Information

4.2: Viruses Lab - Biology


Lab Objectives

At the conclusion of the lab, the student should be able to:

  • Understand the properties of a virus
  • Explain how viruses are spread through a population by sharing bodily fluids

A SlideShare element has been excluded from this version of the text. You can view it online here: pb.libretexts.org/bio2lm/?p=38

A virus is not considered a living organism as it only contains DNA surrounded by a protein coat. However, viruses are serious infectious agents causes conditions such as AIDS, chicken pox, and herpes. Viruses must have a live host cell to reproduce. The virus takes over the protein building machinery of the cell to create new viruses to spread the infection. Viruses can infect many different types of organisms, both prokaryotic and eukaryotic.
One way a virus can be spread through a population is by sharing bodily fluids such as saliva, blood, or semen. We will demonstrate how quickly a virus can spread through today’s simulation activity.

Sharing Bodily Fluids

During this lab you will share “bodily fluids” with other students in the lab to simulate the spread of an infectious disease through a population.

Procedure

  1. Obtain a numbered vial of solution and a plastic pipet from your instructor.
  2. Record your student name and vial number on the class data sheet.
  3. Share bodily fluids with another person in lab. Use the plastic pipet to withdraw solution from your vial and place 5 drops of your solution in another classmate’s vial. Your classmate will also share fluids with you in the same way. Return the cap to the vial and invert to mix.
  4. Record the name of the person you shared bodily fluids with in the table below.
  5. Exchange bodily fluids with another person following the directions above. Record the name of the person with whom you exchanged fluids.
  6. Exchange fluids with another student (different than the first two) and record his/her name below. You should complete three total fluid exchanges.

My vial #:_______________________

Record of Bodily Fluid Exchanges

Exchange 1: ______________________________
Exchange 2: ______________________________
Exchange 3: ______________________________

Your lab instructor will add a drop of the test reagent to determine if you are infected with the disease. If your sample turns pink then you are infected. If it turns yellow you are not infected. If you are positive for the disease you may have originally had the disease or you may have contracted the disease in lab today from sharing bodily fluids.

  • Are you infected?
  • Is it possible to determine if you were originally infected or did you contract the disease from someone during today’s lab?

As a class you will fill in Table 1 below. Include each person’s name. If your test result is positive put a plus sign (+) next to your name. If your result is negative put a negative sign (−) by your name. For those individuals that are positive, record whom they exchange fluids with and whether that person was positive or negative.

Questions

  1. How many people in the class are infected?
  2. Can you determine who was originally infected?
  3. If you can, whom do you think was originally infected?
  4. What do the class results show about the spread of disease through activities in which bodily fluids are shared?

Fill out a table similar to Table 1 for all members of your class. Be sure to add as many tables as there are students!

Table 1. Class results for bodily fluid exchange activity
Student’s NameTest result (+/−)Exchange #1 (+/−)Exchange #2 (+/−)Exchange #3 (+/−)
1.
2.
3.
4.
5.

After you’ve completed Table 1, discuss with your lab group how this experiment simulates a real life infection through a population and answer the following questions.

  1. What are some ways that viruses are spread?
  2. What are some diseases that are spread by contact with bodily fluids?
  3. What are ways to prevent the spread of these diseases?

Our research focuses on viruses found in the extreme environment of volcanic acid hot springs. Because it is presumed that the earliest life lived under similar conditions, studying these viruses can help inform viral evolution, and the evolution of all of life itself.

One main area of study for our lab focuses on the thermoacidophilic archaeon Saccharolobus (previously called Sulfolobus) and related viruses. These viruses are completely different, both in physical capsid structure and genome composition, from almost any other known viruses.

How do they and their hosts function at such high temperatures (80º C /176º F) and high acidity (pH below 4)? Why are these viruses so unique? What can they teach us about the evolution of other viruses, life on earth, and even life beyond earth? The Stedman Lab uses genetic, genomic, structural and biochemical tools to answer these questions and more about these enigmatic viruses.


Research into deadly viruses and biological weapons at US army lab shut down over fears they could escape

America’s main biological warfare lab has been ordered to stop all research into the deadliest viruses and pathogens over fears contaminated waste could leak out of the facility.

Fort Detrick, in Maryland, has been the epicentre of the US Army’s bioweapons research since the beginning of the Cold War.

But last month the Centers for Disease Control and Prevention (CDC) – the government’s public health body – stripped the base of its license to handle highly restricted “select agents”, which includes Ebola, smallpox and anthrax.

The unusual move follows an inspection by the CDC at Fort Detrick which found several problems with new procedures used to decontaminate waste water.

For years the facility used a steam sterilisation plant to treat waste water, but after a storm flooded and ruined that machinery last year, Fort Detrick switched to a new chemical-based decontamination system.

Forgotten Women: Survivors of Ebola 2019

1 /12 Forgotten Women: Survivors of Ebola 2019

Forgotten Women: Survivors of Ebola 2019

Forgotten Women: Survivors of Ebola 2019

Forgotten Women: Survivors of Ebola 2019

Forgotten Women: Survivors of Ebola 2019

Forgotten Women: Survivors of Ebola 2019

Forgotten Women: Survivors of Ebola 2019

Forgotten Women: Survivors of Ebola 2019

Forgotten Women: Survivors of Ebola 2019

Forgotten Women: Survivors of Ebola 2019

Forgotten Women: Survivors of Ebola 2019

Forgotten Women: Survivors of Ebola 2019

Forgotten Women: Survivors of Ebola 2019

But the CDC inspectors found the new procedures were not sufficient, with both mechanical failures causing leaks and researchers failing to properly follow the rules.

As a result, the organisation sent a “cease and desist” order to Fort Detrick, forcing it to suspend all research on select agents.

Recommended

Although the United States officially abandoned its biological weapons programme in 1969, Fort Detrick has continued defensive research into deadly pathogens on the list of “select agents”, including the Ebola virus, the organisms that cause the plague, and the highly toxic poison ricin.

The army’s Medical Research Institute of Infectious Diseases, based at Fort Detrick, says its primary mission today is to “protect the warfighter from biological threats” but its scientists also investigate outbreaks of disease among civilians and other threats to public health.

In recent years it has been involved in testing possible vaccines for Ebola, after several epidemics of the deadly virus in Africa.

A spokeswoman for the lab, Caree Vander Linden, said despite the CDC suspension order, there had not been any threat to public health or any leaks of hazardous material outside the base.

The shutdown of research at Fort Detrick is likely to last several months, she also told the New York Times.

This is not the first time the lab has been temporarily shut down due to failures in handling the dangerous pathogens inside.

In 2009, research at Fort Detrick was suspended because it was discovered it was storing pathogens which were not listed on its inventory.

The regulations on keeping close track of hazardous biological material were tightened after the 2001 anthrax attacks, which saw five people die after spores were posted to several media newsrooms and Democratic senators.

The FBI’s chief suspect in the 2001 case, Bruce Ivins, was a senior biological weapons researcher at Fort Detrick. He killed himself in 2008, shortly before the FBI was planning to charge him with the attacks.


4.2: Viruses Lab - Biology

Viruses are very small particles that can infect animals and plants and make them sick. Viruses are made up of genetic materials like DNA and are protected by a coating of protein.

Viruses hijack the cells of living organisms. They inject their genetic material right into the cell and take over. They then use the cell to make more viruses and take over more cells.

Scientists differ on whether viruses are actually alive or not. Many people say they are non-living because they cannot reproduce without the aid of a host. Viruses also do not metabolize food into energy or have organized cells, which are usually characteristics of living things.

  • They do not have an organized cell structure.
  • They have no cell nucleus.
  • They typically have one or two strands of DNA or RNA.
  • They are covered with a protective coat of protein called the CAPSID.
  • They are inactive when not inside a living cell, but are active when inside another living cell.

When viruses invade a body's cells and begin to multiply, they make the host sick. Viruses can cause all sorts of diseases.

How do viruses spread?

Viruses are very small and lightweight. They can float through the air, survive in water, or even on the surface of your skin. Viruses can be passed from one person to another by shaking hands, touching food, through water, or through the air when a person coughs or sneezes.

Viruses can also be passed on by insect bites, animals, or through bad food.

There are many viruses that can infect people and make them sick. One of the most common is influenza which causes people to get the flu. Other diseases caused by viruses include the common cold, measles, mumps, yellow fever, and hepatitis.

How to Avoid Getting Infected

  • Wash your hands (probably one of the most important ones).
  • Don't put your hands or fingers in your mouth, nose, or eyes. Rubbing your nose or eyes can cause a virus on your hands to infect your body.
  • Make sure your food is well-cooked, especially meat.
  • Take your vitamins each day.
  • Get plenty of sleep and exercise. This helps to strengthen your immune system to fight off viruses.

There is little that doctors can do to treat viruses. In most cases our body's immune system fights off the virus. Scientists have developed vaccines that help our bodies to build up immunity to a specific virus. One example of a vaccine is the flu shot. The flu shot helps the body to develop its own defenses against the flu called antibodies.


Germ warfare

After the war ended, in 1945, as many as 199 Nazi officials faced trials in Nuremberg, Germany, on charges including war crimes and crimes against humanity. Among the cases heard was the so-called Doctors’ Trial of 23 medical personnel. The charges included conducting forced biological and medical experiments on thousands of inmates at concentration camps, such as Ravensbrück and Auschwitz. These experiments included infecting prisoners with such diseases as tuberculosis, malaria and yellow fever during research into the use of biological agents as weapons of war.

Seven of the doctors were convicted and hanged on June 2, 1948, nine faced imprisonment, while seven were acquitted. The doctors were tried before a US military court in Nuremberg, which meant that the extensive records of the biological experiments fell into American hands.

Japan also conducted biological and chemical research during WWII, much of it in Harbin, according to documented accounts. It included forced medical experiments on prisoners as well as attacks against civilians in China using biological agents such as typhoid, smallpox and plague-infected fleas. The unit involved was officially called the Epidemic Prevention and Water Purification Department, but is better known as Unit 731. It was effectively a biological warfare operation led by soldier and microbiologist General Shiro Ishii, whose use of biological weapons in China is estimated to have killed or injured hundreds of thousands of people.

However, unlike the Nazi doctors, Ishii and others involved in Unit 731 escaped prosecution by the US at the Tokyo War Crimes Trials (1946-48), the equivalent in Japan to Nuremberg. According to now declassified documents, US military authorities granted members of Unit 731 immunity from prosecution in return for data they had gathered on biological warfare.

Securing troves of documents on the methods and means of developing biological weapons, their results when used in military attacks, and the individuals who developed them, took on a new significance as the US faced a new adversary in the Soviet Union, and biological warfare was seen as a real threat.

In her 2017 book, Hidden Atrocities: Japanese Germ Warfare and American Obstruction of Justice at the Tokyo Trial, medical anthropologist Jeanne Guillemin says the US military obtained biowarfare documents from Unit 731. And most, if not all, of the Nazi and Unit 731 data that made its way to America ended up at Fort Detrick, home to one of the world’s oldest BSL-4 labs, where the US military ran its biological warfare research programme for more than two decades before it was terminated, in 1969, by President Richard Nixon.

The procedures developed at Fort Detrick later served as the basis for the US Centres for Disease Control and Prevention’s publication Biosafety in Microbiological and Biomedical Laboratories, considered the biosafety bible in labs worldwide.

“Thus, in what we might today call a reverse dual use model, some very important good – lab safety – has ultimately come from a programme that was designed to do harm,” Franz says.

Something else came out of the trial of the Nazi doctors in Germany in 1947: the Nuremberg Code, a list of 10 ethical principles to guide medical research and treatment of patients, written to counter the exploitation, suffering and murder of prisoners in the name of science and ideology in Nazi concentration camps. It remains one of the most influential documents on clinical work.

These principles state that voluntary consent is essential, and the results of any experiment must be for the greater good of society. Principle number six is that the risks should never exceed the benefits. It is this question – do the risks exceed the benefits? – that has split the medical research community in relation to the type of work that takes place today in BSL-3 and BSL-4 labs.

Specifically, this involves the creation of new strains of viruses in the name of research, according to a 2014 statement opposing the work and signed by more than 300 scientists. Known as the Cambridge Working Group Consensus Statement, it called for a halt to what is known as gain-of-function research, which can involve taking an existing virus and giving it new attributes, potentially making the pathogen more dangerous.

“Laboratory creation of highly transmissible, novel strains of dangerous viruses, especially but not limited to influenza, poses substantially increased risks,” the Cambridge Working Group statement says. It points to “incidents” at US labs involving viruses such as anthrax and the “fallibility of even the most secure laboratories”.

The argument about gain-of-function research blew up in 2012 after two labs, in the Netherlands and in Wisconsin, published research showing they had created H5N1 influenza virus strains that were transmissible between ferrets, which have respiratory systems similar to those of humans. Part of the rationale for the work was disagreement over whether H5N1, or bird flu, usually spread by chickens and wildfowl, could be transmitted by mammals.

A 2014 editorial in mBio, a journal published by the American Society for Microbiology, argued that the work carried out by the labs was essentially a “species jump” that gave a virus the capability to transmit between mammals, something it had previously lacked.

Gain-of-function research has also been conducted on coronaviruses, the family from which Covid-19 sprang. This work on coronaviruses disturbs Amir Attaran, a professor in the faculty of law and School of Epidemiology and Public Health at the University of Ottawa, in Canada. He is one of the original signatories and a founding member of the 2014 Cambridge Working Group.

“You are in an area of research [that] were a mistake to be made, you could be introducing into the world and to billions of people, something at least as bad, if not worse than the virus causing Covid-19.”

Supporters of gain-of-function research argue it is necessary to improve detection of dangerous viruses and facilitate vaccine development against future pandemics. Attaran argues the emergence of Covid-19 undermines this view.

“We’ve done gain-of-function research on coronavirus,” he says. “It didn’t prepare our surveillance to catch Covid-19, not in the least. As for vaccine development, none of the front-running candidates for a Covid-19 vaccine had anything to do with gain-of-function research.”

These candidates either used existing technology, such as an inactivated vaccine, or built on research conducted on other viruses, he says.

The conflict among scientists regarding the work done on the world’s deadliest viruses in BSL-4 labs raises another question: who is in charge of monitoring what is going on?

According to Koblentz at George Mason University, government oversight is critical to BSL-4 lab security, but, he says, the people working in BSL labs are the linchpin, highlighting the “insider threat” – as seen in the US anthrax attacks – as the greatest security challenge.

“One thing that US labs have is a personnel reliability programme, which is designed to monitor researchers to ensure they are not suffering from mental distress, financial distress. If someone has been radicalised or blackmailed, then you need to know,” he says. This is “not just about bioterrorism but also about preventing the theft of proprietary information or protecting intellectual property because some of this research and the samples people work with can be very valuable”.

Koblentz says much of that oversight is up to the BSL-4 scientists themselves, and Kurth in Berlin says a network among BSL-4 researchers already exists. “The family of BSL-4 research is very small. We know each other, we meet regularly.”

Kurth says no BSL-4 lab in Europe has a staff of more than 50, in contrast to North America, he says. Smaller teams reduce risk of rogue personnel or sabotage, though “there is never 100 per cent certainty” when it comes to lab security.

But for practical global oversight and verification of BSL-4 labs, Attaran says, “There isn’t a good international inspection regime, which is terrifying.”

The International Atomic Energy Agency (IAEA) was set up to monitor and prevent the military use of nuclear technology and has 171 member states the Organisation for the Prohibition of Chemical Weapons has 193 member countries working to eliminate chemical weapons, according to its mandate. But Attaran does not think the WHO is the right body to police global biosecurity: “I do not believe for a moment it is within WHO’s competence to do that.” However, he feels the first step should be a moratorium on gain-of-function research, and that would be best achieved through the WHO.

Franz, formerly of Fort Detrick, also does not see a biosecurity system under the WHO as the answer, because it is underfunded and understaffed. Koblentz says any organisation created to prevent proliferation of biological weapons would have special headaches.

“You can’t have a bio-IAEA because it would have to inspect tens of thousands of locations,” he says. “It would just not be feasible.”


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SARS outbreaks after the epidemic. The 2003 Severe Acute Respiratory Syndrome outbreak spread to 29 countries, causing more than 8,000 infections and at least 774 deaths. Because 21 percent of cases involved hospital workers, it had the potential to shut down health care services wherever it struck. It is particularly dangerous to handle in the laboratory because there is no vaccine, and it can be transmitted via aerosols.

Moreover, about 5 percent of SARS patients are “super-spreaders” who infect eight or more secondary cases. For instance, one patient spread SARS directly to 33 others (reflecting an infection rate of 45 percent) during a hospitalization, ultimately leading to the infection of 77 people, including three secondary super-spreaders. A super-spreader could turn even a single laboratory infection into a potential pandemic.

SARS has not re-emerged naturally, but there have been six escapes from virology labs: one each in Singapore and Taiwan, and four separate escapes at the same laboratory in Beijing.

The first was in Singapore in August 2003, in a virology graduate student at the National University of Singapore. He had not worked directly with SARS, but it was present in the laboratory where he worked. He recovered and produced no secondary cases. The World Health Organization formed an expert committee to revise SARS biosafety guidelines.

The second escape was in Taiwan in December 2003, when a SARS research scientist fell ill on a return flight after attending a medical meeting in Singapore. His 74 contacts in Singapore were quarantined, but again, fortunately, none developed SARS. Investigation revealed the scientist had handled leaking biohazard waste without gloves, a mask, or a gown. Ironically, the WHO expert committee called for augmented biosafety in SARS laboratories the day after this case was reported.

In April 2004, China reported a case of SARS in a nurse who had cared for a researcher at the Chinese National Institute of Virology. While ill, the researcher had traveled twice by train from Beijing to Anhui province, where she was nursed by her mother, a physician, who fell ill and died. The nurse in turn infected five third-generation cases, causing no deaths.

Subsequent investigation uncovered three unrelated laboratory infections in different researchers at the NIV. At least of two primary patients had never worked with live SARS virus. Many shortcomings in biosecurity were found at the NIV, and the specific cause of the outbreak was traced to an inadequately inactivated preparation of SARS virus that was used in general (that is, not biosecure) laboratory areas, including one where the primary cases worked. It had not been tested to confirm its safety after inactivation, as it should have been.


Watch the video: Ένζυμα - βιολογικοί καταλύτες (November 2021).