Do we have to worry about Ebola in the United States?
Do you remember 42-year-old Thomas Eric Duncan, the first Ebola statistic in the United States?
- On September 19, 2014, Duncan boarded a flight in Liberia, Africa, excited to reunite the next day with his fiancée who lived in Dallas, Texas.
- Five days later, Duncan was in the ER of a Dallas hospital and waited for five hours before being seen and sent home with Tylenol.
- Duncan was admitted to the same hospital on September 30 and ultimately succumbed to Ebola Virus Disease (EVD) on October 8th.
- Tracing back his steps, it seems very likely that he was exposed to Ebola virus on September 15, 2014, in Liberia.
Duncan was part of the largest and most severe EVD outbreak in recorded history, with 28,639 infections and 11,316 deaths.
What has changed since 2014 is the development of a highly effective, rVSV-ZEBOV Ebola vaccine.
- Although not licensed yet, rVSV-ZEBOV has received the designation for “compassionate use” in outbreaks.
- We don’t know yet how long the vaccine keeps people safe, but it is being used to curb the current EVD epidemic in the Democratic Republic of the Congo,
As of May 13, 2019, there have been 1,720 infections and 1,136 deaths, making this the second deadliest Ebola outbreak since 2014 – 2016 and revealing a need for more vaccinations.
Ebola is just one virus that threatens public health.
- As globalization dissolves international borders for most infectious diseases, our best defense is prevention:
- by vaccination when available,
- and by awareness of symptoms as well as transmission.
- It is certainly feasible to see Ebola virus on our shores again.
- EVD can initially mask itself with flu like symptoms such as fever, headache, muscle or body aches and fatigue.
- EVD patients go on to show vomiting and diarrhea, weakness (at times severe), abdominal pain and unexplained bleeding or bruising.
- Additional clues to EVD diagnosis are
- travel history to countries with widespread transmission,
- being healthcare providers taking care of EVD patients,
- having unprotected direct contact with skin or any bodily fluids (such as sweat, urine, blood, tears etc.) of an EVD patient.
- Even corpses are highly contagious, which is why Duncan was cremated and not buried.
There are three important considerations for any infectious disease that can spread through a population:
- A number called the R nought factor (R0):
- this number is 1.5 – 2 for EVD, which means
- each EVD patient infects an average of about 2 additional individuals.
- This makes for a slow moving virus, provided we stop the chain of transmission.
- each EVD patient infects an average of about 2 additional individuals.
- this number is 1.5 – 2 for EVD, which means
- The period of contagion:
- EVD is only contagious when patients are symptomatic.
- This is a tremendous advantage in an ongoing outbreak.
- This means we can isolate symptomatic individuals and
- quarantine those who have already come in contact with symptomatic individuals.
- This means we can isolate symptomatic individuals and
- This is a tremendous advantage in an ongoing outbreak.
- Unfortunately, health centers in Africa have faced grave dangers with this strategy due to
- resistance from the community and violent attacks on treatment centers.
- Although increased security in the area and continued spread of awareness about EVD are immediate solutions,
- there has to be a long-term goal of fostering wide-spread education in the community,
- which will help dispel at least some of the superstitions and fears behind EVD treatment.
- there has to be a long-term goal of fostering wide-spread education in the community,
- EVD is only contagious when patients are symptomatic.
- The incubation period of an infectious disease:
- which refers to the time between exposure to infectious agent and development of symptoms.
- For EVD, this number ranges from 2 to 21 days.
- For Duncan, this number was 10 days.
- All the family members who came in contact with Duncan were quarantined in their apartment for 21 days.
- The intent was to immediately isolate all those who started showing EVD symptoms, so they could receive appropriate treatment and at the same time be prevented from potentially infecting others.
- All the family members who came in contact with Duncan were quarantined in their apartment for 21 days.
- For Duncan, this number was 10 days.
- For EVD, this number ranges from 2 to 21 days.
- which refers to the time between exposure to infectious agent and development of symptoms.
The Ebola saga may not end with recovery.
Some survivors show persistent presence of Ebola virus in bodily fluids such as aqueous humor (ocular fluid), breast milk, cerebrospinal fluid, and semen.
- In fact, the virus may even persist in semen up to 18 months after infection!
- This brings novel challenges to prevention.
- A newer study shows not only persistence of the virus in a female survivor, but also transmission to three members in her family of six, a year after recovering from EVD.
Benjamin Franklin once said, “An ounce of prevention is worth a pound of cure”. Although he was referring to fire safety at the time, this 18th century adage holds true even today, especially as it pertains to matters of public health importance.