Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Elsayed Elsayed Wagih wikipedia , lookup
Neonatal infection wikipedia , lookup
Taura syndrome wikipedia , lookup
Hepatitis C wikipedia , lookup
Human cytomegalovirus wikipedia , lookup
Canine distemper wikipedia , lookup
Influenza A virus wikipedia , lookup
Canine parvovirus wikipedia , lookup
Marburg virus disease wikipedia , lookup
Hepatitis B wikipedia , lookup
Lymphocytic choriomeningitis wikipedia , lookup
Viruses Virus: A non-cellular particle composed of genetic material that can invade living cells. – Viruses are considered by some to be nonliving since they lack metabolism and are not made of cells. • Are extremely small • Are usually very specific as to what cells they can invade Structure of a Virus: • Contain core of genetic information (either DNA or RNA). • Genetic material surrounded by a protein coat called a capsid. Virus Shapes Two Virus Cycles Lytic & Lysogenic Cycles Life Cycles of viruses Lytic infection: Infection: Virus identifies an attaches itself to a host cell. The genetic material is then injected into the host cell. – Growth: Genetic material of virus overrides host cell's activities. Cell is now instructed to replicate viral genetic material and protein coats. – Lysis: Cell is lysed "broken open" and new viruses are released to infect other cells. This kills the host cell Life Cycles of viruses: Lysogenic infection • Similar to lytic infection however important differences exist – Instead of immediately replicating, viral DNA incorporates itself into the host cell's DNA. – Will remain dormant for significant amounts of time. – Give certain conditions, the virus will enter it's lytic phase similar to a normal lytic infection Retroviruses • A new form of virus has been identified known as a retrovirus. – Retroviruses are RNA viruses which can conduct a process known as Reverse Transcription • In reverse transcription RNA is used to make DNA (the reverse of the normal RNA transcription process). – HIV is a retrovirus. Viral Immunity • Viruses are neutralized by special chemical weapons called antibodies. • Antibodies are specific to a single virus strain. • Once a virus has been encountered your body can remember that virus and will quickly produce more antibodies to prevent a second infection. • Immunizations/vaccination involves injecting a killed or weakened virus into your body. This tricks your body into producing antibodies to the virus. Therefore, when you come into contact with the real virus, your body can prevent an infection. Antibodies attacking a virus Killer / Dangerous Viruses HIV •Human immunodeficiency virus (HIV) is a retrovirus that can lead to acquired immunodeficiency syndrome (AIDS), a condition in humans in which the immune system begins to fail, leading to life-threatening opportunistic infections. •Infection with HIV occurs by the transfer of blood, semen, vaginal fluid, pre-ejaculate, or breast milk. •The most common mode of transmission of HIV is unprotected heterosexual sex. HIV Contd. •HIV infection in humans is now pandemic. As of 2006, the Joint United Nations Program on HIV/AIDS and the World Health Organization estimate that AIDS has killed more than 25 million people since it was first recognized in December 1, 1981, making it one of the most destructive pandemics in recorded history •HIV is believed to infect 90 million people in Africa, resulting in a minimum estimate of 18 million orphans. HIV Infection Rates: Global HIV Infection Rates: Africa Ebola / Marburg Viruses Ebola is the common term for a group of viruses belonging to genus Ebolavirus, and for the disease which they cause, Ebola hemorrhagic fever. The virus is named after the Ebola River where the first recognized outbreak of ebola hemorrhagic fever occurred. The viruses are characterized by long filaments and have a similar shape to the Marburg virus.. Since its discovery, Ebolavirus has been responsible for thousands of deaths. Ebola Continued •The virus is believed to be transmitted to humans via contact with an infected animal host. The virus is then transmitted to other people who come into contact with infected blood and bodily fluids of the infected person •Ebola hemorrhagic fever is potentially lethal and encompasses a range of symptoms including fever, vomiting, diarrhea, generalized pain or malaise, and sometimes internal and external bleeding. Mortality rates are extremely high, with the human case-fatality rate ranging from 70–95%, depending on viral subtype. Hanta Virus Hantaviruses belong to the Bunyaviridae family of viruses.. Viruses in the genus Hantavirus are unique in that they are transmitted by aerosolized rodent excreta or rodent bites Hantavirus pulmonary syndrome (HPS) is a deadly disease transmitted by infected rodents through urine, droppings, or saliva. Humans can contract the disease when they breathe in aerosolized virus. HPS is potentially deadly. Rodent control in and around the home remains the primary strategy for preventing hantavirus infection. Dengue Dengue fever is caused by four closely related viruses of the genus Flavivirus. The geographical spread is similar to malaria, but unlike malaria, dengue is often found in urban areas. Dengue is transmitted to humans by the Tiger mosquito (Aedes aegypti ). Tiger Mosquito Dengue & the Tiger Mosquito Dengue Symptoms Dengue is manifested by a sudden onset of with severe headache, muscle and severe joint pains giving it the name break-bone fever. There may also be gastritis with some combination of associated abdominal pain, nausea, vomiting or diarrhea. Other symptoms include •fever; •chills; •constant headaches; •bleeding from nose, mouth or gums; •severe dizziness; and, •loss of appetite.