However, most infections with these types do not cause disease. HIV can be transmitted sexually, via contaminated needles or blood transfusions, and from mother to child during pregnancy, birth or breast-feeding.
The primary navigation template for this category is AIDS. Encephalitis literally means an inflammation of the brain, but it usually refers to brain inflammation caused by a virus. Although several thousand cases of encephalitis also called acute viral encephalitis or aseptic encephalitis are reported to the Centers for Disease Control and Prevention CDC every year, experts suspect that many more may go unreported because the symptoms are so mild. The yellow fever virus is transmitted by the bite of female mosquitoes the yellow fever mosquito, Aedes aegypti, and other species and is found in tropical and subtropical areas in South America and Africa, but not in Asia.
The only known hosts of the virus are primates and several species of mosquito. The origin of the disease is most likely to be Africa, from where it was introduced to South America through the slave trade in the 16th century.
Since the 17th century, several major epidemics of the disease have been recorded in the Americas, Africa and Europe. In the 19th century, yellow fever was deemed one of the most dangerous infectious diseases. Hepatitis is an inflammation of the liver, most commonly caused by a viral infection. These five types are of greatest concern because of the burden of illness and death they cause and the potential for outbreaks and epidemic spread.
In particular, types B and C lead to chronic disease in hundreds of millions of people and, together, are the most common cause of liver cirrhosis and cancer. Hepatitis A and E are typically caused by ingestion of contaminated food or water. Hepatitis B, C and D usually occur as a result of parenteral contact with infected body fluids.
Common modes of transmission for these viruses include receipt of contaminated blood or blood products, invasive medical procedures using contaminated equipment and for hepatitis B transmission from mother to baby at birth, from family member to child, and also by sexual contact. Acute infection may occur with limited or no symptoms, or may include symptoms such as jaundice yellowing of the skin and eyes , dark urine, extreme fatigue, nausea, vomiting and abdominal pain.
Herpes viruses are a leading cause of human viral disease, second only to influenza and cold viruses. They are capable of causing overt disease or remaining silent for many years only to be reactivated, for example as shingles.
The name herpes comes from the Latin herpes which, in turn, comes from the Greek word herpein which means to creep. This reflects the creeping or spreading nature of the skin lesions caused by many herpes virus types. There are at least 25 viruses in the family Herpesviridae. Eight or more herpes virus types are known to infect man frequently. Rotavirus is the most common cause of severe diarrhoea among infants and young children, and is one of several viruses that cause infections often called stomach flu, despite having no relation to influenza.
It is a genus of double-stranded RNA virus in the family Reoviridae. By the age of five, nearly every child in the world has been infected with rotavirus at least once. However, with each infection, immunity develops, and subsequent infections are less severe; adults are rarely affected. The virus is transmitted by the faecal-oral route. It infects and damages the cells that line the small intestine and causes gastroenteritis.
In addition to its impact on human health, rotavirus also infects animals, and is a pathogen of livestock. The destructive power of computer viruses can make them weapons of mass digital destruction, and Stuxnet became the first one.
Spread via a USB thumb drive, it targeted Siemens industrial control systems, causing centrifuges to mysteriously fail and self-destroy at a record rate. The engineers did a remarkable job.
In , the year it appeared, Stuxnet was believed to be the most sophisticated cyberweapon ever deployed. CryptoLocker is not like a typical computer virus that causes harm and spreads itself. CryptoLocker used a trojan disguised as a PDF file that was spread through email attachments. If there is a flaw in the system, somewhere down the line, it will undoubtedly be exploited. Conficker, Downup, Downadup, Kido - these are all computer virus names that appeared on the internet in It used the MS Windows system vulnerability and advanced malware techniques to propagate and install itself into the system.
These techniques included copying itself to shared folders and exploiting the AutoRun utility for removable media. Despite its wide distribution and the hassle caused to get rid of it, the worm itself did not cause much damage. Tinba is the pet name for the Tiny Banker Trojan that hit the headlines in As the name suggests, its main target was financial institution websites. Account numbers, usernames, passwords , credit card numbers, PIN codes - all of these were stolen to later hack into bank accounts.
Its success lies in its tiny size 20KB and ways of spreading. Clicking on a website pop-up, downloading software from an unreliable source, or just opening an infected link could lead to getting infected with Tinba. Viruses can also be created to serve ethical purposes. Welchia or the Nachi worm is one of those. Once the job was done - Welchia took itself down. Yet, it had a weak spot: the ethical virus slowed computers down.
As a result, Welchia caused a nine-hour delay in processing and issuing visas by the US State Department. It also consumed three-quarters of Navy-Marine Corps capacity, rendering it useless for some time.
When it comes to contracting a computer virus , Windows machines dominate the market. Actually, quite the opposite was proved by the Shlayer Trojan. When launched, it ran a series of shell scripts to proliferate various adware or potentially unwanted applications. There are three different virus types that are made distinct by their shape. The cylindrical helical virus type is associated with the tobacco mosaic virus. Envelope viruses, such as influenza and HIV come covered in a protective lipid envelope.
Most animal viruses are classified as icosahedral and are nearly spherical in shape. The viruses within these categories share similar characteristics. Viruses are also the most abundant biological form of life on the planet. The first thing a virion does is enter a cell and becomes a virus. Next, it reproduces, creating viral protein and genetic material instead of the usual cellular products.
A virus can then spread through a wide variety of means, such as touching, coughing and sneezing. The body fights viruses by breaking down the viral genetic material via RNA interference. The immune system then produces antibodies that bind to viruses to make them noninfectious. Lastly, T cells are sent to destroy the virus.
Antiviral drugs can treat viruses by inhibiting viral development and slowing down disease progression. These drugs help fight the flue, chickenpox and forms of hepatitis. Vaccines create a herd immunity that helps prevent an outbreak.
There are five different types of viruses: Conjugate vaccines, inactivated vaccines, live, attenuated vaccines, subunit vaccines and toxoid vaccines. There are several ways people can slow the spread of a virus in lieu of drugs or vaccination. These include thorough and frequent hand washing, eating a fruit and vegetable-rich diet, using an alcohol-based sanitizer and getting enough sleep each night.
Around the world, nurses contribute to the prevention, management and containment of viral outbreaks by caring for infected patients and educating the public on prevention strategies.
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