Itp-Lecture-Viruses.Pdf
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2018-09-07 Viruses, important viral diseases and how to fight them Mikael Berg Professor in Veterinary Virology Secon of Virology Department of Biomedical Sciences and Veterinary Public Health Faculty of Veterinary Medicine and Animal Science Swedish University of Agricultural Sciences hps://www.slu.se/cv/mikael-berg/ Outline of the lecture Short overview of the nature of viruses Examples of viral diseases of veterinary importance How to fight them: 1) Vaccines 2) AnEvirals 3) Prevenon measures Summary and conclusions African swine fever viral parEcle 1 2018-09-07 Viruses in the Marine Environment The estimated 1031 viruses in the ocean, if stretched end to end, would span farther than the nearest 60 galaxies. However, most viruses do not harm us Are some even good for us? Enormous multitude of different animal viruses Some are very species specific-others have a few host and some have multiple hosts Every animal species has its own set of viruses and diseases Some are zoonotic Different shapes, complexity of genetic material, and variation between “same virus” Divided into families Very few functional vaccines and antiviral drugs RNA genomes DNA genomes 2 2018-09-07 THE NATURE OF VIRUSES Some historical aspects The word virus originates from latin and means poison or irritating substances Pioneering studies on tobacco mosaic virus 3 2018-09-07 From Fenner´s Veterinary Virology How do viruses look like? We need electron microscope to see them; Sizes range from 15-300 nanometer (normally) Rhabdovirus Human influensa Adenovirus Ebolavirus Arenavirus Coronavirus Detailed structure of a virus on the molecular level 4 2018-09-07 Basic variants of virus structures Virus relative sizes Also bacteria can be infected by viruses So can also plants and all other living organisms.. 5 2018-09-07 Viruses need a living cell to mulply (cannot mulply in meat/dead animals/food/feed/materials) How are viruses transmitted in nature Horisontally: Indirectly: vectors (insects), aerosol (some very effectively FMDV), water, food/feed, transports, tools, clothes, people handling animals etc Directly: close physical contact Vertically: From mother to offspring Differences in stability in the environment 6 2018-09-07 Extremely stable in various materials Food products Water Dead animals Feces Important viral diseases Foot-and-mouth disease- a viral disease of economical importance For example the outbreak in UK 2001 costed corresponding to 65 billion SEK Endemic in many countries 7 2018-09-07 Dreaded animal viral diseases-high mortality Rinderpest Important historical viral disease of cattle Eradicated since 2011 African swine fever Peste des petits ruminants (PPR) Now called Small ruminant morbillivirus (SRMV) Now in Europe 8 2018-09-07 Common colds https://www.youtube.com ”food/feed poisoning” Lots of important diseases caused by viruses Veterinary importance: Foot-and mouth disease African Swine fever Newcastle disease Peste-des-petits ruminants Avian influenza Bluetongue Rift valley fever Lumpy skin disease Human inportance: Aids Influenza Measles Hepatitis Zoonotic viruses: Rabies West Nile Nipah/Hendra Avian influenza Ebola 9 2018-09-07 From OIE (Office Internaonal des EpizooEes or World Organisaon for Animal Health ) Another list From Fenner´s Veterinary Virology Flaviviridae: The major arboviral families of Genus Flaviviridae veterinary significance JE serocomplex (JE, WN, Zika) TBE serocomplex (Kyasanur forest disease) Reoviridae: Bunyavirales Genus Orbivirus Peribunyaviridae: Bluetongue serogroup (1-27) Genus Orthobunyavirus EpizooEc hemorrhagic disease serogroup Akabane, Aino, Schmallenberg African horse sickeness serogroup Palyam serogroup (Kasba, Chuzan) Phasmaviridae: Equine encephalosis serogroup Genus phlebovirus Eubenangee serogroup Rif valley virus Togaviridae: Nairoviridae: Genus Alphavirus Genus Orthonairovirus Eastern equine encephaliEs virus (EE), WEE, VEE, Getah Nairobi sheep disease Rhabdoviridae: Genus vesiculovirus VSV AsFarviridae: Genus Asfivirus-African swine fever virus 10 2018-09-07 From Fenner´s Veterinary Virology How can we fight viruses? What about vaccines? A number of concepts More later… 11 2018-09-07 What about anvirals? Only a few in use (not in animals) Resistance problems Can other prevenon meassures minimize the viral spread? Knowledge on virus nature; how do they spread, how stable in various materials etc More later… 12 2018-09-07 In conclusion 1) Viruses are the most abuntant life form 2) They need living cells to mulply 3) Many important diseases are caused by viruses 4) Vaccines are good but very few 5) AnEvirals are not in use for animals, and generally very few 6) PrevenEon meassures good way to control viruses 13 .