Viral Diseases 4 H Veterinary Science Extension Veterinary

Viral Diseases 4 -H Veterinary Science Extension Veterinary Medicine Texas Agri. Life Extension Service College of Veterinary Medicine and Biomedical Sciences Texas A&M System http: //aevm. tamu. edu

Objectives n Describe pox diseases n List and describe common viral respiratory diseases n Describe viral abortion diseases n Describe meningitis and encephalitis n Describe hepatitis n Describe anemia

Background n Remember n Five infectious diseases n n n Bacterial Viral Fungal Parasitic Rickettsial

n Infectious disease n 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 n 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 n Not alive nor dead, has DNA or RNA, makes copies of itself, must be inside a living cell

n Antibiotics have no affect n Treatment is to easy symptoms Vaccines available n Entrance of virus into cell is “viral infection” n n Virus uses cell structures to replicate new viruses

n Animal viruses look like n Capsid § Outer shell n Core § Surrounds genetic material n Envelope § Kind of life skin around outside of virus § Lipid bilayer (membrane) n n Genetic material Function n Make more viruses

n Harmful n n n Replication leads to cell death Takes over cell function How exit cell n Budding § Few at a time n Lysis § Cell membrane ruptures

n All living things can be affected n Animals n People n Plants n Infectivity n Single species § Humans – smallpox n 1 -2 Species § Influenza n Particular kind of plant § Tobacco mosaic virus n Particular species of bacteria § Lambda bacteriophage – E. coli

n Different kinds of viruses n n n Double-stranded DNA Single-stranded DNA Double-stranded RNA Single-stranded RNA Retroviruses § Unique kind of single-stranded RNA virus n Can mutate n n Kill virus Make new-strain

n Infectivity n The characteristic of a disease agent that embodies capability of entering, surviving in, and multiplying in a susceptible host n Basically n How efficiently it invades specific animal’s tissues

n Specificity n Its ability to infect certain animal species and tissues

n Symptoms n Depend on tissue affected n Skin n Blood n Liver n Uterus n Fetus n Brain n Lungs n Stomach n Intestines n Bloodstream (viremia) § Phase of the disease

n Exposure – symptoms n Recent exposure n n Normal incubation period Long ago exposure n Replicate/multiply immediately § May become dormant § Recrudesces § After stressful event n After incubation period may exhibit symptoms

General Conditions n Hepatitis n Infectious canine hepatitis (ICH) n Causes § Liver inflammation § Viremia § Affects liver, kidneys, spleen and lungs n n 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 n Prevention § Vaccine (puppy)

n Anemia n n Systemic viral disease Transmitted n n n Symptoms n n n Vectors Vehicles Fever Anemia Weight loss Abortion Examples n n Equine Infectious Anemia (EIA) Bluetongue – cattle Leukosis – cattle Malignant catarrhal fever - cattle

Skin n Warts n Definition n Fibrous tumors of the skin and occasionally the mucous membranes n Species affected n Animals § Cattle, dogs, rabbits n n Transmission n Humans Direct contact Arthropods Symptoms n Cauliflower-type growths § § § n Head Neck Shoulder Mouth Vulva Penis Vaccine available

n Pox n Definition n Acute skin condition caused by replication of poxviruses in the skin n Transmission n Direct transmission (through skin) n Arthropods (vectors) n Types of lesions n Bumps n Blisters n Pustules n Crusts n Named after affected animals

Fowl Pox Swine Pox Fowl Pox Cow Pox

Respiratory System n Pneumonitis; Pneumonia n n Contagious infection of the lungs and causes severe damage to the lung Causes n n n Hemorrhages Edema Emphysema Bacteria can complicate Symptoms n n n Cough Fever Heavy breathing Lethargy Decreased appetite

n Viral respiratory diseases n Infectious Bovine Rhinotracheitis (IBR) n Bovine Parainfluenza-3 (PI³) n Equine Rhinopneumonitis n Equine Influenza n Swine Influenza n Canine Infectious Tracheobronchitis (Kennel Cough) n Canine Distemper n Feline Viral Rhinotracheitis (FVR) n Feline Calicivirus (FCV) n Fowl Infectious Bronchitis n Fowl Infectious Laryngotracheitis (LT) n Fowl Influenza

Reproductive System n Abortion n Viruses terminate pregnancy by attacking n Fetus n Embryo n Placenta n Uterus n Examples n Swine parvovirus n Infectious bovine rhinotracheitis (IBR) n Bovine viral diarrhea (BVD) n Swine pseudorabies n Equine rhinopneumonitis

Nervous System n Meningitis n Definition n Inflammation of the brain covering (meninges) n Encephalitis n Definition n Inflammation of the brain tissue n Causes damage to brain tissues

Digestive System n Gastroenteritis n Affects n n Stomach Intestines Highly contagious n Symptoms n n n Vomiting Diarrhea More severe in young n Dehydration and electrolyte imbalance n

n Types n n n 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

n Meningoencephalitis n Symptoms n n n n Depression Blindness Partial or complete paralysis Wobbling Seizures Coma Delirium

Vaccination is important n No treatment n n Types n n Rabies Equine encephalomyelitis § VEE, WEE, EEE n n n Canine distemper Parvovirus Swine pseudorabies