Following the vaccination developed by Louis Pasteur and Emile Roux, however, fatality rates have declined significantly assuming proper medical care is sought out immediately. For individuals exposed to rabies, rapid treatment is needed within ten days , and includes a fourteen-day series of vaccinations known as HRIG Human Rabies Immunoglobulin. These vaccinations are highly effective, with a percent cure rate when administered promptly.
Pictured above is HIV green attacking healthy cells in the human body. The Human Immunodeficiency Virus HIV is a species of virus from the Retroviridae family that affects the immune system of infected individuals. HIV is believed to have originated from chimpanzees living within Central Africa, and may have been present on the continent as far back as the s. The virus has existed in the United States since the s.
There is currently no cure for the virus; however, effective treatments have been established to control the disease known as ART antiretroviral therapy. Each year, there are approximately 1. The virus, which eventually progresses to AIDS if left untreated , is responsible for an estimated , deaths per year, with the largest number of deaths occurring in Sub-Saharan Africa 66 percent of all cases.
HIV is a life-threatening virus, and is spread via bodily fluids. At the final stage AIDS , the immune system is compromised to a point where even a common cold can become a life-threatening ordeal. Diagnosing HIV is difficult as the disease often shows no signs or symptoms in its early stages. Occasionally, people experience flu-like symptoms during the first two to four weeks of infection, including fever, chills, rash, muscle aches, sore throat, fatigue, mouth ulcers, and swollen lymph nodes.
Routine blood-tests should be conducted if an individual believes they were exposed. Smallpox is an ancient virus caused by the variola virus believed to have originated in Egypt during the Third-Century BC.
The last known case of smallpox occurred in October , with the World Health Organization WHO claiming a complete eradication of the disease in globally. Over the centuries, Smallpox has often occurred in outbreaks, with a fatality rate of approximately 30 percent. During the 18th-Century alone, Europe experience nearly , deaths per year from the disease.
Before the eradication of the Smallpox virus, scientists believe that the disease spread following face-to-face contact with other humans via coughing or sneezing. After about the fourth day, a rash containing small red spots began to appear on both the mouth and tongue of individuals infected with the virus.
After 24 hours, these sores would then fill up with a thick fluid making the bumps round and solid to the touch. After about ten days, the sores begin to scab over, falling off within a week often leaving lifelong scars on the skin.
Although Smallpox has been eradicated worldwide, the potential for an outbreak remains. Bioterrorist attacks, where viruses and bacteria are intentionally released by terrorist groups or countries, remains an ever-present though unlikely threat during the modern age. For this reason, vaccinations and antiviral drugs have been safely stockpiled in the event of a bioterrorist attack in the future.
Hantaviruses are an incredibly dangerous disease from the Hantaviridae family. The viruses, which are found predominantly in Europe and Asia, are believed to be spread through various rodents via saliva, feces, and urine. Due to the small number of cases that have occurred, however, little is known about its overall impact on humans.
Incubation time for the Hantavirus is believed to be approximately one to eight weeks, with symptoms occurring at any time during this span. Early symptoms include fatigue, muscle pain, fever, headaches, abdominal problems including nausea, diarrhea, and vomiting , as well as dizziness, and chills. In cases where the virus results in HPS, extreme coughing, chest pain, shortness of breath, and chest tightness begin to occur after ten days as the lungs begin to fill with fluid.
In cases of HFRS, similar symptoms occur that eventually progress to low blood pressure, shock, internal bleeding, and acute renal failure. No specific treatments for the Hantavirus group have been developed. Intense medical care focusing on hydration, oxygen therapy, as well as dialysis to aid patients undergoing acute renal failure from HFRS are the main source of care.
Controlling mice and rodent populations appears to be the number one source of prevention for this family of diseases. Influenza also known as the "Flu" under a microscope. Of these, only Type A, B, and C are known to actively affect humans. Influenza is extremely contagious, and is believed to spread via coughing and sneezing, or through touching contaminated surfaces.
Nearly three to five million cases of the flu are diagnosed worldwide, with an estimated , deaths per year. Symptoms usually progress rapidly after exposure to the virus beginning less than two days after infection , and include fever, runny nose, sore throat, muscle aches and pains, headaches coughing, sneezing, fatigue, vomiting, diarrhea, and abdominal pain.
In severe cases, the Flu is capable of developing viral pneumonia, as well as secondary bacterial pneumonia particularly in cases involving the young and elderly. Although flu vaccines have been shown to reduce the spread of the virus, doctors are limited in their ability to treat the illness, with the primary treatment involving management of symptoms.
Influenza can be extremely deadly for the elderly, young, and individuals with compromised immune systems. During pandemics, influenza has been known to devastate entire populations of people. During the Flu Epidemic, alone, nearly million people were infected with the virus, worldwide, and claimed an estimated 50 million lives. To this day, influenza remains a constant threat each year that should not be ignored. The Dengue Virus is an extremely deadly virus from the Flaviviridae family, and is responsible for an astounding million infections each year, worldwide.
The virus, which contains five different strands, is believed to be spread via mosquitoes, and is found predominantly in Asia and Africa due to the warm, tropical climates in these regions. After being exposed to the virus, symptoms usually begin three to fourteen days later and include severe headaches, muscle and bone pain, rashes, and bleeding of the gums.
In more serious manifestations of the disease, which include the development of Dengue Hemorrhagic Fever, infected individuals are prone to shock, extreme bleeding, blood plasma leaking, as well as extremely low blood pressure. Occasionally, the disease also affects the brain, liver, and heart, resulting in organ failure or inflammation of the brain. Diagnosis of the disease is often difficult to establish in its early stages, as the virus mimics many other viral infections.
Moreover, treatment for the disease is non-specific, and often involves management of symptoms i. Vaccinations and the maintenance of mosquito populations combined with efforts to reduce mosquito bites appears to be the best course of action in reducing the spread of the Dengue Virus. First identified in during an outbreak in Congo and Sudan, the virus is believed to have originated with primates, and is transmitted via direct contact with bodily fluids including saliva, mucus, vomit, feces, urine, breast milk, sweat, and tears.
Depending on the strain of Ebola, the virus carries an extremely high fatality rate that ranges from twenty-five to ninety percent. One of the most recent viruses to vanish was Sars.
The earliest cases occurred in Guangdong, a coastal province in southeast China known for its many restaurants serving exotic meats. At the time, local wet markets bustled with racoons, badgers, palm civets, doves, rabbits, pheasants, deer and snakes, which were often dispatched on the spot, mere metres from where people ate. It was common to find beheaded and disembowelled animals just lying around.
Even in the earliest days of the epidemic, it was clear how Sars had emerged. Fast-forward two years, and the virus had infected at least 8, people , of whom died. But it could have been so much worse. Like its close relative Covid, Sars had many of the necessary qualities for world domination — it was an RNA virus, meaning it was able to evolve rapidly, and it was spread through droplets expelled when breathing, which are hard to avoid.
Instead, Sars disappeared as abruptly as it arrived. By January , there were just a handful of cases — and by the end of month, the last suspected natural infection was announced. There was another outbreak a couple of months later, when it is thought to have escaped from a Beijing research lab — twice.
In a nutshell, we got lucky. According to Sarah Cobey, an epidemiologist at the University of Chicago, Sars was driven to extinction by a combination of sophisticated contact-tracing and the quirks of the virus itself.
It took a global effort of surveillence and control measures to eliminate Sars Credit: Reuters. When patients with Sars got sick, they got very sick. The virus had a staggeringly high fatality rate — almost one in five patients died — but this meant that it was relatively easy to identify those who were infected, and quarantine them.
There was no extra spread from people without symptoms, and as a bonus, Sars took a relatively long time to incubate before it became contagious, which gave contact-tracers extra time to find anyone who might be infected before they could pass it on.
The case of Liu Jianlun, who caught the virus before it had been properly identified, shows just how differently the Sars pandemic could have played out. The year-old specialist in respiratory medicine became infected after treating a patient at the hospital where he worked in Guangdong Province. On 21 February , Jianlun travelled to Hong Kong to attend a wedding, and checked into a room on the ninth floor of the Metropole Hotel.
Although he had been suffering a slight fever and mild respiratory symptoms for five days, he was well enough to do some sightseeing with a relative. But the following day his symptoms had worsened, so he walked to a nearby hospital and asked to be put into isolation. By then, he had already unwittingly infected 23 people , including guests from Canada, Singapore and Vietnam, who then carried the virus back to their own countries, where they spawned further outbreaks.
In the end, the WHO estimated that around 4, cases could be traced back to Jianlun , who himself succumbed to the virus. Unfortunately this situation is extremely unusual. Other than Sars, only two other viruses have ever been driven to extinction on purpose — smallpox and rinderpest, which affects cattle. So, what about the other viruses that have plagued humanity in recent years? Will Ebola disappear? And where did swine flu go? Vaccinations can help prime the human immune system to fight off viruses, making it harder for them to spread Credit: Press Association.
In humans, outbreaks of Ebola end all the time. There have been at least 26 across Africa since the virus was discovered in , and these are just the ones that caused enough cases to be picked up by health authorities. They tend to occur when the virus hops from an animal — usually a bat — to a human, who then infects other humans. As long as there are bats, it may always be with us, regardless of whether there is a single person infected anywhere on the planet.
Scientists and genetic engineers are considering several techniques to increase the efficacy of pathogens in warfare. This technique involves inserting plasmids, small bacterial DNA fragments, into the DNA of other bacteria in order to increase virulence or other pathogenic properties within the host bacteria 2.
According to the European Bioinformatics Institute, as of December , scientists had sequenced the genomes of viruses, plasmids, and bacteria, some of which are published on the internet and are therefore accessible to the public 6.
With complete genomes available and the aforementioned advances in gene synthesis, scientists will soon be able to design pathogens by creating synthetic genes, synthetic viruses, and possibly entirely new organisms 2. Gene therapy involves repairing or replacing a gene of an organism, permanently changing its genetic composition.
By replacing existing genes with harmful genes, this technique can be used to manufacture bioweapons 2. Stealth viruses are viral infections that enter cells and remain dormant for an extended amount of time until triggered externally to cause disease.
In the context of warfare, these viruses could be spread to a large population, and activation could either be delayed or used as a threat for blackmail 2. Much like the naturally occurring West Nile and Ebola viruses, animal viruses could potentially be genetically modified and developed to infect humans as a potent biowarfare tactic 2. Biotechnology may be used to manipulate cellular mechanisms to cause disease. For example, an agent could be designed to induce cells to multiply uncontrollably, as in cancer, or to initiate apoptosis, programmed cell death 2.
This agent may spread through populations showing minimal or no symptoms, yet it would be fatal to the intended target 4. In addition to creating bioweapons, the emerging tools of genetic knowledge and biological technology may be used as a means of defense against these weapons. As scientific research continues to reveal the functions of specific genes and how genetic components affect disease in humans, vaccines and drugs can be designed to combat particular pathogens based on analysis of their particular molecular effect on the human cell 2.
In addition to enabling more effective drug development, human genome literacy allows for a better understanding of the immune system. Thus, genetic engineering can be used to enhance human immune response to pathogens. As an example, Dr. Ken Alibek is conducting cellular research in pursuit of protection against the bioweapon anthrax 2. Decoding the genomes of viruses and bacteria will lead to molecular explanations behind virulence and drug resistance.
With this information, bacteria can be engineered to produce bioregulators against pathogens. Because the capability of comparing genomes using DNA assays has already been acquired, such technology may be developed to identify pathogens using information from bacterial and viral genomes.
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