Equine Skin, FAD, and review Flashcards
What is the causative agent for Pigeon fever?
Corynebacterium pseudotuberculosis var. equi
What lesions are associated with Corynebacterium pseudotuberculosis var. equi
- Ulcerative lymphanitis
- external abscesses of the chest associated with -“Pigeon fever”
How is Corynebacterium pseudotuberculosis var. equi transmitted?
via breaks in the skin (dermatitis, abrasions, wounds) or biting insects.
What are the 3 forms of Corynebacterum pseudotuberculosis var. equi
External abscesses- large pectoral abscesses, ventral abdomen
Internal abscesses <10% of cases. Liver lungs, spleen, kidney - high rate of fatality
Ulcerative lymphangitis: severe cellulitis of one or more limbs. nodular abscess formation in one or all limbs
How is Corynebacterium pseudotuberculosis var. equi diagnosed?
bacterial culture of external abscesses, peritoneal fluid (internal abscesses) or draining tracts (ulcerative lymphangitis).
Evidence of chronic infection on CBC
Synergistic hemolysis inhibition (SHI) test for horses with internal abscesses- measures response to phospholipase D toxin.
How are external abscesses associated wtih Corynebacterium pseudotuberculosis var. equi treated?
Surgical drainage of mature abscesses, many animals will rupture abscesses and heal on own, antibiotics only in complicated cases, high chance of recovery.
How are internal abscesses and ulcerative lymphangitis treated with Corynebacterium pseudotuberculosis var. equi
Long term (minimum of 4-6 weeks) antibiotic therapy- susceptible to many antibiotics
How do you prevent Corynebacterium pseudotuberculosis var. equi
Isolate infected animals to decrease spread
Can survive for long periods of time in soil- contain abscess drainage
Fly control
Vaccination- conditionally licensed vaccine - efficacy pending.
What are two differentials for ulcerative lymphangitis?
Sporothrix schenckii, and Corynebacterium pseudotuberculosis var. equi
How are infections with Sporothrix schenckii acquired
Growth in organic material- slivers and thorns- introduced via trauma
clinical signs associated with Sporothrix schenckii
Multiple abscesses along lymphatic vessels, Typically affects a single limb
How is sporothricosis diagnosed?
Cytology- cigar bodies: elongated yeast cells
culture- sent to a reference lab
Lack of response to antibiotic therapy
How is sporothricosis treated?
Sodium iodide, Ketoconazole or similar drugs, amphoteracin B
what are causative agents of Dermatophytosis
Trichophyton equinum, T. mentagrophytes, Microsporum gypseum
How are infections with Dermatophytosis acquired
Requires some abrasion to skin to allow entry. Warm, moist environments
Clinical Signs associated with Dermatophytosis
Regions of alopecia, frequently round, erythemic, crusted margins.
Head, neck, forelimbs, under saddle/girth
Methods of diagnosis for Dermatophytosis
wood's lamp- doesn't work Derm database- trichogram (often not successful) Fungal culture (DTM media)
How is dermatophytosis treated?
Most cases are self-limiting “sunshine and time”
Can treat topically with antifungals (miconazole, ketoconazole) or lime sulfur (zoonotic-wear gloves)
Systemic therapy-Griseofulvin
Separate form herd, disinfect equipment
what is the etiology of Dermatophilosis
Dermatophilus congolensis
How are infections of Dermatophilosis acquired
skin abrasion + moisture
How is Dermatophilosis transmitted?
Contagious between animals- crusts
What is the lay term for Dermatophilosis infeciton?
Rain rot
Clinical signs of Dermatophilosis
“Rain rot” - skin lesions similar to moisture runoff
Papules that progress to thick crusts with an erosive underside
“paint brush lesions”
How is Dermatophilosis diagnosed?
direct examination of crusts
Giemsa stain - railroad track bacteria
How is Dermatophilosis treated?
dry environment, crust removal, topical chlorhexidine +/- systemic therapy with antibiotics (penicillin or TMS)
What is the causative agent of Vesicular stomatitis
Vesicular stomatitis virus
How is vesicular stomatitis transmitted?
Direct contact once on property
Transmission via biting insects between properties
T/F vesicular stomatitis is zoonotic
True-
clinical signs of Vesicular stomatitis
Excessive salivaiton with vesicles on the inner surface of the lips, gums, tongue- occasional crusting scabs on muzzle, lips, nostrils, ears, coronary band, sheath, ventral abdomen
Reluctance to eat or drink- weight loss
How is Vesicular Stomatitis diagnosed?
Report any suspicious lesion to State Veterinarian
PCR form lesions
Serology at NVSL- cELISA, VN, CF
how is Vesicular stomatitis treated?
general supportive care
What methods of prevention/control are used in vesicular stomatis cases
quarantine of any identified premises, animals
isolate any new horses for 21 days
Insect control programs
Individual feeders
What is the causative agent of African Hrose sickness?
African Horse sickness virus
Orbivirus related to Bluetongue and EHD
What is the method of transmission of African Horse Sickness?
via Culicoides (biting midges) Can be blown large distances (>300miles) Standing water _ fecal material = breeding grounds
what are the reservoirs for African Horse Sickness?
Donkeys, mules, zebras, elephants, camels, dogs
Clinical signs associated with African Horse Sickness?
Attack vascular endothelium -> edema
Pulmonary form- severe pulmonary edema, frothing at nares. High fever, 95% case fatality rate
Cardiac form- pronounced edema of the head and neck, hydropericardium, high case fatality rate
Mixed (combinatino of both)
Mild- fever only, seen in animals with partial immunity
What are the 2 differentials for frothing from the nares in horses
Hendra and African Horse sickness virus
How is African Horse Sickness diagnosed
Clinical Signs, Virus isolation (thought to be the best), PCR (if available)
Serology- several tests available. Acute deaths complicate serconversion
What are treatment methods for African Horse sickness
none other than supportive care, highly fatal
what methods of prevention and control are associated with African Sleeping Sickness
Strict rules govern importation of aniamls from endemic areas- horses from endemic countries must be quarantined at NY Animal import Center for 60 days.
control culicoides by getting rid of standing water and manure
Screening/Netting at night- only letting horses out during the day
Vaccination- several serotypes to be included in endemic areas.
What is the causative agent associated with Hendra
Hendra virus - henipavirus
What is the reservoir for Hendra Virus
Fruit bats
How is Hendra virus transmitted?
Transmission between horses through direct contact only with respiratory secretions
Zoonotic and highly fatal!
clinical signs of Hendra virus
fever, respiratory distress, and death (high fatality rate)
Severe bilateral pulmonary edema (ddx for AHS)
Replicates in respiratory epithelium first, then spreads hematogenously to other organs
potential for neurologic signs as well- severe obtundation, dementia, head tilt, ataxia
How is hendra diagnosed?
RNA virus- RT-PCR
Serology
Treatment for Hendra
NONE!
Euthanized to protect human health
How has hendra been prevented
vaccination available in Australia as of 2013
What is the causative agent of Glanders
Burkholderia mallei
What are methods of transmission of Glanders
Transmitted through feed, water, and by direct contact
Draining nodules on the nasal mucosa discharge the organism
Recovered carriers are key in transmission
Clinical signs of Glanders
horses tend to develop chronic disease
donkeys and mules tend to develop acute disease
Respiratory disease
Cutaneous disease
What are the 2 forms of Glanders
Respiratory- pneumonia- small nodules on the nasal and pharyngeal mucosa that ulcerate and drain. Ulcers will heal and scars form
cutaneous (farcy)- Nodules on skin, subcutaneous tissues and lymph nodes. Lymphangitis: so swollen they appear as cords.
Humans primarily cutaneous but also acute, fatal pulmonary cases.
How is Glanders diagnosed?
culture or PCR of lesions in acute cases
To detect carriers: serology is most common (CF, ELISA, AGID)
Mallein intradermal skin test (previously used, no longer common)
how is glanders treated
Treatment is not recommended
Antimicrobial therapy is dicouraged because carriers remain
How do you prevent and control glanders?
Test and slaughter is preferred
Immune response is poor, no vaccines available
What is the causative agent for Dourine
Trypanosoma eqiperdum
How is Dourine transmitted
Venereal transmission
What are acute signs associated with Dourine?
initial low-grade fever and urethral or vaginal discharge
Edema, swelling, and ulceration of external genitalia
occcasional abortion
What are chronic signs associated with dourine?
Peculiar raised plaques in skin of the flank that disappear and are replaced by plaques in other areas “Pathognomonic”
CNS signs: incoordination, ataxia, paralysis
Horses lose condition and become progressively weaker
How is Dourine diagnosed?
clinical signs
serologic testing - CF - official test for import
A subspecies-specific real-time PCR was used to identify infected tissues in the outbreak in Italy
how is Dourine Treated
use of trypanosomal drugs in theory possible, but not practicle
How do you prevent & control Dourine
Slaughter of all CF positive carrier animals
AAEP core vaccines
Tetanus
WEE/EEE
West Nile
Rabies
Peeculiar raised plaques in skin of the flank that disappear and are replaced by plaques in other areas- this is pathognomonic for what
Dourine
