RNA Viruses - Microbiology - Lecture Slides, Slides of Microbiology

Download RNA Viruses - Microbiology - Lecture Slides and more Slides Microbiology in PDF only on Docsity! The RNA Viruses Chapter 25 Electron microscope Docsity.com Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. TABLE 25.1 RNA Viruses RNA Viruses Enveloped Nonenveloped Single-stranded Single-stranded genome Single-stranded Double-stranded genome encodes reverse genome genome ranscrii transcriptase = —~_ ; | I | Segmented Non-segmented genome Retroviruses Picornaviruses | |/\(/\ Reoviruses genome —* Calciviruses Orthomyxoviruses Paramyxoviruses Togaviruses @ © Bunyaviruses Arenaviruses Rhabdoviruses Filoviruses Tae Coronaviruses Docsity.com Shift and Drift Yearly variations in the “Seasonal Flu” are the result of antigenic drift. Docsity.com 2009 H1N1...”swine flu” timates Reported by State and Territorial Epidemiologists* Week Ending August 29, 2009- Week 34 Seep oS aa %, al Alaska Hawaii Us Virgin Islands Puerto Rico ; This map indicates geographic spread and does not measure the severity of influenza acti 2009 H1N1...”swine flu” lance Report Prepared by the Influenza Division mates Reported by State and Territ Epidemiologists* Week Ending September 19, 2009- Week 37 Alaska Hawaii us Virgin Islands Puerto Rico *This map indicates geographic spread and does not measure the severity of influenza activity. 3 Docsity.com “WW Ilance Report Prepared by the Influenza Division stimates Reported by State and Territorial Epidemiologists* Week Ending January 2, 2010- Week 52 > District of Columbia LI No Report sa . > x, ne Alaska Hawaii US Virgin Islands Puerto Rico *This map indicates geographic spread and does not measure the severity of influenza activity. 23 Docsity.com AVY Ilance Report Prepared by the Influenza Division imates Reported by State and Territorial Epidemiologists* Week Ending May 22, 2010- Week 20 > District of Columbia CO No Report Hawaii US Virgin Islands Puerto Rico his map indicates geographic spread and does not measure the severity of influenza activi Influenza type A • acute, highly contagious respiratory illness • seasonal, pandemics • among top 10 causes of death in US • respiratory transmission • binds to ciliated cells of respiratory mucosa • causes rapid shedding of cells, stripping the respiratory epithelium, severe inflammation • fever, headache, myalgia, pharyngeal pain, shortness of breath, coughing • treatment: amantadine, rimantadine, zanamivir & oseltamivir • annual vaccine Docsity.com Avian Flu Why would “Bird Flu” be a big deal? Pandemic viruses appear as the result of antigenic shift, which causes new combinations of proteins on the surface of the virus. If the new virus spreads easily from person to person a pandemic can result. Docsity.com Avian Flu Docsity.com Avian Flu aby STH (aS PW ee cs UCL LT Teg cae eg PEM ar Pek OT ee EMU RU Ca tts Docsity.com NOVA Science NOW Pandemic flu video (2006) http://www.pbs.org/wgbh/nova/scienc enow/3302/04.html Docsity.com Paramyxoviruses • enveloped ssRNA – Paramyxoviruses (parainfluenza, mumps virus) – Morbillivirus (measles virus) – Pnuemonovirus (respiratory syncytia virus) • respiratory transmission • virus causes infected cells to fuse with neighboring cells – syncytium or multinucleate giant cells form Docsity.com Giant Cell Fusion of cells allows passage of virus directly between cells Docsity.com Copyright @ The McGraw-Hill Gompanies, inc, Permission required for reproduction or display Parotitis- inflammation and swelling of parotid salivary glands a 26 How Iowa Got The Mumps How Iowa Got the Mumps • In 2006 Iowa got the mumps. Over 2000 individuals got mumps infection in the first half of 2006 (in a normal year there are on avergae 5 cases per year) • Probably originated … in the UK? Docsity.com Measles • caused by Morbillivirus • also known as red measles & rubeola • different from German measles • very contagious • transmitted by respiratory aerosols • humans are the only reservoir • less than 100 cases/yr in US • virus invades respiratory tract • sore throat, , dry cough, headache, conjunctivitis, lymphadenitis, fever, Koplik spots – oral lesions • rash Docsity.com oe (a) Signs of measles Koplik’s spots (b) Docsity.com measles • most serious complication is subacute sclerosing panencephalitis (SSPE), a progressive neurological degeneration of the cerebral cortex, white matter & brain stem • 1 case in a million infections • involves a defective virus spreading through the brain by cell fusion & destroys cells • leads to coma & death in months or years • attenuated viral vaccine MMR Docsity.com RSV respiratory syncytial virus • also called Pneumonvirus • infects upper respiratory tract & produces giant multinucleate cells • most prevalent cause of respiratory infection in children 6 months or younger; Very young are most susceptible to serious disease • epithelia of nose & eye portal of entry • replicates in nasopharynx • rhinitis, wheezing, otitis, croup • treatment: Synagis (a monoclonal antibody that blocks attachment), ribavirin Docsity.com Rabies Reported Cases of Rabies, 2001  RNA Viruses GS Skunk os! 5 Fox G@ Raccoon Docsity.com Coronavirus • relatively large RNA viruses with distinctively spaced spikes on their envelopes • common in domesticated animals • 3 types of human coronaviruses have been characterized – HCV causes a cold – an enteric virus – Severe Acute Respiratory Syndrome (SARS) Docsity.com Coronavirus- SARS Global Spread… Feb 21,2003 …infected medical doctor from Guangdong Province spent a night at a Hong Kong hotel. 12 people staying at or visiting that floor of the hotel became infected. These travelers then dispersed the disease to other countries worldwide Docsity.com SARS Dispersal Superspreaders 144 of Singapore’s 206 cases linked to contact with just 5 individuals Docsity.com Palm civets (SARS reservoir??) Did the SARS epidemic start in Guangdong Province, China as a “civet meal”? Water rat at a market Masked Palm Civet at market Docsity.com Rubella • postnatal rubella – malaise, fever, sore throat, lymphadenopathy, rash, generally mild • congenital rubella – infection during 1st trimester most likely to induce miscarriage or multiple defects such as cardiac abnormalities, ocular lesions, deafness, mental & physical retardation Docsity.com Arboviruses • viruses that spread by arthropod vectors – mosquitoes, ticks, flies, & gnats • More than 400 viruses spread this way • Viruses of many families: togaviruses, flaviviruses, some bunyaviruses & reoviruses • most illnesses caused by these viruses are mild fevers, but some cause severe encephalitis • Examples: dengue fever, western- & eastern equine encephalitis, yellow fever Docsity.com ‘Copyright® The McGraw-Hill Gorpanies, Inc. Perrnission required for reproduction of display, ‘Crimean fever ‘Omsk fever fever ‘ 5 Murray % Valley encephalitis Ross 9 i West Nile fever iu River (outlined areas) oe fever Yellow fever WEE Western equine encephalitis Dengue fever EEE Easter equine encephalitis St. Louis encephalitis VEE Venezuelan equine encephalitis Japanese encephalitis —* Shows relatively restricted distribution & Arboviruses . Docsity.com Aedes aegypti mosquito @ Areas of dengue a6 Range of Aedes La - (b) rigurHeedity.com West Nile • It is estimated that about 20% of people who become infected with WNV will develop West Nile fever. • Symptoms include fever, headache, tiredness, and body aches, occasionally with a skin rash (on the trunk of the body) and swollen lymph glands. • illness can be as short as a few days, but even healthy people have reported being sick for several weeks. • About 1 out of 150 infected people develop serious disease. Encephalitis. Meningitis. • Incubation period 2-15 days Docsity.com West Nile Virus-1999-2001 West Nile Virus in the United States, 1999-2001 GS 1999-2001 HB 2000-2001* Fvermont eoored E333 Pattern indicates human cases 2001 utnot in Docsity.com West Nile Virus — 2005 (Jan 11" HB indicates human disease case(s). ra [J avian, animal or mosquito infections. nH[_ | nal] er] ce bE] np oc wy] Puerto Rico Docsity.com West Nile Virus - Life Cycle chat ae be ey atest cla ‘ \ Utes ULE De tt a ey ; v7 Docsity.com Picorna Viruses Hepatitis A – causes short-term hepatitis – fecal-oral transmission – inactivated viral vaccine (HAVRAX) Rhinovirus – 110 serotypes – Most common cause of “the common cold” Polio Docsity.com Polio • inactivated polio vaccine (IPV) Salk vaccine • oral polio vaccine (OPV) Sabin vaccine, attenuated virus (no longer used in US) • WHO had a goal of eradicating polio by 2005 – ~1,300 cases in 2004 (worldwide) • No natural cases of polio in Americans since 1991 – At the height of the polio epidemic in 1952, nearly 60,000 cases with more than 3,000 deaths were reported in the United States alone. Docsity.com Reports of naturally occurring polio in 2009 Figure 25.3 Docsity.com Reoviruses • nonenveloped, segmented dsRNA viruses • Reovirus – – not a significant human pathogen – may cause upper respiratory disease similar to common cold • Rotavirus – – globally causes 50% of cases of diarrhea & death of over 600,000 children – common but usually mild in US Docsity.com Copwigt 2 2008 Pearse Education ubsing a Baran Cummings. @ ANC] LOH 2. Ebola virus ORI 22 OIVH yet CPocsity.com) Hanta Virus [a Bunyavirus (RNA virus)] Hanta virus is found worldwide (including the US). The virus is spread by human contact with rodent waste. Dangerous respiratory illness (Hantavirus Pulmonary Syndrome) develops. Effective treatment is not yet available and over 50% of cases end in fatality. Docsity.com Retroviruses • enveloped, ssRNA viruses • encode reverse transcriptase enzyme which makes a DNA copy of their RNA genome • Human Immunodeficiency Virus (HIV) the cause of Acquired Immunodeficiency Syndrome (AIDS) • HIV-1 & HIV-2 • Also T-cell lymphotropic viruses I & II – which can cause leukemia Docsity.com HIV • attacks the T helper cells & macrophages • first signs of AIDS are opportunistic infections such as Pneumocystis carinii pneumonia (PCP) and cancers such as Kaposi sarcoma Docsity.com Copyright @ The McGraw-Hill Companies, Inc, Permission required for reproduction of display aposi sarcoma of arm Docsity.com Copyright © The McGraw-Hill Companies, Inc, Permission required for reproduction or display Viral diseases * HIV encephalopathy * Progressive multifocal leukoancephalopathy * Shingles, recurrent (herpes zoster) * Cytomegalovirus retinitis * Recurrent herpes simplex lesions * Hairy leukoplakia (Epstein-Barr virus) Fungal diseases * Cryplococcosis * Pneumocystis pneumonia * Candidiasis * Histoplasmosis, disseminated * Coccidioidomycosis, disseminated Protozoan diseases Toxoplasmosis « ‘Chronic Cryptosporidium diarrhea * Chronic /saspora diarrhea « i? cir tT Bacterial diseases = + Persistent pneumonia _ Cancers i was * Tuberculosis Lymphomas of brain, glands, | * Mycobacterium aviurn complex, disseminated lymphatic tissue « * Salmonella septicemia Kaposi's sarcoma + : * Persistent pelvic inflammatory disease (PID) Invasive cervical cancer * A Miscellaneous conditions Persistent diarrhea + Persistent generalized lymphadenopathy + Wasting syndrome * Night sweats « Persistent fever + Docsity.com HIV replication 1. HIV attaches to cells with the correct receptor (CD4 receptor) 2. HIV fuses with cell membrane, reverse transcriptase makes a DNA copy of RNA 3. viral DNA is integrated into host chromosome (provirus) 4. can produce a lytic infection or remain latent Docsity.com ‘Copyright The McGraw: Hil Companies, Ina. Permission requited tor seprodantion or dleplay, CD4 receptor Coreceptor an ‘on white white blood cell blood cell . (b) Docsity.com Progression of HIV disease • initial infection – mononucleosis-like symptoms that soon disappear • asymptomatic phase 2-15 years (ave. 10) • antibodies are detectable 8-16 weeks after infection • HIV destroys the immune system • when T4 cell levels fall below 200/µL symptoms appear including fever, swollen lymph nodes, diarrhea, weight loss, neurological symptoms, opportunistic infections & cancers Docsity.com