Lecture 22-23 4/23/24 Flashcards by Danika Boltz

What are the characteristics of equine papillomavirus/equine sarcoids?

-skin warts of horses
-not as common as those in cattle
-typically seen on nose and around lips of young horses
-small, elevated, papillary masses
-most common equine skin tumor
-often self-limiting

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What are the characteristics of equine influenza virus?

-type A influenza
-highly contagious
-accounts for majority of upper resp. infections in horses
-able to undergo antigenic drift and shift
-spread via aerosol
-infects and replicates in both upper and lower resp. tracts

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What are the clinical signs of equine influenza?

-inflammation and serous discharge
-febrile for 4-5 days
-cough
-depression and/or inappetence

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Why is it important that equine influenza severely damages resp. epithelium and destroys the mucociliary apparatus?

predisposes horses to secondary bacterial infection, esp. with gram-neg aerobic bact.

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How is equine influenza virus diagnosed?

RT-PCR on nasal swab
-serological testing

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Which options are available for equine influenza prevention?

-inactivated vaccines
-modified live intranasal vaccines

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What are the characteristics of EHV-1?

-herpesvirus
-causes equine rhinopneumonitis
-once present in a population, it will stay

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What are the common clinical signs of EHV-1?

-cough
-mucopurulent nasal discharge
-fever
-depression
-abnormal lung sounds

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How does EHV-1 cause fetal death/abortion?

-after infection the upper resp. tract, EHV-1 infects the WBCs
-WBC infection causes viremia and dissemination of virus to repro. tract

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What are the consequences of EHV-1 spreading to the CNS?

-thrombosis
-ischemic neural damage
-myeloencephalopathy (EHM)
-hindlimb paralysis
-cranial nerve abnormalities
-tail and anus paralysis

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What are the risk factors for EHV?

-positive and susceptible horses in herd
-fall, winter, or spring season
-EHM in horses older than 3 years
-resp. disease in horses younger than 2 years
-abortion in mares at any age/gestation length

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How is EHV-1 diagnosed?

-qPCR
–nasopharyngeal swabs if showing resp. signs
–whole blood if animal is viremic

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What are the characteristics of using serum testing for EHV-1?

-does not indicate whether virus is actively present
-need paired titers to potentially identify infection
-can only be used to rule out infection in adult horses

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What are the characteristics of doing CSF analysis when suspecting EHV-1?

-EHV-1 causes a yellow discoloration of CSF due to breakdown of RBCs
-not specific to EHV-1, but can rule it in or out

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What are the treatment options for EHV-1?

-supportive care
-steroids to decrease CNS inflammation
-acyclovir and valacyclovir

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What are the characteristics of EHV-1 prevention/control?

-inactivated and modified live vx available
-vx do not claim to protect against EHM and are contraindicated in neurologic animals
-viral shedding can occur 2 weeks after infection
-aborted materials are major source of virus

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What are the characteristics of rabies in equine?

-invariably lethal and of public health significance
-five licensed rabies vx in the US
-“dumb” form leads to lots of drooling; can look like other diseases

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What are the characteristics of eastern and western equine encephalitis?

-caused by alphaviruses
-maintained in environment by birds and mosquitos
-most common in mid-summer and fall
-present with fever, depression, blindness, ataxia, convulsions
-EEE is nearly always fatal; WEE has 30-40% mortality

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What are the characteristics of Venezuelan equine encephalitis?

-reportable foreign animal disease
-caused by an alphavirus
-transmitted by mosquitos
-rodent reservoir
-very deadly in humans; zoonotic

How are the equine encephalitis viruses prevented?

-EEE and WEE vx are considered core vx
-VEE is a risk-based vx

What must a practitioner weigh when deciding whether or not to vaccinate for VEE?

vaccination may confound testing in the event of an outbreak

What are the characteristics of west nile virus?

-most significant insect-borne encephalitis virus in US
-flavivirus
-affects birds, humans, and horses
-causes ataxia and motor deficits
-fever is not consistently present

How is west nile virus diagnosed?

serum immunoglobulin M ELISA

How is west nile virus prevented?

-vaccination is considered core
-vx is currently licensed for horses and foals but not pregnant mares
-chimeric vx exists

What are the characteristics of rotaviruses?

-nonenveloped RNA viruses -causes foal diarrhea -morbidity is often high; mortality is low -inactivated vaccine is licensed for use in pregnant mares to induce colostral antibodies

How is rotavirus diagnosed?

-ELISA -rapid antigen detection kits

What are the characteristics of equine coronavirus?

-common but highly contagious -causes colitis and diarrhea -additional clinical signs include anorexia, lethargy, fever -generally resolves with minimal supportive care

How is equine coronavirus diagnosed?

molecular detection/RT-qPCR on feces (antemortem) or intestinal tissue (postmortem)

How is equine coronavirus prevented?

-any horse with clinical signs should be strictly isolated -strict isolation procedures and secondary quarantine of source stable after virus is confirmed -cleaning and disinfection

What are the characteristics of equine infectious anemia?

-caused by a lentivirus (a retrovirus) -closely related to HIV-1 -reportable -once infected, a horse remains so for life

How is EIA transmitted?

-blood feeding flies -unclean/reused medical supplies -in utero from mare to foal

What happens when an animal survives the acute phase of EIA?

they become a chronic, in-apparent carrier

How is EIA diagnosed?

serologic detection at an EIA approved lab -agar gel immunodiffusion -ELISA

Which proteins from EIA are detected on serologic testing?

-p26 capsid protein (AGID and ELISA) -gp45 glycoprotein (ELISA only)

How is EIA prevented?

-reducing exposure to biting flies -never reusing needles/syringes/IV sets -blood transfusions performed by licensed individuals with tested blood -surveillance and testing -NO VX

How far away should a suspected EIA horse be moved from other horses, and why?

200 yards; the biting flies that spread the virus cannot travel this far

What are the characteristics of equine viral arteritis?

-caused by an arterivirus -typically causes minimal clinical signs and recovery occurs without incident; can go undetected -can cause abortion in pregnant mares -breeding stallions can be long term carriers

What are the possible clinical signs for equine viral arteritis?

-fever -depression -anorexia -edema -hives -conjunctivitis -abortions/stillbirths -decreased fertility

How is equine viral arteritis transmitted?

resp. secretions in close contact settings

How is equine viral arteritis diagnosed?

RT-qPCR on nasopharyngeal swabs and whole blood

How is equine viral arteritis prevented?

-modified live vx -determining known carriers -biosecurity

What are the characteristics of vesicular stomatitis?

-arbovirus -spread by biting flies and midges -reportable -zoonotic -causes vesicular lesions -differential is FMD, which horses do not get

How is VSV diagnosed and treated?

-clinical signs -serologic or antigen detection -supportive care

How is VSV controlled?

-biosecurity -vector control -involvement of state vet

Which vaccines are considered core?

-EEE and WEE -rabies -west nile virus -tetanus