A virus is a small infectious agent that replicates inside the living cells of other organisms. Viruses can infect all types of life forms, from animals and plants to bacteria and archaea. While not inside an infected cell or in the process of infecting a cell, viruses exist in the form of independent particles, also known as virions. About 5,000 virus species have been described in detail, although there are millions of types of viruses. 5 deadly viruses are described here.
1. The Ebola virus
Ebola, previously known as Ebola hemorrhagic fever, is a rare and deadly disease caused by infection with one of the Ebola virus species. Ebola can cause disease in humans and mammals.
Ebola is caused by infection with a virus of the family Filoviridae, genus Ebolavirus. There are five identified Ebola virus species, four of which are known to cause disease in humans: Ebola virus (Zaire ebolavirus); Sudan virus (Sudan ebolavirus); Taï Forest virus (Taï Forest ebolavirus, formerly Côte d’Ivoire ebolavirus); and Bundibugyo virus (Bundibugyo ebolavirus). The fifth, Reston virus (Reston ebolavirus), has caused disease in nonhuman primates, but not in humans.
Ebola viruses are found in several African countries. Ebola was first discovered in 1976 .The 2013–2014 Ebola virus epidemicin West Africa has resulted in at least 13,567 suspected cases and 4,922 confirmed deaths. The 2014 Ebola epidemic is the largest in history, affecting multiple countries in West Africa.
People get Ebola through direct contact with blood or body fluids, objects (like needles and syringes and infected fruit bats or primates (apes and monkeys).
2. Rotavirus
Discovered in 1973 by Ruth Bishop and her colleagues by electron micrograph images, the Rotavirus is the most common cause of diarrheal disease among infants and young children. This virus is easily transmitted with a child touches a surface that is contaminated, and put their fingers in their mouth. Nearly every child in the world is infected with rotavirus at least once by the age of five. It infects and damages the cells that line the small intestine and causes gastroenteritis (which is often called "stomach flu" despite having no relation to influenza). It caused 37% of deaths of children from diarrhea and 215,000 deaths worldwide, and almost two million more become severely ill. Rotaviral enteritis is a mild to severe disease characterized by nausea, vomiting, watery diarrhea and low-grade fever. Once a child is infected by the virus, there is an incubation period of about two days before symptoms appear. The period of illness is acute. Symptoms often start with vomiting followed by four to eight days of profuse diarrhea. Dehydration is more common in rotavirus infection than in most of those caused by bacterial pathogens, and is the most common cause of death related to rotavirus infection.
3. Hepatitis C
Hepatitis C is an infectious disease caused by the hepatitis C virus (HCV) that primarily affects the liver. There are not really any symptoms when you get Hepatitis C. Silently. Occasionally a fever, dark urine, abdominal pain, and yellow tinged skin occurs. It works on your liver, destroying it. Symptoms of liver damage can take decades to reveal themselves, sometimes making it too late to treat and often leads to liver disease and occasionally cirrhosis. In some cases, those with cirrhosis will develop complications such as liver failure, liver cancer, or dilated blood vessels in the esophagus and stomach. HCV is spread primarily by blood-to-blood contact associated with intravenous drug use, poorly sterilized medical equipment, needle stick injuries in healthcare, and transfusions.
4. Measles
Measles is a highly contagious infection caused by the measles virus. Initial signs and symptoms typically include fever, often greater than 40 °C (104.0 °F), cough, runny nose, and inflamed eyes. Two or three days after the start of symptoms, small white spots may form inside the mouth, known as Koplik's spots. A red, flat rash which usually starts on the face and then spreads to the rest of the body typically begins three to five days after the start of symptoms. Measles is an airborne disease which spreads easily through the coughs and sneezes of those infected. It may also be spread through contact with saliva or nasal secretions.
Measles has been around for over 150 years and has killed over 200 million people. With a fatality rate of 30%, there are twenty one Measles strains to date. When an epidemic strikes it kills thousands, like the 40,000 people who died from it in Fiji in 1875.
5. Rabies
Humans catch the rabies virus from another animal through a bite or scratch. In countries where dogs commonly have rabies more than 99 percent of human cases are the result of dog bites. In the United States less than five percent of cases are the result of dogs, and bats are the primary vector. The virus can only be identified in humans after symptoms begin to appear. It is notorious for transforming animals into violent creatures, as if they were famous murderers. Rabies vaccines for pets, which were introduced in the 1920s. The first symptoms of rabies may be very similar to those of the flu including general weakness or discomfort, fever, or headache. These symptoms may last for days. There may be also discomfort or a prickling or itching sensation at the site of bite, progressing within days to symptoms of cerebral dysfunction, anxiety, confusion, agitation. As the disease progresses, the person may experience delirium, abnormal behavior, hallucinations, and insomnia.
