It Can't Happen Here: Examining the Odds of an Ebola Outbreak in the US

News reports on the first case of Ebola diagnosed in the US have stoked fears that we could be facing an outbreak of the disease. However, experts say that characteristics of the disease itself, plus a robust public health infrastructure, make that highly unlikely.

The news that a patient with Ebola is hospitalized in Dallas, TX, has fueled speculation that there will be a major outbreak of the disease in the United States. Although there is the risk of further spread from this case, or introduction of new cases due to global travel, the risk of an epidemic for the United States is mitigated by two factors. The first is the biological characteristics of the disease and the causative virus.

Ebola Virus Disease (EVD) is an infection characterized by sudden onset of fever and malaise, accompanied by other nonspecific signs and symptoms, such as myalgia, headache, vomiting, and diarrhea. Patients with severe forms of the disease may develop hemorrhagic symptoms and multi-organ dysfunction, including hepatic damage, renal failure, and central nervous system involvement, leading to shock and death. The fatality rate can vary from 40-90%.

In outbreak settings, such as in West Africa, Ebola virus is typically first spread to humans after contact with infected wildlife and is then spread person-to-person through direct contact with bodily fluids such as, but not limited to, blood, urine, sweat, semen, and breast milk. The incubation period is usually 8—10 days (ranges from 2–21 days). Patients can transmit the virus while febrile and through later stages of disease, as well as postmortem, when persons touch the body during funeral preparations.

Transmission from human to human occurs when the patient is symptomatic. Most patients will go from having mild, non-specific symptoms to being critically ill in a very short time period. This means that the disease will not spread from a patient without symptoms to another person. Additionally, as noted above, the virus is spread only by secretions, such as vomit, urine, sweat, or blood. Unlike the flu, it is not an airborne infection.

The key for healthcare facilities is to ask any patient presenting with symptoms, even early mild ones, if they have traveled to the countries in Africa that are currently affected by the Ebola outbreak. If the patient answers yes, the patient should be immediately placed into isolation until an Ebola infection is established or ruled out. All healthcare workers should use personal protective equipment when caring for the patient. These processes will ensure that the disease doesn’t spread within the healthcare facility.

The second factor that will limit the spread in the United States is our robust public health infrastructure. As seen in the Dallas case, the local and federal health agencies are tracing contacts and placing them in isolation. This type of public health effort will help control the spread of the disease.

If the public is armed with the scientific facts about Ebola, they can be prepared and show appropriate concern and caution, yet take comfort that the disease will be very unlikely to have any impact on them personally.

Mark P. Jarrett, MD, MBA, is Chief Quality Officer and Associate Chief Medical Officer of North Shore-LIJ Health System in New York.