Infectious Lecture 6 PDF

Dr.Adel INFECTIOUS Lecture 6 Written By/ Abdelrahman Sadawy  Dr.Adel Bovine Lympha...

Dr.Adel INFECTIOUS Lecture 6 Written By/ Abdelrahman Sadawy  Dr.Adel Bovine Lymphangitis Another name: Edematous skin disease Problems Edema of legs and brisket Nodules and abscess on skin Ulcerations of skin Enlarged lymph nodes More common in buffaloes Etiology Corynebacterium pseudotuberculosis Gram positive organism, Intracellular bacteria The organism produces necrotizing exotoxins (phospholipase) Can survive in macrophages and resist phagocytosis OSD- equine Biovar equi Reduce nitrates ulcerative lymphangitis Corynebacterium pseudotuberculosis Does not reduce Caseous Biovar ovis nitrates. lymphadenitis Susceptibility, Source, MOT SUSCEPTIBILITY SOURCE MOT 1. BUFFALOES Discharging pus from infected 1. Thorough wound infection MORE COMMON: - animals 2. Insects − SCANTY HAIR The disease is more common − COOL BODY WITH during summer months WATER AND MUD 2. CATTLE Pathogenesis increases vascular The organism enters the Then invade the local Permeability Abscess and body through skin lymphatic vessels (inflammation) edema a cytotoxic surface lipid coat facilitates intracellular survival produces a phospholipase o exotoxin SADAWY 1  Dr.Adel Clinical signs 1. Fever − return to normal after few days 2. Mild loss of appetite 3. Mild reduction in milk production 4. Swellings appear on skin 1) Firm, moderately warm, painful 2) Soften and 3) Traumatized ooze 4) Abscess and large contain blood- blood-tinged fluid formation tinged fluid − Puncture of swelling in this stage by a syringe fails to reveal any fluid 5. Inflammatory edema − Brisket − Limbs especially fore limbs 6. Enlargement of regional lymph nodes − mainly prescapular and may form abscess 7. Ulcerations of skin which may be hemorrhagic 8. Pyogranulomatous lesion on skin especially lower limbs 9. Visceral forms − Mastitis, Pneumonia, Pyelonephritis Diagnosis Clinical signs and history Differential diagnosis − Filariasis (No fever, no pus and can be detected by blood film) − Bovine farcy (Zheel Nelsen stain) − Dermatophilosis − LSD Laboratory diagnosis Sample Pus or fluid from unopened swelling Lymph node biopsy Ulcerated skin Granuloma Direct smear from pus Culture Lab animal Stained by Gram stain, the Culture on blood agar Intraperitoneal injections of pus organism is Gram positive into G. pig produce purulent Coccobacilli of Chinese litters. orchitis (Strauss reaction). SADAWY 2  Dr.Adel Treatment 1. Antibiotic 2. Anti-inflammatory 3. Diuretic o Penicillin o Dexamethasone 10.20 ml per o 30 sodium\ potassium citrates o Penicillin streptomycin animal I/V or I/M for 3 days (not orally for 3-4 days. o Amoxicillin used in pregnant animal) o Long acting Oxytetracycline o Lasix one or two ampoule o 1–2-month treatment o Flunixin (finadyne. 1.2 ml/45 intravenous in glucose 25% kg B.wt. I/V or I/M for 3-5 days. solution. o DIURIZONE (20ml for 2-3 days) 4. Surgical interference with abscesses and wounds. o As handling of large abscess and skin wounds Control Insect control Hygienic disposal of pus Autogenous vaccine (vaccine made from the organism itself that infect the animal ) BCG (not recommend as its give false +ve tuberculin test) Infectious Bovine Keratoconjunctivitis (IBK) Pinkeye Etiology Causative bacteria Moraxella Moraxilla bovis gram negative coccobacilli bovis Environmental predisposing factors Rough Smooth Ultraviolet light colonies colonies Plant pollens Face flies Tall grass Has pili know as fimbriae facilitate attachment to Non Dust corneal epithelium and piliated establish infection Other infection predisposes to diseases IBR Non Pathogenic pathogenic Mycoplasma SADAWY 3  Dr.Adel Susceptibility, Source, MOT Susceptibility Source MOT 1. Cattle and buffaloes Ocular and nasal discharges Flies 2. Younger cattle, 3 months to 2 o Mechanical vector years The organism is located in the − Younger have colostral eyes and nasal cavities of infected Direct and indirect contact with immunity cattle for one year nasal and ocular secretions of − Older animals have infected animals developed acquired surface immunity (protective Pinkeye most commonly occurs in antibodies on the eye summer surface) as a result of previous exposure. Pathogenesis An inflammatory reaction occurs Attach to corneal Destruction of Edema Produce hemolysins corneal epithelium Infection of eye epithelium through Red eye and other endotoxin fimbriae Corneal ulceration Enlarged corneal ulcer Granulation tissue Clinical signs − The incubation period is 2-7days − There are four stages of IBK. o The disease may resolve at any of these stages o Without treatment, the most severe cases will progress through all four stages Stage 1 Stage 2 Stage 3 Stage 4 1. Blepharospasm (excessive within 24-48 h after stage 10. The ulcer continues to 12. Ulcer heals and blinking) 1 progress and covers reduces, leaving a 2. Photophobia 7. Corneal opacity spread most of the cornea scar. 3. Conjunctivitis on cornea (central to 11. The interior of the eye 13. Occasionally, 4. Lachrymal discharge peripheral) fills with fibrin and perforation of the 5. Corneal opacity 8. Ulcer appear in center white blood cells. corneal ulcer results a. There is a grey of cornea in iris prolapses appearance of the 9. Neovascularization of This gives the eye a Cone-shaped cornea cornea from sclera yellow appearance bulging of the eye 6. Less appetite due to pain in which case, and a moderate fever. blindness may result Corneal scar Once the ulcer has healed (except Stage 4) the blood vessels recede; Eventually the eye appears clear again with a white scar that slightly impedes vision SADAWY 4  Dr.Adel Diagnosis 1. Clinical 2. Laboratory Isolation of the Moraxella bovis from lachrymal or nasal swab 3. Differential includes Foreign bodies in the cornea or the conjunctival sac, Ocular infection by the IBR virus, Malignant catarrhal fever. Mycoplasma Treatment Good prognosis with early treatment before large ulcer development Most strains of M. bovis are susceptible to Oxytetracycline, Ampicillin, Erythromycin, Florfenicol, Ceftiofur penicillin, Telmicosin, Sulfa- trimethoprim Resistant to Tylosin and lincomycin Systemic antibiotic Subconjunctival antibiotic Topical antibiotic Generally, lipophilic drugs achieve higher o lower dosages may be used o topical administration is intracorneal and intraocular concentrations o Less cost oil-based formulations of and are more effective at penetrating the o Yield higher ocular antibiotic blood-tear barrier than hydrophilic drugs concentrations o Difficulty of o Only effective if used o Intramuscular administration of a subconjunctival multiple times daily, long-acting oxytetracycline (LA-200) administration is a which generally is not (20 mg/kg of body weight) in two drawback practical doses given 72 hours apart (1 ml (300,000 U) procaine penicillin o Spray easily washed out of o Tulathromycin 2.5 mg/kg eye by tears so need frequent o Ointment stays longer but hard to apply Other treatments 1. Astringent Topical instillation of silver nitrate (1%) and zinc sulphate (0.4%) eye drops. for relief of eye irritation. Help in healing. 2. Anti-inflammatory Nonsteroidal anti-inflammatory reduces ocular inflammation and improve comfort level. Dexamethasone 4 mg subconjunctival injection with antibiotic. o Should not be used in presence of ulcer 3. Eye patches To protect eye from further irritation through sun or dusts SADAWY 5  Dr.Adel Control 1. Fly control 2. Providing shaded areas helps to decrease the amount of UV light exposure. 3. Vaccination Killed vaccine two doses one month apart then annual, Calves 2 months old then 3-month-old Annual dose 21 days before fly summer season Partial ly protective because o Ability of M. bovis to change type, o Presence of other organisms in the eyelid tissues o Environmental factors Blackleg Other names Black quarter – Quarter ill – Pseudo-anthrax Definition An acute febrile disease of ruminants Characterized by myositis of skeletal and/or heart muscle tissue Etiology CLOSTRIDIUM CHAUVOEI o Anaerobic spore forming bacteria. o The spores are highly resistant o When condition become favorable (anaerobic) they change to vegetative multiplying form o They produce powerful necrotizing exotoxins Susceptibility, Source, MOT Susceptibility Source MOT Sheep and goats Soil born Soil contains All ages are affected Decomposition of spores recently tilled soil carcasses of animals that Cattle died of the disease and Young ages (6-24 contaminate pasture and Cattle Sheep and goats months) soil with spore calves growing Ingestion of food rapidly on a high Spore occurs naturally or water contain Wound plan of nutrition in intestine of healthy infection spores Affected animals animals, Feces usually in good contaminate pasture and No history of Shearing, navel, trauma fighting, after condition soil (endogenous) vaccination, lambing SADAWY 6  Dr.Adel Pathogenesis Bacterial activation and Bacteria multiply and Absorption of the Bacteria pass to Spores in food or vegetate and produce necrotizing toxin to lymphatic and blood and water reach multiply(Unknown toxin damage muscle circulation lead to stay dormant in heavy intestine etiology) lack of oxygen and produce gas by toxemia and muscle in tissue glucose fermentation death Clinical signs, Postmortem lesions Clinical signs Postmortem lesions Rapidly progressing disease 1. Cattle found dead of Blackleg are often 1. Sudden death without clinical signs − Lying on the side with the affected hind leg 2. Depression, high fever, anorexia stuck out stiffly. 3. Subnormal temperature before death − Bloating and purification occur quickly. 4. Acute lameness or recumbency − Blood-stained froth exudates from nostrils 5. Swelling in one of the heavy skeletal muscle and anus regions − Rapid clotting of the blood o The swelling is hot and painful in the early stage 2. Incision of the affected muscle mass reveals o Later becomes cold and painless presence of dark, swollen tissue with rancid odor. 6. Edema and emphysema 3. Myocardial tissue and diaphragm may be o (Crepitating of the swelling upon the only tissues affected in some cases. palpation) 4. 7. The skin is discolored dry and cracked 5. All skeletal muscles of the body must be examined Usually, lesions confined to the upper part of one limb Occasional cases − At the base of the tongue, − Heart muscle, − Diaphragm − Psoas muscles, − Brisket. Diagnosis Clinical symptoms and post-mortem Differential diagnosis: o Anthrax (blood doesn’t clots) o Malignant edema Laboratory diagnosis FA test (piece of muscle, exudates) Isolate a pure culture PCR SADAWY 7  Dr.Adel Treatment Sick animals Healthy animal Recovery rates are low Immediately vaccinate with two doses 6 weeks Large doses (44,000 IU/kg BW) penicillin apart commencing with crystalline penicillin If vaccinated before - booster intravenously Followed by longer-acting preparations procaine penicillin IM for 5 days minimum Anti-inflammatory corticosteroid Prevention and Control 1. Vaccination with polyvalent or bivalent clostridial vaccine a. Two doses 4-6 weeks apart b. Annual booster dose 2. Proper disposal of dead - burn or bury in quick lime Malignant edema Gas gangrene Definition Acute wound infection Associated with organisms of the genus Clostridium. There is acute inflammation at the site of infection and a profound systemic toxemia Etiology C.novyi C.sordellii С.septicum C.chauvoei C.perfringens In some cases, there can be mixed infections Susceptibility, Source, MOT Susceptibility Source MOT All ages and species of Highly resistant spores Deep puncture wound animals are affected Soil born Surgical or accidental wound Feces of normal animals. Vaccination or intramuscular injection Castration Through umbilical cord Following parturition. After shearing, docking SADAWY 8  Dr.Adel Pathogenesis Potent toxins are produced in Contamination of If anaerobic condition the local lesions. The toxins Absorption of toxin wound with spore in in wound bacteria cause extensive edema and cause toxemia soil vegetate and multiply necrosis Clinical signs 1. The illness is of short duration, and affected animals die within 24 to 48 hours of the first appearance of signs 2. Fever and Depression 3. Weakness Stiffness Lameness 4. Congested mucous membranes 5. A local lesion at the site of infection consisting of a soft, doughy swelling with marked local erythema Severe pain on palpation. At a later stage the swelling becomes tense and the skin dark 6. Emphysema may or may not be present, depending on the type of infection, 7. Extensive frothy exudation from the wound. 8. When infection occurs at parturition, swelling of the vulva accompanied by the discharge of a reddish- brown fluid Diagnosis 1. The association of profound toxemia with local inflammation is characteristic. 2. specific FA test 3. Isolation of organism 4. Differential diagnosis: Blackleg, Anthrax Treatment − Rapid treatment with antibiotic penicillin − Ant inflammatory − Antitoxin - very expensive − Surgical incision and hydrogen peroxide − Vaccination of healthy animal Prevention and Control − Vaccination − Hygiene Proper disposition of carcass − Hygienic condition in operation and injections SADAWY 9  Dr.Adel RINGWORM Other names Dermatophytosis, Trichophytosis, Microsporosis, Dermatomycosis Definition − Superficial fungal diseases caused by invasion of keratinized epithelial layers of skin and hair by dermatophytes fungi − characterized by o circular areas of alopecia and crusts formation Etiology Trichophyton Trichophyton Microsporum Microsporum Spore verrucosum equinum equinum gypseum forming fungi Susceptibility, Source, MOT Susceptibility Source MOT − Affect all animals and human − Crusts on infected animals − Direct − Calves are more susceptible o Contact with other than adult animals (Skin pH) − Spores can remain viable for infected cattle − The disease is more common months in the soil or bedding, − Indirect in winter and in housed grooming equipment, o Spores from objects as animals in close contact working facilities grooming utensils, bedding Pathogenesis Damage to the hair Body fluid exudes Fungi are aerobes The The fungus does not fiber causes it to from the damaged and die out under characteristic attack living tissue. break, leading to skin mixes with the crust in the ring form of hair loss dead tissue center of lesions, the lesions. It feeds on keratin in the hair fiber produce the classic So leaving to the alopecia and outer layer of gray circular scab periphery the skin SADAWY 10  Dr.Adel Clinical signs 1. Ringworm is usually found on the head, neck and trunk of calves, a. particularly around the eyes, ears, and muzzle 2. Affected animal develop lesions which are usually circular, to about three centimeters in diameter a. lesions may coalesce to form larger irregular patches 3. The lesions consist of an area of alopecia and a prominent whitish grey, asbestos like accumulation of scales. 4. This is a self-limiting disease in that animals develop immunity to the fungus and the infection usually resolves in 2-6 months without treatment 5. No systemic signs Diagnosis 1. Clinical signs 2. Deferential diagnosis with Mange shape of lesions Itching, location of lesions, skin scraping 3. Wood's lamb It is a good screening test, Dermatophytes produce an apple-green color upon fluorescence False positive False negative − Some drugs and other products, notably − Fluorescing hairs are often covered by crusts tetracycline drugs and ointments will also and these need to be lifted to see the glowing fluoresce hairs beneath. Only hair shafts fluoresce; − Non-pathogenic fungi crusts, skin or nails do not fluoresce − Fault in technique Laboratory diagnosis: Skin scraping Examination of a skin scraping taken from the periphery of the lesion may reveal spores on the external surface of the hair The spores appear as round or oval refractive bodies in chain (trichophyton) or mosaic appearance (microsporum) Culture on sabouraud dextrose agar Treatment 1. Local application Localized low number of animals Infection in a group is widespread − The lesions are first scraped or brushed to − Washes or sprays that can be applied over remove the crusty scab. the entire body surface of all animals − After scraping the medicament should be Sprays have a big advantage of prophylactic brushed or rubbed in vigorously treatment of all in-contact animals SADAWY 11  Dr.Adel − Daily application for at least 5 days is 1) White field ointment required. 2) Thiabendazole 1) Captan spray 3) 5% tincture of iodine at 3-day intervals over a Treating groups of calves with whole body sprays 12-day period. of dilute Captan 250 gram in 75 litter of water and 4) Miconazole, tolnaftate, or clotrimazole sprayed with a power sprayer. (antifungal creams used in human and small animal medicine) 2) Lime sulfur Lime sulfur 2% to 5% (is produced through the reaction of lime (calcium oxide) or hydrated/slaked lime (calcium hydroxide) with sulfur in water. − 1 volume to 8 volume water 2. Systemic treatments include − IV sodium iodide as a 10% solution (1 g/14 kg body weight). − Griseofulvin feed supplements has been beneficial (10 mg/kg) for at least 7 consecutive days. − Spontaneous recovery is common Mange Other names: Scab, scabies, Acariasis, Mite infestation Etiology Psoroptes Surface mites Mite Chorioptes Surface mites Sarcoptes Burrowing mite Demodex Hair follicles Mode of spread Life cycle is 10-14 days Infection is usually spread by 1. Direct contact between cattle. 2. Indirect through straw bedding and other objects that come into contact with infected animals SADAWY 12  Dr.Adel Pathogenesis The feeding and burrowing activities of mites produce an intense irritation. mite In Demodectic mange excreta contain proteinases that result in a severe allergic pruritus the injury to the Rubbing against hard objects Invasion of hair follicles and sebaceous glands lead to hair loss, bleeding and the skin produces leads to a fluid exudate and serum in response to allergy The exudate hardens and forms a crust, which chronic inflammation, loss of the hair fiber, the produces the condition known as scab or development of secondary staphylococcal scabies pustules or small abscesses. Clinical signs 1. Intense pruritus causes loss of condition and production, there is constant scratching 2. In advanced cases, animals scratch and bite themselves constantly and become emaciated. 3. thickened skin becomes wrinkled, fissured 4. The lesions are covered by scabs and some time is bleeding Demodectic mange − Invasion of hair follicles causes chronic inflammatory loss of hair fibers and a secondary pustular infection with staphylococci, giving a nodular appearance. Diagnosis Areas of thickened skin in obviously itchy animals are very suggestive of mites, To confirm a diagnosis o microscopic examination of deep skin scrapings taken at the edge of a scaly area. o The scraping should be made deep enough to cause bleeding of the skin. Treatment 1. Local treatment The repeated dipping or spraying with acaricides, diazinon, malathion, lime sulfur Sulfur ointment the skin reaction can mean that contact between the product and the mite is limited. In such cases, scabs may have to be removed before treatment Two treatments 10-14 days apart as eggs may not be affected with drug 2. Macrocyclic lactone (ivermectin, eprinomectin, moxidectin, and doramectin) products in pour-on or injectable formulations Because of the residual activity of these compounds, retreatment is not usually necessary SADAWY 13