2018-09-07
Viruses, important viral diseases and how to fight them
Mikael Berg Professor in Veterinary Virology Sec on of Virology Department of Biomedical Sciences and Veterinary Public Health Faculty of Veterinary Medicine and Animal Science Swedish University of Agricultural Sciences h ps://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) An virals
3) Preven on measures
Summary and conclusions African swine fever viral par cle
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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
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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
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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
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Basic variants of virus structures
Virus relative sizes
Also bacteria can be infected by viruses
So can also plants and all other living organisms..
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Viruses need a living cell to mul ply (cannot mul ply 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
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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
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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
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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
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From OIE (Office Interna onal des Epizoo es or World Organisa on 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 Epizoo c hemorrhagic disease serogroup Akabane, Aino, Schmallenberg African horse sickeness serogroup
Palyam serogroup (Kasba, Chuzan) Phasmaviridae: Equine encephalosis serogroup Genus phlebovirus Eubenangee serogroup Ri valley virus
Togaviridae: Nairoviridae: Genus Alphavirus Genus Orthonairovirus Eastern equine encephali s virus (EE), WEE, VEE, Getah Nairobi sheep disease
Rhabdoviridae: Genus vesiculovirus VSV
Asfarviridae: Genus Asfivirus-African swine fever virus
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From Fenner´s Veterinary Virology
How can we fight viruses?
What about vaccines?
A number of concepts
More later…
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What about an virals?
Only a few in use (not in animals) Resistance problems
Can other preven on meassures minimize the viral spread?
Knowledge on virus nature; how do they spread, how stable in various materials etc
More later…
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In conclusion
1) Viruses are the most abuntant life form 2) They need living cells to mul ply 3) Many important diseases are caused by viruses 4) Vaccines are good but very few 5) An virals are not in use for animals, and generally very few 6) Preven on meassures good way to control viruses
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