Don't Panic: The Science of Ebola Transmission

Catalyst Volume 8

In 2014, the Ebola virus gained notoriety for the lives it took in such a short amount of time. While the panic surrounding the virus has since died down, Ebola continues to wreak havoc in West Africa. To properly contextualize the implications of this epidemic, it is important to understand the basics of how Ebola works—how the virus itself functions, how it spreads, and how it affects the human body.

The Ebola virus is classified in the order Mononegavirales, which includes the mumps, measles, and rabies viruses.¹ There are currently five species of Ebola viruses: Zaire, Bundlibugyo, Sudan, Reston, and Tai Forest. The most lethal of these species, Zaire, is responsible for the 2014 outbreak. Ebola carries a negative-sense RNA genome that works by encoding mRNA (a type of RNA called messenger RNA) in the host cell.² The mRNA strand is translated into seven viral proteins that allow replication of the Ebola virus. Newly formed Ebola virus buds out of the cell, and once the cell dies, it lyses, or bursts, releasing viral RNA to other cells within the body.

Ebola, like the swine flu, was likely first introduced into the human population through close contact with the bodily fluid of infected animals such as chimpanzees, gorillas, monkeys, porcupines, or fruit bats, which are the virus’ natural hosts.¹ Although the virus is highly transmittable through bodily fluid, it is not an airborne disease; instead, the virus is transmitted only through direct contact of broken skin or mucous membranes with the bodily fluids of infected organisms and through direct contact with materials contaminated with these fluids.¹ People are not infectious until they develop symptoms; however, they remain infectious as long as their bodily fluids contain the virus. For example, the Ebola virus can persist in semen for up to three months subsequent to recovery. The incubation period, or time interval from infection to onset of symptoms, is 2 to 21 days.¹ The delayed onset of symptoms means that the infected individual may be unaware that he or she is carrying the disease.

During the 2014 outbreak, poor infrastructure, unsafe practices in burial ceremonies, and close contact between health-care workers and patients facilitated the spread of the virus.¹ In West Africa, improperly disposed bodily fluids contaminated materials such as clothing led to infection of healthy individuals. Burial ceremonies themselves have contributed to the transmission of Ebola in West Africa; mourners who came into direct contact with the bodies of deceased individuals contracted the disease.¹ In the U.S., the transmission of Ebola from patient Thomas Eric Duncan to nurses Nina Pham and Amber Vinson was likely caused by a breach in safety protocol; while healthcare workers are typically obligated to wear full body suits, any error in wearing or removing the suit could have exposed the nurses to Duncan’s bodily fluids.⁴

Ebola’s initial symptoms include the sudden onset of fever, fatigue, muscle pain, headache, and sore throat. These initial symptoms can often be confused with those of the flu, but they are followed by more severe ones including vomiting, diarrhea, rashes, and internal and external bleeding. While this disease has a high mortality rate of 50%,¹ its transmission is more indirect than that of more common viruses such as the flu. Because of the routes of Ebola transmission are so limited, especially in areas with developed infrastructure, the CDC and other health experts predict that an Ebola outbreak in the U.S. would be highly improbable.⁵ The events of 2014 serve as a reminder of the importance of adequate infrastructure and safety protocols in order to limit the spread of future viral epidemics.

References

1. World Health Organization. http://www.who.int/mediacentre/factsheets/fs103/en/ (accessed Nov. 1, 2014).
2. Feldmann, H. K. Arch. Virol. Suppl. 1993, 7, 81–100.
3. Mucous membrane. http://www.britannica.com/EBchecked/topic/395887/mucous-membrane (accessed Nov. 1, 2014).
4. Alexander, H. Second Texas nurse contracts Ebola after treating Thomas Eric Duncan. http://www.telegraph.co.uk/news/worldnews/ebola/11164105/Second-Texas-nurse-contracts-Ebola-after-treating-Thomas-Eric-Duncan.html (accessed Jan. 17, 2015).
5. Ebola transmission. http://www.cdc.gov/vhf/ebola/transmission/index.html?s_cid=cs_3923 (accessed Jan. 17, 2015).

The Reality of Virtual Reality

Catalyst Volume 8

People experience the world around them, what we call “reality,” by receiving sensory input and processing these messages. Sources of sensory stimulus are greatly varied and include anything from sound waves picked up by your ears to the feeling of wearing socks. Because the basis of perception is founded on stimulation, manipulation of these inputs can effectively enable people to experience false sensations. A virtual world indistinguishable from reality—perfectly stimulating all senses—is the end-goal of researchers developing virtual reality interfaces.

Virtual reality (VR) refers to computer-generated simulation of a realistic or imaginary world that uses visual, tactile, and auditory cues to manipulate the user's sensations and perceptions. While VR interfaces usually include head-mounted displays that provide visual input, more sophisticated devices for simulating senses of touch, taste, smell, and sound are being researched. An important goal of VR research is attaining the ability to provide a highly realistic environment in which individuals can interact with their surroundings and receive sensory feedback. Unfortunately, due to the limitations of computing power and research in the field of VR, a program inducing complete immersion into the virtual worlds is not yet possible.

Although VR seems to be a technology borrowed from science fiction novels, it has actually existed in some fashion for eight decades. In 1929, Edward Link invented the first flying simulator, which used pneumatics to mimic aerial maneuvers and provided haptic feedback to the user. The Link Trainer, which initially gained popularity as an amusement park ride, later became a standard training module for U.S. pilots during World War II.¹ The Link Trainer is a very primitive example of VR, as it leaves much to imagination; pilots would be hard pressed to believe they were actually within the cockpit of an aircraft during a dogfight and not in a cramped box, rocking back and forth. However, since its creation, the Link Trainer has promoted the idea that simulators could be utilized to recreate situations that would otherwise be difficult to experience.

The advent of computers initiated an explosion of advanced VR interfaces such as head mounted displays (HMDs) that allow the user to interact with the virtual world and receive enhanced sensory information. In 1991, Virtuality Group developed the 1000CS gaming system, which was a pioneer in the field of head tracking and enabled players to turn their heads to view their surroundings within the games they were playing.² The 1000CS was an important first step for commercially available VR technology. Modern HMDs are much less bulky than their predecessors, less prone to causing neck cramps due to their lighter weight, and more responsive to rotation. Recent advances in virtual reality focus on providing as realistic an environment as possible. Higher resolution screens and faster computers are becoming cheaper to produce and more widely available, spurring the growth of VR.

While most interfaces prioritize visual and audio simulation, technologies are being developed that will be able to stimulate touch, taste, and smell to provide a highly life-like world. Researchers at the Universities of York and Warwick have presented a prototype of the Virtual Cocoon, a helmet that uses tubes, fans, and a high definition (HD) screen to fully immerse the user in what the team calls “Real Virtuality.”³ Another recent advance from the University of Singapore used “non-invasive electrical and thermal stimulation … [to] recreate the taste of virtual food and drinks.”⁴ Such technologies could lead to a perfect virtual environment that stimulates all of the senses. Additionally, this research introduces exciting possibilities such as virtually sampling a dish before ordering it at a restaurant or experiencing the feeling of snow on a hot summer day.

The last decade has seen both great advances in VR technologies and expansion into a wide range of practical fields such as military training.⁵ Although simulators have been used by the military since the simple Link Trainer in 1929, new methods of virtual simulation have greatly increased the diversity and immersion of training available. Soldiers can be placed in various virtual scenarios and learn the tactics and skills necessary in real combat, including developing assault plans on military targets, managing disaster and field casualties, and adapting to new environments.^5,6 While it cannot replace field experience, VR serves as a useful tool to augment their training.

There are many projected uses for VR in the field of medicine as well. An experiment led by Dr. Patrice Crochet of La Conception Hospital in Marseille tested whether surgeons using a VR surgical training simulator could improve the quality of their surgical skills. Their findings indicated that VR training improved surgeons’ dexterity, supporting the claim that VR could potentially serve as a medical training tool.⁷ With the high number of annual medical malpractice deaths, using VR to provide doctors with practical experience is most definitely a useful tool.

Perhaps the most anticipated application of VR is its extension into video games and other multimedia. The Oculus Rift, an HMD currently in development, is a highly anticipated game system that incorporates HD graphics with high-fidelity head tracking to create a unique gaming experience.^8,9 Combined with omnidirectional treadmills and directional audio, players may soon be able to engage in a highly realistic environment. Virtual controllers such as the Leap Motion—which uses sensors to process hand and finger motions as input data—are also being incorporated for further immersion and interactive capabilities. These VR technologies are not only limited to video games; virtual tourism or impossible real-world experiences such as flying could be simulated.

With ever-increasing computer processing speeds and extremely high resolution 8K displays in development, the future of VR holds great promise. Currently, VR is proving invaluable to military and medical training. A major limitation of VR is its inability to create perfect, interference-free environments due to inadequate hardware and software capabilities. However, these obstacles will be overcome as VR technology advances. Perhaps one day it will be impossible to distinguish between simulated reality and reality itself.

References

1. Van Embden, E. Rare flight trainer can be found at Millville Army Airfield Museum / Link Trainer one of 5 working models in world. The Press of Atlantic City, Feb. 23, 2008, p. C1.
2. Davies, H. Dr. Waldern’s dream machines: arcade thrills for spotty youths today, but revolutionary tools for surgeons and architects tomorrow, says the pioneer of virtual reality. http://www.independent.co.uk/life-style/ the-hunter-davies-interview-dr-waldernsdream-machines-arcade-thrills-for-spottyyouths-today-but-revolutionary-tools-forsurgeons-and-architects-tomorrow-says-thepioneer-of-virtual-reality-1506176.html (accessed Jan. 17, 2015.)
3. First virtual reality technology to let you see, hear, smell, taste, and touch. www.sciencedaily. com/releases/2009/03/090304091227.htm (accessed Jan. 17, 2015).
4. National University of Singapore. Simulator recreates virtual taste online.http://www.sciencedaily.com/ releases/2014/01/140102114807.htm (accessed Oct. 31, 2014).
5. Bymer, L. Virtual reality used to train soldiers in new training simulator. http://www.army.mil/ article/84453/ (accessed Jan. 17, 2015).
6. Virtual reality army training. http://www.vrs. org.uk/virtual-reality-military/army-training. html# (accessed Oct. 31, 2014).
7. Crochet, P. et al. Ann. Surg. 2011, 253, 1216-1222.
8. Corriea, A. Oculus Rift HD drops you into a world so real it hurts. http://www.polygon. com/2013/6/14/4429086/oculus-rift-hd-e3 (accessed Nov. 9, 2014).
9. Oculus Rift. https://www.oculus.com/ (accessed Jan. 17, 2015).

Honey, Where's My Supersuit? New Underwater Technology Emerges

Catalyst Volume 8

A plot line from a comic book unfolds as scientists and artists alike take inspiration from superheroes to develop technology that could allow humans to further explore ocean environments. Despite mankind's attempts to explore the world’s oceans since the 18th century, 95% of this vast, watery expanse remains a mystery.¹ Heavy oxygen tanks and burdensome helmets are still needed to get to moderate depths, while the deep ocean lies mostly uncharted. Without super strength or super flexibility, divers turn to the next best superpower: the ability to breathe underwater.

Deep-sea exploration necessitates the design of equipment that functions under extreme conditions, challenge that seemingly only a technological genius like Iron Man could conquer. After all, the self-made billionaire created his own armor to escape captivity. A suit similar to Iron Man’s was needed for an expedition to an abandoned shipwreck off the coast of the Antikythera islands in the fall of 2014.² In order to reach the 55 foot-deep shipwreck, the Canadian company HUBLOT developed the Exosuit, a 550 pound atmospheric diving system (ADS) that allows explorers to dive deeper and longer.³ The full metal suit combined with semi-closed rebreathing technology pragmatically favored function over form. A semi-closed rebreather involves a constant flow rate of oxygen, and any excess oxygen that is not inhaled is released back into the water in the form of small bubbles.⁴ Paired with the suit is a remotely operated vehicle (ROV) that takes high-quality photos in any lighting, which is useful in deep waters.³

Upon first glance, the suit seems incredibly cumbersome with its daunting rigidity and thick, pipe-like legs. However, many smaller components like foot pads and rotary joints make the suit more flexible; this allows the user to access previously uncharted deep waters with robotic efficiency.⁴ As the underwater version of Iron Man’s suit, the Exosuit has an exterior that can withstand extremely high pressures. The sturdy exterior, paired with the ROV camera, will allow scientists to identify new species of marine life, especially those that are visible due to phospholuminescence. The dangers of the depths unknown explored with a one-of-a-kind suit and camera seem to come right off the page of one of Stan Lee’s comics. Tony Stark would definitely approve.

Although Iron Man is revered for his cleverness and intelligence, the best superhero inspiration for diving technology is Aquaman and his ability to breathe freely underwater. Many innovators, including South Korean designer Jeabyun Yeon, have tried to mimic the ease with which Aquaman is able to breath below the surface. In January 2014, Yeon created a device that would allow divers to breathe underwater with only a piece of standalone equipment attached to the mouth, leaving behind the typical mask, alternate air source, air gauge, and other equipment necessary for a normal dive.⁵ Called the Triton, this gill-like mouthpiece extracts oxygen from water and compresses it into small storage tanks located on either side of a mouthpiece.⁵ While swimming, users would only need to bite into the mouthpiece for oxygen to begin flowing. Although aesthetically pleasing, this design received a lot of negative attention from scientists and scuba divers that prevented it from gaining funding from investors and traction in the media. For the design to be feasible, there must be a pump that can bring 24 gallons of water through its filtering system per minute; however no such pump is available at present.⁵ The Triton also does not account for possible oxygen toxicity, the condition where high pressures of stored oxygen can cause convulsions and potentially be fatal.⁶ Yeon originally intended for the design to be a revolutionary breakthrough in the diving community, but now the Triton is displayed on his website as a “product innovation studio project.”⁷ Although his project had little impact on the diving community, other scientists continue to find ways to bring Aquaman to life.

The University of Denmark are doing just that with the “Aquaman” crystal, marking a shift from developing wearable technology to researching materials science. In October of 2014, the university released news of the “Aquaman” crystal, a cobalt-based crystalline material that can absorb, store, and release oxygen without deteriorating or changing form through processes known as known as chemisorption and desorption. These processes involve multiple chemical transformations that produce a denser form of oxygen gas that can be stored in a compact form without causing toxicity to the user.⁸ As a result, this inorganic material possesses properties that rival diving equipment in both size and efficiency, potentially allowing divers to have almost superhuman, Aquaman-like characteristics when underwater. A powerful example of the crystal’s abilities is the absorption of the amount of oxygen in an average-sized room using just 10 liters of the material.⁸ Although the size of a scuba tank varies with the type of dive, the fact that the “Aquaman” crystal can hold three times as much pressurized pure oxygen as a conventional tank of the same size will inevitably decrease the weight of equipment that divers need underwater. Professor Christine Mackenzie, a scientist on the team, claims that only few grains of the crystal are needed to sustain a full trip underwater.⁸ The team is currently working on ways to access the stored oxygen, possibly by directly inhaling the crystal or by using a specialized tank.⁸ By eliminating or reducing the size of the tank, the “Aquaman” crystal would allow divers to explore hard-to-reach areas and put them in even closer contact with the organisms they are examining.

The parallels between scuba equipment and superhumans like Iron Man and Aquaman show how far underwater diving equipment has progressed. Even far-fetched concepts like the Triton give a glimpse of what the future may look like. The ability to breathe underwater opens the door to new discoveries both by granting divers to either dive more flexibly at moderate depths or get a more personal glimpse into the deep ocean. Scuba equipment continues to play a major role in how we understand one of the earth’s most mysterious ecosystems, especially in the face of climate change. What was once written off as superhuman and fantastic might just develop into our reality.

References

1. National Oceanic and Atmospheric Administration. http://www.noaa.gov/ocean.html (accessed Oct. 12, 2014).
2. Wallace, R. ‘Iron Man’ suit allows divers to reveal more of Antikythera shipwreck. http://www.sciencetimes.com/articles/677/20141012/iron-man-suit-allows-divers-to-reveal-more-of-antikythera-shipwreck.htm (accessed Oct. 12, 2014).
3. The Exosuit. http://www.amnh.org/exhibitions/past-exhibitions/the-exosuit/the-exosuit (accessed Oct. 12, 2014).
4. Scuba diving. http://www.scubadiving.com/training/basic-skills/are-you-ready-rebreathers (accessed Oct. 28, 2014).
5. ‘Triton’ oxygen mask claims to draw oxygen from water while you swim. http://www.huffingtonpost.co.uk/2014/01/17/triton-oxygen-mask_n_4615558.html (accessed Oct. 12, 2014).
6. Patel, D. N. et al. JIACM 2003, 4, 234-237.
7. Yeon. Yanko Design. http://www.yankodesign.com/2014/01/03/scuba-breath/ (accessed Oct. 23, 2014).
8. Sundberg, J. et al. Chem. Sci. 2014, 5, 4017-4025.