Contact with Ebola virus — Likelihood of infection?

Dear Alice,

What is the likelihood of someone who has come into contact with the Ebola virus to actually get the disease?

Dear Reader,

It depends on what kind of contact or exposure that person had with Ebola virus disease (EVD) — previously known as Ebola hemorrhagic fever, now referred to as Ebola virus or simply Ebola. For example, if said person has Ebola-infected body fluids (e.g., blood, vomit, diarrhea, urine, etc.) come in direct contact with mucous membranes (e.g., eyes, nose, or mouth), the risk for transmission is high. On the other hand, contact with a person who has Ebola, but is not yet showing symptoms, carries no risk. Ebola is a severe, often deadly and highly contagious disease; however, it’s less contagious than other infectious diseases such as the flu or measles. It’s also very rare in the United States.

Here are more details regarding the transmission of Ebola:

  • Ebola is spread through direct contact with an infected and contagious person’s body fluids, such as blood, vomit, diarrhea, urine, sweat, feces, breast milk, or semen.
  • Direct contact with infected body fluids through a needle stick or splashes to the eyes, nose, or mouth carries the highest risk for transmission.
  • There is no evidence that Ebola is spread to humans through the air or water.
  • Mosquitos and domesticated dogs and cats have not been implicated in the spread of the virus.
  • More specific infection patterns and levels of transmission risk are outlined in the Guidance on Monitoring Symptoms and Controlling Movement to Stop Spread of Ebola Fact Sheet from the Centers for Disease Control and Prevention (CDC).

As mentioned before, Ebola infections are exceedingly uncommon in the United States and very few cases have been confirmed. If you live in New York City, you can rest assured that there’s an established public health infrastructure in place to address any suspected cases of Ebola. Those at greatest risk of contracting Ebola are caregivers who are in direct contact with infected individuals: health care providers, aid workers, and family members. Though the virus can only live outside the body for a short period of time, cleaning up the fecal matter, blood, diarrhea, or vomit of someone who is sick with or has just died of Ebola can put a person at considerable risk of contracting it. For this reason, health care providers working in populations with Ebola undergo extensive measures to protect themselves by wearing special gloves, masks, gowns, and boots (commonly referred to as PPE or personal protective equipment), so as not to contract or transmit the virus.

If a person becomes infected with Ebola, there is an initial incubation period which can last anywhere from 2 to 21 days (though the average is 8 to 10 days). People are not infectious until symptoms develop, some of which include:

  • Fever.
  • Muscle pain, headache, sore throat, stomach pain.
  • Vomiting and diarrhea.
  • As the disease progresses, a person will eventually experience sometimes severe deterioration of kidney and liver function, the development of disseminated intravascular coagulation, as well as internal bleeding.

If a person starts to develop symptoms and is known to have had contact with a person infected with Ebola, it’s recommended that s/he seek immediate medical attention. Symptoms and any other concurrent infections are treated as they appear and maintenance of electrolyte balance, blood pressure, and oxygen levels are also a part of the general treatment for infected individuals. Unfortunately, there are no drugs that will cure Ebola and a vaccine is not yet available. The World Health Organization (WHO) estimates the average mortality rate across all strains (and in all parts of the world) is around 50 percent. However, among the different strains, the mortality rate ranges from 25 percent to 90 percent.

Prevention recommendations for those traveling to areas where there are known Ebola infections include avoiding contact with body fluids of infected individuals (both alive and dead), practicing good hygiene such as washing hands with soap and water and using alcohol-based hand sanitizer, and monitoring your health for signs of infection for 21 days upon returning from the area.

For complete and up-to-date information about Ebola, visit the CDC Ebola website and the WHO Ebola website

Originally published Oct 31, 2014

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