Common Equine Diseases

Common Equine DiseasesChapter 9Learning Outcomes Describe and recognize clinical signs associated with specific diseases Understand the etiology of the diseases Understand and describe common treatments for disease Know the common scientific names of parasites associated with this species Know the common vaccinations and their schedules associated with this speciesBotulismEtiological Agent: Clostidium botulinum toxinSigns Paralysis of cranial nerves- creeping paralysis that begins at the head and moves caudallyTreatment Supportive- usually RIPPrevention NoneZoonotic None

CankerEtiological Agent: Fusobacterium necrophorumSigns- chronic hypertrophic, moist pododermatitis- frog is very friable and has cottage cheese like appearanceTreatment- debridement and topic antimicrobial agentsPrevention Keep environment dryZoonotic: No

Lyme DiseaseEtiological Agent: Borrelia burgdorferiSigns- low-grade pyrexia, depression, lameness, loss of appetitie, joint swellingTreatment- IV tetracycline and oral doxycyclineDiagnosis: ELISA or IFAPrevention Keep environment dryZoonotic: YEs

Potomac Horse FeverEtiological Agent: Neorickettsia risticii Horse infected by eating one of the flys which is intermediate carrierSigns: Depression, diarrhea, fever, toxemia, abortion, laminitisDiagnosis: PCRTreatment: oxytetracycline, fluid therapy, nsaidsZoonotic:

Rain RotEtiological Agent: Dematophilus congolensisSigns: Crusty scabs or matted tufts of hair with yellow to green pus under larger scabsDiagnosis: Isolation of D. congolensisTreatment: Antimicrobial therapyZoonotic: No

SalmonellosisEtiological Agent: Salmonella spSigns: carrier, mild clinical, or acute clinical Mild clinical: depressed, anorexia, depression and watery diarrheaAcute: foul smelling diarrhea, abdominal pain, depression, anorexia, and pronounced neutropeniaDiagnosis: clinical signs, neutropenia and fecal culturesTreatment: IV Fluids, electrolytes, plasmaZoonotic: YESDue to the zoonotic risk and contamination of other horses with Salmonella, it is extremely important to educate clients and other facility staff of the importance of quarantine If the abscesses spread throughout the body, the disease is often called metastatic strangles or bastard stranglesRespiratory SystemStranglesSystem: RespiratoryEtiologic Agent: Streptococcus equiClinical Findings: Pyrexia, Mucopurulent nasal discharge, difficut swallowing, abcessationDiagnosis- Bacterial culture, signsTreatment- supportive care, penicillinPrevention-vaccineControl- morbidity high, mortality lowZoonosis- noStrangles

TetanusEtiological Agent: Clostridium tetani- Signs: Entrance through puncture wounds- incubation period- 1 to 60 days Generalized stiffness, to saw horse appearnaceTreatment: placing horse in quiet dark area, Water high in stall, tetanus antitoxin, sedatives and muscle relaxants, Mortality is 50 %Feed and water should be placed high in the stall of tetanus patients so that the horse does not have to lower its head to eat and drink.ThrushEtiological Agent: Fusobacterium necrophorumSigns: Characteristic odor, lamentessDiagnosis: Clinical signsTreatment : Cleaning away affected area.

Equine Protozoal MyelitisEtiological Agent: Sarcocystits neurona or Neospora hughesiSigns: Asymmetric muscle atrophy quadriceps and gluteal, atrophy of tongue and recumbencyDiagnosis: NecropsyTreatments Antiprotozoal drugs and nsaids, vitamin EPrevention: involves reducing opossum access tohorse feeds and pastures.

PiroplasmosisEtiological Agent: Protozoa Babesia equi and Babesia caballi- tick borneSigns: Pyrexia, depression, anemia, thirst and eye problemsDiagnosis: blood smears, IFA, PCRTreatment: Imidocarb dipropionate and or tetracyclinesPrevention: restriction of movement of infected horses and tick feeding preventionLife cycle

DermatophytosisEtiological Agent: Trichophyton equinumSings: Small round lesions covered with small scales.Diagnosis: Wood lamp, culture or histopathologyTreatment: povidone iodine, thiabendazole, Prevention: Treeat the environment with diluted bleach

White Line DiseaseEtiological Agent: invasion of bacteria, fungus or yeast into the intter hornClinical signs: Lameness, sole warm to touch, black foul smelling substance similar to thrushTreatment: Resection of the underlying hoof wall and topical application of antiseptic

EncephalomyelitisEtiological Agent: Equine alphavirus spread by vector mosquitoSigns: fever, ataxia, anorexia, paralysis, circling, head pressing, hyperexciteabilityDiagnosis: Presumptive until deathTreatment: None, but supportivePrevention: VaccinationZoonotic, noEquine ArteritisEtiological agent: Equine arteritis virusSigns: Flu like symptoms, abortion and in young horse- pneumoniaTransmission: bodily fluids, aborted feturs, and semen from stallions can be chronically or actuely affected by the virus.Diagnosis: Paired serum samples, virus isolation, viral antigen, or viral nucleic acid detectionTreatment: NSAIDs diruetics, and restPrevention: Stallions that carry the equine -arteritis virus should be surgically castrated

Equine Infectious AnemiaEtiological Agent: equine lentivirus of retroviridae familySigns: Fever, lethargy, anorexic, anemic, thrombocytopeniaDiagnosis: AGID, Vira-CHECK ELISA- EIA is a reportable diseaseTreatment: None- Euthanasia or quarantineZoonotic: No

Equine InfluenzaEtiological Agent: OrthomyxoviridiaeSigns: Pyrexia, anorexia, and weight loss, mucopurulent nasal discharge, tachypneaDiagnosis: Virus issolation, immunoassay, PCR or antibody titersTreatment: Supportive, NSAIDSPrevention: vaccinationZoonotic: noEquine influenza A often affects horses that intermingle with other horses, as occurs at rodeos and horse shows.

RabiesEtiological Agent: Rhabdovirus: The rabies virus enters the horses body via the saliva of the infected animalSigns: Progressive disease lameness, ataxia, cranial nerve, ataxia, loss of bladder controlDiagnosis: HistologyTreatment: RIPPrevention: VaccinationZoonotic: YES

RhinopneumonitisEtiological Agent: Equine herpesvirus Type 1 and 4Signs: Mucopurulent discharge, lympadenopathy and coughing, abortionDiagnosis: PCR, postmortemTreatment: Isolation of horses that are infected , treat with supportive careHorses with the respiratory form of equine herpes infection should be isolated because they are contagiousVesicular StomatitisEtiological Agent: Rhabdoviridae- transmitted through black fly, sand fly, mosquito and housefly.Signs: Pyrexia, excessive salivation. White vesicles on the oral mucosa, coronary band, prepuce, muzzle and udderDiagnosis: antibody detection, detection of viral genetic material and viral isolationTreatment: limited-as horse recover in 7-14 days

West Nile VirusEtiological agent: Faviviridae, spread by mosquitosSigns: Low grade fever, depression, colic, personality change, coma, paralysis, and comaDiagnosis: IMG, capture enzyme-linked immunosorbent assay, of serum or csf, PRNT of serum or viral isolation and PCR performed on brain tissueTreatment: supportivePrevention: vaccination

Cutaneous papillomasEtiological Agent: Equus caballus papillomavirus type 1 Can be spread by fomitesSigns: warts around the lips and muzzles of horses but can appear on eyelids, prepuce, inner thighs and distal limbs.Most dissappear spontaneouslyPrevention: Vaccination

Recurrent Airway ObstructionSystem: RespiratoryEtilogic Agent: Allergic respiratory dixClinical findings: Chronic cough, nasal discharge, and respiratory difficultyDiagnosis: basis of history and characteristic physical examination findings. Treatment: Reduce allergen exposure, bronchodilators, levamisolePrevention: Reduce dustControl: Reduce dustZoonosis: NOHeaveshttp://www.merckvetmanual.com/mvm/servlet/CVMHighLight?file=htm/bc/reshs921.htm&word=heavesVaccination ScheduleSee holtgrewVaccination ScheduleEquine rhinopneumonitis (killed virus)3, 5, 7, and 9 mo of gestation and after foaling Tetanus (toxoid)4-6 wk before foaling Equine influenza4-6 wk before foaling; every 2-3 mo during gestation for mares exposed to transient population Eastern and Western equine encephalomyelitis Usually administered to mares in late spring or early summer before onset of insect season; depends on location; if foaling late in season, should be administered again 4-6 wk before foaling Rabies4-6 wk before foaling; annual if endemic Botulism (toxoid)Initially 3 injections at 1 mo intervals, then annual booster 4-6 wk before foaling Equine viral arteritis (modified live virus)EVA titer should be documented prior to vaccination; pregnant mares should not be vaccinated; mares should be vaccinated before breeding to a positive stallion that is shedding the virus; mares must be isolated from other horses for 3 wk after vaccination; annual boosters recommended; positive titers may cause problems if mare is to be shipped overseas or to certain farms. (Stallions should also be vaccinated 3 mo before breeding.) Strangles (bacterin)Not routinely administered, used only if warranted for a specific mare and situation; occasional problems with abscesses and sore muscles; questionable efficacy West Nile virus Recommendations not yet available for pregnant mares; clinically, vaccination during pregnancy seems safe but efficacy is not knownCushings DiseaseEtiological Agent: Cortisol excessSigns: PU/PD, long thick curly hair coats, not sheddingd, laminitis, loss of muscle tone over backDiagnosis: ACTH testTreatment: cyproheptaine of pergolide mesylate

Exertional Myopathies (Tying UP, Azoturia)Etiological agent: exerciseSigns: cramping, fatigue and muscle painTwo typesSporadic exertional RhabdomyolysisChronic exertional RhapbdomyolysisDiagnosis: Increased CK or AST levelsTreatment: feeding the horse a diet of forage at 1.5-2.0% of its body weight

Recurrent Exertional RhabdomyolysisClinical Signs: muscle stiffness, sweating and refusal to moveTreatment: trying to reduce anxiety, regular exercise, turnout or use of hot walker, dantrolene or phenytoinLaminitisSystem: Musculo skeletal systemEtilogic Agent: laminitis is now thought to be a transient ischemia associated with coagulopathy that leads to breakdown and degeneration of the union between the horny and sensitive laminae Signs: the horse is depressed and anorectic and stands reluctantly.Diagnosis: diagnosis is based on the history (eg, grain overload) and posture of the horse, increased temperature of the hooves, a hard pulse in the digital arteries, and reluctance to moveTreatment: Antiinflammatories, nerve blocksPrevention: Decrease concussionControl: Zoonosis: NONormal hoof angles

Laminitic angles

Laminitis palmar/plantar view

What is this called?

Correction of angles

Ringbone

Navicular diseaseSystem: Musculo skeletal systemEtilogic Agent: chronic degenerative condition of the navicular bursa and navicular boneSigns: LamenessDiagnosis: Clinical diagnosis, radiographic changes, diagnostic nerve blocks,Treatment: Antiinflammatories, nerve blocksPrevention: Decrease concussionControl: Zoonosis: NOLocation of distal sesamoid

Laryngeal Hemiplegia(Roaring, Left laryngeal hemiplegia)System: Respiratory SystemEtiologic Agent: progressive loss of fibers of recurrent laryngeal nerveClinical Findings: inspiratory noise during exercise and exercise intoleranceDiagnosis: EndoscopingTreatment: Prosthetic laryngoplasty can stabilize the affected side of the larynx during inspiration and prevent dynamic collapse of the airway during exercise. Laryngeal ventriculectomy may improve airflow and reduce the roaring sound during exercise.Prevention: noneControl: noneZoonosis : NoVideo of laryngeal hemiplegiahttp://www.youtube.com/watch?v=utxrpiKFfIMCase 1A 3-month-old foal arrives at your clinic with abscessation of the throatlatch. Where should you keep the foal until the veterinarian can diagnose the condition? Why would you want to limit the contact this foal has with other horses at your clinic? What equipment will you want to prepare for treatment if Streptococcus equi is confirmed?Case 2A 13-year-old Percheron arrives at the clinic for gastrointestinal upset. The veterinarian is running late, so you decide to groom the horse to improve the clients perception of your clinic. Upon grooming the front legs, you find yellow specks randomly distributed over the legs.Should you tell the veterinarian about your findings? Could your finding possibly be involved with the horses gastrointestinal upset?