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47 Cards in this Set
- Front
- Back
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Herpesvirus Diseases
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Equine herpesvirus 1 (Abortion/Neuro disease)
Equine herpesvirus 3 (Rhinopneumonitis) Equine herpesvirus 4 (Coital exanthema) |
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Properties of Herpesvirus
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-Unstable in environment
-Latent infections in presence of serum antibody |
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Equine herpes virus 4 (Equine Rhinopenumonitis)
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-Mild, slowly spreading respiratory disease within a stable
-Leukocyte-associated viremic spread--invasion of fetus (isolate virus from liver of fetus) -does NOT have high fever like in influenza |
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Diagnosis of EHV 4
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Isolation from deep nasal swabs, virus neutralization on tests on paired serum samples
-isolation from liver and lung of aborted fetuses |
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Necropsy of EHV4
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-Aborted fetuses not autolyzed, focal necrosis of liver common, intranuclear inclusions of fetal liver and lungs
-Acute bronchopneumonia, intranuclear inclusions in germinal centers of bronchial lymph nodes |
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Equine Herpesvirus 1 (Equine Neurological disease)
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-Neuro disease from ascending infection (different than from encephalitis)
-Progressive ataxia -Modified live and inactivated vax available -all confirmed cases should be isolated for 28 days -Transmitted through respiratory tract |
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EHV1 vaccine
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Does not prevent disease; prevents abortion in pregnant mares and reduces signs and spread of respiratory disease
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Equine Herpesvirus 3 (Equine Coital Exanthemia)
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-Vesicles on skin of vulva or penis, progress to erosions, scabs, heals about 2 weeks
-Secondary bacterial infection common -Local superficial infection only |
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EHV3 diagnosis, txt, control
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-Virus isolation from swabs or scrapings of erosions, serological diagnosis by SN test
-Txt: sexual rest, topical antibiotics -Control: no vax, horses without active lesions are not considered infective |
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Papilloma viruses
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Equine papillomavirus 1 and 2
-cutaneous papilloma and aural plaques |
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Properties of Papillomaviruses
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-Resistant to environment
-No serum antibody response -Chronic infections, do not induce long lasting cellular immunity -Infectious virus only present in keratinized cells |
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Equine Sarcoids
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-Caused by bovine wart viruses
-colder climates: head and abdomen; warmer climates: limbs -Large firm lesions, from ulcerated to hyperkeratotic to flat and smooth |
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Adenovirus diseases
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Asymptomatic or mild upper respiratory disease
-Bronchopneumonia and generalized disease in ARABIAN foals (combined with immunodeficiency disease) |
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Properties of Adenoviruses
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-Resistant to environment
-More important in mammals -Virus used as a vaccine vector |
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Retrovirus Diseases
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Equine Infectious Anemia (Swamp Fever)
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Retrovirus Characteristics
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-Unstable in environment
-Chronic disease-prolonged nature, immune compromise -Persistant infection |
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Equine Infectious Anemia
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*Edema and anemia
-weakness, depression, intermittent fever, icterus, petechial hemorrhages on conjuctiva and ventral surface of tongue -Anemia more noticeable in recurrent attacks -Relapses -case fatality is 50% |
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EIA Pathogenesis
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-Virus replicates in macrophages
-->anemia, hypergammaglobulinemia, leukopenia at time of primary infection--->lymphocytosis and monocytosis |
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EIA Necropsy
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-Hemorrhages on serosal and mucosal surfaces, enlargement of spleen and liver, subcutaneous edemia in acute cases
-Chronic cases: emaciation and pale mucous membranes |
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EIA Transmission, diagnosis, and control
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-Mainly by biting insects
-Coggins test-->seropositive for life -Positive coggins test-->Euth or quarantine for life |
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Rhabdovirus Diseases
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Rabies, Vesicular Stomatitis
-Lyssaviruses (neuro) -Vesiculovirus (epithelial) -Ephemerovirus |
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Properties of Rhabdoviruses
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-Unstable in environment
-Many serotypes with specific immunity |
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Vesicular Stomatitis (Vesiculovirus in Rhabdoviridae family)
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-Can be confused with Foot-and-Mouth disease
-Could be transmitted by black fly -Vesicles on tongue, snout or muzzle, coronary band (this leads to laminitis) -Diff from foot and mouth: secondary lesions on other parts of body are rare |
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Diseases of Orthomyxoviruses
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Equine Influenza
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Properties of Influenza
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-Unstable in environment
-Respiratory disease but sometimes systemic -Antigenic shift and drift |
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Equine influenza
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-Explosive outbreaks with HIGH TEMPS (103-106)
-High fever, frequent dry cough, nasal discharge -Virus replicated in upper and lower respiratory tract |
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Equine Influenza Necropsy
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-Bronchiolitis with infilatration of lymphocytes and histiocytes around bronchioles
-Mononuclear cell infiltration of alveolar walls |
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Equine Influenza Treatment and Control
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-Antibiotic therapy if secondary bacterial infection
-vaccines, need frequent boosters (canarypox) |
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Arterivirus disease
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Equine arteritis virus; systemic influenza-like disease, arteritis, abortion, pneumonia in foals
-Caused by RNA virus, family Arteriviridae |
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Properties of Arteriviruses
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-Unstable in environment
-Clinical presentation linked to vasculitis - Vaccines available |
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EVA
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-Fever, respiratory signs, nasal discharge and lacrimation
-Edematous swellings of dependent parts -High percentage of pregnant mares abort during the course of clinical disease |
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EVA pathogenesis
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-Virus replicated in macrophages and endothelial cells-->edema and hemorrhage
-Stallions can become persistently infected |
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EVA diagnosis
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-Edema of legs and head, lacrimation, respiratory signs, fever
-Isolate from nasal or conjuctival swabs or from lungs and spleen of aborted fetuses -Rise in antibody in paired sera |
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EVA Transmission
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-Pharyngeal secretions, urine and semen
-Spread by droplet infection, contact during breeding -Persistant infection in stallions |
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EVA Vaccine
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-Modified live virus vaccine
-Can spread to in contact horses -Not DIVA compatible |
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Equine Encephalitides
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EEE, WEE, VEE, West Nile, African horse sickness
-Arthropod-borne -Domestic animal species and humans are infected accidentally |
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Togavirus Diseases
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Eastern Equine Encephalitits
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Properties of Togaviruses
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-Unstable in environment
-Fever and encephalitis -Transmitted via mosquitoes with birds and rodents as reservoir hosts -EEE and VEE select agents |
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EEE Clinical Presentation
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-Fever, anorexia, depression, lowered head
-Cerebral signs (Obtundation, head pressing, stupor, blindness) -SC/brainstem abnormalities (ataxia, paralysis, incoordination, circling, flaccid lips, protruding tongue) -Not sensitive to stimuli |
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EEE Vaccines
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-Inactivated
-Aluminum hydroxide or Iscoms as adjuvants to enhance immunologic response -Slower release and degradation of antigens and stimulate phagocytosis |
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Flavivirus Diseases
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West Nile virus (fever, generalized disease, encephalomyelitis)
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Properties of Flaviviruses
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-Unstable in environment
-Many serotypes with type specific immunity -Transmitted by arthropods (falviviruses) and direct contact (pestiviruses) |
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WNV dead end hosts?
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Humans and horses
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WNV Clinical Presentation in horses
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Facial fasiculations, muscle twitching, changes in behavior, ataxia progressing to recumbency,
-all horses present with full set of clinical signs -seizures uncommon -Surviving horses do not exhibit residual neuro signs |
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WNV Pathogenesis and Necropsy
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-Viruses replicate in vascular endothelial cells, can invade CNS
-Histological lesions in grey matter, more sever in cerebrum, focal necrosis, neutrophil infiltration, perivascular cuffing |
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WNV differential diagnoses
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Equine herpesvirus myelitis, equine encephalitis virus, or equine protozoal myelitis
-Not present in blood in high titer (unlike EEE and WEE) |
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WNV Vaccine
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Inactivated viral vaccine and recombinant vaccine based on canary pox
(canary pox doesn't replicate in mammals, but does express genes) |
