Animal viruses are self replicating, intracellular parasites that completely rely on host animal cell for reproduction. They use the host's cellular components to replicate, then leaves the host cell to infect other cells.
Animal viruses are self replicating, intracellular parasites that completely rely on host animal cell for reproduction. They use the host's cellular components to replicate, then leaves the host cell to infect other cells.
Viral classification and Types of Replication in virus Rakshith K, DVM
Precise presentation on Viral classification and Types of replication in Virus.
Entry of virus
Spread of virus
General steps in a virus replication cycle
Attachment, Penetration, Uncoating, Multiplication
Multiplication of Single-Stranded RNA (ss RNA) Viruses
Multiplication of Double-Stranded RNA (ds RNA) Viruses
Multiplication of Single-Stranded DNA (ss DNA) Viruses
Multiplication of Double-Stranded DNA (ds DNA) Viruses
Release of new virions
Common viral diseases of Bovines
General Characters and Classification of Viruses. Includes ICTV classification and Baltimore classification of viruses. A brief explanation of the Viral structure and Lifecycle.
Viral classification and Types of Replication in virus Rakshith K, DVM
Precise presentation on Viral classification and Types of replication in Virus.
Entry of virus
Spread of virus
General steps in a virus replication cycle
Attachment, Penetration, Uncoating, Multiplication
Multiplication of Single-Stranded RNA (ss RNA) Viruses
Multiplication of Double-Stranded RNA (ds RNA) Viruses
Multiplication of Single-Stranded DNA (ss DNA) Viruses
Multiplication of Double-Stranded DNA (ds DNA) Viruses
Release of new virions
Common viral diseases of Bovines
General Characters and Classification of Viruses. Includes ICTV classification and Baltimore classification of viruses. A brief explanation of the Viral structure and Lifecycle.
Concept of virology
Viruses
Types of viruses
Viral characteristics
Virion
Size and Shape
Structure
Replication
Viral Variation
Classification
Quiz
BEST OF LUCK
Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
The increased availability of biomedical data, particularly in the public domain, offers the opportunity to better understand human health and to develop effective therapeutics for a wide range of unmet medical needs. However, data scientists remain stymied by the fact that data remain hard to find and to productively reuse because data and their metadata i) are wholly inaccessible, ii) are in non-standard or incompatible representations, iii) do not conform to community standards, and iv) have unclear or highly restricted terms and conditions that preclude legitimate reuse. These limitations require a rethink on data can be made machine and AI-ready - the key motivation behind the FAIR Guiding Principles. Concurrently, while recent efforts have explored the use of deep learning to fuse disparate data into predictive models for a wide range of biomedical applications, these models often fail even when the correct answer is already known, and fail to explain individual predictions in terms that data scientists can appreciate. These limitations suggest that new methods to produce practical artificial intelligence are still needed.
In this talk, I will discuss our work in (1) building an integrative knowledge infrastructure to prepare FAIR and "AI-ready" data and services along with (2) neurosymbolic AI methods to improve the quality of predictions and to generate plausible explanations. Attention is given to standards, platforms, and methods to wrangle knowledge into simple, but effective semantic and latent representations, and to make these available into standards-compliant and discoverable interfaces that can be used in model building, validation, and explanation. Our work, and those of others in the field, creates a baseline for building trustworthy and easy to deploy AI models in biomedicine.
Bio
Dr. Michel Dumontier is the Distinguished Professor of Data Science at Maastricht University, founder and executive director of the Institute of Data Science, and co-founder of the FAIR (Findable, Accessible, Interoperable and Reusable) data principles. His research explores socio-technological approaches for responsible discovery science, which includes collaborative multi-modal knowledge graphs, privacy-preserving distributed data mining, and AI methods for drug discovery and personalized medicine. His work is supported through the Dutch National Research Agenda, the Netherlands Organisation for Scientific Research, Horizon Europe, the European Open Science Cloud, the US National Institutes of Health, and a Marie-Curie Innovative Training Network. He is the editor-in-chief for the journal Data Science and is internationally recognized for his contributions in bioinformatics, biomedical informatics, and semantic technologies including ontologies and linked data.
(May 29th, 2024) Advancements in Intravital Microscopy- Insights for Preclini...Scintica Instrumentation
Intravital microscopy (IVM) is a powerful tool utilized to study cellular behavior over time and space in vivo. Much of our understanding of cell biology has been accomplished using various in vitro and ex vivo methods; however, these studies do not necessarily reflect the natural dynamics of biological processes. Unlike traditional cell culture or fixed tissue imaging, IVM allows for the ultra-fast high-resolution imaging of cellular processes over time and space and were studied in its natural environment. Real-time visualization of biological processes in the context of an intact organism helps maintain physiological relevance and provide insights into the progression of disease, response to treatments or developmental processes.
In this webinar we give an overview of advanced applications of the IVM system in preclinical research. IVIM technology is a provider of all-in-one intravital microscopy systems and solutions optimized for in vivo imaging of live animal models at sub-micron resolution. The system’s unique features and user-friendly software enables researchers to probe fast dynamic biological processes such as immune cell tracking, cell-cell interaction as well as vascularization and tumor metastasis with exceptional detail. This webinar will also give an overview of IVM being utilized in drug development, offering a view into the intricate interaction between drugs/nanoparticles and tissues in vivo and allows for the evaluation of therapeutic intervention in a variety of tissues and organs. This interdisciplinary collaboration continues to drive the advancements of novel therapeutic strategies.
This pdf is about the Schizophrenia.
For more details visit on YouTube; @SELF-EXPLANATORY;
https://www.youtube.com/channel/UCAiarMZDNhe1A3Rnpr_WkzA/videos
Thanks...!
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
2. What are Viruses
• Small, Filterable, infectious agents
– Cannot be seen by light microscope
– Electron Microscope
• Obligatory Intracellular Parasites
– Not enough ATP by itself
3. Characteristics Of Viruses
• Genetic Material: DNA or RNA – never both!
– Single stranded (ss) or double stranded (ds)
– Linear or circular
• Capsid
– Protein subunits (shell)
– Protect the genetic material
– May be involved in cell entry
• Envelope (required for entry if present)
– Lipid, protein and carbohydrate
– Protein: viral origin
– Lipid, carbohydrate: host origin
– Involved in cell entry (located outside the capsid)
• Subunit Replication only
– Assembled after parts are made (quick log phase)
• NEVER contain enzymes for protein synthesis or ATP metabolism!!
– Always appropriate the host cell machinery
6. Virus Classification
• Based on Host Range (determined by specific receptors)
– Bacterial Viruses (Bacteriophages)
– Animal Viruses
– Plant Viruses
– Others – (amoeba, insects)
• Based on genome structure
– DNA or RNA (never both)
• ssDNA viruses
• dsDNA viruses
• ssRNA viruses
– Plus Strand (+RNA viruses)
» Same
– Negative strand (- RNA viruses)
» Complementary
– Retroviruses
» Converted into complementary DNA, then into the cell for replication
• dsRNA viruses
– Linear or circular
– Size
• 2000 to 200,000 nucleotides
7. Virus Classification (cont.d)
• Based on Shape
– Polyhedral viruses (icosahedral -20 faces, 12 vertices)
– Helical Viruses
– Complex viruses
• Based on Envelope
– Naked viruses
– Enveloped viruses
• Based on Disease caused
– Respiratory viruses
– Gastrointestinal viruses
– Sexually transmitted viruses
8. Viral Structure: Capsid
Capsid = protein coat that encloses and protects the nucleic
acid of a virus
• Accounts for most of the viral mass
• Composed of single or multiple proteins
• Each subunit = capsomeres
9. Viral Structure: Envelope
Sometimes, Capsid covered with envelope
•spikes = carbohydrate-protein complexes (glycoproteins)
that project from the envelope
• Can be used to attach to host cell
• Influenza virus causes hemagglutination – clumping
of red blood cells by use of spikes
Non-enveloped viruses/ Naked Viruses = viruses whose
capsids are not covered by an envelope
11. Virus mutations and immunity
When a virus infects a host cell:
•Host immune system produces antibodies
•Antibodies = proteins that inactivate the virus by reacting
with virus surface proteins
Stops further infection
Why you can get some viruses more than once:
• Genes that code for viral surface proteins are
susceptible to mutation
• Antibodies can’t react with the altered surface
proteins infection
• Ex) influenza; frequent mutations in its spikes
Non-neutralizing antibodies do not inhibit function
Neutralizing inhibits function
12. Viral Structure:
General Morphology
Capsid Structure determines shape:
Helical Viruses = nucleic acid is inside a hollow cylindrical
capsid with a helical structure
• Rabies, Ebola viruses, Tobacco Mosaic Virus
Polyhedral viruses = many sided; icosahedron is common
with 20 equilateral triangles as sides and 12 vertices
• Poliovirus, Adenovirus, herpes, others??
13. Viral Structure:
General Morphology
Enveloped Viruses = can be helical or polyhedral, but the
capsid is surrounded by an envelope
• Helical: influenza virus
• Polyhedral (icosahedral): Herpes simplex virus
Complex viruses = Complex structures; additional structures
attached to capsids, combos of helical and polyhedral, may
have several coats around nucleic acid
• Bacteriophage, poxviruses
15. Virus Taxonomy
International Committee on Taxonomy of Viruses (ICTV)
groups viruses based on:
• Nucleic acid type
• Mode of replication
• Morphology
Viral species = defined as a group of viruses sharing the
same genetic information and host range
• Viral species are given common names
• Ex) human herpesvirus
• The suffix –virus is used for genus names
• Ex) Simplexvirus
• Family of viruses is given the suffix –viridae
• Ex) herpesviridae
18. Isolation & cultivation of viruses
Our understanding of viruses comes mostly from
bacteriophages, as they are easily grown on bacterial
cultures
• Liquid suspensions or solid media
Plaque method for detecting & counting viruses:
1) bacteriophages are mixed with host bacteria and melted
agar, poured onto petri plate with existing layer of solid
growth medium
2) Top layer solidifies ~ one cell thick
3) After several rounds of infection, multiplication and lysis,
bacteria surrounding the virus are destroyed plaque
19. Bacteriophage lambda
on a lawn of E. coli
• Each plaque is from a single virus (theoretically)
• Number of plaques can be used to calculate
plaque forming units (PFU) in initial suspension
20. Bacterial Viruses
• Bacteriophages
• DNA and RNA viruses
– ds and ss
– Linear and circular
• Important tool
– Alternative to antibiotic therapy
• Basis to study viral replication in host cells
– Lytic cycle (lyses cell)
– Lysogenic cycle
http://www.youtube.com/watch?v=gU8XeqI7yts
It is very easy to grow viruses in bacteria, so it another reason it’s an important tool
Never marketed phage therapy because it doesn’t work too well
21. Lytic Cycle of a T-Even Bacteriophage
1
2
3
Figure 13.11
HAS TO BE A DNA VIRUS
Only infects cells with specific receptors
“syringes in”
25. Lysogeny: importance
• Lysogenic cells are immune to infection by the same phage
(but not to other phages)
• Phage conversion = tendency of host cell to exhibit new
properties when carrying lysogenic phage
• Ex) Cornyebacterium diptheriae produces toxin only
when carrying lysogenic phage diptheria
• Same is true for shiga toxin by pathogenic E. coli
• Specialized transduction = since bacterial DNA is
incorporated with phage DNA, adjacent genes on host
DNA may remain attached when phage DNA is excised for
initiation of the lytic cycle
• Introduce foreign genes into a new cell’s genome
Specialized transduction – horizontal gene transfer
26. Multiplication of Animal Viruses
• Entry
– Adsorption (not misspelled)
• Sticks to the surface
– Entry/ Penetration
– Uncoating (if capsid goes in)
• Replication/ Synthesis
• Assembly/Maturation
• Release
– Affect on host cell
DNA matures in the nucleus, RNA matures in the cytoplasm
27. Multiplication of Animal Viruses:
Attachment
• Attachment
– Virus attachment sites
• Spikes or capsid proteins
– Receptor Sites
• Proteins, glycoproteins on host cell membrane
28. Multiplication of Animal Viruses: Entry
• Endocytosis
– Pinocytosis (unseen)
• Plasma membrane folds inward into vesicles
– Receptor mediated Endocytosis (creates own
vesicles)
• Influenza virus
• Fusion (membranes are the same)
– Viral envelope fuses with cell membrane
31. Multiplication of Animal Viruses: Uncoating
• Separation of nucleic acid from protein capsid
– Capsid digested by host enzymes
– Viral proteins synthesized to uncoat
• poxviruses
32. Replication/Biosynthesis/Maturation/Release:
DNA viruses
• Gene expression in most viruses
– Stage specific
– Temporal Cascade
• DNA viruses
– DNA shuttled to host nucleus
– EARLY Gene transcription
• Uses host RNA polymerase
• mRNA shuttled to protein translation sites in cytoplasm
• Viral Enzymes (proteins) shuttled back to nucleus
– Viral DNA replication
• Viral DNA polymerase replicates DNA
– LATE gene expression
• Uses host RNA polymerase
• mRNA shuttled to protein translation sites in cytoplasm
• Viral structural proteins Proteins shuttled back to nucleus
– VIRIONS assembled, shuttled back to cytoplasm
– Trafficked via ER, Golgi, to Cell membrane for release
“Too much detail, I just need you to remember
that some genes are expressed before
replication, some are expressed after. It just
depends on when it needs that expression.”
33. It’s acidity is what causes the endosome to fuse with the envelope
and release the capsid
budding
35. RNA viruses
• Multiplication is same as that of DNA viruses except
mechanisms of how mRNA is generated
• Four nucleic acid types of RNA viruses
• Single (+) strand of RNA
• Ex) picornaviridae, togaviridae
• Single (–) strand of RNA
• Ex) rhaboviridae
• Double stranded RNA
• Ex) reoviridae
• “Reverse transcriptase” RNA (retroviruses)
• Ex) retroviridae
+ transcription - translation +
- strand makes message, so
- stays -
- Strand will make one part (like capsid)
+ will make other part (like the RNA)
Prophage – bacteriophage DNA incorporated???
Provirus – any other virus DNA incorporated???
RNA polymerase is more
likely to make errors than
DNA polymerase
36. Avian Influenza
Clinical Focus, p. 371
Antigenic drift – mutations in how it looks
Antigenic shift – so many mutations, very virulent, no antibodies to fight it
38. Multiplication of Animal Viruses:
Release
Non-enveloped viruses = released from host through ruptures
in plasma membrane host cell death
Enveloped viruses = the envelope develops around the capsid
by budding: virus takes portion of plasma membrane as it
pushes through it to extracellular space
• Doesn’t immediately kill host cell
40. Viruses and Cancer
Oncogenic viruses (cancer generating) = viruses capable of
inducing tumors in animals (aka oncoviruses)
• ~10% of cancers induced by viruses
Oncogenes = parts of the genome that cause cancer when
mutated; expressed at high levels in tumor cells
Transformation = viral genetic material integrates into host
DNA and replicates with it (like bacterial lysogeny)
• Used by all oncogenic viruses
Oncolytic – viruses that grow in and lyse cancer cells
41. DNA oncogenic viruses
Herpesviridae
•Epstein Barr virus causes infectious mononucleosis
- remains latent in some throat and blood cells
throughout life
various lymphomas (Hodgkin’s, Burkitt’s)
Papovaviridae
•all uterine (cervical) cancers are caused by human
papillomavirus
Hepadnaviridae (Hep B) & Flaviviridae (Hep C)
•hepatitis B and C can cause liver cancer
42. RNA oncogenic viruses
• ONLY the retroviridae family of RNA viruses cause
cancer
Human T-cell leukemia viruses 1 & 2 = cause adult T-cell
(white blood cell) leukemia and lymphoma
Mechanism of tumor generation:
Viral reverse transcriptase generates the double
stranded viral DNA (provirus) that integrates into the
host chromosome
• Changes in genetic material always put the cell at
risk for tumor formation
Know oncogenic viruses and diseases with them
43. Latent viral infections
Viruses may infect host cells but cause disease only after a
long period of time = latent infections
All human herpesviruses can remain in host cells for a
person’s lifespan, until reactivation:
• Immune suppression (ex: AIDS)
• Fever, sunburn (cold sores from herpes simplex)
•Reactivation may never occur no symptoms
Chronic can be latent or persistant
44. Persistent viral infections
Persistent (chronic) viral infections occur gradually over a
long period of time
• Infectious virus builds up over time, rather than
appearing suddenly (like latent infections)
• Typically fatal
Example:
Subacute sclerosing panencephalitis (SSPE) = a
progressive, debilitating, and deadly brain disorder
• Caused by immune resistant measles
• No cure; may be managed with medication
Remember this one
45. Figure 13.21
Latent and Persistent Viral
Infections
Peaks, looks like it will go away, then spikes (can be lethal)
46. Prions
Prions = proteinaceous infectious particles
• No nucleic acid, just purely protein
• Cause infections diseases - neurological
• Bovine spongiform encephalophathy (mad cow)
• Creutzfeldt-Jakob disease (CJD)
• Gerstmann-Straussler-Sheinker syndrome
Run in families, indicating genetic component
not purely genetic:
Eating infected meat transmits mad cow
CJD transmitted via transplanted nerve tissue
Only killed by formaldehyde, very resistant
KNOW ALL PRIONS
48. Plant viruses and viroids
Plant viruses = similar in morphology and nucleic acid types to
animal viruses
Common crop viruses:
- Bean mosaic virus
- Wound tumor virus
corn and sugarcane
- Potato yellow dwarf virus
Must penetrate cell wall by:
- Wounds
- Parasites
Ex) aphids that eat sap
Result = color change, deformed/stunted growth, wilting
Only destructive
49. Plant viruses and viroids
Infected plant spreads virus via pollen and seeds
viroids = short pieces of RNA with no protein coat
• Known to cause some plant diseases
• Pathogens of plants only
• Potato spindle tuber viroid
Prions are only protein
Viroids are only RNA
54. DNA virus families
Papovaviridae = named for the papillomas (warts)
polyomas (tumors) and vacuolation (development of
cytoplasmic vacuoles)
• Genus papillomavirus causes warts
- HPV: cervical cancer and cauliflower-like growths
in cervix
- Vaccine: Gardasil
• Polyomavirus diseases primarily affect the
immunocompromised tumors
55. DNA virus families
Hepadnaviridae = named for their role in causing hepatitis
and containing DNA
• Only one genus causes hepatitis B
• The other hepatitis viruses (A,C,D,E,F,G) are RNA
viruses
Hepatitis = inflammation of liver
• Hep B is similar to Hep C (an RNA virus)
• Both transmitted through blood
- Associated with intravenous drug use
• Cirrhosis, liver failure, liver cancer
• Vaccine for Hep B, no vaccine for Hep C!
56. RNA viruses
Picornaviridae = small (-pico) and contain RNA
• Single stranded RNA viruses
Important genera:
Rhinovirus = responsible for >50% of common colds
Enterovirus = fecal oral transmission
poliovirus, coxsackie virus (aseptic meningitis)
Hepatovirus = only species in the genus causes Hep A
• Fecal-oral transmission
• Contaminated food or water
• Primarily affects less developed countries
• Replication: mucosa intestine liver
• Symptoms: fever, nausea, diarrhea, jaundice
• Prevention: vaccine
57. Togaviridae are enveloped (toga = covering)
• Like picornaviruses, have a single strand of RNA
Important genera:
Rubivirus = only member is rubella virus
• Part of MMR vaccination series
• Rubella = (latin: little red) aka german measles
- Itchy red rash
- Swollen glands, fever
• Transmission: respiratory droplets
• Treatment: none, usually subsides in days
- Less severe than measles (rubeola virus)
RNA viruses
58. RNA viruses
Paramyxoviridae = enveloped viruses with spikes
• single stranded RNA viruses
Important genera:
Rubulavirus = contains the species Mumps virus
• Transmitted by respiratory droplets
• Was common before MMR vaccine (1960s)
• Symptoms: fever, headache, muscle aches, tiredness
- swelling of parotid (salivary) glands!
- Orchitis = swelling of testicles (~30% of males)
59. RNA viruses
Rhabdoviridae = bullet-shaped viruses with a single strand
of RNA
• ~150 viruses of vertebrates,
invertebrates and plants
Lyssavirus = genus that contains the
species rabies virus
• Transmission: animal bite
• Salivary glands highly concentrated with virus
• Spreads from muscle cells into CNS
• Fatal if not treated prior to severe symptoms
60. RNA viruses
Orthomyxoviridae = enveloped helical viruses with a
single strand of RNA
Influenza virus = three genera (A,B,C) that cause influenza,
a contagious respiratory illness
Symptoms: cough, sore throat, aches, fatigue
and serious complications:
- Pneumonia
- Bronchitis
- Worsening of chronic health problems
TEM of H1N1 Influenza
62. RNA viruses
Reoviridae = respiratory, enteric, orphan
• Affect gastrointestinal system, respiratory tract
• Double-stranded RNA viruses
Rotavirus = genus in family reoviridae
• Most common cause of severe diarrhea
among infants and children
Fecal-oral transmission
• 2009: included into U.S. recommended
vaccination program by W.H.O.
Stylized SEM: rotavirus
63. RNA viruses
Retroviridae = reverse transcriptase viruses
• Reverse transcriptase = uses viral RNA as template to
produce double-stranded DNA
• integrated into host chromosome provirus
- protected from host immune system & antivirals
- Replicates with host DNA
- Can be expressed to produce new virions and infect
adjacent cells
Human Immunodeficiency virus (HIV)
• Infects immune cells, progresses to AIDS
• No cure: hard to target latent infected cells