Viral Diseases and Immune Response Overview

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary purpose of organizing viral diseases by clinical manifestations?

To standardize treatment protocols for all viral infections

To recognize patterns in disease presentation and management (correct)

To classify viruses based on their genetic material

To understand the laboratory techniques used to diagnose viruses

Which of the following factors does NOT influence susceptibility to viral diseases?

Immune status

Host genetics

Environmental conditions

Viral replication speed (correct)

What is a critical characteristic of inflammation in response to viral infections?

Symptoms such as redness, heat, swelling, and pain (correct)

Immediate destruction of the virus

Presence of white blood cells only

Complete absence of pain

Which structural component distinguishes viruses from other pathogens?

Nucleic acids and protein coats Signup and view all the answers

What role do T-cells and B-cells play in the immune response to viral infections?

They are involved in both innate and adaptive immune responses Signup and view all the answers

How does host-pathogen interaction influence the outcome of viral infections?

Complex interactions determine susceptibility and disease outcome Signup and view all the answers

Which of the following resources serves as a foundational text for veterinary virology?

Fenner's Veterinary Virology, 4th edition Signup and view all the answers

What aspect of viral taxonomy is critical for understanding relationships among viral pathogens?

Organizing by species and viral family Signup and view all the answers

Which method is primarily used for propagating influenza A viruses?

Embryonated eggs Signup and view all the answers

What is a key characteristic of continuous cell cultures?

Propagated indefinitely Signup and view all the answers

What is the significance of mycoplasma contamination in viral research?

It alters cellular characteristics Signup and view all the answers

Which purification technique involves separating viruses from debris using differences in sedimentation rates?

Differential centrifugation Signup and view all the answers

What storage condition is most suitable for long-term preservation of viruses?

-70°C or liquid nitrogen Signup and view all the answers

Cytopathic effects in infected cells can include which of the following?

Rounding and aggregation Signup and view all the answers

Which assay involves adding red blood cells to virus dilutions to assess viral activity?

Hemagglutination assay Signup and view all the answers

What is essential for accurate viral diagnostics?

Proper specimen collection and submission Signup and view all the answers

Sensitivity to lipid solvents is utilized to identify which type of viruses?

Enveloped viruses Signup and view all the answers

Which method is NOT commonly used for virus visualization?

Fluorescence in situ hybridization (FISH) Signup and view all the answers

Which step of viral replication involves the release of the viral genome and often requires host proteins?

Uncoating Signup and view all the answers

What is the primary way in which enveloped viruses exit the host cell?

Budding Signup and view all the answers

During which stage of the viral replication cycle is the host cell's ribosomes utilized?

Protein synthesis Signup and view all the answers

What characterizes the genome of most RNA viruses?

They are typically linear and mostly single-stranded. Signup and view all the answers

Which of the following statements about viral attachment is true?

It determines tissue tropism. Signup and view all the answers

Which type of viral genome is typically replicated in the nucleus?

DNA genomes Signup and view all the answers

What mechanism do naked virions use to leave the infected host cell?

Cell lysis Signup and view all the answers

What aspect of RNA viruses complicates their replication process?

Ambisense RNA characteristics Signup and view all the answers

What can a viral infection lead to in host cells under certain conditions?

Cytopathology or malignant transformations Signup and view all the answers

Which of these statements regarding viral entry is correct?

Receptor-mediated endocytosis is one method of entry. Signup and view all the answers

Which of the following mechanisms helps enveloped viruses avoid the host immune response?

Acquisition of an external envelope Signup and view all the answers

What role does genome size play in distinguishing RNA viruses from DNA viruses?

DNA viral genomes can exceed 300,000 nucleotides. Signup and view all the answers

Which of the following is a common outcome of viral infections that can lead to enhanced spread of the virus?

Development of syncytia Signup and view all the answers

What aspect of viral release can vary based on the type of virus?

Release mechanisms can influence pathogenicity. Signup and view all the answers

What is a significant feature used in laboratories to identify certain viral infections, such as RSV?

Syncytia formation Signup and view all the answers

How does the intracellular location of viruses impact treatment efforts?

It complicates treatment due to reduced visibility to immune cells. Signup and view all the answers

What determines the susceptibility of cells to viral infections?

Surface receptors on host cells Signup and view all the answers

What is the term for the viral preference for specific tissues or cell types?

Tropism Signup and view all the answers

Which immune response can lead to chronic inflammation and tissue damage due to viral infections?

Viral-induced immunopathology Signup and view all the answers

What role do interferons play in the context of viral infections?

They halt viral replication and boost immune recognition. Signup and view all the answers

How do some viruses evade the immune system effectively?

By infecting immunologically privileged sites. Signup and view all the answers

What is a common characteristic of chronic-carrier infections?

They persist in the host without causing immediate harm. Signup and view all the answers

What classification system categorizes viruses based on their replication strategies?

Baltimore classification system Signup and view all the answers

What does the suffix '-viridae' indicate in virus family names?

Their family classification Signup and view all the answers

What is a characteristic of viruses in the order Mononegavirales?

Negative-sense, single-stranded RNA genomes Signup and view all the answers

What term describes the process of a virus maintaining its genome in a dormant state within host cells?

Latency Signup and view all the answers

What is the significance of understanding viral replication mechanisms?

It allows for better vaccine development and treatment strategies. Signup and view all the answers

What structural feature distinguishes helical viruses from icosahedral viruses?

Helical viruses have a tubular structure, while icosahedral viruses have a cubic shape. Signup and view all the answers

Which type of viral protein primarily mediates interactions between the virus and host cells?

Glycoproteins Signup and view all the answers

How do nonenveloped viruses differ from enveloped viruses regarding stability?

Nonenveloped viruses can withstand ice crystal damage, whereas enveloped viruses cannot. Signup and view all the answers

What is a primary challenge in applying Koch’s postulates to viruses?

Some viruses cannot be cultured in vitro, complicating their study. Signup and view all the answers

Which viral disease is caused by the Herpesviridae family?

Feline Viral Rhinotracheitis Signup and view all the answers

What defines a complex virus structure?

Complex viruses have a head and tail structure and do not fit simple classifications. Signup and view all the answers

In what way do viral envelopes influence infectivity?

Envelope proteins can be targeted by antiviral drugs to reduce infectivity. Signup and view all the answers

What type of viral genome can only be partially double-stranded?

Partially double-stranded DNA Signup and view all the answers

What is a characteristic of naked helical viruses?

No known human or animal viruses exhibit this structure. Signup and view all the answers

Which of the following is a non-structural protein function in viruses?

Mediating genome transcription Signup and view all the answers

What is the primary role of capsid proteins in viruses?

Packaging the viral genome Signup and view all the answers

How does Bovine Viral Diarrhea affect cattle?

Leads to severe gastrointestinal disease. Signup and view all the answers

Which property differentiates viral capsids from other cellular structures?

Capsids are made up of protein subunits. Signup and view all the answers

Which viral family is associated with causing respiratory symptoms in horses?

Herpesviridae Signup and view all the answers

What primarily characterizes enveloped viruses concerning their interaction with the environment?

They are sensitive to lipid solvents and detergents. Signup and view all the answers

Which disease is primarily caused by Feline Herpesvirus?

Feline Viral Rhinotracheitis Signup and view all the answers

What significant concept did Robert Koch contribute to microbiology?

Koch's postulates Signup and view all the answers

Which viral disease in horses is transmitted by insects and can lead to severe anemia?

Equine Infectious Anemia Signup and view all the answers

What is one of the requirements of Koch's postulates for establishing a viral infection?

The virus must be grown in vitro in living cells Signup and view all the answers

Which theory posits that many diseases are caused by microorganisms?

Germ Theory of Disease Signup and view all the answers

What is the primary mechanism of release for non-enveloped viruses from host cells?

Lysis Signup and view all the answers

Which viral family is characterized by having a double-stranded DNA genome?

Herpesviridae Signup and view all the answers

In the context of viral replication, which step follows uncoating?

Multiplication Signup and view all the answers

Which type of viral genome is typically characterized as positive-sense RNA?

It can directly serve as mRNA. Signup and view all the answers

What characteristic distinguishes enveloped viruses from non-enveloped viruses regarding stability?

They are sensitive to heat, detergents, and solvents. Signup and view all the answers

Study Notes

Organization of Viral Diseases

Viral diseases can be organized by species, viral family, or affected systems for a structured approach to study.
Understanding the taxonomy of viruses can help identify relationships and similarities among viral pathogens.
Grouping by clinical manifestations can aid in recognizing patterns in disease presentation and management.

Basics of Inflammation and Immune Response

Inflammation is a critical response to viral infections, characterized by redness, heat, swelling, and pain.
The immune response involves both innate and adaptive mechanisms, including the activation of T-cells and B-cells.

Host-Pathogen Relationships

Host-pathogen interactions are complex and can determine the outcome of viral infections.
Factors such as host genetics, immune status, and environmental conditions influence susceptibility to viral diseases.
Viruses can manipulate host cellular machinery to enhance their replication and spread, leading to disease.

General Characteristics of Viruses

Viruses are smaller than prokaryotic and eukaryotic cells, requiring host cells for replication.
They possess a simple structure, typically consisting of a nucleic acid genome and a protein coat (capsid).
Some viruses have an envelope derived from host cell membranes, which aids in infection.

Koch’s Postulates and Viral Infections

Koch’s postulates provide a framework for establishing a causal relationship between a virus and a disease.
Challenges in applying Koch’s postulates to viruses include the inability to culture some viruses in vitro and the presence of asymptomatic carriers.

Types of Virions and Capsid Symmetry

Helical Viruses: Characterized by a tubular structure; most have an outer envelope.
- Naked Helical: Tobacco mosaic virus, notable for its lack of an envelope; no known human or animal viruses exhibit this structure.
- Enveloped Helical: Includes rhabdoviruses and paramyxoviruses, which possess an outer lipid envelope.
Icosahedral Viruses: These can be isometric or cubic and may or may not have an envelope.
- Naked Icosahedral: Adenoviruses and picornaviruses, which lack an envelope.
- Enveloped Icosahedral: Togaviruses and flaviviruses, which have an outer lipid layer.
Complex Viruses: These do not conform to the helical or icosahedral structures.
- Examples include bacteriophages and poxviruses, which may have a head and tail structure.

Capsid Geometric Shapes

Icosahedral Structure: Characteristic of several viral families, including naked (picornaviruses, polyomaviruses) and enveloped (herpesviruses).
Helical Structure: Can be naked (tobacco mosaic virus) or enveloped (rabies virus).
Complex Structures: Mixtures of arrangements, such as those seen in bacteriophages and poxviruses.
Size Variation: Viruses vary significantly in size, from circoviruses at 17-22 nm to poxviruses approaching 300 nm, which can be observed under a light microscope.

Example of Icosahedral Symmetry

Adenovirus: Approximately 90 nm in size, serves as a model for understanding icosahedral symmetry.
Classification of Structures: Different icosahedral structures are classified based on their symmetry, although detailed knowledge of these classifications is not essential for basic understanding.

Viral Envelope and Properties

Characteristics of Viral Envelopes
- Origin of Envelope: The envelope's origin depends on the virus and the cellular compartment where replication occurs.
- Composition: Composed of a lipid bilayer with viral proteins, primarily glycoproteins that are virus-encoded.
- Role of Envelope Proteins: Antiviral drugs targeting envelope proteins can reduce virus attachment and infection, thus decreasing infectivity.
- Impact on Host Cells: The release of many virions can compromise the host cell membrane, potentially leading to cell death.

Biological and Physico-Chemical Properties

Characteristic	Nonenveloped Virus	Enveloped Virus
Ultraviolet radiation	Sensitive	Sensitive
Gamma radiation	Sensitive	Sensitive
Thermostability	Thermostable	Thermolabile
Susceptibility to ice crystal damage	Yes	Extensive
Inactivation by lipid solvents	Yes	No

Viral Proteins and Genomes

Types of Virus-Encoded Proteins
- Structural Proteins: Include capsid and genome packaging proteins; in some enveloped viruses, a protein layer (tegument) exists between the capsid and envelope.
- Glycoproteins: Processed in the rough endoplasmic reticulum, these proteins mediate interactions between virions and host cells, making them targets for neutralizing antibodies.
- Non-structural Proteins: Primarily enzymes involved in genome transcription, replication, and protein processing. An example is reverse transcriptase in retroviruses.

Characteristics of Viral Genomes

DNA Genomes: Can be single-stranded (ss), double-stranded (ds), or partially double-stranded. Examples include parvoviruses (ss) and herpesviruses (ds).
RNA Genomes: Typically linear; most are single-stranded, with a few being double-stranded. RNA viruses can be monopartite or segmented, with varying segment numbers.
Genome Size: RNA virus genomes are generally smaller (up to 30 kb), while DNA virus genomes can reach up to 300,000 nucleotides.

Viral Replication Process

Steps of Viral Replication
- Attachment: Involves receptor-ligand interactions, determining species specificity and cell type.
- Penetration: Internalization of the nucleocapsid via receptor-mediated endocytosis or fusion with the plasma membrane.
- Uncoating: The viral genome is released, often requiring host proteins.
- Multiplication: The viral genome is replicated, with most viruses encoding their own replication enzymes.
- Translation: Host cell machinery translates viral mRNA into proteins, dedicating resources to viral product synthesis.
- Assembly: Complete virus particles are assembled, with nonenveloped viruses forming nucleocapsids from genome and capsid proteins.
- Release: Newly formed virions are released from the host cell, often leading to cell death.

Variations in Replication

The replication process can vary significantly based on the type of nucleic acid and its structure.
Not all attachment events lead to productive infections, highlighting the complexity of viral-host interactions.

Overview of Viral Structure and Release Mechanisms

Viral Structure and Envelope Acquisition
- Virions are composed of a nucleocapsid that can acquire an external envelope from various cellular membranes (nuclear, Golgi, endoplasmic reticulum, or plasma membranes).
- The process of acquiring an envelope is crucial for enveloped viruses, allowing them to evade the host immune response.
- Non-enveloped viruses typically rely on lysis for release, while enveloped viruses can exit through budding, which is a more controlled process.
Mechanisms of Viral Release
- Enveloped viruses exit the host cell by budding, which allows them to take a portion of the host membrane, thus disguising themselves.
- Naked virions exit through lysis, which can lead to cell death and inflammation, contributing to disease symptoms.
- The site of budding can affect the course of infection; for example, apical budding can lead to respiratory or genital secretions, while basal budding can result in systemic spread.

Viral Entry and Replication Cycle

Steps of Viral Replication: The viral replication cycle consists of several key steps: attachment, penetration, uncoating, protein synthesis, genome replication, maturation, and release.
- Attachment: Involves specific receptor-ligand interactions, which determine the host range and tissue tropism of the virus.
- Penetration: Can occur via receptor-mediated endocytosis or direct fusion with the plasma membrane, leading to the virus's entry into the cytosol.
- Uncoating: Is the process where the viral nucleocapsid is disassembled, often requiring host factors, allowing the viral genome to be expressed.
- Protein synthesis: Involves the host's ribosomes translating viral mRNA into proteins, which are essential for new virion assembly.
- Genome Replication: Varies based on the type of nucleic acid (DNA or RNA) and its structure, with most viruses encoding their own replication enzymes.

Viral Genome Characteristics

DNA viruses typically replicate in the nucleus, with exceptions like poxviruses that replicate in the cytoplasm.
RNA viruses generally replicate in the cytoplasm and do not rely on nuclear machinery, with notable exceptions such as retroviruses.
The genome of RNA viruses can be monopartite (single molecule) or multipartite (segmented), affecting their replication strategies.
Positive-sense RNA can be directly translated into proteins, while negative-sense RNA must first be transcribed into positive-sense RNA by viral polymerases.
Ambisense viruses possess both positive and negative-sense RNA, complicating their replication process.

Pathogenesis and Cellular Impact of Viral Infections

Mechanisms of Pathogenesis: Pathogenesis refers to the origination and development of disease, with viral infections classified as acute, chronic, latent, or persistent.
- Viruses can enter the host through various portals, including the respiratory tract, alimentary tract, and skin breaches, influencing susceptibility.
- The interaction between viral and host cell processes can lead to cell death, decreased host cell function, and cytopathology.
- Some viruses induce the formation of syncytia, which are multinucleate giant cells formed by the fusion of infected cells, aiding in viral spread.
- Viral infections can lead to malignant transformations in host cells, with specific DNA and RNA viruses associated with oncogenesis.

Cellular Responses to Viral Infections

Infected cells may exhibit normal function, cell death, or cytopathology, depending on the virus and host response.
Cytopathology can include the formation of inclusion bodies, which are aggregates of viral proteins or particles within infected cells.
Syncytia formation is a diagnostic feature for certain enveloped viruses, such as RSV, and is used in laboratory settings to identify infections.
The disruption of cellular homeostasis by viruses can lead to significant physiological changes and disease symptoms.
The immune response to viral infections can be hindered by the intracellular location of viruses complicating treatment efforts.

Viral Pathogenesis

Susceptibility and Infection Types: The susceptibility of cells to viruses is primarily determined by the presence and type of surface receptors on the host cells, which facilitate viral entry.
- Infections can be classified as localized (affecting a specific area) or disseminated (spreading throughout the body), with tropism indicating the preference of a virus for specific tissues or cell types.
Mechanisms of Disease: Viral infections can lead to tissue or organ dysfunction, which may manifest as various clinical symptoms depending on the extent of cellular damage.
- Environmental and host factors, such as preexisting immunity, genetics, age, and stress, significantly influence the outcome of viral infections.
- Disease can arise from direct effects of the virus, such as cell death and cytopathic effects (CPE), or from indirect effects mediated by the host's immune response.

Immune Response and Pathology

Viral-induced immunopathology refers to tissue damage caused by the immune response to the virus, including interactions like antibody-antigen complexes and cytotoxic T cell activity.
The immune response can lead to chronic inflammation and tissue damage, as seen in conditions like Borna disease in horses, where the immune response to infected neurons causes neurological symptoms.
An example of an indirect physiological response is rotavirus infection, which leads to diarrhea through cytokine-mediated stimulation of enteric neurons.

Host Defenses Against Viral Infections

Immune System Components: The host's defense mechanisms include physical barriers, non-specific immune responses, and specific adaptive immunity involving antibodies and T cells.
- Interferons (α and β) play a critical role in halting viral replication and enhancing the recognition of infected cells by cytotoxic T cells.
- Cytotoxic T lymphocytes kill infected cells by releasing perforins and granzymes, leading to apoptosis of the host cell.

Evasion of Host Defenses

Viruses have evolved various strategies to evade the immune system, such as infecting immunologically privileged sites and exhibiting antigenic variability.
Some viruses reduce MHC class I expression on infected cells, making them less recognizable to T cells, while still being targeted by natural killer cells.
The presence of multiple serotypes for certain viruses, like rhinovirus, complicates immune responses and vaccine development.

Chronic Infections and Their Characteristics

Types of Chronic Infections:
- Chronic-carrier infections, such as those caused by equine arteritis virus, can persist in the host without causing immediate disease.
- Latent infections (herpesviruses), involve the maintenance of the viral genome in a dormant state within host cells, often neurons.
- Slow virus infections (subacute sclerosing panencephalitis following measles), have a prolonged asymptomatic phase before disease onset.

Virus Taxonomy and Classification

Classification Schemes: Viruses are classified based on various features, including structure, nucleic acid type (DNA or RNA), and morphology.
- The International Committee on the Taxonomy of Viruses (ICTV) provides a dynamic classification system that includes orders, families, genera, and species.
- The Baltimore classification system categorizes viruses based on their replication strategies and the nature of their genetic material.

Characteristics of Viral Families

Key characteristics for classifying viral families include nucleic acid type, virion morphology, host range, and immunological properties.
For example, the order Mononegavirales includes viruses with negative-sense, single-stranded RNA genomes, highlighting the importance of genome organization in classification.
Understanding the replication mechanisms of different virus types, such as dsDNA and +sense RNA viruses, is essential for developing targeted treatments.

Overview of Virus Taxonomy

The International Committee on the Taxonomy of Viruses (ICTV) is responsible for the classification and naming of viruses.
Viruses are classified into orders, families, genera, and species, with examples such as Mononegavirales (order), Rhabdoviridae (family), Vesiculovirus (genus), and Vesicular stomatitis virus (species).
Virus family names conventionally end with the suffix '-viridae', indicating their classification.
Taxonomy is based on various characteristics including morphology, location, lesions, and enzymes.

Morphological and Functional Classification

Virus morphology includes terms like corona (crown), rhabdo (rod), and toga (cloak), which describe the physical structure of the virus.
Location-based terms include adeno (gland), entero (gut), and rhino (nose), indicating where the virus is typically found in the host.
Lesion-related terms such as pox (poxvirus) and flavi (yellow fever virus) describe the symptoms or lesions caused by the virus.
Enzymatic classifications include retro (reverse transcriptase), which is crucial for understanding viral replication mechanisms.

Viruses: Isolates and Strains

Viruses within a species are categorized into isolates and strains.
Isolates are grouped by antigens into subtypes or serotypes.
A strain is a specific isolate that is well-defined and often used in vaccine development.
Sequencing technology confirms the identity of new viruses.

Viral Propagation Methods

Viral propagation is essential for isolating, characterizing, and identifying viruses.
Common methods include using host animals, embryonated eggs, and cell/tissue cultures.

Host Animals and Embryonated Eggs

Host animals are used for viruses that do not grow well in cell cultures.
Embryonated eggs are historically significant for virus propagation and remain the preferred method for influenza A and many avian viruses.

Cell and Tissue Culture Techniques

Explant cultures involve small tissue fragments from the host.
Primary cell cultures are derived from fresh tissues and have limited lifespan.
Continuous cell cultures can be propagated indefinitely, facilitating large-scale virus growth.

Virus Concentration and Purification

Virus purification involves cleaning up host cells and debris.
Techniques include differential centrifugation, dialysis, and chromatography.

Storage Conditions for Viruses

Long-term storage methods include freezing at -70°C or in liquid nitrogen (-196°C).
Lyophilization is used for room temperature storage.

Virus Visualization and Enumeration

Electron microscopy and atomic force microscopy visualize viruses and changes in infected cells.
Cytopathic effects (CPE) can be observed in infected cells.

Indirect Enumeration Methods

Hemagglutination assays involve adding red blood cells to virus dilutions to observe agglutination.
The plaque-forming assay estimates viral concentration by counting clear zones (plaques) formed in host cell cultures.

Characterization Techniques

Sensitivity to lipid solvents helps identify enveloped viruses.
Nucleic acid type identification is performed using synthesis inhibitors.

Diagnostic Approaches

Diagnostic methods include virus isolation, ELISA, PCR, and virus neutralization tests.
Proper specimen collection and submission are critical for accurate diagnostics.

Viral Diseases in Animals

Feline Viral Rhinotracheitis (FVR) is caused by Feline Herpesvirus, leading to respiratory issues in cats.
Canine Parvovirus is a highly contagious virus causing severe gastrointestinal disease in dogs.
Rabies is a viral disease affecting the central nervous system, often transmitted through bites from infected animals.
Feline Infectious Peritonitis (FIP) is a serious viral disease caused by a mutation of Feline Coronavirus.
Equine Infectious Anemia is a viral disease in horses that can lead to severe anemia and is transmitted by insects.

Key People in Microbiology

Robert Koch pioneered microbiology by formulating Koch's Postulates, essential for linking pathogens to diseases.
Louis Pasteur developed the principles of vaccination and pasteurization, making significant contributions to microbiology and immunology.

Fundamental Theories in Microbiology

Germ Theory of Disease states that many diseases are caused by microorganisms.
Viral Theory of Cancer proposes that certain viruses can cause cancer in animals and humans.

Seminal Studies in Virology

The Tobacco Mosaic Virus Study discovered the first virus, leading to the understanding of viruses as filterable agents.
The Rabies Vaccine Development by Louis Pasteur demonstrated the principles of immunization.

Koch's Postulates for Viral Infection:

The virus must be present in every case of the disease.
The virus must be grown in-vitro in living cells.
The disease must be reproduced when a pure culture of the virus is inoculated into a healthy susceptible host.
The virus must be recovered again from the experimentally-infected host.

Viral Genome Types:

DNA: single-stranded (ss) or double-stranded (ds)
RNA: positive-sense or negative-sense

Basic Steps of Viral Replication:

Attachment
Penetration
Uncoating
Multiplication
Translation
Assembly
Release

Common Viral Families and Characteristics:

Herpesviridae: enveloped, dsDNA
Paramyxoviridae: enveloped, ssRNA
Retroviridae: enveloped, ssRNA with reverse transcriptase
Picornaviridae: non-enveloped, ssRNA

Enveloped vs. Non-enveloped Viruses:

Enveloped Viruses have a lipid bilayer with viral proteins, are sensitive to heat, detergents, and solvents, and are released by budding from the host cell. Examples: HIV, Influenza, Herpes Simplex.
Non-enveloped Viruses have only a protein capsid, are more stable and resistant to environmental factors, are released by lysis of the host cell, and have less complex immune evasion strategies. Examples: Adenovirus, Poliovirus.

Differential Diagnosis of Viral Infections:

Gather Clinical Signs: Collect all relevant clinical signs presented by the animal.
Consider Signalment: Take into account the species, age, and sex of the animal.
Review Epidemiology: Look at the history of exposure to potential viral sources.
Analyze Pathology: Consider any laboratory findings or pathological changes observed in tissues.
Prioritize Diagnoses: Based on the information gathered, prioritize potential viral infections that match the clinical picture.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz explores the organization of viral diseases by taxonomy and clinical manifestation, along with the basics of inflammation and immune response. Understand the complex relationships between hosts and pathogens, and how these interactions influence viral infections.