Lecture 24: Lower Respiratory disease: viral, fungal, verminous Flashcards
What is EHV-1 and what does it cause
Alpha herpes virus, causes respiratory disease, neurological disease, abortion storms/weak foals, and chorioretinopathy
What is EHV-4 and what does it cause
Alpha herpes virus, causes respiratory disease, rarely associated with abortion and neurological disease
How is EHV-1 and 4 spread
Respiratory route- direct and indirect contact with nasal secretions, aerosolized droplets
Herpesviruses establish __infection and majority of horses become ___
Latent, asymptomatic carriers
Essentially every horse has ___ and is reactivated by ___
Herpes, stress
EHV survives in environment for __days, max __days
7, 35
EHV is easily inactivated by __ and ___
Heat and disinfectants
EHV can fly __ft
35 ft
What herpesvirus is more likely to cause respiratory disease
1
What are some signs of respiratory disease caused by EHV
depression, nasal discharge, anorexia, biphasic fever, secondary bacterial infection
Which herpesvirus is more likely to cause abortion and when do they abort
1, abort in last trimester
When do you vaccinate pregnant mares for EHV
5,7, 9 months
What herpesvirus causes neurological disease
4
T or F: you should avoid testing healthy horses for EHV because all horses have herpes
True
What is the test of choice for EHV and why
PCR of nasal swabs and whole blood
Fast results, distinguish between neuropathic vs non-neuropathic
Virus isolation and serum titers are not as effective in dx EHV because they take
Weeks
What is tx for EHV
Supportive care, isolation
Clenbuterol: b2 agonist initiates mucociliary clearance
What are the primary indications for EHV vaccines
Prevent abortion, decrease respiratory signs, duration and shedding
EHV vaccines not do what
Block infection, development of viremia and establishment of latency
Horses exposed to EHV can have immunity for __-___ months
3-6 months
When should you give booster vaccine for horse exposed to EHV
6 months after disease
Vaccines for EHV are only licensed for protection against
Respiratory disease and abortion
Viral shedding of EHV is reduced in horses with ___ and been vaccinated with ___
High circulating titers of virus neutralizing antibodies and vaccinated with Rhinomune MLV vaccine
What EHV vaccine has high antigenic mass and marketed for prevention of abortion, and stimulates highest levels of VN antibody
Calvenza
What influenza do horses get
Orthomyxovirus highly contagious type A, all H3N8
What is the morbidity of Equine influenza in naive vs exposed/vaccinated herds
Naive: 60-90%
Exposed/vaccinated: 20-37%
What is the mortality rate of Equine influenza
1-20%
How is is equine influenza transmitted
Direct horse to horse contact, droplets from coughing, airborne
Spread of Equine influenza is enhanced by __
Short incubation period, fever and shedding in 48hrs
Equine influenza can survive in water for ___hrs and dry environments for __hrs
72, 48
What is the pathogensis of equine influenza
Damages respiratory epithelial cells of trachea and bronchial tree, impairing mucocilary clearance leading to secondary bacterial infection
In uncomplicated cases of equine influenza the trachea epithelium regenerates in __weeks
3
Damage from equine influenza predisposes horses to __ and __
RAO, EIPH
Natural infection with equine influenza can provide immunity for __-
Year
What are some clinical findings of equine influenza
Fever, anorexia, depression, serous to mucopurlent nasal discharge, paroxysmal cough
Signs of Equine influenza resolve in __ days, coughing can persist for __ days
7-14, 21 days
What can you use to dx equine influenza
Nasopharyngeal lavage- PCR, ELISA
What is tx for equine influenza
- NSAIDS for fever
- Antibiotics for secondary pneumonia
- Rest: 1 week for every day of fever or 2-3 months
What is the primary opportunistic bacterial infection associated with equine influenza
Streptococcus equi zooepidemicus
What modified live vaccine can you give for equine influenza
FluAvert IN single dose protective after 7 days, IgA
What multicomponent vaccines can you give for equine influenza
Calvenza, innovator, prestige
What kind of viruses are picornaviruses
Rhinitis type A and B
How is equine viral arteritis transmitted
respiratory or venereal
Equine viral arteritis spread to ___, then ___ causing __ and __
Lymph nodes, vascular endothelium causing vasculitis and conjunctivitis
Who is the persistently infected carrier and source of equine viral arteritis
Stallion
What are some signs of equine viral arteritis
Respiratory signs, leukopenia, fever, depression, anorexia, peripheral edema, conjunctivitis, rhinitis, hives, abortion
Stallions may experience __with equine viral arteritis
Transient infertility
Only option for stallions with equine viral arteritis is to breed __ or ___
Vaccinated mares or castrate
How do you dx equine viral arteritis
Serology 21-28 days apart
Virus isolation of nasopharyngeal swabs, blood, ejaculate
How do you prevent equine viral arteritis
Vaccinate mares or vaccinate stallions after confirming negative tiger
What part of valley fever is highly contagious, zoonotic and can cause fungal pneumonia in horses (rare)
Arthoconidia
What are the clinical findings with valley fever
Respiratory, pneumonia, pleuropneumonia, mastitis, abortion, osteomyelitis
How is valley fever spread in body
Lymphohematogenous
How do you dx valley fever
- Cytology showing spherules- TTW, biopsy, aspirate
- Serology- antigen coated latex agglutination
__on antigen coated latex agglutination for valley fever is consistent with infection
1:16
Who does C. Gatii cause fungal pneumonia in
Immunocompetent individuals
Who does C. Neoformans cause fungal pneumonia in
Immunocompromised
What is the mechanism of action of azoles
Interferes with ergosterol synthesis in fungal cell walls
What azoles are used to tx fungal pneumonia in horses
Fluconazole and itraconazole
What azole is poorly absorbed in horses
Ketoconazole
What is an negative affect of azoles
Hepatotocity
What is the mechanism of action of polyenes
Interact with ergosterol in fungal cell membrane
What Polyene is used to tx fungal pneumonia in horses and what is adverse effect
Amphotericin B, nephrotoxicity
What worm typically caused verminous pneumonia in weanlings/yearlings
P. Equorum
What lungworm typically causes cough and bronchopneumonia in horses/ponies
Dictyocaulus arnfieldi
Who is the natural host for D. Arnfieldi
Donkeys
What are some clinical signs of verminous pneumonia
Chronic cough, mucopurulent nasal discharge, crackles, wheezes, poor response to antibiotics
Ho can you dx verminous pneumonia
TTW with abundant eosinophils
Fecal in donkeys