Coronaviruses are a large family of viruses that cause respiratory illnesses. Because nCoV is so new, many unknowns remain about the virus, including exactly how easily it spreads, how deadly it is and whether it will cause a global pandemic.
The World Health Organization has declared the nCoV outbreak a "public health emergency of international concern," but has not yet declared it a pandemic. Studies suggest nCoV likely originated in bats, but made it's "jump" to people through a yet-to-be-identified animal, which acted as a bridge between bats and humans.
Scientists think that smallpox , which causes skin lesions, emerged about 3, years ago in India or Egypt, before sweeping across the globe.
The Variola virus, which causes smallpox, killed as many as a third of those it infected and left others scarred and blinded, according to the World Health Organization. A photo taken in shows the village cemetery in the Bangladesh countryside where smallpox victims were buried. The disease is believed to have killed 46 percent of its victims at a hospital in the Dacca, Bangladesh, ravaging the country for centuries. In , the WHO declared the disease officially eradicated, after a decade-long vaccination campaign.
The last remaining samples of the virus are being held in facilities in the United States and Russia. Unlike smallpox, this ancient killer is still with us.
Caused by a bacterium carried by fleas, plague has been blamed for decimating societies including 14th-century Europe during the Black Death , when it wiped out roughly a third of the population, including in Basel, Switzerland, depicted in this painting from The disease comes in three forms, but the best known is bubonic plague, which is marked by buboes, or painfully swollen lymph nodes.
Although it is preventable and curable, malaria has devastated parts of Africa, where the disease accounts for 20 percent of all childhood deaths, according to the World Health Organization. It is present on other continents as well. A parasite carried by blood-sucking mosquitoes causes the disease, which is first characterized by fever, chills and flu-like symptoms before progressing on to more serious complications.
By , the disease was eliminated from the U. A subsequent WHO campaign to eradicate malaria was successful only in some places, and the goal was downgraded to reducing transmission of disease, according to the U. Centers for Disease Control and Prevention. The WHO has distributed so-called long-lasting insecticidal nets in order to reduce bites from malaria-carrying mosquitoes, including in Cambodia shown in image.
A seasonal, respiratory infection, flu is responsible for about 3 million to 5 million cases of severe illness, and about , to , deaths a year across the globe, according to the World Health Organization. Periodically, however, the viral infection becomes much more devastating: A pandemic in killed about 50 million people worldwide. As became apparent from "swine flu" and "bird flu" scares in recent years, some influenza viruses can jump between species.
Potentially fatal, tuberculosis or "TB" is caused by the bacterium Mycobacterium tuberculosis , which usually attacks the lungs and causes the signature bloody coughs. In patients suffering from an advanced stage of TB, you can see the effects in a lung X-ray shown in image. The bacterium does not make everyone it infects sick, and up to one-third of the world's population currently carries the bacterium without showing symptoms.
At the end of , about While many of the worst offenders on this disease list have a long-standing relationship with humans, HIV is a recent arrival. HIV's decimating effect on certain immune system cells was first documented in By destroying part of the immune system , HIV leaves its victims vulnerable to all sorts of opportunistic diseases.
Cholera causes acute diarrhea that if left untreated can kill within hours. People catch the disease by eating or drinking substances containing the bacterium Vibrio cholerae. The bacteria tend to contaminate food and water through infected feces. Since it can take 12 hours to 5 days to show symptoms, people can unwittingly spread the disease through their feces.
Thanks to improved sanitation, cases of cholera have been rare in industrialized nations for the last years, but worldwide it kills between 21, and , individuals every year, the WHO estimates. During the 19th century, however, cholera spread from its home in India, causing six pandemics that killed millions of people on all continents, according to the World Health Organization. During a cholera epidemic in Peru in , a hospital waiting room shown in image was converted to an emergency cholera ward.
More recently, a cholera outbreak in Haiti, which began after that country's devastating earthquake, had sickened more than people and killed nearly 9,, according to a report published in in The Journal of Infectious Diseases. No longer a significant threat in the United States, rabies is still a deadly problem in other areas of the world. Rabies causes "tens of thousands" of deaths every year in countries in Africa and Asia, according to the WHO.
Approximately two people die yearly in the U. The initial symptoms of rabies can be hard to detect in humans, as they mimic that of the flu and include general weakness, discomfort and fever. But as the disease progresses, patients may experience delirium, abnormal behavior, hallucinations and insomnia, according to the Centers for Disease Control and Prevention CDC. To date, fewer than 10 people who have contracted rabies and started to exhibit symptoms have survived.
However, a rabies vaccine does exist and is usually very effective in both preventing infection with the virus and treating infected individuals before they begin to show symptoms. Pneumonia might not conjure up the same dread as diseases like rabies or smallpox, but this lung infection can be deadly, especially for those older than 65 or younger than 5. The disease can be caused by bacteria, a virus or a combination of both, according to Dr.
A person can also get pneumonia from a fungal infection, parasites or reactions to certain medicines, Adalja told Live Science in September Rotavirus, the most common cause of viral gastroenteritis inflammation of the stomach and intestines , is a diarrheal disease that can be deadly.
In , rotavirus killed , children under the age of 5 globally, according to the WHO. About 22 percent of those deaths occurred in India alone; and overall most of the deaths occur in children living in low-income countries.
The virus causes dehydration, brought upon by severe, watery diarrhea and vomiting. There are four rotavirus vaccines that are considered highly effective at preventing the disease, the WHO says. Though rare, Ebola virus disease EVD is an often fatal infection caused by one of the five strains of the Ebola virus.
The virus spreads very rapidly, overcoming the body's immune response and causing fever, muscle pain, headaches, weakness, diarrhea, vomiting and abdominal pain. The coronavirus, which has been named SARS-CoV2, is part of a family of viral infections that afflict people around the world and were first identified in the s.
Seven different types of coronavirus have been identified, four of which are fairly common. The other three evolved from infected animals to created deadly coronaviruses, all of which are illustrated on this chart. View All Notifications. Alzheimer's and Dementia. How much does CEUfast cost? How soon do I get my certificate? Entertainment Pop Culture Entertainment. Print Share. Click here to download the printable PDF version of the chart. What Is a Virus? Ebola: The Evolving Catastrophe The goal of this course is to prepare healthcare profes.
As a result, treatment options are limited, with supportive care being the primary course of action for infected individuals. Rapid detection and control of outbreaks has become a matter of national emergency in regions susceptible to viral outbreaks, and have proven effective in controlling the spread of Ebola strains. Of these cases, 1, individuals died. The largest outbreak in West Africa, occurring between and and involving 28, cases of Ebola, resulted in the death of 11, individuals.
Although vaccinations are currently in development to curtail the spread of Ebola during future outbreaks, there is still much to be learned about the virus before positive outcomes can be implemented with effect.
Following exposure to the Ebola Virus, incubation takes approximately two to twenty-one days before the onset of symptoms first occurs. Initial symptoms involve a sudden flu-like stage that is characterized by extreme fatigue, high fever, muscle weakness and pain, sore throat, and decreased appetite.
As the virus spreads, nausea, vomiting, abdominal pain and cramps , as well as diarrhea are also common, leading to severe dehydration in many cases. Severe rashes, respiratory problems, and chest pain are also likely to develop within five to seven days, followed by the onset of internal and external bleeding.
In severe cases, individuals often enter a coma in the final stages of the disease, followed by low blood pressure that often results in death. In individuals that survive Ebola, lifelong complications are common, including liver inflammation, deafness, chronic fatigue, poor vision, and decreased appetite. Microscopic image of the Marburg Virus; the deadliest and most dangerous virus in the world.
The Marburg Virus is an extremely deadly disease from the Filoviridae family, and is considered the most dangerous virus in the world. After German workers were exposed to infected Grivet Monkeys, seven of the thirty-one people infected by the virus died shortly after. Although the virus has only had a handful of outbreaks over the last fifty years, mortality rates are incredibly high for the Marburg Virus an astounding 90 percent.
The most recent outbreak involved the cases in Angola, where approximately individuals were infected by the virus. Of these, people died from the disease.
In addition to primates, it is believed that Fruit Bats are the primary carriers of the virus. For this reason, individuals exposed to mines or caves for prolonged periods of time are particularly susceptible to the disease. Although little is known about the virus, it is believed that the Marburg Virus spreads between humans via direct contact with broken skin, bodily fluids, or contaminated surfaces such as bedding or clothing that has been contaminated with blood, urine, or fecal matter.
Incubation periods for the virus vary from two to twenty-one days. Initial symptoms often begin rapidly, and include high fevers, headaches, fatigue, muscle aches, severe diarrhea, abdominal pain and cramps , as well as nausea and vomiting.
After five to seven days, infected individuals often develop severe bleeding both internally and externally from the gums, nose, and genital regions. Severe bleeding near venipuncture sites is also common due to the inability of the blood to naturally clot.
By the ninth day, death usually follows. Rapid response and control of outbreak areas remains the best option for controlling the spread of Marburg Virus pathogens. For these reasons particularly its high death rate and lack of treatment options , the Marburg Virus is an incredibly dangerous disease capable of eradicating large populations of people particularly in the event of a Bioterrorist attack.
Preston, Richard. Cunha, John P. Accessed August 06, July 23, March 05, December 11, Do not stop or alter your current course of treatment. If pregnant or nursing, consult with a qualified provider on an individual basis.
Seek immediate help if you are experiencing a medical emergency. Such an interesting and well structured article Larry. The only one I wasn't familiar with was the 'Marburg Virus'.
I love learning something new. Thanks for sharing Larry. I agree percent, Louise! I had heard of most of these as well. Marburg was a new one for me though. Some scary stuff for sure! Some of them viruses I don't know about, but some I do.
There are certainly a lot of deadly viruses out there. We need to be very careful. This is an excellent article on the most serious viruses. I was somewhat familiar with most of them, but I still learned a lot from you well-written article. Marine Biology. Electrical Engineering. Computer Science. Medical Science. Writing Tutorials. Performing Arts.
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