Viral Diseases 4-H Veterinary Science Extension Veterinary Medicine Texas AgriLife Extension Service College of Veterinary Medicine and Biomedical Sciences.
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Viral Diseases
4-H Veterinary ScienceExtension Veterinary Medicine
Texas AgriLife Extension ServiceCollege of Veterinary Medicine and Biomedical Sciences
Texas A&M Systemhttp://aevm.tamu.edu
Objectives
Describe pox diseases List and describe common viral respiratory
diseases Describe viral abortion diseases Describe meningitis and encephalitis Describe hepatitis Describe anemia
Background
Remember Five infectious diseases
Bacterial Viral Fungal Parasitic Rickettsial
Infectious disease An illness due to a specific infectious agent or its
toxic products that arises through transmission of that agent or its products from an infected person, animal or reservoir to a susceptible host, either directly or indirectly
Viruses
Viruses An ultra-microscopic micro-organism, parasitic
within living cells and of which many can cause disease. They consist of a strand of nucleic acid (DNA or RNA) that contains genetic instructions concerning viral reproduction that is enveloped by a protein coat
Not alive nor dead, has DNA or RNA, makes copies of itself, must be inside a living cell
Antibiotics have no affect Treatment is to easy symptoms
Vaccines available Entrance of virus into cell is “viral infection”
Virus uses cell structures to replicate new viruses
Animal viruses look like Capsid
Outer shell Core
Surrounds genetic material Envelope
Kind of life skin around outside of virus Lipid bilayer (membrane)
Genetic material
Function Make more viruses
Harmful Replication leads to cell death Takes over cell function
How exit cell Budding
Few at a time Lysis
Cell membrane ruptures
All living things can be affected Animals People Plants
Infectivity Single species
Humans – smallpox 1-2 Species
Influenza Particular kind of plant
Tobacco mosaic virus Particular species of bacteria
Lambda bacteriophage – E.coli
Different kinds of viruses Double-stranded DNA Single-stranded DNA Double-stranded RNA Single-stranded RNA Retroviruses
Unique kind of single-stranded RNA virus
Can mutate Kill virus Make new-strain
Infectivity The characteristic of a disease agent that
embodies capability of entering, surviving in, and multiplying in a susceptible host
Basically How efficiently it invades specific animal’s tissues
Specificity Its ability to infect certain animal species and
tissues
Symptoms Depend on tissue affected
Skin Blood Liver Uterus Fetus Brain Lungs Stomach Intestines Bloodstream (viremia)
Phase of the disease
Exposure – symptoms Recent exposure
Normal incubation period Long ago exposure
Replicate/multiply immediately May become dormant Recrudesces
After stressful event
After incubation period may exhibit symptoms
General Conditions Hepatitis
Infectious canine hepatitis (ICH) Causes
Liver inflammation Viremia
Affects liver, kidneys, spleen and lungs Not zoonotic Symptoms
Decreased appetite Appear depressed Fever Opacity of one or both corneas of their eyes (so-called ‘Blue Eye’)
one to two weeks later Respiratory signs
Eye and nose discharge Cough
Prevention Vaccine (puppy)
Anemia Systemic viral disease Transmitted
Vectors Vehicles
Symptoms Fever Anemia Weight loss Abortion
Examples Equine Infectious Anemia (EIA) Bluetongue – cattle Leukosis – cattle Malignant catarrhal fever - cattle
Skin Warts
Definition Fibrous tumors of the skin and occasionally the
mucous membranes Species affected
Animals Cattle, dogs, rabbits
Humans Transmission
Direct contact Arthropods
Symptoms Cauliflower-type growths
Head Neck Shoulder Mouth Vulva Penis
Vaccine available
Pox Definition
Acute skin condition caused by replication of poxviruses in the skin
Transmission Direct transmission (through skin) Arthropods (vectors)
Types of lesions Bumps Blisters Pustules Crusts
Named after affected animals
Fowl Pox
Fowl Pox
Swine Pox
Cow Pox
Respiratory System
Pneumonitis; Pneumonia Contagious infection of the lungs and causes severe
damage to the lung Causes
Hemorrhages Edema Emphysema
Bacteria can complicate Symptoms
Cough Fever Heavy breathing Lethargy Decreased appetite
Viral respiratory diseases Infectious Bovine Rhinotracheitis (IBR) Bovine Parainfluenza-3 (PI³) Equine Rhinopneumonitis Equine Influenza Swine Influenza Canine Infectious Tracheobronchitis (Kennel Cough) Canine Distemper Feline Viral Rhinotracheitis (FVR) Feline Calicivirus (FCV) Fowl Infectious Bronchitis Fowl Infectious Laryngotracheitis (LT) Fowl Influenza
Reproductive System
Abortion Viruses terminate pregnancy by attacking
Fetus Embryo Placenta Uterus
Examples Swine parvovirus Infectious bovine rhinotracheitis (IBR) Bovine viral diarrhea (BVD) Swine pseudorabies Equine rhinopneumonitis
Nervous System
Meningitis Definition
Inflammation of the brain covering (meninges)
Encephalitis Definition
Inflammation of the brain tissue
Causes damage to brain tissues
Digestive System
Gastroenteritis Affects
Stomach Intestines
Highly contagious Symptoms
Vomiting Diarrhea
More severe in young Dehydration and electrolyte imbalance
Types Rotavirus Coronavirus Parvovirus Feline panleukopenia Bovine viral diarrhea (BVD) Swine transmissible gastroenteritis (TGE)
Summarize
Viral condition Affects System
Encephalitis Brain Nervous
Hepatitis Liver General
Anemia Blood General
Abortion Fetus Reproductive
Meningitis Meninges Nervous
Gastroenteritis Stomach, intestine Gastrointestinal
Pneumonitis Lungs Respiratory
Warts Skin Skin
Meningoencephalitis Symptoms
Depression Blindness Partial or complete paralysis Wobbling Seizures Coma Delirium
Vaccination is important No treatment
Types Rabies Equine encephalomyelitis
VEE, WEE, EEE Canine distemper Parvovirus Swine pseudorabies
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