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Ebola and Enterovirus D68, Pandemic or Panic Part II

by Stephen Propatier

October 8, 2014

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Recently, fear of infectious disease has become a constant drumbeat on the Internet and television. This is primarily due to two viral diseases. Disease one is the deadly West African Ebola Virus. Disease two is Enterovirus D68. Mike Rothschild did a nice post about the enterovirus on September 16th titled "EV-D68: The (Not) New Disease to (Not) Panic About." Events surrounding these diseases this week seems to have piqued the obsessive interest of the news media: the first-ever case of Ebola diagnosed in the US in Dallas Texas (who was reported as deceased today) and the recent news reports linking the death of a healthy child to the enterovirus. This is part two of my informational posts. This one is focused on the Ebola Virus and the Epidemic in West Africa.

Ebola Virus

*Warning Technical Jargon!*

The filoviruses, Ebola and Marburg, are among the most virulent pathogens of humans, causing severe disease that resembles fulminant septic shock. The case-fatality rate in the epidemic of Ebola virus in West Africa has been estimated to be approximately 70 percent; rates in earlier outbreaks in Africa (including Marburg virus disease in 2005) reached 80 to 90 percent.

All isolates of Marburg virus are currently considered to be members of a single species. However, there is evidence that they vary in their pathogenicity for humans, since the overall fatality rate in the 1967 outbreak in Europe was 21 percent, whereas mortality among identified cases in 2000 in the Democratic Republic of Congo (DRC) and in 2005 in Angola was in the range of 80 to 90 percent. Alternatively, the striking difference in outcome may reflect the paucity of medical resources where the latter outbreaks took place.

Ebola virus — The genus Ebola virus is divided into five different species (the Zaire, Sudan, Ivory Coast, Bundibugyo, and Reston agents), which differ in their virulence for humans. Since its first recognized appearance in 1976, the Zaire species has caused multiple large outbreaks with mortality rates of 55 to 88 percent.

  • The Sudan virus has been associated with an approximate 50 percent case-fatality rate in four known epidemics: two in Sudan in the 1970s, one in Uganda in 2000, and another in Sudan in 2004.

  • The Ivory Coast virus has only been identified as the causative agent in one person, who survived. The exposure occurred when an ethologist performed a necropsy on a chimpanzee found dead in the Tai Forest, where marked reductions in the great ape population had been observed.

  • The Bundibugyo virus emerged in Uganda in 2007, causing an outbreak of hemorrhagic fever with a lower case-fatality rate (approximately 30 percent) than has typically been caused by the Zaire and Sudan viruses. Sequencing has shown that the agent is most closely related to the Ivory Coast agent.

  • The fifth Ebola species, the Reston virus, differs markedly from the others, because it is apparently maintained in an animal reservoir in the Philippines and has not been found in Africa. Ebola Reston virus was first recognized when it caused an outbreak of lethal infection in macaques imported into the United States in 1989. This episode brought the filoviruses to worldwide attention through the publication of Richard Preston's book, The Hot Zone. Three more outbreaks occurred among nonhuman primates in quarantine facilities in the United States and Europe before the Philippine animal supplier ceased operations. None of the personnel who were exposed to sick animals without protective equipment became ill, but several animal caretakers showed evidence of seroconversion.

  • Nothing further was heard of the Reston virus until 2008, when the investigation of an outbreak of disease in pigs in the Philippines unexpectedly revealed that some of the sick animals were infected both by an arterivirus, porcine reproductive and respiratory disease virus, and by Ebola Reston virus. Serologic studies have shown that a small percentage of Philippine farm workers exposed to swine have IgG antibodies against the agent, in the absence of any history of severe illness, providing additional evidence that Ebola Reston virus is able to cause asymptomatic infection in humans. The relationship between the virus circulating in swine and that previously recovered from Philippine macaques is not known.

EPIDEMIOLOGY — The filoviruses were first recognized in 1967, when the inadvertent importation of infected monkeys from Uganda into Germany and Yugoslavia resulted in explosive outbreaks of severe illness among vaccine plant workers who came into direct contact with the animals by killing them, removing their kidneys, or preparing primary cell cultures for polio vaccine production. Since that time, with the exception of a few accidental laboratory infections, all cases of filoviral disease have occurred in sub-Saharan Africa. The frequency of recognized outbreaks has been increasing since 1990. Ebola virus has also been spreading among wild nonhuman primates, apparently as a result of their contact with the unidentified reservoir host. This has contributed to a marked reduction in chimpanzee and gorilla populations and has also triggered human epidemics, presumably due to consumption of sick or dead animals as a source of food.

So you see we have a pretty good idea where the illness originates. There is absolutely no evidence that this is some type of disturbing population control or government plot as some people have suggested... e.g. the Alex Jones show.

The current West African epidemic is by far the largest outbreak of Ebola virus disease ever recorded. It is currently occurring in West Africa with the Zaire species of the virus. Although most previous Ebola outbreaks occurred in Central Africa, this outbreak started in the West African nation of Guinea in late 2013 and was confirmed by the World Health Organization in March 2014. The initial case was a two-year-old child in Guinea who developed fever, vomiting, and black stools, without other evidence of hemorrhage. The outbreak subsequently spread to Liberia, Sierra Leone, Nigeria, and Senegal. Sequence analysis of viruses isolated from patients in Sierra Leone indicates that the epidemic has resulted from sustained person-to-person transmission, without additional introductions from animal reservoirs. The case-fatality rate has been estimated to be approximately 70 percent. Ebola Virus Disease first 9 months of epidemic Pubmed

The magnitude of the outbreak, especially in Liberia and Sierra Leone, has probably been underestimated; this is due in part to individuals with Ebola virus disease being cared for outside the hospital setting. As of September 28, 2014, the cumulative number of probable, suspected, and laboratory-confirmed cases attributed to Ebola virus is 7,178, including 3,338 deaths. However, Nigeria and Senegal have not reported any new cases since September 5, 2014, and August 29, 2014, respectively.

On September 30, 2014, the first travel-associated case of Ebola was reported in the United States. An individual who traveled from Liberia to Dallas, Texas first developed clinical findings consistent with Ebola virus disease approximately five days after arriving in the United States. The patient was asymptomatic prior to and during the flight. Initially it was not recognized as Ebola and there are conflicting reports about who knew about his West African travel and when it was know. It was not suspected until his symptoms progressed and he returned to the hospital that sent him home on the first visit. Unfortunately due to complications of the disease he passed away on October 8, 2014. Once this was recognized, proper isolation and quarantine procedures were put in place. It is very likely that he will be the only death directly related to the exposure.

Although this is a deadly and terrifying disease it is much easier to contain than something like influenza, which is airborne. Person-to-person transmission occurs through direct contact of broken skin or unprotected mucous membranes with virus-containing body fluids (e.g. blood, vomit, urine, feces, semen, and probably sweat) from a person who has developed signs and symptoms of illness. This mode of transmission may lead to outbreaks. The most common routes of transmission are as follows:
  • One type of direct contact that leads to transmission is the ritual washing of Ebola victims at funerals. An epidemiologic study found that family members were only at risk of infection if they had physical contact with sick individuals or their body fluids, or helped to prepare a corpse for burial.

  • Healthcare workers are at risk of infection if they care for a patient with Ebola or Marburg virus disease without appropriate protective measures. Over 370 healthcare workers have become infected during the epidemic in West Africa, due in large part to shortages of personal protective equipment and/or exposure to patients with unrecognized Ebola virus disease. Approximately 50 percent have died.

  • Ebola virus is rarely, if ever, spread from person to person by the respiratory route. Although aerosolized filoviruses are highly infectious for laboratory animals, in humans, airborne transmission has only been reported among healthcare workers who were exposed to aerosols generated during medical procedures.

Prior to the epidemic in West Africa, outbreaks of Ebola and Marburg virus disease were typically controlled within a period of weeks to a few months. This outcome was generally attributed to the relatively inefficient person-to-person transmission of the virus in areas of the African rainforest where population density was low and residents rarely traveled far from home. However, the epidemic in West Africa has shown that Ebola virus disease can spread rapidly and widely as a result of the extensive movement of infected individuals (including undetected travel across national borders) and the avoidance and/or lack of adequate medical isolation centers. Epidemiological studies

So should we be very concerned about Ebola spreading to other continents? Will "Patient Zero" spread an uncontrolled infection to the US or Europe? Could it create a widespread outbreak world wide?

If you drift away from speculation and look at the science there is little cause for concern from this epidemic. There are essentially three overall ways to have an uncontrolled outbreak in the western world.
  1. The virus mutates into an airborne strain - Despite alarmist discussions in the media and pop culture end-of-world epidemic scenarios, this is unlikely in the extreme. There is no known precedent for any human disease spontaneously mutating from a contact-spread disease into an airborne-transmission method—NEVER, not even historically. Although it's possible hypothetically, it is a virtual certainty this will not happen. Some viruses mutate rapidly, like HIV and influenza; Ebola does not and has a very slow mutation rate. CDC

  2. Ebola becomes contagious during the prodromal period - In the early stages of the disease the viral load is exceptionally low and it is not contagious until you begin to exhibit symptoms. This means that if you are not having symptoms it's very unlikely that you'll spread the disease. The viral load curve follows the symptom curve. If you have enough virus to be symptomatic then you have enough virus to spread it. In the western world, which is well supplied and equipped to combat the virus, plus now hyper-vigilant, most cases will be quickly blunted.

  3. A deliberate bioweapon attack -This is the only scenario that could result in the number and severity of cases that would overwhelm western medicine. It's difficult—nearly impossible—to accomplish such a feat with infected individuals. It would require coordination that is practically impossible. You would need thousands of purposely infected-but-mildly symptomatic individuals distributed throughout the world. Essentially, medical suicide bombers by the thousands, if not tens of thousands, would need to be coordinated and deployed. Since that contagious-but-not severely ill window is very small for Ebola (1-2 days), it would be difficult for single individuals to infect the kind of numbers needed to overwhelm the modern medical system. Essentially the disease progresses too rapidly for this to be truly possible. Plus, everyone develops the disease at a different time. The exception is a weaponized agent. That would be effective, and of course a disaster. Hemorrhagic fever as a biologic weapon

Overview: The current Ebola (Zaire strain) epidemic is terrifyingly deadly and deserves caution and action. It is extremely unlikely to become a global pandemic. What has made this Ebola epidemic so troublesome is poverty and mobility. And in western Africa, the lack of proper isolation equipment, facilities, and proper screening methods has contributed significantly to its unabated spread. Coupled with increasing mobility of infected individuals, poor education, lack of understanding about disease transmission, and a absence of coordinated medical system, the virus has tragically affected thousands, and is likely to endanger millions in one way or another. In my opinion, the World Health Organization should have sought out more international help much more quickly. They even refused the Centers for Disease Control's offer of help in the early stages. They dropped the ball badly. This epidemic could have been limited to an outbreak if early, aggressive measures were taken. They overestimated the historically self-limiting aspect of the disease, and underestimated the rural poor's access to transportation, resulting in rapid dissemination.

On a personal note: I understand people wanting to quarantine the whole region and be self-serving or protective of themselves. It is easy to fear this disease. While there's no cure and it's deadly and contagious, the disease is just not that easily spread in the western world, which has adequate supplies, medical personnel and sophisticated sanitation/public health measures. We don't need to isolate ourselves. Additionally by quarantining the region completely you will prevent medical personnel from going over to help curb the epidemic. Halting all jet travel (the only way to get there and back) would mean that workers won't go to help since they can't come back. A dedicated few might still go, most will hesitate, thereby critically depriving the area of desperately needed trained medical workers. It will doom thousands to painful death and will worsen the spread of the disease.

So don't be like this ZIDIOT (sic), and see Ebola around every corner. It's not, and it's not likely to be, no matter how bad it gets in Africa.

Disclaimer: This post is my personal opinion, it is not a substitute for medical care. It is for informational purposes only. The information on Skeptoid blog is not intended nor recommended as a substitute for medical advice, diagnosis, or treatment. Always seek the advice of your own physician or other qualified health care professional regarding any medical questions or conditions. This post does not reflect the opinion of my partners, professional affiliates, or academic affiliations. I have no financial conflicts of interest to disclose.


by Stephen Propatier

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