AY Honors/Viruses/Answer Key/es

Virus
Asociación General Salud y ciencia	Destreza: 2 Año de introducción: 2012

Requisitos

1

Describir o discutir el siguiente con un grupo. Si es necesario, investigar posibles respuestas a estos temas para poder hacer contribuciones significativas al grupo.

1a

¿Qué significa la palabra virus? Explicar la controversia sobre si se trata de un ser vivo o no.

1b

Nombrar las características distintivas de los virus y por qué no están incluidos en ningún reino.

1c

Nombrar algunas formas morfológicas de los virus y dar un ejemplo de cada una.

1d

Explicar la importancia de las vacunas para combatir los virus. ¿Cómo funcionan?

1e

Describir cómo los virus reproducen y cómo ocurren las modificaciones genéticas llamadas mutaciones y la resistencia viral.

The way viruses reproduce in their host cells makes them particularly susceptible to the genetic changes or mutations. The RNA viruses are especially prone to mutations. In host cells there are mechanisms for correcting mistakes when DNA replicates and these kick in whenever cells divide. These important mechanisms prevent potentially lethal mutations from being passed on to offspring. But these mechanisms do not work for RNA and when an RNA virus replicates in its host cell, changes in their genes are occasionally introduced in error, some of which are lethal. One virus particle can produce millions of progeny viruses in just one cycle of replication, therefore the production of a few "dud" viruses is not a problem. Most mutations are "silent" and do not result in any obvious changes to the progeny viruses, but others confer advantages that increase the fitness of the viruses in the environment. These could be changes to the virus particles that disguise them so they are not identified by the cells of the immune system or changes that make antiviral drugs less effective. Both of these changes occur frequently with HIV.

Many viruses (for example, influenza A virus) can "shuffle" their genes with other viruses when two similar strains infect the same cell. This phenomenon is called genetic shift, and is often the cause of new and more virulent strains appearing. Other viruses change more slowly as mutations in their genes gradually accumulate over time, a process known as genetic drift.

Through these mechanisms new viruses are constantly emerging and present a continuing challenge to attempts to control the diseases they cause.

1f

¿Se han erradicado enfermedades virales? ¿Por qué es tan difícil tratar a los pacientes con enfermedades virales?

Eradication is the reduction of an infectious disease's prevalence in the global host population to zero. It differs from elimination, which means reducing the disease to zero cases in a regional population. Eradication is not easy to accomplish and many considerations go into selecting diseases to attempt eradication on. See Eradication of infectious diseases for more information.

Successes

Two viral diseases (smallpox and rinderpest) have been eradicated so far and one (polio) is close to eradication. Also regional efforts are being made to eradicate viral human diseases measles and rubella. Some scientists believe that ovine rinderpest, affecting goats and sheep, can be eradicated.

Smallpox was caused by infection with variola virus. The English physician Edward Jenner discovered the first vaccine - cowpox to protect humans from smallpox in 1796, making it the first vaccine. Various attempts were made to eliminate smallpox on a regional scale starting soon after this discovery. Ultimately worldwide vaccinations combined with a isolate and containment strategy were successful in eradicating smallpox, with Ali Maow Maalin of Somalia bring the last naturally occurring infection occurring in 1977. Pathfinders are urged to read about how smallpox was eradicated and the efforts to ensure it stays eradicated and is not reintroduced via weapons or accident.

Rinderpest, was a viral disease which infected cattle, domestic buffalo, and some other species of even-toed ungulates, including buffaloes, large antelope and deer, giraffes, wildebeests, and warthogs. Rinderpest belonged to the same family as measles. Mainly a live attenuated vaccine was used, starting in the early 1900s on a regional or national basis. The Food and Agriculture Organization (FAO) of the United Nations gave a final push, and on 14 October 2010, with no diagnoses for nine years, the FAO announced that the disease had been completely eradicated in all countries. Rinderpest is the first (and so far the only) disease of livestock to have been eradicated by human undertakings and only the second disease of any type after smallpox.

Polio is a viral disease now close to eradication, with only Pakistan and Afghanistan still reporting wild cases as of September 2015. The public health effort to eliminate all cases of poliomyelitis (polio) infection around the world, begun in 1988, led by the World Health Organization (WHO), UNICEF and the Rotary Foundation. This global effort has reduced the number of annual diagnosed cases from the hundreds of thousands to 291 in 2012, though case counts rose in 2013 and 2014. In 2014, Pakistan had the largest number of polio cases at 328, an increase from 43 in 2013. This increase was blamed on Al Qaeda and Taliban militants preventing aid workers from vaccinating children in rural regions of the country. Hopefully the increases are over because there were only 41 wild cases in between January and September 2015. The live vaccine, now being phased out, can trigger circulating vaccine-derived type 1 cases as well.

Of the three types of polio, and all reported cases since 11 November 2012 have been of type 1. The last recorded wild case of type 2 was in 1999 (declared eradicated in September 2015). The last recorded case of type 3 was on 11 November 2012.

Reasons for failure

Efforts to eradicate Yellow Fever have failed. Virus eradication programs have mostly relied upon vaccination in Africa where the programs have largely been unsuccessful because they were unable to break the sylvatic cycle involving wild primates. With few countries establishing regular vaccination programs, measures to fight yellow fever have been neglected, making the future spread of the virus more likely.

Difficulty of treatment

Viruses cause familiar infectious diseases such as the common cold, flu and warts. They also cause severe illnesses such as HIV/AIDS, smallpox and hemorrhagic fevers.

Viruses are like hijackers. They invade living, normal cells and use those cells to multiply and produce other viruses like themselves. This eventually kills the cells, which can make you sick.

Viral infections are hard to treat because viruses live inside your body's cells and are basically "protected" from medicines, which usually move through your bloodstream. Antibiotics do not work for viral infections, which is while you are wasting your time fighting the common cold with antibiotics. However, there are a few antiviral medicines available today. The most effective weapon against most viruses is vaccines to prevent infection in the first place.

2

Por medio de imágenes, video o descripciones detalladas, explicar las diferencias de las siguientes enfermedades exantemáticas o eruptivas:

2a

Rubéola

Rubella, sometimes called German measles or three-day measles, is a contagious disease caused by a virus. The infection is usually mild with fever and rash.

Symptoms Rubella usually causes the following symptoms in children:

Rash that starts on the face and spreads to the rest of the body Low fever (less than 101 degrees) These symptoms last 2 or 3 days.

Older children and adults may also have swollen glands and symptoms like a cold before the rash appears. Aching joints occur in many cases, especially among young women.

About half of the people who get rubella do not have symptoms.

Complications Birth defects if acquired by a pregnant woman: deafness, cataracts, heart defects, mental retardation, and liver and spleen damage (at least a 20% chance of damage to the fetus if a woman is infected early in pregnancy)

Transmission Spread by contact with an infected person, through coughing and sneezing

Prevention Rubella vaccine (contained in MMR vaccine) can prevent this disease.

2b

Sarampión

The symptoms of measles generally appear about seven to 14 days after a person is infected.

Measles typically begins with

high fever, cough, runny nose (coryza), and red, watery eyes (conjunctivitis). Two or three days after symptoms begin, tiny white spots (Koplik spots) may appear inside the mouth.

Three to five days after symptoms begin, a rash breaks out. It usually begins as flat red spots that appear on the face at the hairline and spread downward to the neck, trunk, arms, legs, and feet. Small raised bumps may also appear on top of the flat red spots. The spots may become joined together as they spread from the head to the rest of the body. When the rash appears, a person’s fever may spike to more than 104° Fahrenheit.

After a few days, the fever subsides and the rash fades.

Measles can be prevented with the MMR (measles, mumps, and rubella) vaccine. One dose of MMR vaccine is about 93% effective at preventing measles if exposed to the virus, and two doses are about 97% effective. In the United States, widespread use of measles vaccine has led to a greater than 99% reduction in measles cases compared with the pre-vaccine era. Since 2000, when measles was declared eliminated from the U.S., the annual number of people reported to have measles ranged from a low of 37 people in 2004 to a high of 668 people in 2014. Most of these originated outside the country or were linked to a case that originated outside the country.

Measles is still common in other countries. The virus is highly contagious and can spread rapidly in areas where people are not vaccinated. Worldwide, an estimated 20 million people get measles and 146,000 people die from the disease each year—that equals about 400 deaths every day or about 17 deaths every hour.

2c

Varicela

Chickenpox is a very contagious disease caused by the varicella-zoster virus (VZV). It causes a blister-like rash, itching, tiredness, and fever. Chickenpox can be serious, especially in babies, adults, and people with weakened immune systems. It spreads easily from infected people to others who have never had chickenpox or received the chickenpox vaccine. Chickenpox spreads in the air through coughing or sneezing. It can also be spread by touching or breathing in the virus particles that come from chickenpox blisters.

The best way to prevent chickenpox is to get the chickenpox vaccine. Before the vaccine, about 4 million people would get chickenpox each year in the United States. Also, about 10,600 people were hospitalized and 100 to 150 died each year as a result of chickenpox.

Anyone who hasn’t had chickenpox or received the chickenpox vaccine can get the disease. Chickenpox most commonly causes an illness that lasts about 5-10 days.

The classic symptom of chickenpox is a rash that turns into itchy, fluid-filled blisters that eventually turn into scabs. The rash may first show up on the face, chest, and back then spread to the rest of the body, including inside the mouth, eyelids, or genital area. It usually takes about one week for all the blisters to become scabs.

Other typical symptoms that may begin to appear 1-2 days before rash include:

high fever tiredness loss of appetite headache Children usually miss 5 to 6 days of school or childcare due to their chickenpox.

Vaccinated Persons Some people who have been vaccinated against chickenpox can still get the disease. However, the symptoms are usually milder with fewer blisters and mild or no fever. About 25% to 30% of vaccinated people who get chickenpox will develop illness as serious as chickenpox in unvaccinated persons.

3

Escoger tres de las siguientes enfermedades virales y describir la forma de contagio, síntomas y prevención. Demostrar su aprendizaje de manera creativa por medio de una exhibición, presentación o discurso preparado:

It is impractical to fully cover each disease in depth enough for a presentation within the wiki. A good place to get an overview of each virial disease is Wikipedia and the CDC website.

3a

COVID-19

Template:Adventist Youth Honors Answer Book/Problematic requirement Some alternatives could be: Ebola Virus, Varicella Zoster Virus (causes chicken pox and shingles), West Nile Virus, Zika Virus, Hand-Foot-and-Mouth Virus

3b

Zika

There are several types of herpes.

• Genital herpes is the most common and serious threat to humans. See CDC site
• [(Herpes Zoster)] is caused by the same virus as chickenpox. 1 in 3 Americans will get shingles, often after age 60.
• B virus is found in macaque monkeys

3c

Ébola

HIV/AIDS continues to be studied extensively, with great effort being made to find a cure. It is transmitted via exchange of bodily fluids. site and Wikipedia are good starting points.

3d

Nilo Occidental

Mumps is commonly vaccinated for. [on mumps] and Mumps on Wikipedia

3e

Mano-pie-boca (aftosa humana)

Polio is a crippling and potentially fatal infectious disease. There is no cure, but there are safe and effective vaccines. Therefore, the strategy to eradicate polio is based on preventing infection by immunizing every child to stop transmission and ultimately make the world polio free. This should happen within the next few years. Polio cases have decreased by over 99% since 1988, from an estimated more than 350 000 cases to 359 reported cases in 2014. Today, only Pakistan and Afghanistan have never stopped transmission of polio. http://www.cdc.gov/polio/ and http://www.who.int/topics/poliomyelitis/en/

3f

Herpes

Don't fall into researching Meningococcal meningitis, the bacterial form of meningitis [1] since this is the Virus honor. Look at Viral meningitis on Wikipedia for an overview of this disease.

3g

SIDA

There are 5 kinds of Hepatitis labeled A-E. Explore them here: http://www.cdc.gov/hepatitis/index.htm

3h

Papera

With more than one-third of the world’s population living in areas at risk for infection, dengue virus is a leading cause of illness and death in the tropics and subtropics. As many as 400 million people are infected yearly. Dengue is caused by any one of four related viruses transmitted by mosquitoes. There are not yet any vaccines to prevent infection with dengue virus and the most effective protective measures are those that avoid mosquito bites. When infected, early recognition and prompt supportive treatment can substantially lower the risk of medical complications and death. http://www.cdc.gov/dengue/

4

Explicar las diferencias entre la gripe y el resfriado. ¿Por qué el virus de la influenza causa epidemias periódicas (como la gripe española, gripe aviar, gripe A, etc.)?

The flu and the common cold are both respiratory illnesses but they are caused by different viruses. Because these two types of illnesses have similar flu-like symptoms, it can be difficult to tell the difference between them based on symptoms alone. Special tests that usually must be done within the first few days of illness can be carried out, when needed to tell if a person has the flu.

In general, the flu is worse than the common cold, and symptoms such as fever, body aches, extreme tiredness, and dry cough are more common and intense. Colds are usually milder than the flu. People with colds are more likely to have a runny or stuffy nose. Colds generally do not result in serious health problems, such as pneumonia, bacterial infections, or hospitalizations.

[Source CDC http://www.cdc.gov/flu/about/qa/coldflu.htm]

The flu continues to mutate, creating hundreds of strains a year. Therefore vaccines need to be developed with educated guesses as to which will be strain that spreads most. Sometimes the guess is wrong, or a new dangerous strain gets out of control.

5

¿Cuál es la diferencia entre un virus y prion? Nombrar una enfermedad causada por un prion.

The word prion, named in 1982 by Stanley B. Prusiner, is short for “proteinaceous infectious particle” and the word is derived from the words protein and infection. While viruses (and all other known infectious agents, including bacteria, fungi, and parasites) universally contain DNA or RNA, prions contain neither. Instead they are a protein that can fold in multiple, structurally distinct ways, at least one of which is self-propagating and transmissible to other prion proteins. This form of replication leads to disease that is similar to viral infection.

The first prion protein discovered in mammals is the major prion protein (PrP). This infectious agent causes mammalian transmissible spongiform encephalopathies, including bovine spongiform encephalopathy (BSE, also known as "mad cow disease") and scrapie in sheep. In humans, PrP causes Creutzfeldt-Jakob Disease (CJD), variant Creutzfeldt-Jakob Disease (vCJD), Gerstmann–Sträussler–Scheinker syndrome, Fatal Familial Insomnia and kuru.

All known prion diseases in mammals affect the structure of the brain or other neural tissue and all are currently untreatable and universally fatal.

6

Hacer una de las siguientes:

6a

Dar un breve informe acerca de una pandemia viral y el impacto que causó/está causando en el mundo.

A pandemic (from Greek πᾶν pan "all" and δῆμος demos "people") is an epidemic of infectious disease that has spread through human populations across a large region; for instance multiple continents, or even worldwide. A widespread endemic disease that is stable in terms of how many people are getting sick from it is not a pandemic. Further, flu pandemics generally exclude recurrences of seasonal flu. More recent pandemics include the HIV pandemic as well as the 1918 and 2009 H1N1 pandemics. The Black Death was a devastating pandemic, killing over 75 million people.

Be sure the pandemic you cover is caused by a virus, since many pandemics are bacterial. Historic or current viral pandemics include:

• Yellow fever In 1927 yellow fever virus became the first human virus to be isolated. Yellow fever has been a source of several devastating epidemics.Cities as far north as New York, Philadelphia, and Boston were hit with epidemics. In 1793, one of the largest yellow fever epidemics in U.S. history killed as many as 5,000 people in Philadelphia—roughly 10% of the population. About half of the residents had fled the city, including President George Washington. In colonial times, West Africa became known as "the white man's grave" because of malaria and yellow fever. Yellow fever remains a serious problem in Africa.
• Measles is an endemic disease, meaning that it has been continually present in a community, and many people develop resistance. In populations that have not been exposed to measles, exposure to a new disease can be devastating. In 1529, a measles outbreak in Cuba killed two-thirds of the natives who had previously survived smallpox. The disease had ravaged Mexico, Central America, and the Inca civilization. Before the vaccine was introduced in 1963, there were an estimated 3–4 million cases in the U.S. each year. Measles killed around 200 million people worldwide over the last 150 years. In 2000 alone, measles killed some 777,000 worldwide out of 40 million cases globally.
• Influenza pandemic
• Ebola
• HIV/AIDS considered the main viral long term pandemic
• COVID-19 Also known as COVID-19.

6b

Crear un drama, presentación multimedia u otra exhibición interactiva que informa a una audiencia del peligro de uno o más de estos virus y les da capacitación acerca de cómo combatir o controlar el virus.

6c

Tener un trabajador de ayuda humanitaria dar una charla o presentación acerca de epidemias y control de virus en los países que haya servido. Recaudar dinero como un grupo para apoyar a la ayuda humanitaria al país de que le informa el trabajador.