by fever, malaise, and anorexia. However, in measles, this is followed by conjunctivitis, coryza, cough, and a characteristic maculopapular, blanching rash that begins on the face. The diagnosis of measles is typically established via antibody or PCR testing.
• Meningococcal Disease
  • Patients infected with Neisseria meningitidis can present with meningitis and bacteremia, and specific signs and symptoms (headache, fever) may overlap with those seen in EVD.
• Travelers' Diarrhea
  • The condition develops during or within ten days after returning from travel, most commonly from resource-limited regions. Patients typically present with malaise, anorexia, and abdominal cramps, followed by the sudden onset of diarrhea. Nausea, vomiting, and low-grade fever may also occur. When attempting to distinguish between travelers' diarrhea and diarrhea in EVD, clinicians should note whether the condition appears to be part of a systemic illness or is mainly confined to the gastrointestinal tract. A patient who develops diarrhea in the setting of EVD is likely to have a several-day history of fever, myalgia, fatigue, and other signs of a rapidly progressive systemic disease.
• Typhoid
  • Typhoid fever is a systemic illness characterized by fever and abdominal pain. The organism responsible for enteric fever syndrome is Salmonella Typhi (formerly S. typhi). Worldwide, typhoid fever is most prevalent in impoverished and overcrowded areas with poor access to sanitation. The diagnosis is typically made by identifying the organism in blood cultures.

All healthcare workers caring for patients with suspected or confirmed EVD should rigorously observe infection control precautions, including the proper use of PPE.

Two monoclonal antibodies (Inmazeb and Ebanga) were approved in 2020 by the US Food and Drug Administration for treating Ebola. These have only been proven effective against the Zaire ebolavirus thus far (WHO, 2021). Also approved by the FDA in 2020 was the Ervebo vaccine, which effectively protects people against the Zaire ebolavirus (WHO, 2021).

The mainstay of treatment for EVD involves supportive care to maintain adequate organ function (e.g., cardiovascular, respiratory, renal). At the same time, the immune system mobilizes an adaptive response to eliminate the infection (CDC, 2021c). Whenever possible, such patients should receive care in designated treatment centers and by clinicians trained to care for such patients (CDC, 2023d).

Fundamental aspects of supportive care involve preventing intravascular volume depletion, correcting profound electrolyte abnormalities, and avoiding the complications of shock.

During the outbreak in West Africa, 27 patients with EVD were treated in the US or Europe, receiving aggressive supportive care (Uyeki et al., 2016). Among those patients, 82% survived. Specific lessons learned from the care of patients with EVD during the outbreak include the following: (CDC, 2023b).

Patients may lose significant amounts of fluid through vomiting and diarrhea, requiring rapid volume replacement to prevent shock. Antiemetic and antidiarrheal agents may also be beneficial. Careful attention to the volume of fluid losses and intake will assist with fluid repletion targets.

When available, patients will benefit from hemodynamic monitoring and intravenous fluid repletion. However, patients in the early phase of illness who respond to oral antiemetic and antidiarrheal therapy may be able to take in sufficient fluids by mouth to prevent or correct dehydration (Kortepeter et al., 2016).

Patients may develop significant electrolyte disturbances (e.g., hyponatremia, hypokalemia, hypomagnesemia, and hypocalcemia) and require frequent electrolyte repletion to prevent cardiac arrhythmias.

Intensive care nursing may be required to respond to the patient's changing clinical situation.

Patients who experience fluid loss from vomiting and diarrhea may require a balanced crystalloid solution of five or more liters daily. Fluid and electrolyte replacement can be administered orally (WHO-recommended oral rehydration salts) or intravenously (0.9% sodium chloride solution). The approach largely depends upon the stage of illness and the clinical presentation. For example, in resource-limited settings, oral therapy to prevent or correct dehydration may be suitable for patients in the early phase of illness who respond to oral antiemetic and antidiarrheal therapy (Kortepeter et al., 2016). However, patients in shock and those unable to tolerate or manage self-directed oral replacement therapy will require intravenous fluids.

In resource-limited areas with little or no monitoring and laboratory capacity, qualitative assessments of urine frequency, volume, and color and evaluation of skin turgor and mucous membranes may assist in guiding volume replacement without more accurate measures.

In areas with more significant resources, careful attention to the volume of fluid losses and intake and indirect assessments of intravascular volume status (e.g., vascular ultrasound and indwelling catheters for central venous pressure monitoring) will assist with fluid repletion targets. Plasma values should guide electrolyte replacement since patients can present with various abnormalities.

In resource-rich areas, clinicians may employ standard supportive measures for critically ill patients in shock, including invasive blood pressure and continuous pulse-oximetry monitoring. Hypotension may persist despite adequate volume resuscitation, requiring vasopressor infusions such as norepinephrine. Aggressive volume resuscitation may contribute to developing pulmonary edema, and acute lung injury in the setting of shock may necessitate supplemental oxygen therapy (e.g., nasal cannula or face mask).

Invasive mechanical ventilation (intubation) may be the best option for patients with progressive respiratory failure. When considering the management of such patients with EVD, clinicians should recognize that some types of respiratory support present a hazard of generating infectious aerosols. Noninvasive mechanical ventilation or high-flow oxygen therapy (e.g., Vapotherm) is generally not recommended, given the potential for continuous aerosol production.

As with other severely ill patients, persons with EVD may require evaluation and treatment of other concomitant or possible infections (e.g., malaria).

In addition, empiric antimicrobial treatment should be administered to patients with clinical evidence of bacterial sepsis, which may be a late complication.

• The choice of agent should provide adequate coverage for gram-negative pathogens.
• Empiric gram-positive therapy should be added in certain patients, such as those with hospital-acquired pneumonia or indwelling central venous catheters.

In some cases from the Ebola epidemic in West Africa, empiric antimicrobial therapy was given to patients at the time of initial presentation or to patients with gastrointestinal dysfunction, even if clinical evidence of bacterial sepsis was absent. However, data to justify this approach are lacking.

EVD is associated with a high risk of fetal death and pregnancy-associated hemorrhage (CDC, 2022d). Those who are pregnant or breastfeeding should have access to early supportive care measures. Vaccines and monoclonal antibodies should be offered if healthcare professionals feel the risk versus benefit warrants the treatments (CDC, 2022d).

The CDC and the American College of Obstetrics and Gynecology have issued recommendations for caring for pregnant women with EVD (CDC, 2022d). However, no data suggests whether cesarean or vaginal delivery is preferred or when the baby should be delivered. Thus, decisions regarding obstetrical care must be made on a case-by-case basis.

Patients should be informed that clinical sequelae, including mental health issues, may persist after recovering from the illness. A comprehensive plan should be developed to support EVD survivors and reduce the risk of transmitting the disease to others. EVD has been reported to remain in some sites of humans after recovery, such as the central nervous system, testicles, and eyes. After infection in pregnant or breastfeeding women, the virus may remain in breast milk or amniotic fluid (WHO, 2020).

All survivors should be educated to refrain from sexual activity (or practice safe sex) until their semen has tested negative twice for the virus. Initial semen testing should be scheduled three months after the virus onset and every month for those continuing to test positive.

The WHO suggests that patients be seen for follow-up two weeks after discharge, monthly for six months, and then every three months to complete one year (WHO, 2016).

• Males should have semen testing during these visits until they test negative for virus RNA.
• If fever develops, patients should be tested for Ebola RNA by RT-PCR and be evaluated for other causes of infection (e.g., malaria).
• Uveitis and meningitis may be suggestive of an EVD relapse. If meningitis is suspected, a lumbar puncture should be performed (using appropriate PPE), even if the blood tests are negative for Ebola RNA.

EVD survivors with ocular findings also require follow-up for vision care (CDC, 2019).

When caring for patients with confirmed or suspected acute EVD, healthcare personnel should follow infection prevention and control recommendations from the CDC and the WHO (CDC, 2022f). These guidelines provide control measures to manage patients known or suspected to be infected with the virus or other highly pathogenic agents.

Infection control recommendations for patients who present with acute infection include:

• Correct use of appropriate PPE
• If possible, aerosol-generating procedures should be avoided. However, if they must be performed, patients should be placed in an airborne infection isolation room (CDC, 2022f)
• Isolation of hospitalized patients with known or suspected EVD
• Proper hand hygiene
• Use of standard, contact, and droplet precautions

The type of PPE used, and its careful placement and removal are critical to preventing nosocomial transmission of the Ebola virus. During the 2014 - 2016 epidemic, several patients were cared for in the US. The staff at Emory University used full-body suits. It powered air-purifying respirators (PAPR) to help staff work for extended periods, decrease the physical discomfort of working in multi-component PPE, and avoid difficulties like fogged face shields. The donning and doffing of PPE were constantly observed by another staff member.

The PPE used for EVD depends partly upon the patient's clinical presentation (e.g., presence or absence of diarrhea, vomiting, bleeding). Clinicians should refer to the CDC and WHO guidelines when caring for patients. The CDC has also released a video that demonstrates the donning and doffing of PPE.

Highlights from these guidelines include the following:

• Rigorous and repeated training of health care workers in correct donning and doffing of PPE. In addition, healthcare workers should demonstrate competency in performing Ebola-related infection control practices and procedures.
• PPE should cover all clothing and skin, protecting mucous membranes. Such PPE includes gloves, boot covers, fluid-resistant gowns or coveralls, single-use disposable hoods that cover the head and neck, single-use disposable full-face shields, and PAPR or N95 respirators. Additional measures, such as waterproof aprons, may also be required depending on the patient's symptoms. The healthcare facility providing care should determine the combination of PPE used.
• Healthcare workers should frequently disinfect gloved hands using an alcohol-based hand rub, particularly after touching body fluids.
• A trained monitor should actively observe and supervise each worker donning and doffing PPE. Monitors should not serve as an assistant in taking off PPE.

Using the recommended PPE for healthcare workers caring for patients with EVD for extended periods can potentially result in heat-related illness, which was of particular concern in West Africa (CDC, 2022f). Recommendations to help prevent such complications include staying hydrated, working short shifts until the healthcare worker can adjust to the heat, taking time to rest and cool down, and watching for signs of heat-related illness.

Healthcare workers who are pregnant should not provide care for patients with EVD. In addition to the increased maternal and fetal risks of EVD during pregnancy, PPE may not be well-suited for pregnant healthcare workers.

Strict infection control precautions must be used when caring for pregnant patients with EVD. PPE is recommended for providers at high risk of exposure to bodily fluids. These precautions should be used even if the mother has recovered from the infection since data suggest that the fetus of a mother who survived EVD while pregnant may continue to harbor the virus and be infectious (WHO, 2020).

Suppose a patient with suspected or confirmed EVD is cared for in a healthcare setting. In that case, specific precautions should be taken to reduce the potential risk of virus transmission through contact with contaminated surfaces. Frequent cleaning of the floor in the doffing area is necessary (CDC, 2021b)

In a study that surveyed EVD treatment centers in Sierra Leone, viral RNA was frequently detected on materials in direct contact with patients (Poliquin et al., 2016). For example, Ebola virus RNA was detected on four of six gloves tested despite a lack of visible soiling. However, viral RNA was no longer detected after gloves were rinsed with a chlorine solution.

The CDC has guided medical waste management and specific recommendations for environmental infection control in hospitals, healthcare settings, and laboratories.

Sexual transmission

• The CDC and WHO suggest that patients with EVD refrain from sexual activity (oral, anal, vaginal) and that condoms should be used if abstinence is impossible. In addition, hand hygiene is recommended following contact with semen (CDC, 2019).
• It is not known when unprotected sexual activity can be safely resumed. For men, the WHO has suggested that the semen be tested for the Ebola virus by RT-PCR three months after the onset of the disease. Further recommendations are as follows:
  • For those men who test negative, the test should be repeated with an interval of one week between tests. Sexual activity can be resumed if their semen has tested negative for the Ebola virus twice by RT-PCR.
  • For those men who test positive for the Ebola virus at three months, testing should be repeated every month until their semen tests negative. Sexual activity can be resumed if the semen has tested negative for the Ebola virus twice by RT-PCR.
  • The WHO recommends that if semen testing is unavailable, men should practice safe sex for at least 12 months from the onset of illness.
• Studies evaluating the persistence of the Ebola virus have detected viral RNA in vaginal fluids for up to 33 days and in semen for up to two years after the onset of EVD.

Breastfeeding and infant care

• The Ebola virus can be transmitted through close contact between an infected mother with her children. The CDC recommends that most who are under investigation for EVD, have confirmed infection, or have recently recovered should avoid breastfeeding (CDC, 2021a).
• Where available, breast milk testing can guide when it is safe for mothers who have survived EVD to resume breastfeeding. If Ebola virus RNA is detected, the breast milk should be retested every 48 hours until two consecutive negative results are obtained.
• In resource-limited settings, the risk of virus transmission during breastfeeding must be weighed against the risk of the infant becoming malnourished or developing a diarrheal or respiratory disease or other infections if safe alternative options for feeding are not available.

Monitoring and travel restrictions

• Persons who have had possible exposure to the Ebola virus should be monitored for signs and symptoms of the disease. Monitoring should continue for 21 days after the last known exposure. The development of fever and other clinical manifestations suggestive of EVD should be reported immediately.
• During the West African epidemic, the CDC and WHO provided information about restrictions on the travel and transport of asymptomatic persons exposed to EVD.

The registered nurse phones the main desk to relay her obtained information. She requests that the physician gown up and wear gloves and a mask before he enters the triage room. Meanwhile, since she has been inadvertently exposed to the suspected Ebola virus, the triage RN uses her cell phone to contact the hospital infection control professionals/resources. After being informed of the ongoing situation, the infection control professional immediately closed down the urgent care center for the time being, diverting arriving patients to the hospital emergency room. She follows protocol, which usually includes informing the administration and the local and state health departments. All patients exposed to the two sisters were asked to be patient and remain in the waiting room for the time being. All patients in the other examination rooms in the urgent care center were either discharged home or transported to the main emergency room.

A hazmat/public health team arrives at the urgent care center to assess the other waiting room patients and admission secretaries as PUIs. Another hazmat/public health team visits the convent where the two sisters reside to evaluate the other sisters as PUIs and any other contacts they may have had.

All suspected PUIs in the urgent care center and convent were immediately isolated to prevent the possible spread of suspected EVD. Federal, state, and local healthcare agencies were immediately notified and responded promptly. Levels of risk assessment were ongoing.