PATHOGENIC ORGANISM AND DISEASE TERMS Pathogen microorganism that

PATHOGENIC ORGANISM AND DISEASE TERMS � Pathogen � microorganism that produces disease � A living organism of microscopic dimensions � Not all microorganisms are pathogens � The microorganism in the pictures is not a pathogen-does not produce a disease, in fact…

PATHOGENIC ORGANISM AND DISEASE TERMS � Disease � deviation from normal � infectious disease � noninfectious disease � contagious (communicable) disease � iatrogenic disease � idiopathic disease

INFECTIOUS DISEASES � 4 classes of agents (an agent is something that produces an effect) � Bacterium/Bacteria � Virus/Viruses � Fungus/Fungi � Parasites

BACTERIA � Is a living cell � Prokaryote cell – No Nucleus � Made up of cytoplasm, DNA, ribosomes, flagella

BACTERIA � � Cocci _ round Staphylococci– round, clusters � � � Streptococci- round, chains � � clostridium Rickettsia –rod shaped, small � � Anthrax Endospore – oval body inside, resistant � � Strangles Bacilli – rod shaped � � Skin infections, wounds, food poisoning Gram positive ehrlichia Spirochetes – spiral � Leptospirosis

STAPHYLOCOCCI � Staphylococci- � (cocci means round) – round, clusters � Skin infections, wounds, food poisoning � MRSA � Gram positive � Have thick wall that takes a stain (purple)

STREPTOCOCCI � Streptococci-round, chains � Gram positive � Strangles � Pinkeye � Strep throat � Necrotizing fasciitis � Sepsis

BACILLI � Bacilli – rod shaped � Anthrax � E. coli � Salmonella � Listeria � Clostridium

E. COLI � Gram negative � Anaerobic � Lower intestines

CLOSTRIDIUM � Gram positive rod shaped bacteria � Anaerobic (lives without oxygen) � Food poisoning � Clostridium perfringens enterotoxin

RICKETTSIA Gram Negative bacteria Intracellular parasites • Typhus • Rocky Mountain Spotted Tick Fever

SPIROCHETTE Lyme disease Leptospirosis

1. EXAMPLES OF INFECTIOUS BACTERIAL DISEASES � Swine � � � Yersinia Cattle � E Coli � Mastitis � Anthrax Canine � Leptospirosis (Lepto) � Ehrlichiosis (Tick Fever) � Bordatella Bronchiseptica (kennel cough) � Rabbit � � � Horse � � � Pasteurella (Snuffles) Tuleremia (vector-ticks, flies) Tetanus Strangles Cat � � Enteritis Cystitis

BACTERIA � Is a living cell � Prokaryote cell – No Nucleus � Made up of cytoplasm, DNA, ribosomes, flagella

VIRUS � Not a living cell! � But are considered alive because they reproduce, grow, develop, adapt, use energy sources from their environment � Made up of genetic material/ nucleic acid � (DNA or RNA) enclosed in a protein shell � All sorts of shapes � but are extremely tiny/ cannot see with a regular microscope

� Viruses insert their genetic material into a living cell The cell becomes the virus’ host. The virus DNA/RNA becomes a part of the cells DNA so that during cell division the virus is being replicated and passed on. Eventually the virus’ DNA takes over, completely changes the host cell/ kills it’s host cell and continues to replicate and create lots more viruses

� What about Retroviruses (Feline Leukemia and FIV) � constantly change/ difficult to treat

VIRUS VS RETROVIRUS Virus tends to contain DNA which can be replicated � Retrovirus contains RNA which must be transcripted (“converted”) into DNA. � this process is not accurate � “mistakes” are made in the process � DNA constantly varies because of the mistakes � Reason why retroviruses are harder to treat/ prevent � � HIV, Feline Leukemia

2. EXAMPLES OF INFECTIOUS VIRUSES � Rabies - most warm blooded Rabies animals � Dogs � Parvovirus � Distemper � Horses � West Nile Virus � Equine Encephalomyelitis Cattle � � � Bovine Viral Diarrhea (BVD) Cats � � Feline Panleukopenia Calicivirus Feline Leukemia Virus Feline Immunodeficiency Virus

Comparison chart bacteria vs virus Bacteria Virus Ribosomes Present Absent Living attributes Living organism Opinions differ on whether viruses are a form of life or organic structures that interact with living organisms Number of cells Unicellular; one cell No cells; not living Structures DNA and RNA floating freely in cytoplasm. Has cell wall and cell membrane DNA or RNA enclosed inside a coat of protein. Treatment Antibiotics Vaccines prevent the spread antiviral medications help to slow reproduction but can not stop it completely. Enzymes: Yes, in some Nucleus No No Virulence Yes Infection Localized Systemic Benefits: Some bacteria are beneficial Viruses are not beneficial. Reproduction Fission- a form of asexual reproduction Invades a host cell and takes over the cell causing it to make copies of the viral DNA/RNA. Destroys the host cell releasing new viruses. Size Larger (1000 nm) Smaller (20 - 400 nm) Cell wall Peptidoglycan/Lipopolysaccharide No cell wall. Protein coat present

PRIONS � Are proteins � Not alive � They do not have DNA or RNA � They have an ability to reproduce � Can cause inherited or transmissible diseases

PRIONS � Prion diseases are fatal and cause progressive, neurodegenerative problems literally, holes in the brain � The brain resembles a sponge / diseases are called spongiform � Examples of spongiform encephalopathies are…. � � 1) Scrapie…. in sheep and goats 2) BSE …. ”Mad Cow Disease” 3) Chronic Wasting Disease…wild deer and elk Transmitted by inherited disease, or ingested from tissue of infected animals (brain, spinal cord)

FUNGUS � Is a living cell… � a “plant” type cell with a stronger protein wall (chitin) � Plants have a cellulose wall (a “sugar”) � Mold, yeast, mushroom � Study of fungus is mycology � Fungus “move” by growing

3. EXAMPLES OF INFECTIOUS FUNGI (MYCOSES) � Dermatophytes (Ringworm) � Require keratin for growth � Thrush � Coccidioidomycosis (Valley Fever) � Blastomycosis (South East) � Histoplasmosis � Candida (yeast infection)

BUDDING YEAST

VALLEY FEVER � Coccidioidomycosis (disease) � Round fungus � (Coccidioides Immitis) � Lives in the soil � Dormant during dry spells � Develops as a mold with long filaments that break off into airborne spores when it rains � The spores get into the air by disruption of soil � (construction, earthquakes, farming, dust storms)

4. EXAMPLES OF INFECTIOUS PARASITES � Heartworm (Dirofilaria immitis) � Trichinella…Trichinosis � Hookworm (Ancylostoma), Whipworm (Trichuris vulpis), Roundworm (Toxocara) � Giardia (protozoan) � Coccidiosis (protozoan)

NONINFECTIOUS DISEASE CLASSIFICATIONS � Classifying diseases helps aid the veterinarian in obtaining a diagnosis � Helps the diagnostic process � Clinical signs and symptoms could be the result of several different disorders � Differential diagnosis-a list of possible causes of disease � Rule Outs-ruling out possible causes of disease through diagnostic testing, observation, trial treatment

� Metabolic-disruption of normal chemical reactions Metabolic � Diabetes, hypothyroidism, hyperthyroidism, Cushings, Addisons

� Anomalies – Congenital Birth Defects Anomalies � Cleft palate, deaf, retinal dysplasia, dwarfism

� Degenerative – progressive, permanent, longterm deterioration Degenerative � DJD (osteoarthritis), Bovine Spongioform Encephalopathy (BSE)

� Trauma – Trauma � Traumatic reticuloperitonitis, high rise syndrome, sucking chest wound, diaphragmatic hernia, peritonitis, prolapsed uterus

� Toxins - ingestion, inhalation, contact Toxins � Antifreeze, misapplication of flea and tick products, warfarin (rat poison), toads, OTC medications, illegal drugs, plants

� Immune Mediated Hemolytic Anemia (IMHA), System Lupus Erythematosus (SLE), Pruritis and Atopy (itchiness and hairloss) [allergies]

� Iatrogenic- a condition that develops as a result of treatment � � Hyperadrenocorticism (Cushings)- can be caused by treatment for a severe allergy problem Surgery-excision of Thyroid glad to treat hyperthyroidism in cats…parathyroid may also be removed causing iatrogenic hypoparathyroidism.

� Idiopathic- no explanation for underlying cause of the disease � � Idiopathic seizures Idiopathic renal hematuria

� Neoplasm - benign or malignant tumor

� Nutrition – Nutrition � Acute acidosis in ruminants, malnutrition, skeletal disease, hypoglycemia, obesity, iodine deficiency

MADTIN � � M � � Trauma � Toxins � metabolic A � � T � Immune � Iatrogenic � idiopathic anomalie � D � degenerative I � N Neoplasm � nutritional �

NONINFECTIOUS DISEASE CLASSIFICATIONS � Metabolic-disruption of normal chemical reactions Metabolic � � Anomalies – Congenital Birth Defects Anomalies � � Traumatic reticuloperitonitis, high rise syndrome, sucking chest wound, diaphragmatic hernia, peritonitis, prolapsed uterus Toxins - ingestion, inhalation, contact Toxins � � DJD (osteoarthritis), Bovine Spongioform Encephalopathy (BSE) Trauma – Trauma � � Cleft palate, deaf, retinal dysplasia, dwarfism Degenerative – progressive, permanent, longterm Degenerative deterioration � � Diabetes, hypothyroidism, hyperthyroidism, Cushings, Addisons Antifreeze, misapplication of flea and tick products, warfarin (rat poison), toads, OTC medications, illegal drugs, plants Immune � Immune Mediated Hemolytic Anemia (IMHA), System Lupus

NONINFECTIOUS DISEASE CLASSIFICATIONS � Iatrogenic- a condition that develops as a result of treatment � � � Idiopathic- no explanation for underlying cause of the disease � � Hyperadrenocorticism (Cushings)- can be caused by treatment for a severe allergy problem Surgery-excision of Thyroid glad to treat hyperthyroidism in cats…parathyroid may also be removed causing iatrogenic hypoparathyroidism. Idiopathic seizures Idiopathic renal hematuria Neoplasm - benign or malignant tumor Nutrition – Nutrition � Acute acidosis in ruminants, malnutrition, skeletal disease, hypoglycemia, obesity, iodine deficiency

3 SEIZURE CASES Seizure Case 1: A 3 month old male toy poodle. The dog is strictly a house dog and does not run free, In addition to the seizures, it has had intermittent diarrhea and is quite thin. Differential Diagnosis (Df. Dx): Developmental Disorder- brain malformation Hypoglycemia-could be secondary to poor diet, diarrhea, intestinal parasites Head Trauma- not likely with indoor dog Toxins-potential for ingesting medications or illegal drugs, chocolate Infectious causes of encephalitis- Distemper Idiopathic epilepsy-very unlikely due to age of dog

Seizure Case 2: A 2 ½ year old male golden retreiver. This dog is in excellent physical condition and has been eating well. This dog is free to roam the neighborhood and recently had one episode of vomiting and one episode where it was limping and stiff. Dx: Idiopathic epilepsy-this is high on the list because of age and breed of dog at the onset of seizures. Head Trauma-the recent limping and stiffness raises this possibility Toxins- the list is long, but possibilities include insecticides, chocolate Liver Disease-definitely needs to be ruled out but dog has been doing well otherwise Infectious Encephalitis

Seizure Case 3: A 14 year old female schnauzer. This dog had its first seizure and since that time has not been acting normal. There has been some weight loss and a poor appetitie, and the owners feel the dog can no longer see. The dog is strictly an indoor dog with no history of trauma. Df. Dx: Metabolic Disease-liver dx, hypogylcemia (insulinoma in the pancreas), Diabetes Neoplasia- the age of the dog, the blindness, lack of normalcy after the seizure make this a high likelihood Ideopathic epilepsy-very unlikely with the age of the animal