Viruses are known to be microscopic organisms, but they are creative killers. A virus is a tiny infectious agent that is capable to replicate only within the living cells of other organisms and have the ability to infect almost all types of life forms, from plants and animals, to archaea and bacteria. There are over 5,000 viruses that are known to human and they are progressing every day. Advanced researches and medicine has been able to face and exterminate some of the noxious little prolific killers through the ages. However, there are number of viruses that are dangerous and can cause various life threatening conditions. Here we have the list of Top 10 Most Dangerous And Deadliest Viruses that are very nasty and have taken away the lives of various individuals.
10. Influenza Virus
Influenza viruses are RNA viruses that belong to family Orthomyxoviridae and cause an infectious disease named as Influenza in birds and mammals. The most common symptoms of this infection include fever, chills, sore throat, runny nose, headache, muscle pains, fatigue, coughing and general discomfort. Influenza is a severe disease that should not be confused with other influenza like illnesses. This virus spreads from person to person through droplets and small particles that are produced when infected individual sneeze or cough. Various individuals completely cure from flu within 10 to 14 days. However this disease can be lethal for the elder patients and those having certain health issues.
9. Yellow Fever Virus
It is a small 40 to 50 nm wide enveloped ribonucleic acid virus, and belongs to the family Flaviviridae. This virus is responsible for a disease named as yellow fever that is historically known as yellow plague or yellow jack. Its symptoms include fever, chills, nausea, and loss of appetite, headache and muscles pains especially in the back. Symptoms generally improve within 5 days. In some individuals within a day of improving the person again suffers from fever, there is abdominal discomfort and pain, and liver damage starts causing yellow skin. If this happens then there is an increased risk of kidney diseases and bleeding.
This disease expands by the bite of the female mosquito containing yellow fever virus. It was the first disease shown to be communicable through filtered human serum and spread by mosquitoes, by Walter Reed over 1900. This virus is prevalent in numerous parts of the world and South Africa is seen to be a home of yellow fever.
This virus attacks the vital organs and the lymphatic system, killing almost one out of two infected individuals. There is no treatment for yellow fever, although there is a potent vaccine that provides immunity from the virus for ten years.
8. Dengue Virus
It is a mosquito borne single positive stranded RNA virus and causes dengue fever. It is known that dengue fever virus has not responsible for taking away the lives of millions of people in all over the world, but according to World Health Organization reports this infection has presently acquired an epidemic state in over 100 countries and two fifth of the population of world is at a risk of developing dengue fever.
It is extremely important to know that this virus is extremely dangerous as once the infected human is bitten by a mosquito, it can transmit the virus to further victims. Dengue virus is the leading cause of death in tropical and subtropical regions. Dengue virus causes severe headache, high grade fever joint and muscle pain and in the life threatening conditions hemorrhage.
There is no vaccine available for this virus, however numerous potential vaccines are under development.
7. Rabies Virus
The rabies virus is a neurotropic virus and causes rabies in animals and humans. The transmission of rabies is possible through the saliva of animals and less frequently through contact with human saliva. This virus has a cylindrical morphology, it is enveloped and possesses a single stranded ribonucleic acid genome with negative sense. People often wonder that why the authorities are killing road dogs or wild animals that are too close to residential areas, but they do in order to prevent an infection with rabies. The virus has derived its name from the Latin word and it means madness. Once the virus enters in the body it makes it way towards brain along the peripheral nerves.
Rabies is an acute inflammation of the brain in humans and animals. The time duration between contracting the illness and the begin of the symptoms is generally 1 to 3 months, however it can vary as it depends on the time the virus reaches central nervous system. Early symptoms include fever, tingling sensations, followed by violent movements, uncontrolled excitement and water phobia, or inability to move body parts, followed by loss of consciousness. In both possibilities, once the symptoms appear it almost or always results in death. Vaccine is available to prevent this infection.
6. Hantavirus
Hantavirus is an enveloped, single stranded, negative sense ribonucleic acid virus in the Bunyaviridae family. Hantaviruses commonly infect rodents but interestingly do not cause infection in them. Humans get infected with this virus through contact with rodent saliva, feces or urine. Some strains of Hantaviruses are very dangerous and cause lethal diseases in humans like Hantavirus pulmonary syndrome and Hantavirus hemorrhagic fever with renal syndrome.
Direct contact with rodents is not required for spread of this infection, and infection usually occurs by the inhalation of dried or dust particles that contain dried waste products or saliva of an infected rodent. Most of the victims die within a few days of infection as their symptoms starts manifesting. HFRS can be cured with ribavirin that is injected intravenously to shorten the disease and minimize the risk of death. On the other hand, until now there is no effective treatment for it.
5. Measles Virus
Measles virus is a single stranded, enveloped, negative sense ribonucleic acid virus and belongs to family Paramyxoviridae. Evidences show that the humans are the natural hosts of the virus and this disease is not seen in animals. This virus causes a very dangerous disease known as measles, it resides in the mucous of the throat and nose of individuals with this infection and when an infected individual coughs, sneezes or breathes this virus spreads. Getting infected with measles virus is not so much injurious in itself and there are various treatments are available that limit the spreading of infection.
The reason of measles to kill almost 200,000 individuals in all over the world is due to the fact that most infected individuals ignore initial symptoms of infection and as a result individuals develop lethal complications like measles encephalitis, myocarditis, pneumonia and various other secondary infections.
4. Hepatitis B Virus
Hepatitis B virus also known as HBV is a small DNA virus that belongs to family Hepadnaviridae of viruses. This virus is responsible for causing hepatitis B in humans. The related viruses in this family are responsible for causing hepatitis in woodchuck, ground squirrels and ducks. In addition to causing hepatitis, infection with hepatitis B virus can lead to hepatocellular carcinoma and cirrhosis. Hepatitis B is an infectious disease of the liver and many individuals experience no symptoms during the initial stage. Some experience vomiting, abdominal pain, yellow skin and dark urine.
As compared to Hepatitis C the symptoms of hepatitis B are more unpleasant. This nasty virus is spread from exposure to infected blood. There is no specific treatment for acute hepatitis B, however chronic infection can be cured with drugs.
3. Hepatitis C Virus
It is a small, enveloped, positive sense single stranded ribonucleic acid virus that belongs to family Flaviviridae, and is the cause of Hepatitis C in humans. Hepatitis C is an infectious disease and is known as the most common chronic infection that is transmitted through blood in the USA. This infection primarily affects the liver, often asymptomatic, but chronic infection causes scarring of the liver and ultimately leads to permanent and irreversible liver damage.
In some cases, those individuals with irreversible liver damage will develop liver failure, liver cancer, or lethal gastric and esophageal varices. This virus is transmitted through blood to blood contact associated with blood transfusions, piercing, intravenous drug use and contaminated medical equipment. The chronic infection can be cured with medication but unlike Hepatitis A and B, presently no vaccine has been designed that can prevent this disease.
2. Rotavirus
The virus that is commonly responsible for causing severe diarrhea among infants and young children id rotavirus. Rotavirus is a genus f double stranded RNA virus and belongs to family Reoviridae. Almost each and every child in the world has been infected with this dangerous virus at least once by the age of 5. In under developed countries, this virus is responsible for taking away the lives of over half of a million children. It mainly affects the digestive system and the main symptoms are diarrhea, many children can experience diarrhea due to some other infection.
This merciless virus spread through oral- fecal route, as this virus is capable of living a long time outside the host, therefore spread can occur by ingestion of contaminated water or food or by direct contact with infectious surfaces. A vaccine is now recommended for all kids in order to prevent this infection. Treatment of this infection depends on the symptoms, if left untreated then the children can get severe dehydrated and can even die.
1. Human immunodeficiency Virus
The human immunodeficiency virus is a lentivitus that causes the acquired immunodeficiency syndrome in humans. HIV is the most dangerous virus, this deadly virus is a blood borne that is transmitted through Intravenous drug abuse, sexual intercourse, mother to child during birth and breast feeding. HIV affects the immune system of the body and weakens it. Without a strong immune system the body faces trouble in frightening with various diseases.
AIDS is a serious condition in which there is a progressive failure of the body’s immune system occurs and it allows life threatening cancers and opportunistic infections to thrive. If this condition remains untreated, then the average survival time after this lethal infection is approximately nine to eleven years, depending on the subtype of HIV. This is the most dangerous and deadliest virus yet .
The early symptoms of HIV infection include weight loss, skin rashes, mouth ulcers and recurrent respiratory infections. Once a patient suffers from this infection, common infections and tumors that are controlled by cells, start to affect the individual.
In the latter stages, pneumonia and numerous sorts of herpes can invade the patient and cause death. This deadliest virus kills more than three million individuals each year, it has no specific and effective treatment except prevention, no vaccine is available too. This lethal infection can be cured by using anti-retroviral drugs that aid in keeping the amount of virus at a low level in the body. It results in restricting the weakening of body’s immune system and helps the patient from becoming sick for many years.
