DISEASES, by CALLIE PARR Materials produced for classroom use in conjunction with permission from the University of Illinois Agricultural Education Program. Diseases Submitted by Callie Parr and used in cooperation with the University of Illinois at Urbana- Champaign. The materials that appear in this document may be freely reproduced for educational/training activities. There is no requirement to obtain special permission for such uses. We do, however, ask that the following statement appear on all reproductions: This permission statement is limited to the reproduction of material for educational/training events. Systematic or large-scale reproduction or distribution (more than one hundred copies per year)—or inclusion of items in publications for sale—may be done only with prior written permission. Also, reproduction on computer disk or by any other electronic means requires prior written permission. Contact the University of Illinois Agricultural Education Program to obtain special permission. The University of Illinois and its affiliated entities, in addition to the individual submitting the materials, assumes no liability to original work or activities therein.

Diseases

Disease Can be broken down into infectious and non-infectious diseases Infectious diseases are a result of pathogens. -Viruses - Protozoa- Parasites - Bacteria - Fungi Pathogens are carried by vectors. - animals - insects - inorganic surfaces

Koch’s Postulates Used to detect infectious diseases. – The infectious agent should be detectable in sick animals and not in healthy ones. – It should be possible to isolate and culture the organism. – Organisms taken from the culture introduced into healthy animals should cause the same disease. – The same organism should be isolated from the second animal as well.

Ways a pathogen can enter the body Wounds – breaks in the skin Respiratory – breath it in Mucus membranes – eyes, nose, mouth Bites – insect bites (same as wound) Ingestion – eat it (contaminated food/water)

Course of a disease Exposure – no physical response yet Incubation – levels of pathogen increase Prodromal – the first signs of illness – Fever, muscle aches Decline – either immune system kicks in or medication takes effect – If not, then enter chronic illness Convalescent – animal regains strength

Bacterial Infections 4 major categories of bacteria by shape – Staphylococcus – Streptococcus – Bacillus – Spirochete

Bacterial Infections Sickness is a result of toxins released by the bacteria. – Exotoxins – excreted by cells – Endotoxins – released when cells die Treatable with antibiotics Immune System fights with phagocytes – Blood cells that surround and destroy pathogens

Common Bacterial Diseases

Strangles Streptococcus equi Horses Swollen lymph glands in neck, fever, reduced appetite, nasal discharge, abortion Highly contagious

Scours (E. Coli diarrhea) Escherichia coli All species Animals less than 2 weeks old Severe diarrhea leading to dehydration and death Preventable with medication

Pneumonia Rhodococcus (equi) All (horses) Nasal discharge, fever, respiratory difficulty, inflammation that can spread to joints. Treatable with antibiotics

Leptospirosis Leptospirosis sp. All species Abortions, fever, anemia, jaundice

Pinkeye Moraxella bovis Cattle Inflamed conjunctiva, cloudy cornea, sensitivity to light, fluid discharge from eye Treatable with topical ointment or systemic antibiotic Highly contagious

Foot Rot Fusobacterium necrophorum Cattle, sheep, goats Deep infection of the cloven section of the hoof, foul odor, pain, lameness Preventable with clean facilities Treatable with antibacterial soaps

Rain Scald/Rot Dermatophilus congolensis Horses, cattle, sheep, goats Crusting of the skin at the base of the hair follicle mostly on the back and rump Similar to cradle cap in babies Most prevalent in animals exposed to excessive moisture Treatable with antibacterial soaps

Lockjaw Clostridium tetani Horses, cattle, sheep, goats Muscle spasms, locked jaws, stiffness of joints, death Enters through punctures and/or breaks in skin (lives in soil naturally) Preventable with booster shot

Greasy Pig Disease Swine Staphylococcus hyicus Reddened skin, anorexia, fever, thickened skin with purulent (pus) discharge

Lyme Disease Borrelia bugdorferi All species Spread by ticks Chronic arthritis, lethargy, loss of appetite, paralysis

Viruses

What is a Virus No cell wall, no organelles, maybe not even be considered living DNA or RNA surrounded by a protein coat Hijack a healthy cell and program it to create new viruses Destroys host cell in process Often dies of suppressed immune system or reaction to enzymes released by cells

Treatment Prevent with vaccine – modified live – killed Body’s natural immune system Very limited anti-viral medications

Shipping Fever Cattle Bovine Respiratory Syncytial Virus, Bovine Virus Diarrhea, Infectious Bovine Rhinotracheitis, Parainfluenza-3 High Fever, nasal discharge, coughing

Panleukopenia Cats Feline parvovirus Fever, vomiting, extreme diarrhea, anorexia

Feline Leukemia Cats Retrovirus Chronic weight loss, anemia, anorexia, tumors

Equine Infectious Anemia Retrovirus Horses Fever, hemolytic anemia (breakdown of red blood cells), icterus (jaundice/yellowing), weight loss

Canine Distemper Canine distemper virus Dogs Fever, nasal discharge, seizures, pneumonia

Rabies All species Rhabdovirus Paralysis, inability to swallow (foaming at mouth), aggression, stupor, brain lesions

Pseudorabies Pigs Herpesvirus Shaking, ataxia (gross uncoordination), convulsions, seizures, fever

Fungal Infections

Fungal infections Usually spread by spores or direct contact Spores very resistant to heat, moisture, or dryness Treatable with fungicides

Ringworm Red, crusty/flaky ring on the skin that expands outwards Has nothing to do with worms Microsporum or Trichophyton Live in hair folicles

Others Blastomycosis (canine) Sporotrichinosis (feline, canine) Cryptococcosis (feline, canine) Histoplasmosis (feline, canine)

Parasites

What is a Parasite? Any organism that lives off another organism and causes harm Detrimental to host’s health in many ways – Compete for nutrients and “starve” the host – Damage tissues of the host – Release toxins into the host – Suck the blood causing anemia – Serve as a vector for bacteria or viruses

Life cycle May parasites have a complex life cycle that help them survive and spread from one host to another. – Egg, larvae, pupa, adult or egg, nymph, adult Definitive host is the animal that carries the mature parasite. Intermediate host carries the immature (egg or larvae) parasite.

Example A dog (definitive host) has a tapeworm (parasite). The head of the tape worm attaches to the lining of the small intestine causing malnourishment. As the parasite develops, segments containing the eggs break off and exit the anus (look like grains of rice). The segments rupture releasing the eggs. A flea larva (intermediate host) on the dog eats the eggs. When the flea matures it jumps onto another animal. The animal bites at the fleas, ingesting the contaminated flea. The tapeworm eggs are released in the second dog’s stomach and move to the small intestine where they hatch and implant completing the cycle.

Intestinal Parasites Typical clinical signs – Diarrhea – Vomiting – pot-bellied – dull coat – poor weight gain – Anemia – coughing

Common Internal Parasites

Roundworms Dogs and Cats Toxocara canis/cati or Toxascaris leonina Ingested eggs hatch into larvae in the intestine. Lavae travel through liver and lungs. The larvae are then coughed up and re-swallowed where they develop into adults and attach in the intestine. Eggs are shed in the feces. Passed through ingestion of feces, mother’s milk, placental wall, eat infested animals (rabbits, rats)

Hookworms Dogs and cats Ancylostoma sp. or Uncinaria sp. The larvae are ingested and develop into adults which attach to the intestinal lining and suck blood. Eggs are released in the feces where they hatch into larvae. Ingest larvae, placental wall, mother’s milk, through the skin of the food pads.

Tapeworms Dogs and cats Dipylidium caninum, Taenia pisformis/ taeniaeformis Requires an intermediate host eggs/larvae must be ingested

Heartworms Dogs Dirofilaria immitis Adult worms live in the major vessels and chambers of the heart. Clog the blood flow. Transmitted by mosquitoes (intermediate host) Incubation time is about 6 months

Strongylosis Strongylus sp. Horses Eggs passed in the feces develop into larvae. Larvae migrate into blood stream causing damage, enter large intestine and mature, then release eggs. Horse eat the larvae as they graze

Bot flies Horses Gasterophilus intestinalis/nasalis Flies lay eggs on horse’s legs which get licked and ingested. Larvae travel down esophagus into the stomach. Then they are passed out through feces to develop into flies.

Trichostrongyles Ruminants Hemonchus, Ostertagia, Trichostrongylus, Cooperia, Bunostomum Eggs passed through feces and consumed by grazing. Develop into larvae and adults in stomach and intestine. Able to go dormant during winter.

Coccidiosis Ruminants Species of protozoa including Eimeria sp. Oocyst (egg) passed in feces. Ingested and goes through several stages of development being absorbed into the lining of the intestines.

Common External Parasite

Mostly blood suckers – Fleas – Ticks – Mites – Various flies – Mosquitoes