Introduction of SARS
Severe acute respiratory syndrome (SARS) is an upper respiratory infection caused by a coronavirus. The etiological agent responsible for SARS is called SARS-associated coronavirus (SARS-CoV). SARS-CoV is a relatively novel mutated form of coronavirus, resulting in a virus capable of becoming infectious in a human host. Typically, coronaviruses express themselves much like a common cold. However, SARS-CoV can cause complications uncommon in other coronavirus strains. A host infected with SARS-CoV may develop additional infections, like pneumonia or respiratory failure6,7. According to the World Health Organization (WHO),37 SARS-CoV presents itself as an atypical cold but with similar symptoms, resulting in a virulent pathogen
…show more content…
In general, coronaviruses are positive-stranded and are enveloped in a lipoprotein outer layer. Before the SARS outbreak in 2002, coronaviruses were atypical in the human population and common among animals.3,21 The SARS-CoV genetic expression is nearly identical to other coronaviruses.4,9 However, SARS-CoV lacks the gene to produce hemagglutin-esterase (HE), a protein found in the envelope of some viruses to help it bind to the mucosal layer of the intestines. The lack of the HE-protein may be a possible explanation for why the pathogenesis of SARS-CoV is different from other coronaviruses. The lifecycle of SARS begins at the point of inoculation. The incubation period of SARS is between 2-10 days.37,38 Once the virus has infected a human host, it immediately begins to replicate by un-coating the lipoprotein outer layer, replicating and translating a single, positive RNA strand. The protein responsible for apoptosis in cells is the SARS-CoV U122 protein. Upon infection, healthy cells undergo pro-apoptotic (MAPK) or anti- apoptotic activation (Akt), causing either cell survival or programmed cell death. This mechanism remains unknown in SARS-CoV. Once SARS-CoV infects a cell and activates pro-apoptosis, the virus is destroyed along with the …show more content…
The highest risk group was among comorbid patients aged 65 or older. In Canada,24 the highest SARS frequency group, based on probable/suspected cases, occurred in adults aged 40 and above (62.7% of cases). Type of exposure also played a pivotal role in who was most at-risk of infection. Based on the Ontario, Canada study,24 people in healthcare were most vulnerable to infection, followed by: members of a household, social gathering, and those who traveled among infected
VanderBent, S. D. (2009, September). Home Care and Pandemic Flu. In Ontario Home Care Association Bringing Health Care Home. Retrieved March 10, 2014, from https://www.homecareontario.ca/public/docs/publications/position%20papers/2009/Home-Care-and-Pandemic-Flu.pdf
The virus is primarily spherical shaped and roughly 200nm in size, surrounded by a host-cell derived membrane. Its genome is minus-sense single-stranded RNA 16-18 kb in length. It contains matrix protein inside the envelope, hemagglutinin and neuraminidase, fusion protein, nucleocapsid protein, and L and P proteins to form the RNA polymerase. The host-cell receptors on the outside are hemagglutinin and neuraminidase. The virus is allowed to enter the cell when the hemagglutinin/ neuraminidase glycoproteins fuse with the sialic acid on the surface of the host cell, and the capsid enters the cytoplasm. The infected cells express the fusion protein from the virus, and this links the host cells together to create syncitia.
Influenza is defined as an acute, commonly epidemic disease, occurring in several forms, caused by numerous rapidly mutating viral strains and characterized by respiratory symptoms and general prostration. Spanish flu was more than just a normal epidemic, it was a pandemic. Epidemics affect many people at the same time in areas where the disease doesn’t normally occur. A pandemic is an epidemic on a national, international, or global scale. The Spanish flu was different from the seasonal flu in one especially frightening way, there was an unusually high death rate among healthy adults aged 15 to 34 and lowered the life expectancy by more than ten years. Such a high death rate has not occurred in this age group in and epidemic prior to or since the Spanish flu pandemic of 1918. (Tumpey, 2005)
A few years before 1918, in the height of the First World War, a calamity occurred that stripped the globe of at least 50 million lives. (Taubenberger, 1918) This calamity was not the death toll of the war; albeit, some individuals may argue the globalization associated with the First World War perpetuated the persistence of this calamity. This calamity was referred to the Spanish Flu of 1918, but calling this devastating pestilence the “Spanish Flu” may be a historical inaccuracy, as research and historians suggest that the likelihood of this disease originating in Spain seams greatly improbable. Despite it’s misnomer, the Spanish Flu, or its virus name H1N1, still swept across the globe passing from human to human by exhaled drops of water that contained a deadly strand of RNA wrapped with a protein casing. Individuals who were unfortunate enough to come in contact with the contents of the protein casing generally developed severe respiratory inflammation, as the Immune system’s own response towards the infected lung cells would destroy much of the lungs, thus causing the lungs to flood with fluids. Due to this flooding, pneumonia was a common cause of death for those infected with Spanish Flu. Due its genetic similarity with Avian Flu, the Spanish Flu is thought to be descended from Avian Flu which is commonly known as “Bird Flu.” (Billings,1997) The Spanish Flu of 1918 has had a larger impact in terms of global significance than any other disease has had because it was the most deadly, easily transmitted across the entire globe, and occurred in an ideal time period for a disease to happen.
The human population has a high susceptibility to the contraction of new diseases and outbreaks of these diseases are of high risk. Diseases in recent times that have broken out into the human population are the H7N9 flu strain and SARS. Despite the risk, outbreaks like H7N9 and SARS have been controlled due to epidemiology and other disease control methods. Outbreaks of disease are not uncommon to the human population as they move to new areas around the world with foreign diseases that the native residents would have developed a resistance to.
The swine influenza or swine flu is a respiratory disease in pigs that is caused by the type A influenza viruses. These viruses are referred to as swine flu viruses but scientifically the main virus is called the swine triple reassortant (tr) H1N1 influenza virus. When the viruses infect humans they are called variant viruses. This infection has been caused in humans mainly by the H1N1v virus in the United States. The H1N1 virus originates in animals due to improper conditions and the food they ingest. The virus stays in latency form, thus harmless to the respective animal. The longer the animals survive the more likely the virus is to develop and strengthen making it immune to vaccines. The virus reproduced through the lytic cycle. The virus injects its own nucleic acids into a host cell and then they form a circle in the center of the cell. Rather than copying its own nucleic acids, the cell will copy the viral acids. The copies of viral acids then organize themselves as viruses inside of the cell. The membrane will eventually split leaving the viruses free to infect other cells.
The Flu was first founded in Seattle September, 1918. The avian flu can also be known as the “Bird Flu”. The bird flu is being passed around by migratory birds. It can be transmitted from birds to mammals and in some limited circumstances to humans. The flu will also be known as the H5N1 virus. The H5N1 virus has raised concerns about a potential human pandemic because its virulent (deadly; extremely dangerous) and it can evolve like other influenza viruses. As many other viruses and illnesses the flu can be a lot more deadlier. When you get the flu the lungs are severely harmed from infected cells called macrophages and T-cells. The virus can spread way beyond the lungs but generally do not. Many people catch the flu and think they have the common cold because of some of the same symptoms. But actually the flu can be more dangerous if you don’t treat it immediately.
People will argue when the first documented case of pandemic actually happened. The Peloponnesian War Pestilence recorded to have taken place in 430 BC during the war between Athens and Sparta, it was documented by a historian Thucydides. This was a great pestilence that wiped out 30,000 of the citizens of Athens (roughly one to two thirds of all Athenians died). It is said that not many days after Attica was invaded by Archidamus, the plague first began to show itself among the Athenians. Since the devastation of the plague was so extent and the physicians at first were ignorant, that they had never experienced anything of this magnitude before. They had no proper way to treat it, and ultimately died themselves, as they visited the sick most often. It is said that the sickness first began in Ethiopia and descended into Egypt and Libya, then spreading into Athens. The symptoms were described as something that spread at an incredible rate, causing fever, vomiting and diarrhea, and a general delirium, often killing the infected after only a few days. Ironically the detailed desc...
Influenza is an acute respiratory illness caused by infection of influenza A and B viruses. The disease can affect both the upper and lower respiratory tract and is often followed by systemic signs and symptoms, such as: sudden onset of fever, chills, non-productive cough, myalgias (muscle pain), headache, nasal congestion, sore throat, and fatigue. (Cox et al.1998). Influenza viruses evolve continuously, challenging mammalian and avian hosts with new variants and causing complex epidemic patterns with regard to age, place, and time. Human influenza viruses cause disease through a variety of direct and indirect pathological effects. The direct effects include destruction of infected cells, damage to respiratory epithelium, and immunological responses that cause general malaise and pneumonia. Indirect effects of infection include secondary bacterial infections due to the tissue damage and other disease such as cardiovascular disease, renal disease, diabetes or chronic pulmonary disease (Schoenbaum S.1996). In the USA, clinical illness affects 5–20% of the population and asymptomatically infects a larger number (Noble G.1982). Infants, who are exposed to influenza epidemics as a novel antigenic challenge after maternal antibodies decline, may have attack rates as high as 30–50% in their first year of life, depending on the frequency of contacts with older siblings (Glezen et al.1997). For reasons, influenza viruses cause epidemics in the northern and southern hemisphere during their respective winters. In the tropics, the timing of activity is less defined, with sometimes year-round circulation or bi-seasonal peaks during the year (Viboud et al.2006).
The flu, is characterized as an infection of the respiratory tract caused by influenza viruses. Influenza infection is commonly ranked as one of the most dangerous diseases on Earth because it affects all age groups and can re-occur in any individual. Influenza A, B and C viruses belong to the orthomyxovirus, which is the family of enveloped viruses with segmented, single-stranded, negative-sense RNA genome (Calder et al., 2010; Cox & Subbarao, 1999). Type C cause sporadic mild influenza-like illness in children. Type B are known to cause recurring regional and local epidemic disease, but it is only found in human. Type A virus is the most
The SARS-CoV is spread through close person-to-person contact, fomites, and through respiratory droplets through coughing or sneezing. It is also thought to be potentially airborne and may be spread through some other unknown ways. Due to the virus’ short lived transmission cycle, there is not a lot of in-depth information and studies on how exactly it may spread. And while we know some ways it spread, we may not know all. (Serradell, 2010). The virus itself primarily infected the elderly, people with chronic illnesses, and healthcare workers with direct exposure to those infected. SARS was the first new disease of the twenty-first century and as a result, was one of the first diseases to see such a rapid, global spread. SARS may have only taken place from 2003-2004, but in that time it spread to over 24 other countries around the
The microorganism would be embedded within the droplets of an infected host. So when they sneeze or cough, tiny droplets would spread throughout the air, often landing on a susceptible host causing them to obtain the pathogens themselves. Transmission is even able to occur by having a simple conversation across a table with a person harboring the virus. Even though SARS is a highly contagious virus, simply just walking by a person carrying the pathogen did not contribute in the spreading the virus. On the other hand, if someone simply touches an object that belonged to the infected host and later touches any of the openings on their face, they would be doing a great disservice to themselves by becoming the new mode of entry for the pathogen. ________“it is possible that the SARS virus might spread more broadly through the air (airborne spread) or by other ways that are not now known.” Still today, there is no vaccine for SARS, nor do people have any natural defenses to aid off the virus if it was to currently reappear itself. If a hospital suspects someone to be infected with the SARS virus, immediate treatment must be given along with quarantine. Unfortunately, the elderly and those with compromised immune systems are the most at risk of dying from the
In the 1960s, doctors in the United States predicted that infectious diseases were in decline. US surgeon Dr. William H. Stewart told the nation that it had already seen most of the frontiers in the field of contagious disease. Epidemiology seemed destined to become a scientific backwater (Karlen 1995, 3). Although people thought that this particular field was gradually dying, it wasn’t. A lot more of it was destined to come. By the late 1980s, it became clear that people’s initial belief of infectious diseases declining needed to be qualified, as a host of new diseases emerged to infect human beings (Smallman & Brown, 2011).With the current trends, the epidemics and pandemics we have faced have created a very chaotic and unreliable future for mankind. As of today, it has really been difficult to prevent global epidemics and pandemics. Although the cases may be different from one state to another, the challenges we all face are all interconnected in this globalized world.
World Health Organization “Frequently Asked Questions on Severe Acute Respiratory Syndrome (SARS),” Communicable Disease Surveillance & Response (CSR), March 24. (2003). World Health Organization . Retrieved March 29, 2004.
In 1918-19 approximately 50 million deaths were a detriment of the Spanish H1N1 virus pandemic; a respiratory virus. According to the World Health Organization, the second Influenza A H1N1 pandemic in 2009 spread to more than 200 countries causing more than 18 000 deaths. Before the World Health Organization had announced the official end of the pandemic in August 2010, in July 2009 the World Health Organization sent out a phase 6 warning that H1N1 could soon be a global pandemic. It is important to recognize that the 2 different outbreaks had different A/H1N1strains effecting the world population; this suggests A/H1N1has a high ability for mutation, severely complicating the human body’s natural immune mechanism of antigenic drift. (Qi-Shi Du et al., 2010)