Presentation on Adenovirus
- 1. Adenovirus Presented by: Mohammad Luqman Aditya Sarkar BBT SEM VI Adenoviridae
- 4. INTRODUCTION Adenoviruses (members of the family Adenoviridae) are medium- sized (90–100 nm), nonenveloped (without an outer lipid bilayer) viruses with an icosahedral nucleocapsid containing a double stranded DNA genome. Their name derives from their initial isolation from human adenoids in 1953. Adenoviruses are a group of viruses that can infect the membranes (tissue linings) of the respiratory tract, eyes, intestines, urinary tract, and nervous system. They are classified as Group 1(dsDNA) in the Baltimore classification of virus.
- 5. HISTORY Dr Trentin Adenoviruses were first discovered in 1953 by Wallace Rowe and his colleagues. They were isolated from adenoid tissue cell culture, hence the family name of Adenoviridae. In 1962, Dr John Trentin and his colleagues showed that human adenovirus type 12 causes cancer in baby hamsters in a laboratory setting. This was the first demonstration of oncogenic activity by a human virus. Since then, adenoviruses have been suspected in inducing human cancer but have yet to be strongly linked to it.
- 6. Contd….. Experiments involving adenoviruses, which are easy to culture and work with, have made important contributions to eukaryotic molecular biology. Adenoviruses have helped scientists understand messenger RNA splicing, alternative polyadenylation, enhancers, and protein inactivation of tumor suppressor genes.
- 7. CLASSIFICATION Adenovirus can be classified into fives genera that are Genus Aviadenovirus, Genus Mastadenovirus, Genus Atadenovirus, Genus Siadenovirus and Genus Ichtyadenovirus.
- 8. DIVERSITY Diversity of adenovirus is very complex. There are 54 types of human adenovirus comprising of seven species (A to G). • A: 12, 18, 31 • B: 3, 7, 11, 14, 16, 34, 35, 50 • C: 1, 2, 5, 6 • D: 8, 9, 10, 13, 15, 17, 19, 20, 22, 23, 24, 25, 26, 27, 28, 29, 30, 32, 33, 36, 37, 38, 39, 42, 43, 44, 45, 46, 47, 48, 49, 51, 53, 54 • E: 4 • F: 40, 41 • G: 52
- 9. GENERAL CHARACTERISTICS Adenoviruses are the group of medium sized, non enveloped ds larger DNA virus that share common complement fixing antigen. Size: 70-90nm in diameter Shape: IcosahedralLinear ds DNA molecule of 26-45 kbp long and DNA have inverted terminal repeats of approximately 100bp at both ends. Capsid is Icosahedral in shape and is composed of 292 capsomeres with 20 triangular facets and 12 vertices. The capsid consists of 240 hexons and 12 pentons.
- 10. GENOME ORGANISATION The length of adenovirus linear genome is between 26 and 45 Kbp and therefore allows the virus to theoretically carry 22 to 40 genes. Generally, this linear virus genome is about 36 Kbp in size and consists of immediate early (E1A), early (E1-E4), intermediate and late genes (L1-L5) . Transcription of these genes can be divided into early and late phase, respectively, occurring before or after DNA replication. advantageous feature of this viral genome is that it has a terminal 55 kDa protein associated with each of the 5' ends of the linear dsDNA.
- 11. LIFE CYCLE OF ADENOVIRUS
- 12. Contd… Different steps involved in replication of adenovirus 1) Attachment (Adsorption) 2) Penetration 3) Uncoating 4) Targeting 5) Gene expression. -synthesis of viral mRNA (transcription) -synthesis of viral proteins (translation) 6) Genome replication 7) Virion assembly/maturation 8) Release of new infectious virus -lysis : breakdown of cell membrane and release of virus -budding: viruses "bud" through cell membrane and are released without necessarily killing the cell.
- 13. PATHOGENESIS
- 14. EPIDEMIOLOGY The reservoir for adenovirus is in humans. Adenoviruses have a worldwide distribution, and they are ubiquitous in the environment where contamination of human feces or sewage has occurred. Most adenovirus infections are mild, fatality and a number of sequelae are associated with immunocompromised patients. Adenovirus is a very common infection, estimated to be responsible for between 2% and 5% of all respiratory infections. All ages are susceptible to adenovirus infection, but infection usually occurs during childhood. In the winter, adenovirus has caused many cases of illness in military recruits, with about 25% requiring hospitalization for fever and lower respiratory tract disease. Some cases result in death.
- 15. SIGNS & SYMPTOMS Adenoviruses can cause a wide range of illnesses such as •Common cold •Sore throat •Bronchitis (a condition that occurs when the airways in the lungs become filled with mucus and may spasm, which causes a person to cough and have shortness of breath) •Pneumonia (infection of the lungs) •Diarrhea •Pink eye (conjunctivitis) •Fever •Bladder inflammation or infection •Inflammation of stomach and intestines (gastroenteritis) •Neurologic disease (conditions that affect the brain and spinal cord)
- 16. DIAGNOSIS Polymerase chain reaction assay These can be used to identify the viral nuclear material or the viral DNA. Adenovirus has a double stranded linear DNA genome of length 36-40 kilo basepairs (kbp). Serology tests These tests utilize measures to assess the levels of the antibodies that have been generated against an active infection with adenovirus. Antigen detection The adenovirus, like other viruses, contains numerous proteins on its surface. Within the body these act as antigens against which several antibodies are formed. This helps the body to fight off an adenovirus infection
- 17. TREATMENT There is no specific treatment for people with adenovirus infection. Some antiviral drugs such as Ganciclovir, Vidarabine, Ribavirin, Cidofovir won't help adenovirus infections because these drugs only kill bacteria. Children often get over the illness on their own within a few days. Most adenovirus infections are mild and may require only care and prevention measures to help relieve symptoms .
- 18. PREVENTION Adenovirus vaccine is for U.S. military recruits entering basic training only. Adenovirus vaccine comes as two tablets, taken orally (by mouth) at the same time. The tablets should be swallowed whole, not chewed or crushed. It was used by the United States military from 1971 to 1999, but was discontinued when the only manufacturer stopped production. On March 16, 2011, the U.S. Food and Drug Administration approved an adenovirus vaccine manufactured by Teva Pharmaceuticals under contract to the U.S. Army. In its first year of use, adenovirus vaccine prevented 15,000 cases of Febrile Respiratory Illness, as evidenced by a reduction in the rate of Febrile Respiratory Illness that began soon after October 2011. There is currently no adenovirus vaccine available to the general public.
- 19. Contd... Simple steps to protect yourself from Adenovirus infection; 1. Wash your hands often with soap and water. 2. Cover your mouth and nose when coughing or sneezing. 3. Avoid touching your eyes, nose, or mouth with unwashed hands. 4. Avoid close contact with people who are sick. 5. Stay home when you are sick .