Human struggle against the virus had begun long before our species to have evolved into the perfect modern form.
For some diseases caused by viruses, no vaccines and antiviral drugs that can prevent a wider spread of the disease. In fact, the disease has been successfully eradicated smallpox. However, ebola outbreak that occurred in West Africa shows that our war against the virus is far from over.
The virus that triggered epidemics, Ebola Zaire, killing up to 90 percent of people infected with the Ebola family and make it difficult to be destroyed.
Ebola is a deadly, but actually out there are still many other viruses that are even more dangerous. See explanation Elke Muhlberger, ebola virus expert and professor of microbiology at the University of Boston.
Here are the 9 harmful viruses on Earth is based on a person's risk of death if infected, and the large number of deaths and people who are threatened by this virus.
1. Marburg Virus
Scientists have identified Marburg virus in 1967, when a small outbreak occurred among laboratory workers in Germany who come into contact with monkeys imported from Uganda.
Marburg virus similar to ebola both of which can cause high fever and bleeding. This means that an infected person will experience high fever and bleeding throughout the body that can lead to shock, organ failure and death.
The death rate when the first outbreak was 25 percent, but the figure rose to 80 percent in the 1998-2000 outbreak in the Democratic Republic of Congo, and in 2005 an outbreak override in Angola, according to the World Health Organization (WHO).
2. The Ebola Virus
First ebola outbreak in humans occurs simultaneously in Sudan and the Democratic Republic of Congo in 1976. Ebola is transmitted through contact with blood, body fluids, or tissues of infected persons or animals ebola
One virus, Ebola Reston, did not make people sick. But for Bundibugyo virus, the mortality rate by 50 percent and increased to 71 percent for Sudan virus, according to WHO.
Although rabies vaccines for pets that were introduced in 1920 have made these infections are rare in developed countries, but rabies is still a serious problem in developing countries, including Indonesia.
"The virus of this disease destroys the brain and the bad. But we have antirabies vaccine, and we have antibodies that work against rabies, so if someone was bitten by a rabid animal we can heal this," he said. Even so, someone could die without treatment.
In the modern world, HIV still be one of the biggest killers. An estimated 36 million people have died of HIV since the disease was first recognized in the early 1980s. "Infectious diseases are the most adverse impact on mankind today is HIV," said Dr.Amesh Adalja, an expert in infectious diseases.
Strong antiviral drugs has made it possible for people to live for years with HIV. But this is still a killer disease in low and middle income countries, where HIV infection occurs by 95 percent. Nearly 1 out of every 20 adults in sub-Saharan Africa are HIV-positive, according to WHO.
In 1980, the World Health Assembly declared the world has been free from smallpox. But before that, the human struggle against smallpox for thousands of years and the disease killed an estimated 1 in 3 people are infected. Victims who can still survive with the survivors suffered permanent injury and usually blindness.
6. Hanta Virus
Hantavirus pulmonary syndrome (HPS) gained widespread attention in the United States in 1993, when a young man who initially healthy is Navajo and his fiancee lived in the Four Corners area of the United States, died within a few days while experiencing shortness of breath.
The virus is not transmitted from one person to another, but people have contracted the disease from exposure to infected mice droppings. Previously, the different causes hantavirus outbreak in the early 1950s, during the Korean War. More than 3,000 soldiers are infected and about 12 percent of them died.
According to WHO, during the flu season about 500,000 people worldwide die from the disease. But sometimes, when a new flu virus appears to be a pandemic and the number of death higher.
The most deadly pandemic flu, sometimes called the Spanish flu, started in 1918 and caused pain in 40 percent of the world's population and killed about 50 million people. The experts are now worried about the emergence of a new influenza virus could spread quickly among manausia.
Dengue virus first appeared in 1950 in the Philippines and Thailand, and has since spread throughout the tropical and subtropical regions around the world. Approximately 40 percent of the world's population now live in areas where dengue is endemic, and diseases carried by mosquitoes is likely to spread further.
According to the WHO, dengue affects 50 to 100 million people per year. Although dengue fever death rate is lower than some other viruses, by 2.5 percent, this virus can cause shock condition, the same as that experienced by patients ebola.
There is no vaccine to prevent dengue fever, but large clinical trials of experimental vaccines developed by French drug maker, Sanofi has promising results.
Two vaccines have been available to protect children from rotavirus, the leading cause of severe diarrheal disease in infants and children. The virus is spread by the fecal-oral, which means there are particles of feces that goes into food and inedible.
Although children in developed countries rarely die from rotavirus infection, this disease is a killer in developing countries. WHO estimates that around the world, 453,000 children under age 5 die from rotavirus infections in 2008